Metallic coatings-Measurement of coating thickness-Coulometric method by anodic dissolution
Some standard content:
GB/T 4955—1997
This standard is a revision of GB/T 4955—1997 based on the revised version of ISO2177:1985 developed by ISO/TC107 Technical Committee for Metallic and Other Non-Organic Coatings. It adopts the revision of International Standard ISO2177:1985-1485 in terms of technical content and writing methods, making it equivalent to the corresponding international standards, and can better meet the needs of international trade, technical and economic exchanges and the development of international standards. According to the revision of ISO2177:1985 to its previous version, this standard has also made major revisions to the national standard GB4955-1997, increasing the original 6 chapters to 11 chapters, adding reference standards, definitions, factors affecting the accuracy of measurement, test reports, etc., and adding Appendix 13. The entire standard content is greatly enriched. Appendix A of this standard Appendix B and Appendix C are informative appendices. This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard was submitted by the National Technical Committee for Standardization of Metallic and Non-metallic Coatings. The unit that initiated this standard is the Wumei Material Protection Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Song Zhiling and Zhong Lichang. This standard was first issued in 1985.
GB/T4955—1997
ISO Foreword
ISO(International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing international standards is usually carried out through ISO technical committees. If a member body is interested in a subject determined by a technical committee, it has the right to make representations to the committee. International organizations and non-governmental international organizations in liaison with ISO may also participate in this work. Draft international standards adopted by the technical committee shall be sent to the member bodies for approval before being adopted as international standards by the ISO Council. According to the ISO procedure, at least 75% of the member bodies voting shall approve them. International Standard ISO 2177 was prepared by ISO/TC 107 Technical Committee Metallic and other non-organic coatings. This first edition makes technical revisions to the first edition (ISO 2177-1972) and replaces it. Users should note that all International Standards are subject to revision. Therefore, unless otherwise stated, the other international standards referenced in this International Standard are the latest versions:
1 Scope
National Standards of the People's Republic of China
Metallic coatings
Measurement of coating thickness
Anodic dissolution coulometric method
Metallic coatings Measurement of coating thickness Coulometric method by anodic digsoluthn
GB/T 4955
idt [So 2177:1985
Substitute GB 495585
This standard specifies the anodic dissolution coulometric method for measuring the thickness of single and multi-layer metallic coatings: Table 1 lists typical combinations of metallic coatings and substrates. Testing other combinations with existing electrolytes (see Appendix B) or testing new electrolytes developed for other combinations requires verification of suitability for the entire system. This method is applicable to the measurement of the thickness of coatings obtained by various methods, including the measurement of multilayer systems, such as (u/Ni/r < see 8.6), as well as the thickness of alloy coatings and alloying diffusion. This method can not only measure the coating thickness of flat specimens, but also the coating thickness of cylindrical and velvet materials:
Table 1 Typical combinations of coatings and substrates that can be tested by coulometric method (substrate
coating
chemical nickel
-lead alloy
plastic and plastic alloy
only on yellow and copper
Ni o Fe alloys (such as Kovar)
1] For some alloys, it is possible to detect a voltage change in the electrolytic cell. 2) The phosphorus or tin content of these coatings must be within certain limits to enable the coulometry method. 2) This method is sensitive to alloy composition.
: indicates a combination of coating and substrate that can be tested by this method X: indicates a combination of coating and substrate that cannot be tested by this method 2 Referenced Standards Www.bzxZ.net
Non-metals
The following standards contain provisions that are incorporated by reference in this standard The following are the provisions of this standard. When this standard is revised, the versions shown are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards: Approved by the State Administration of Technical Supervision on March 4, 1997 and implemented on September 1, 1997
GB/T4955
(:12334-9U Definitions and general rules for thickness measurement of metals and other inorganic coatings 3 Definitions
This standard adopts the following definitions.
3.1 Measuring area
The area on the main surface of the test piece where a single measurement is made. The size of the measuring area in this method is the area covered by the sealing ring of the electrolytic cell. 3.2 Reference area area
Required specification is the area of the number of measurements.
4 Principle
A suitable electrolytic electrode is used to dissolve the coating of precisely defined area. The dramatic change in the cell voltage indicates that the coating is substantially completely dissolved. The thickness of the coating is calculated from the amount of electricity consumed. Due to the different methods of anode dissolution, the calculation of the electricity consumed (in coulombs) for the thickness of the measured coating is divided into:
a) When using constant current density for dissolution, the time from the start of the test to the end of the test can be calculated; b) When using non-constant current density for dissolution, the accumulated electricity consumed is calculated, and the accumulated electricity consumed is displayed on the electricity meter. 5 Instruments
5.1 Applicable instruments can be assembled using easily available components , but generally use special instruments (see Appendix A). 5.2 Use special direct reading instruments, usually using the electrolyte recommended by the manufacturer. The calculation of the cover thickness is completed by heart measurement according to the different current densities. For other instruments, the power consumed by the cover layer in the dissolved measurement area (see Chapter 3) is measured in coulombs, and the measurement area is usually an optional unit. The cover thickness is calculated using the conversion coefficient or table. 5.3 Use calibration standards to check the performance of the instrument. If the instrument thickness reading and the calibration standard cover thickness do not differ by more than ± 5%, the instrument can be used without further adjustment. Otherwise, the cause of the error should be eliminated, but the special instrument should be calibrated according to the manufacturer's instructions.
The type of the cover and base of the calibration standard and the sample to be tested should be the same, and the error should be 5%. If the master alloy cover thickness is measured, it is particularly important to use the correct calibration standard. 6 Electrolyte
The electrolytic solution should have a known and sufficiently long storage life and should: a) not react with the metal coating when no external current is applied; b) the current efficiency of the anodic dissolution of the coating should be as close to 100% as possible; when the thin coating is anodic dissolved to the point of penetration and the exposed substrate area continues to increase, the electrode potential should undergo a detectable sharp change;
[1] The test area in the exposed electrolytic cell should be completely wetted. The electrolyte composition is selected based on the coating, substrate material, current density and electrolyte flow in the test electrolytic cell. Appendix B describes typical electrolytes suitable for testing various electrodeposited layer thicknesses on a specific body with a test instrument. For special instruments, the electrolyte should generally be selected according to the manufacturer's recommendations. Factors Affecting Measurement Accuracy
The following factors may affect the accuracy of the measurement of the overburden thickness: 7.1 Overburden Sequence
Usually, the accuracy of the overburden thickness measurement with a depth greater than 50 μm and less than 0.2 μm is low without the use of special equipment.
GB/T4955--1997
When the overburden thickness is greater than 50 μm, obvious oblique or side etching may occur during the anodic dissolution process. The degree of oblique etching depends mainly on the method of stirring the electrolyte. Increasing the dissolution rate, that is, increasing the test current density, can eliminate or reduce the side etching phenomenon. 7.2 Current Change
For instruments using constant current and timing measurement technology, current changes will cause errors. For instruments using current-time integrators, large current changes may change the anode current efficiency or disturb the end point and cause errors. 7.3 Area Change
The accuracy of the area measurement will not be higher than the accuracy achieved by the known measurement area. The Lian An in the Ben Feng Tu,Area changes caused by seal pressure etc. may lead to measurement errors. If the cell is designed so that the seal always gives a precisely defined measurement area, much higher accuracy can be achieved. In some cases, measuring the area of the cation coating and correcting accordingly will give more accurate results.
4 Stirring (if required)
Improper stirring will lead to a false end point. 5 Alloy layer between cover and substrate
The coulometric method for measuring the thickness of a cover always assumes a well-defined interface between the cover and substrate: if an alloy layer exists between the cover and substrate, such as a cover obtained by hot dip, the endpoint of the coulometric method may occur at a point within the alloy layer, giving a higher value than the original thickness of the cover without alloying. 7.6 Purity of the cover
The deposited substances of the cover metal (including alloy metal) may change the effective electrochemical equivalent of the cover, the anodic current efficiency and the density of the cover.
7.7 Condition of the test surface
Oil, grease, paint, corrosion products, polishing ingredients, conversion films, passivation of the cover, etc. may interfere with the test. 7.8 Density of the coating material
The coulometric method is essentially a measurement of the mass of the coating per unit area: therefore, deviations from the normal density of the coating metal will cause deviations in the linear thickness measurement and response. Abnormal changes in alloy composition will cause small but significant changes in alloy density and electrochemical equivalents. 7.9 Cleanliness of the cell
In some electrolytic waves, metal deposits may occur on the cathode of the cell. Such deposits can change the cell voltage or block the cell aperture. Therefore, the cleanliness of the cell should be checked and maintained before each test. 7.10 Cleanliness of circuit connections
When using instruments other than the constant current type, if the circuit connections are not clean, they will interfere with the current/potential relationship and cause false end points. 7.11 Calibration standard (if used)
Measurements using calibration standards are affected by the additional error of the calibration standards. If the thickness of the alloy coating is to be determined, it is generally necessary to use an alloy coating calibration standard and test the coating calibration standard and the test piece in the same procedure. 7.12 Uneven dissolution
If the dissolution rate of the coating is uneven over the measured area, the end point may be premature and the result may be low. Therefore, the surface obtained after dissolution should be checked to verify that most of the coating has dissolved. On some substrates, a visible portion of the coating will remain, but its effect is within the range of measurement error.
The quality of the coating, the roughness of the coating surface and interface, and the porosity of the coating will cause fluctuations in the cell voltage. Such fluctuations will cause the end point to be premature.
1) In some cases, the error caused by the change in the measurement area can be minimized by calibrating the instrument with a coating thickness calibration standard. The preparation of such a coating thickness calibration standard should be similar to the actual test conditions, especially the test curve. 2) See A1.
8 Operating procedures
8.1 Overview
GB/T 4955—1997
The operating procedures of commercial instruments, the use of electrolytes, and, if necessary, the calibration of the instruments (see 5.3) should be carried out in accordance with the manufacturer's instructions. Special attention should be paid to the factors listed in Chapter 7: 8.2 Preset voltage
If an instrument requiring a preset positive voltage is used, it should be noted that the actual voltage value depends on the specific metal coating, current density, electrolyte concentration and temperature, and the resistance of the circuit connected to the terminal. For these reasons, a first measurement test should be made. B.3 Preparation of the test surface
If necessary, clean the test surface with a suitable organic solvent (see 7.7). It may also be necessary to activate the test surface by mechanical or chemical methods. Care must be taken to avoid damaging the metal. 8.4 Use of the Electrolytic Cell
Press the electrolytic cell with the elastic seal fitted onto the cover layer so that a known area is exposed to the test electrolyte. If the cell body is metal, such as stainless steel, it is usually used as the cathode of the electrolyte, but in some cases a suitable cathode is inserted (which also serves as a mechanical part for stirring the electrolyte in some instruments).
8.5 Electrolysis
Add a suitable electrolyte, ensuring that there are no bubbles on the measuring surface. If necessary, place a selector in the cell, connect the circuit, and let the stirrer work. Continue electrolysis until the anode potential or the cell voltage changes sharply or the test is automatically cut off to indicate that the cover layer is finished: 8.6 Bottom Cover Layer
When measuring a double-layer or multi-layer cover layer, after measuring the upper layer, ensure that the upper layer is completely removed from the entire measuring area. Use a suitable liquid suction device to remove the electrolyte in the cell. Rinse the electrolyte with hot distilled or deionized water. During the operation, the electrolytic cell shall not be moved at any time to cause displacement. If it is displaced, the test shall be invalidated regardless of the size of the displacement.
When measuring the lower layer and the covering layer, reset the instrument control, add the corresponding electrolyte, and continue the test according to the above method. 8.7 Inspection after the test
After the test, weigh the electrolyte in the electrolytic cell, wash it with water, lift the electrolytic cell, and check whether the covering layer in the area surrounded by the sealing ring on the sample is completely removed (see 7.12) to determine whether the test is valid. 8.8 Covering layer on the sample
If the surface area is too small to use an electrolytic cell with a conventional elastic sealing ring, an electrolytic thimble and corresponding fixing device can be used instead, and a stirrer can be used if necessary. This device must be adjustable and should be pre-adjusted to allow a known length of the sample to be immersed in the electrolysis. Direct-reading instruments, especially those with interchangeable cell sizes, need to calculate the sample immersion length so that the sample in any cell used as the cathode has the same known test area. In large-scale applications, the same electrolyte can be used, but in order to obtain the best sensitivity and accuracy of the instrument, it is necessary to adjust the operating conditions, such as cut-off voltage and stripping current. Note: To ensure accuracy, an accurate stripping surface is required. The main source of error is the current field between the bend and the electrolyte surface. 9 Results are expressed in μm for the coating thickness. It is expressed as follows: QE
10000 yuan
Where: * The current efficiency during the dissolution process is equal to 1 when the current efficiency is 100%): L---The electrochemical equivalent of the metal of the covering layer under the test conditions·g/CA-\The area of the covering layer dissolved, that is, the measurement area, cm*(1)
The density of the covering layer·name/cm\;
GB/T 4955-1997
Q--The amount of electricity consumed to dissolve the covering layer, C. If the test is not performed using an integral instrument, Q is calculated according to the following formula: Q-It-
武: I
{—Test duration, s.
The thickness d can be expressed as:
Here, X is a constant under the conditions of known metal covering layer, electrolyte and electrolytic filtration. The value of X can be calculated theoretically from the sample area, the current efficiency of anodic dissolution (usually 100%), the electrochemical directivity and the density of the coating metal, or it can be determined by measuring the coating of known thickness.
Most commercial instruments can directly read the thickness from the instrument.The instrument readings may also be converted to serial degrees using factors corresponding to the exposed measurement area of the cell and the thickness of the hard cover. 10 Measurement uncertainty The test instrument and operating procedures shall be such that the measured results of the hard cover thickness are within 10 % of their true value. Test report The test report shall include the following: The reference number of this standard; The name or number of the test specimen; The area on which the measurements were made, in cm; The location of the reference area; The various locations on the cover specimen where the measurements were made; The marking or number of the electrolyte used; The thickness measured on each test area, in m; The average number of measurements for each reported measurement; A statement of any deviation from this method; Factors affecting the results; The name or type of the instrument used; Lastly: The name of the operating and testing laboratory.
A1 Overview
GB/T 4955—1997
Appendix A
(Instructions)
Instrument Type
The instrument can be operated in any of the following two ways: a) measuring the time of anode dissolution under constant electrolytic current; b) measuring the amount of electricity consumed during the test time by the current-time integration method. For the former, the current through the electrolytic cell must be controlled at a constant value and a timer is used to measure the time from the start to the end of the test. For the latter, the amount of electricity consumed is measured by an electric meter, and it is not necessary to accurately know the magnitude of the current and the time interval for separate measurements. The results displayed by the instrument can be expressed in time units, or in units of the product of current and time (electricity), or directly expressed in thickness through a computing device. The test trigger point can be determined by observing the sudden change of the electrolytic cell voltage with an appropriate voltmeter or the test can be automatically terminated by a circuit disconnection device. Where a circuit breaker is used, the circuit breaker is adjusted to operate at the cut-off value of the electrolytic cell stripping or at a preset value of the electrolytic cell voltage increase rate. Other non-essential but useful devices of the coulometer 1 may include a mathematical display, an electronic timer and switch that can accurately detect the end point, and a device that allows different sized test cells or the use of different current densities. The seal of the test cell should be easily replaceable. Many modern instruments can directly display the results of the thickness measurement and automatically set the circuit breaker to its disconnection control value at the beginning of each test so that the test is terminated at the correct end point. A2 electrolytic cell The electrolytic cell is a container with a cylindrical band fixed to the test piece I by a non-conductive elastic seal (such as made of rubber or plastic material). If the electrolytic cell is made of metal (such as stainless steel), it can act as a cathode by itself, and the seal acts as an insulator between the cathode and the anode. If the electrolytic cell is made of insulating material, a separate cathode should be used and placed in the electrolytic cell before the test begins. The area enclosed by the seal must be precisely defined and small enough to be used on curved surfaces. Measuring the thickness of the coating on a complex shape may require a smaller cell. Due to the shape, special attention should be paid to the size of the sealing area and the degree of definition during the measurement. For any cell, the accuracy of the method is largely controlled by the accuracy of the measuring area. When a seal of a given measuring area is placed on a curved surface and inaccurate measurements are obtained during the test, a seal of a more appropriate size should be selected, a new seal should be replaced, and the degree of definition of the seal should be checked during the measurement. Additional errors can also be caused by wear of the seal or tilting of the end face. This error can be estimated by checking the circumference of the coating to be measured. For flat substrates, the stripping area is usually 0.2 cm2. For curved surfaces, the stripping area can be measured using an electrolytic cell of the size shown in Table A1 according to the stripping area diameter.
1) For heat-dissipated layers or other layers that can form a protective layer between the substrate and the metal, this preset value or the value when the cover layer is exposed is the value when the protective layer is removed to completely expose the substrate metal. Delayed surface diameter
GB/T 4955
Dimensions of electrolytic cell for measurement on curved surfaces
Meaning area
Appendix B
(Suggestive Appendix)
Commonly used electrolytes
Minimum true diameter of curved surface
Although higher current densities can be used when using certain special electrolytes (particularly some of the electrolytes listed in this appendix), the following electrolytes (B1 B1 to B6) The cation current efficiency of 100% is basically achieved in the range of current density of 100~～400mA/cm. However, there are several electrolytic waves that are only applicable at the lower or upper limit of the current density range, which are marked with "*". These electrolytic waves basically dissolve the metal coating with 100% cation current efficiency, so the density (in um) can be calculated according to the formula: QE
d=10 000
. Or the instrument coefficient calculated by this formula (symbol definition see Chapter 9), these electrolytes do not need to use the coating density calibration standard. Generally, the result directly calculated according to the above expression is more accurate than the result obtained by calibrating the coulometric method with the coating thickness calibration standard.
B1 to 4 The electrolytes in the electrolytes shall be prepared with analytical grade reagents and distilled water or deionized water. Slight changes in solution concentration will not affect the accuracy of the results. However, when using an instrument that automatically disconnects when the preset voltage is condensed, the voltage preset will be affected. Except for H9, all electrolytes have a storage life of more than months. The manufacturer's suggestions or instructions should be submitted to consider whether these electrolytes can be used in the manufacturer's instruments, and whether special electrolytes are required for certain special combinations of cover layers and substrates. The uses of the electrolytes described in B1 to B16 are summarized in Table L1. Table 1 Application of electrolytes
Coating
Saw-stone alloys
B2 and 3
B5 and B6
Xie and alloys (such as Huangsu)
Non-metals
B2 and B4
B5, B6 and BF
B8 and B10
B12 and B13
B15 and B16
1) Both direct comparison and the use of positive standards have inherent errors that must be considered. For example, a 3% error in the diameter of the test electrolytic cell will cause a 9-year error in the measurement.
B1 Electrolyte for steel, copper or brass coatings CB/T4955—1997
Prepare a solution containing 30g potassium oxide (KcI) and 30g ammonium chloride (VH.C1) per liter. This electrolyte requires a strict preset voltage: B2 Electrolyte for chromium coatings on steel, cast or aluminum Dilute 95mL of phosphoric acid (H,P) with water, p=1.75g/ml.) Add 25g of chromic anhydride (Cr0,) to 1000mL. Note that phosphoric acid can cause burns, avoid contact with eyes and skin Skin contact. Chromic anhydride may ignite and cause burns when in contact with flammable materials. Avoid inhaling its dust and avoid contact with eyes and skin. This solution is suitable for current densities of about 100mA/cm and coatings less than 5um thick. The measurement error is about +e.
Note: Chromium cations in this electrolyte and in the B3 and B1 electrolytes can generate hexavalent ions Ct. When calculating the sequence, use (r\ electrochemical idle,
B3* or B1 steel coating electrolytic preparation
prepare a solution containing 100g sodium carbonate (Na,C) per liter). This electrolyte is only suitable for current densities of about 100mA/cm\ and coatings less than 5um thick. 4* Electrolyte for nickel or lead chromium coatings
Dilute 64 mL of phosphoric acid (H2PO4, m=1.75 g/mL) with water to 100 mL. Note: See R2
This electrolyte is best used at a current density of about 100 mA/cm and is specifically designed for measuring thin or decorative chromium coatings (see B2).
B5 Electrolyte for copper coatings on steel or steel
Dissolve 800 g of ammonium nitrate (NH4NO3) in water and dilute to 1000 mL, and add 10 mL of nitrogen water (NH2=0.88 g/mL). Note: Ammonium nitrate may explode under strong heat and may come into contact with flammable materials. Can cause fire, do not contact with heat sources and flammable materials. Oxygen can cause burns, irritate the eyes, respiratory system and skin, avoid inhaling its vapor and prevent it from contacting the eyes and skin. The thickness result measured by this electrolyte is about 2 light lower than the exact value. B6 Beam or lead 1. Electrolyte for copper storage layer
Dissolve 100g potassium sulfate (KS) in water, dilute to 1000ml, and then add 20mL acid (H.P020=1.75g/mL). Note: See B2,
B7 Zinc or zinc alloy die castings 1. Electrolyte for copper covering layer Use pure hexafluorosilicic acid (II.SiF,). Note: Hexachlorosilicic acid can cause burns and is toxic by inhalation, skin contact and swallowing. Avoid inhalation of its vapor and prevent contact with eyes and skin.
This circuit can decompose the copper coating with a current efficiency of 100% at a very low voltage. There is almost no anodic corrosion on the exposed zinc substrate at the end of the test. However, there are microscopic copper dots on the zinc layer within the test area. Although these traces of copper are visible, they generally do not affect the accuracy of the results.
Clearing method notes:
a) Use analytically pure hexafluorosilicic acid, which should be basically free of impurities such as chlorides and sulfides to avoid severe corrosion of the zinc matrix at the test end point
b) It should not have too high a moisture content, which will cause the phase effect described in a). If the moisture content of the acid used is too high, a small amount of magnesium hexafluorosilicate can be dissolved in the acid to overcome its adverse effects. B8 steel, steel or nickel (whether with or without tin bottom layer) 1. Clamp the cover layer with electrolyte to prepare a solution containing 200g sodium acetate (CH,COO)Na) and 200g ammonium acetate (CI1,COONH,) per liter. The current efficiency of this electrolyte may be less than 100%, but the test error will not be greater than 5%. B9 Nickel coating on steel or pot electrolyte
Dissolve 800g of ammonium nitrate (NH4SO4, VO4, see B5 Note) in water and dilute to 1000ml. Add 50mL of 7g/L sulfuric acid [CS(NH4SO4)] solution
GB/T 4955:1997
The storage life of this mixed solution is quite long, so it should be prepared within 5 days before use. It is made by mixing 800g/L ammonium nitrate and 76g/L sulfuric acid solution prepared in advance. The storage life of the two pre-prepared solutions is at least 6 months. In the past, passivation of the nickel coating will reduce the current efficiency of this electrolyte. During surface purification, the plating cannot dissolve nickel at a current efficiency of 1005. Before measuring the thickness of the slow coating, the surface layer is removed with gel electrolyte. The phase polarization of the acid electrolyte will also passivate the surface of the nickel coating. 2 During the test, the voltage of the electrolytic cell can indicate the occurrence of this phenomenon. If tested at about 400mA/cm, the nickel is dissolved at a current efficiency of 100%. The positive voltage of the electrolytic cell is generally lower than 2.4V, and when the cell voltage is 2-5V or higher, it usually means that the nickel is dissolved at a much lower current efficiency than 100%. At this time, it is usually accompanied by the flash of rust, or it means that the nickel is dissolved while releasing oxygen without dust. If necessary, a small amount of dilute hydrochloric acid [InLal/1.C(HC1)2no]/L can be added to the electrolytic cell before the test to activate it. After 0.5min, the filter well is rinsed clean by deacidification, and then ammonium nitrate/sulfur electrolyte is added to test the nickel layer sequence. B10 The nickel cover layer on copper, yellow or other alloys or stainless steel is diluted with 100mL of hydrochloric acid (HCl9=1.18g/mL) to 1000mL with water. Note: Hydrochloric acid will cause Burns, irritation to respiratory system. Avoid inhalation of its vapor and prevent contact with eyes and skin. This electrolyte is only reliable when measuring the coating on copper or copper alloy at a current density of about 40mA/cm. It is not suitable for currents of 100mA/cm. Standard: electrolytes B9 and B10 are also widely used to test the thickness of cobalt, cobalt-copper or nickel-iron alloy coatings. The electrochemical equivalent of iron is very close to that of nickel, so there will be no significant error in the thickness of these alloy layers calculated based on pure nickel. B11 Copper, copper alloy or silver coating electrolyte is used to prepare a 100g/T potassium fluoride (KF) solution. Note: Potassium oxide is toxic if inhaled, in contact with skin or swallowed. Avoid inhalation. The dust should be kept away from the eyes and skin. This electrolyte is suitable for dark silver coating or bright silver coating with sulfur brightener, but it is not suitable for coating with small amount of antimony or sufficient silver-filled gold.
Design: When testing silver coating with L11 electrolyte, silver is easily deposited on the inner surface of stainless steel electrolytic cell. This deposit is a uniform coating and will not block the opening, but it will reduce the electrolytic positive of the free silver coating. Therefore, after each test, the deposit on the stainless steel electrolytic cell needs to be dissolved with nitric acid.
B12 electrolyte for coating on steel, stainless steel alloy or nickel pot is diluted with 170ml of hydrochloric acid (HCl, m=1.1g/mL) to 1000ml: Note: See 10.
This solution degrades the coating in the electrolytic cell at a very low temperature, and will not cause anodic corrosion to the substrate at the end of the test. However, during the test, the aluminum in the solution tends to form a sponge-like deposit on the cathode (such as a stainless steel electrolytic cell). After a period of time, this deposit will block the cell orifice, and the test will be terminated prematurely when testing very thick or even some thin tin coatings, so the deposits on the cell orifice must be removed before and after each test.
Note: This electrolyte has a current efficiency of 100%. B13'Aluminum 1 pot coating electrolyte
Dilute 50m sulfuric acid (11.SOp=1.84g/ml.3) with water to 1000mL, carefully add the acid slowly into the water, and dissolve the fluoride (KF) in the solution.
Note: See H11, sulfuric acid can cause severe burns, prevent it from contacting the skin and eyes, and do not add water to the acid. B14 Electrolyte for zinc coating on steel, copper or brass Prepare 100g/1. potassium chloride (KC1) dissolved in ammonium. This electrolyte A relatively strict preset voltage is required, but not as strict as the test cover layer (see 131) B15 steel 1: Electrolyte for tin-nickel alloy
Mix 100ml phosphoric acid (HP (, p = 1.75g/ml.) and 50mL hydrochloric acid (HCl, p = 1.18g/ml.) and 50ml. (saturated at room temperature) benzimidazole (C,H,O,·2H,O) solution GB/T4955-1997
Note: See B2 and B10, oxalic acid can cause damage if in contact with the skin or if swallowed, avoid contact with eyes and skin. This electrolyte is only suitable for current densities of about 100 mA/cm. It was found that the copper in the alloy was dissolved as divalent tin ions at this current density. For 65/35-nickel alloy dissolved in the form of monovalent tin, the correct electrochemical equivalent, i.e. 0.453 mg/C, must be used to calculate the thickness. For higher accuracy, the factor should be adjusted according to the actual alloy composition (P 7. 8). B16" steel or brass nickel alloy electrolyte is prepared containing 12g nickel chloride (NiCl·6H2O), 13g anhydrous tin (SnCl2), 200tmL water, 40tmL hydrochloric acid (HCl, p=1. 18g/ml.) and 50mL phosphoric acid (H2PO4, p=1. 75g/mL). Note: See B2 and B10, oxidation has harmful dust, irritating eyes and skin, avoid inhalation of dust, do not contact with eyes and skin.
Tetrachloride causes burns and irritates the respiratory system. Do not contact with eyes and skin. Do not allow inadvertent contact with water. This electrolyte is suitable for a current density of about 400) mA/cm, at which the amount of tetravalent tin ions in the alloy dissolves. For the 65/35 tin-nickel alloy dissolved in the form of tetravalent tin, the correct electrochemical equivalent, i.e. 0.306 mg/C, should be used to calculate the thickness. For higher accuracy, the coefficient should be adjusted according to the actual alloy composition (see 7.8).1997
The storage life of this mixed solution is quite long, so it should be prepared within 5 days before use. It is made by mixing 800g/L ammonium nitrate and 76g/L sulfur solution prepared in advance. The storage life of the two pre-prepared solutions is at least 6 months. In general, passivation of the nickel coating will reduce the current efficiency of this electrolyte. During surface purification, the plating cannot dissolve nickel at a current efficiency of 1005. Before measuring the thickness of the slow coating, the surface layer is removed with a gel electrolyte. The phase polarization of the acid electrolyte will also passivate the surface of the nickel coating. 2 The cell voltage during the test can indicate the occurrence of this phenomenon. If tested at about 400mA/cm, the cell voltage for dissolving nickel at a current efficiency of 100% is generally lower than 2.4V, and when the cell voltage is 2-5V or higher, it usually indicates that nickel is dissolved at a much lower current efficiency than 100%. At this time. The electric light usually accompanies rust, or indicates the decomposition of nickel in the process of releasing oxygen without generating dust. If necessary, a small amount of dilute hydrochloric acid [InLal/1.C(HC1)2no]/L can be added to the electrolytic cell before the test to activate it. After 0.5min, the filter well is rinsed clean by deacidification, and then ammonium nitrate/sulfur electrolyte is added to test the nickel layer sequence. B10 Electrolyte for nickel coating on copper, yellow or other alloys or stainless steel Dilute 100mL of hydrochloric acid (HCl9=1.18g/mL) to 1000mL with water. Note: Hydrochloric acid can cause burns and irritate the respiratory system. Avoid inhaling its vapor and prevent it from contacting the eyes and skin. This electrolyte is only reliable when measuring the coating on copper or copper alloys at a current density of about 40mA/cm. Not suitable for currents of 100 mA/cm2
Standard: electrolytes B9 and B10 are also used to test the thickness of cobalt, cobalt-copper or nickel-iron alloy capping layers. The electrochemical equivalent of iron is very close to that of nickel, so there will be no significant error in calculating the thickness of these alloy layers based on pure nickel. B11 Copper, copper alloy or silver capping electrolyte is used to prepare a 100 g/t potassium fluoride (KF) solution. Note: Potassium oxide is poisonous if inhaled, in contact with the skin or swallowed. Avoid inhaling its dust and prevent it from contacting the eyes and skin. This electrolyte is suitable for dark silver capping layers or bright silver capping layers containing sulfur brighteners, but is not suitable for silver-containing capping layers containing a small amount of antimony or sufficient silver.
Design: When testing silver coating with L11 electrolyte, silver is easily deposited on the inner surface of the stainless steel electrolytic cell. This deposit is a uniform coating and will not block the opening, but it will reduce the electrolyte positive charge of the free silver coating. Therefore, after each test, the deposit on the stainless steel electrolytic cell needs to be dissolved with nitric acid.
B12 Electrolyte for coating on steel, nickel alloy or nickel is diluted with 170ml of hydrochloric acid (HCl, m=1.1g/mL) to 1000mL: Note: See 10.
This solution degrades the coating in a very cyclic electrolytic cell and will not cause anodic corrosion to the substrate at the end of the test. However, during the test, the aluminum in the solution tends to form a sponge-like deposit on the cathode (such as the stainless steel electrolytic cell). After a period of time, this deposit will block the cell orifice and will terminate the test prematurely when testing very thick or even some thin tin coatings, so the deposits on the cell orifice must be cleared before and after each test.
Note: This electrolyte has a current efficiency of 100%. B13'Aluminum 1 pot coating electrolyte
Dilute 50m sulfuric acid (11.SOp=1.84g/ml.3) with water to 1000mL, carefully add the acid slowly into the water, and dissolve the fluoride (KF) in the solution.
Note: See H11, sulfuric acid will cause severe burns, avoid contact with skin and eyes, and do not add water to acid. B14 Electrolyte for zinc coating on steel, copper or brass Prepare 100g/1. potassium chloride (KC1) dissolved in ammonium. This electrolyte A relatively strict preset voltage is required, but not as strict as the test cover layer (see 131) B15 steel 1: Electrolyte for tin-nickel alloy
Mix 100ml phosphoric acid (HP (), p-1.75g/ml.) and 50mL hydrochloric acid (HCl, p=1.18g/ml.) and 50ml. (saturated at room temperature) benzimidazole (C,H,O,·2H,O) solution GB/T4955-1997
Note: See B2 and B10, oxalic acid can cause damage if in contact with the skin or if swallowed, avoid contact with eyes and skin. This electrolyte is only suitable for current densities of about 100 mA/cm. It was found that the copper in the alloy was dissolved as divalent tin ions at this current density. For 65/35-nickel alloy dissolved in the form of monovalent tin, the correct electrochemical equivalent, i.e. 0.453 mg/C, must be used to calculate the thickness. For higher accuracy, the factor should be adjusted according to the actual alloy composition (P 7. 8). B16" steel or brass nickel alloy electrolyte is prepared containing 12g nickel chloride (NiCl·6H2O), 13g anhydrous tin (SnCl2), 200tmL water, 40tmL hydrochloric acid (HCl, p=1. 18g/ml.) and 50mL phosphoric acid (H2PO4, p=1. 75g/mL). Note: See B2 and B10, oxidation has harmful dust, irritating eyes and skin, avoid inhalation of dust, do not contact with eyes and skin.
Tetrachloride causes burns and irritates the respiratory system. Do not contact with eyes and skin. Do not allow inadvertent contact with water. This electrolyte is suitable for a current density of about 400) mA/cm, at which the amount of tetravalent tin ions in the alloy dissolves. For the 65/35 tin-nickel alloy dissolved in the form of tetravalent tin, the correct electrochemical equivalent, i.e. 0.306 mg/C, should be used to calculate the thickness. For higher accuracy, the coefficient should be adjusted according to the actual alloy composition (see 7.8).1997
The storage life of this mixed solution is quite long, so it should be prepared within 5 days before use. It is made by mixing 800g/L ammonium nitrate and 76g/L sulfur solution prepared in advance. The storage life of the two pre-prepared solutions is at least 6 months. In general, passivation of the nickel coating will reduce the current efficiency of this electrolyte. During surface purification, the plating cannot dissolve nickel at a current efficiency of 1005. Before measuring the thickness of the slow coating, the surface layer is removed with a gel electrolyte. The phase polarization of the acid electrolyte will also passivate the surface of the nickel coating. 2 The cell voltage during the test can indicate the occurrence of this phenomenon. If tested at about 400mA/cm, the cell voltage for dissolving nickel at a current efficiency of 100% is generally lower than 2.4V, and when the cell voltage is 2-5V or higher, it usually indicates that nickel is dissolved at a much lower current efficiency than 100%. At this time. The electric light usually accompanies rust, or indicates the decomposition of nickel in the process of releasing oxygen without generating dust. If necessary, a small amount of dilute hydrochloric acid [InLal/1.C(HC1)2no]/L can be added to the electrolytic cell before the test to activate it. After 0.5min, the filter well is rinsed clean by deacidification, and then ammonium nitrate/sulfur electrolyte is added to test the nickel layer sequence. B10 Electrolyte for nickel coating on copper, yellow or other alloys or stainless steel Dilute 100mL of hydrochloric acid (HCl9=1.18g/mL) to 1000mL with water. Note: Hydrochloric acid can cause burns and irritate the respiratory system. Avoid inhaling its vapor and prevent it from contacting the eyes and skin. This electrolyte is only reliable when measuring the coating on copper or copper alloys at a current density of about 40mA/cm. Not suitable for currents of 100 mA/cm2
Standard: electrolytes B9 and B10 are also used to test the thickness of cobalt, cobalt-copper or nickel-iron alloy capping layers. The electrochemical equivalent of iron is very close to that of nickel, so there will be no significant error in calculating the thickness of these alloy layers based on pure nickel. B11 Copper, copper alloy or silver capping electrolyte is used to prepare a 100 g/t potassium fluoride (KF) solution. Note: Potassium oxide is poisonous if inhaled, in contact with the skin or swallowed. Avoid inhaling its dust and prevent it from contacting the eyes and skin. This electrolyte is suitable for dark silver capping layers or bright silver capping layers containing sulfur brighteners, but is not suitable for silver-containing capping layers containing a small amount of antimony or sufficient silver.
Design: When testing silver coating with L11 electrolyte, silver is easily deposited on the inner surface of the stainless steel electrolytic cell. This deposit is a uniform coating and will not block the opening, but it will reduce the electrolyte positive charge of the free silver coating. Therefore, after each test, the deposit on the stainless steel electrolytic cell needs to be dissolved with nitric acid.
B12 Electrolyte for coating on steel, nickel alloy or nickel is diluted with 170ml of hydrochloric acid (HCl, m=1.1g/mL) to 1000mL: Note: See 10.
This solution degrades the coating in a very cyclic electrolytic cell and will not cause anodic corrosion to the substrate at the end of the test. However, during the test, the aluminum in the solution tends to form a sponge-like deposit on the cathode (such as the stainless steel electrolytic cell). After a period of time, this deposit will block the cell orifice and will terminate the test prematurely when testing very thick or even some thin tin coatings, so the deposits on the cell orifice must be cleared before and after each test.
Note: This electrolyte has a current efficiency of 100%. B13'Aluminum 1 pot coating electrolyte
Dilute 50m sulfuric acid (11.SOp=1.84g/ml.3) with water to 1000mL, carefully add the acid slowly into the water, and dissolve the fluoride (KF) in the solution.
Note: See H11, sulfuric acid will cause severe burns, avoid contact with skin and eyes, and do not add water to acid. B14 Electrolyte for zinc coating on steel, copper or brass Prepare 100g/1. potassium chloride (KC1) dissolved in ammonium. This electrolyte A relatively strict preset voltage is required, but not as strict as the test cover layer (see 131) B15 steel 1: Electrolyte for tin-nickel alloy
Mix 100ml phosphoric acid (HP (, p = 1.75g/ml.) and 50mL hydrochloric acid (HCl, p = 1.18g/ml.) and 50ml. (saturated at room temperature) benzimidazole (C,H,O,·2H,O) solution GB/T4955-1997
Note: See B2 and B10, oxalic acid can cause damage if in contact with the skin or if swallowed, avoid contact with eyes and skin. This electrolyte is only suitable for current densities of about 100 mA/cm. It was found that the copper in the alloy was dissolved as divalent tin ions at this current density. For 65/35-nickel alloy dissolved in the form of monovalent tin, the correct electrochemical equivalent, i.e. 0.453 mg/C, must be used to calculate the thickness. For higher accuracy, the factor should be adjusted according to the actual alloy composition (P 7. 8). B16" steel or brass nickel alloy electrolyte is prepared containing 12g nickel chloride (NiCl·6H2O), 13g anhydrous tin (SnCl2), 200tmL water, 40tmL hydrochloric acid (HCl, p=1. 18g/ml.) and 50mL phosphoric acid (H2PO4, p=1. 75g/mL). Note: See B2 and B10, oxidation has harmful dust, irritating eyes and skin, avoid inhalation of dust, do not contact with eyes and skin.
Tetrachloride causes burns and irritates the respiratory system. Do not contact with eyes and skin. Do not allow inadvertent contact with water. This electrolyte is suitable for a current density of about 400) mA/cm, at which the amount of tetravalent tin ions in the alloy dissolves. For the 65/35 tin-nickel alloy dissolved in the form of tetravalent tin, the correct electrochemical equivalent, i.e. 0.306 mg/C, should be used to calculate the thickness. For higher accuracy, the coefficient should be adjusted according to the actual alloy composition (see 7.8).1g/mL) to 1000mL: Note: See 10.
This solution removes the coating layer in the downstream of the electrolytic cell, and will not cause anodic corrosion to the substrate at the end of the test. However, during the test, the aluminum in the solution tends to form sponge-like deposits on the cathode (such as stainless steel electrolytic cells). After a period of time, this deposit will block the cell orifice, and the test will be terminated prematurely when testing very thick or even some thin tin coatings, so the deposits on the cell orifice must be removed before and after each test.
Note: This electrolyte has a current efficiency of 10%. B13 'Aluminum 1 pot coating electrolyte
Dilute 50m sulfuric acid (11.SOp=1.84g/ml.3) with water to 1000mL, carefully add the acid slowly into the water, and dissolve the fluoride (KF) in the solution.
Note: See H11, sulfuric acid can cause severe burns, prevent it from contacting the skin and eyes, and do not add water to the acid. B14 Steel, copper or brass zinc coating electrolyte prepared 100g/1. potassium chloride (KC1) dissolved in ammonium. This electrolyte A relatively strict preset voltage is required, but not as strict as the test cover layer (see 131) B15 steel 1: Electrolyte for tin-nickel alloy
Mix 100ml phosphoric acid (HP (, p = 1.75g/ml.) and 50mL hydrochloric acid (HCl, p = 1.18g/ml.) and 50ml. (saturated at room temperature) benzimidazole (C,H,O,·2H,O) solution GB/T4955-1997
Note: See B2 and B10, oxalic acid can cause damage if in contact with the skin or if swallowed, avoid contact with eyes and skin. This electrolyte is only suitable for current densities of about 100 mA/cm. It was found that the copper in the alloy was dissolved as divalent tin ions at this current density. For 65/35-nickel alloy dissolved in the form of monovalent tin, the correct electrochemical equivalent, i.e. 0.453 mg/C, must be used to calculate the thickness. For higher accuracy, the factor should be adjusted according to the actual alloy composition (P 7. 8). B16" steel or brass nickel alloy electrolyte is prepared containing 12g nickel chloride (NiCl·6H2O), 13g anhydrous tin (SnCl2), 200tmL water, 40tmL hydrochloric acid (HCl, p=1. 18g/ml.) and 50mL phosphoric acid (H2PO4, p=1. 75g/mL). Note: See B2 and B10, oxidation has harmful dust, irritating eyes and skin, avoid inhalation of dust, do not contact with eyes and skin.
Tetrachloride causes burns and irritates the respiratory system. Do not contact with eyes and skin. Do not allow inadvertent contact with water. This electrolyte is suitable for a current density of about 400) mA/cm, at which the amount of tetravalent tin ions in the alloy dissolves. For the 65/35 tin-nickel alloy dissolved in the form of tetravalent tin, the correct electrochemical equivalent, i.e. 0.306 mg/C, should be used to calculate the thickness. For higher accuracy, the coefficient should be adjusted according to the actual alloy composition (see 7.8).1g/mL) to 1000mL: Note: See 10.
This solution removes the coating layer in the downstream of the electrolytic cell, and will not cause anodic corrosion to the substrate at the end of the test. However, during the test, the aluminum in the solution tends to form sponge-like deposits on the cathode (such as stainless steel electrolytic cells). After a period of time, this deposit will block the cell orifice, and the test will be terminated prematurely when testing very thick or even some thin tin coatings, so the deposits on the cell orifice must be removed before and after each test.
Note: This electrolyte has a current efficiency of 10%. B13 'Aluminum 1 pot coating electrolyte
Dilute 50m sulfuric acid (11.SOp=1.84g/ml.3) with water to 1000mL, carefully add the acid slowly into the water, and dissolve the fluoride (KF) in the solution.
Note: See H11, sulfuric acid can cause severe burns, prevent it from contacting the skin and eyes, and do not add water to the acid. B14 Steel, copper or brass zinc coating electrolyte prepared 100g/1. potassium chloride (KC1) dissolved in ammonium. This electrolyte A relatively strict preset voltage is required, but not as strict as the test cover layer (see 131) B15 steel 1: Electrolyte for tin-nickel alloy
Mix 100ml phosphoric acid (HP (, p = 1.75g/ml.) and 50mL hydrochloric acid (HCl, p = 1.18g/ml.) and 50ml. (saturated at room temperature) benzimidazole (C,H,O,·2H,O) solution GB/T4955-1997
Note: See B2 and B10, oxalic acid can cause damage if in contact with the skin or if swallowed, avoid contact with eyes and skin. This electrolyte is only suitable for current densities of about 100 mA/cm. It was found that the copper in the alloy was dissolved as divalent tin ions at this current density. For 65/35-nickel alloy dissolved in the form of monovalent tin, the correct electrochemical equivalent, i.e. 0.453 mg/C, must be used to calculate the thickness. For higher accuracy, the factor should be adjusted according to the actual alloy composition (P 7. 8). B16" steel or brass nickel alloy electrolyte is prepared containing 12g nickel chloride (NiCl·6H2O), 13g anhydrous tin (SnCl2), 200tmL water, 40tmL hydrochloric acid (HCl, p=1. 18g/ml.) and 50mL phosphoric acid (H2PO4, p=1. 75g/mL). Note: See B2 and B10, oxidation has harmful dust, irritating eyes and skin, avoid inhalation of dust, do not contact with eyes and skin.
Tetrachloride causes burns and irritates the respiratory system. Do not contact with eyes and skin. Do not allow inadvertent contact with water. This electrolyte is suitable for a current density of about 400) mA/cm, at which the amount of tetravalent tin ions in the alloy dissolves. For the 65/35 tin-nickel alloy dissolved in the form of tetravalent tin, the correct electrochemical equivalent, i.e. 0.306 mg/C, should be used to calculate the thickness. For higher accuracy, the coefficient should be adjusted according to the actual alloy composition (see 7.8).
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