Metallic coatings-Electrodeposited coatings of nickel plus chromium and of copper plus nickel plus chromium
Some standard content:
GB/T 9797—1997
This standard is revised according to ISO 1456:1988 "Metallic micro-covering nickel + chromium and copper + nickel + chromium electrodeposition layer" GB9797·88, and is equivalent to the IS standard in technical content 1, and the code is in accordance with GBT1.1: 1993. The original standard B9797-88 "Metallic covering layer nickel + chromium and copper + nickel + chromium electroplating layer" was formulated with reference to ISO 1156:1974 "Metallic covering layer - nickel + chromium electroplating layer" and ISO 1454:1974 "Metallic micro-covering layer - copper + nickel + chromium electroplating layer". IS01456:19888 Gold overlay - Nickel + chromium and copper - nickel: chromium deposits> ISO1456:1974 and ISO1157:1971 revised version of the standard since the release of the original G979788 "Gold overlay coal ten chromium and steel nickel ten road electroplating", the public standard Appendix A is the standard appendix.
Non-standard record 1 is a reminder of the record.
The standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is organized by the National Technical Committee for Standardization of Enterprises and Non-Enterprises. The responsible unit for this standard is the Institute of Material Protection of the Ministry of Machinery Industry. The drafting unit of the standard is: Hubei Import and Export Commodity Inspection Bureau, Shanghai Yongniu Additive Factory, and the Institute of Technology of the Ministry of Electronics Industry. The main drafters of this standard are: Heng Ming'an, Xing Buxin, Li Yingming, Shen Pinhua, Yu Donglin, Mao Zujian: This standard was first issued in September 1988. GH/T 9797-1997. ISO (formerly ISO) is a global association of national standard bodies (ISO member groups). The work of formulating international standards is generally carried out by ISO technical committees. If the member groups are interested in a topic determined by a technical committee, they have the right to state their interests to the committee in contact with ISO. Non-governmental international organizations can also participate in the work. In all aspects of electronic standardization, ISO and the International Electrotechnical Commission (IEC) work closely together. The draft international standards adopted by the technical committees are sent to the member groups for approval before being adopted as international standards by the ISO Council. According to the ISO procedure, at least 75% of the member groups participating in the voting must approve it for it to be considered as approved. International Standard IS01456 was developed by IS0/TC.107 Technical Committee for Metallurgical Coatings. This second edition replaces and cancels the first edition (15S01456:1974) and is a revision of International Standard IS01457:1974. Users should be aware that all international standards are subject to revision. Therefore, unless otherwise stated, the other international standards referenced in this standard are the latest versions.
1 Scope
National Standard of the People's Republic of China
Metallic Coatings
Nickel-Chromium and Copper-Nickel-Chromium Electrodeposited Coatings
Metallic CoalingsElectrodeposited cuatings of nickel plus chromium and
of copper plus nickel plus chromiumGB/T 97971997
eqISO 1456:1988
Replaces GB79768
This standard specifies the requirements for decorative and protective nickel plus chromium and copper plus nickel plus chromium electrodeposited coatings on steel, zinc alloys, copper and copper alloys, aluminium and aluminium alloys, gives several grades of coatings of different thicknesses and types, and provides guidance for selection of coating grades for coated parts exposed to corresponding service conditions. This standard is applicable to decorative and protective nickel plus chromium and copper plus nickel electrodeposited coatings on steel, zinc alloys, copper and copper alloys, aluminium and aluminium alloys.
This standard does not specify the required surface condition of the base metal before electroplating. This standard is not applicable! The requirements for the nickel-plated and electroplated coatings are similar to those for the surface coatings without chromium or nickel-plated coatings on threaded fasteners or rings. The requirements for the surface coatings without chromium or nickel-plated coatings are similar to those for the surface coatings without chromium or nickel-plated coatings on threaded fasteners or rings. See GB 978 for the requirements. 2 Reference standards The following standards contain the following provisions: The provisions of this standard are constituted by reference in this standard: The versions shown are valid at the time of publication of this standard. All the standards may be revised. The parties using this standard should explore the possibility of using the latest version of the following standards. GB/T 4955-1997 Thickness measurement of metal micro-coatings (electrodeposition and chemical deposition) (eqv[S] 2177: 1972) Metal micro-coatings (electrodeposition and chemical deposition) on metal substrates - Test method for strength G13 5270-8] (egv IS0) 2819:1980)
(36462-8G Microscopic measurement method for cross-sectional thickness of gold and oxide floor covering layers (e9V1S) 1463, 1982) Corrosion test of metal and other inorganic particle covering layers (C)RR test) (eV1S04541:1978) FB 6465- -86
GB/T9798-1997 Nickel electroplating for gold coating (eVS) 1458:1988) GB113798% metal coating for engineering nickel plating (1eyIS06158:1984) Metal pre-covering engineering nickel plating (eVJSO1526:1985) GB 12332--90
GB 12334--90
Metallic and other non-inorganic non-metallic layers - Definitions and general rules for thickness measurement (c4v IS0 2061: 1580)
GB1260990 Inspection procedures for accumulated metal bulk housing and related finishing counting shaft samples e4V1S04519:1980)GH/[13744-92 Measurement of thickness of electroplated coatings on inductive and non-magnetic substrates (IDIS) 2361:1982) GB/T169211907 Measurement of thickness of metal coverings by X-ray spectrometry method (VIS) 3497:1990) CB10125:1907 Artificial atmospheric corrosion test salt spray test (EV1S0) 9227+1990) Approved by the State Bureau of Technical Supervision on June 1, 1997
Implementation on January 1, 1998
3 Definitions
This standard adopts the definitions in GB12334.
4 Information to be provided by the purchaser to the electroplater
4.1 Necessary information
GB/T 9797—1997
When ordering electroplated parts in accordance with this standard, the purchaser shall provide the electroplater with the following information: 4.1.7 This standard number.
4.1.2 The required base metal and service condition number indicating the severity of the service environment of the plated parts (see 5.1) and the grade number of the specific key layer required (see 5.2).
If the purchaser only provides the base metal and service condition number but does not provide the grade number of the coating, the electroplater may provide any grade of coating for the corresponding service conditions, but shall inform the purchaser of the selected grade number of the key layer (see 5.2). 4.1.3 Surface finishing requirements, such as: bright, dark or satin (see 7.2), also known as samples indicating surface finishing requirements or finishing specifications provided by the purchaser or finally approved.
4.1.4 Major surfaces shall be marked on the part drawing or a sample with appropriate markings shall be provided. 4.1.5 Type of corrosion test to be used (see 7.4). 4.1.6 Type of metallurgical stress test to be used (see 7.3). 4.1.7 Degree of permissible imperfections on non-major surfaces (see 7.1). 4.1.8 Location of tool marks and contact marks on major surfaces that cannot be avoided (see 7.1). 4.1.9 Sample method and acceptance level (see Clause 8). 4.2 Additional Information
The following additional information may also be provided upon request.
4.2.1 Tensile strength of steel parts and heat treatment requirements before and/or after electroplating (see Chapter 6) 4.2.2 Thickness requirements of the surface that cannot be contacted by a ball with a diameter of 20 mm (see 7.2.1) 4.2.3 Whether to have a copper-plated base (see 5.2b) 5 Grading
5.1 Service condition number
The service condition number is used by the purchaser to specify the severity of the service environment of the plated parts. The number is as follows: 1-extremely severe 3-severe 2-moderate 1-mild 0-mild The typical conditions of various service condition numbers are shown in Appendix B (Appendix of the requirements). 5.2 Coating grading number
Coating grading number is composed in the following order:
a) Chemical symbol of base metal (main metal in alloy matrix) + followed by a slash: as follows: Fe/
indicates that the base is steel!
Zn/—— indicates that the base is zinc or zinc alloy;
indicates that the base is copper or copper alloy:
Al/—— indicates that the base is aluminum or aluminum alloy,
b) Chemical symbol (indicates copper and copper alloy coating when copper or copper alloy layer with copper content exceeding 50% is used as base coating. r) The number after Cu indicates the minimum local purity of copper coating, unit is umd) Chemical symbol of nickel Ni.
e) The number after Ni indicates the minimum local purity of nickel coating, unit is um. [ ] indicates the type of nickel coating (see the letter in 7.2.3.2, g) chemical symbol (r indicates the coating is completely coated.
G8/r 9797. 1997
h) The letter after Cr (lowercase) indicates the type of chromium coating (see 7.2.4). Complete classification number Example: A copper layer with a minimum thickness of 20um is plated on a steel substrate. Copper 1 is plated with a minimum thickness of 30um of bright nickel, and a micro-cracked chromium with a minimum thickness of C.3II is plated on nickel. The complete classification number is: Fe/Cu20 Ni30b Cr mc
Note: Unless otherwise specified by the purchaser, the minimum thickness requirements of the coating specified in this standard are applicable to the main surface part that can be contacted by a ball with a diameter of 2Umm (see 7.2.1).
5.3 Coatings corresponding to each service condition number
The corresponding coating grade numbers for each service condition of various base metals are shown in Table 1 and Table 4: Table 1A Nickel-coated coating on steel
Service condition number
Mirror layer grade number!
Fe/NizOd Cr r
Fe/N:3cedl Cr mt
Fe/Ni30d Ct m:p
Fe?Ni.Gp rr
Fe/Nison Cr ue
Fe/Nisop Ct mp
Fe/si3Gd Cr r
Fe/Ni25d t't mc|| tt | C+ r
Fe/Ni(h t- r
Fe/NiS Ce r
11 When the service conditions are 3.2.1 and 3.2.2, b can be replaced by c; r can be replaced by mc or mp. When the service conditions are 2 and 1, p or d can be replaced by d.
1B Nickel + chromium plating on steel
Service part number
Coating grade number Industry
Fe/Cu20 N302 Crr
Fe/Cu20 Ni25d Cr nc
Fr/cu20 Ni25d Crmp
Fe/t2u Ni3μ Cr T
Fe/Cu20 Ni25p Cr m
Fa/t.u20 Ni25p Ce rnp
Fe/n26 Ni30h Crme
F-/Cu20Ni30bCemp
Fetul5 Ni25d Cr r
Fe/Cu15 Ni20d Cr rmc
Fe/cu15 Ni2ixl Cr nip
Fe/c15 Ni25p Cr r
Fe/tu15 Ni2p Cr mr.
Fe/Cu15 Ni20p Crmp
Fe/Cu20Vi3shCrr
Fe/Cn20Vi25hCrme
Fe/Lu20Ni23hCrmp
Fe/Cu20Nilob(Cr1
Fe/CulQ Ni5L (Cr 1
Fu/Cuh Nish (Cr r
1) service condition number is 1,2,10 tons, nickel can be used to replace nickel; - or p-chromium can be used to replace chromium. When the service condition number is 2 and 1, p-nickel or d-nickel can be used to replace b-nickel. 2B Copper + chromium coatings on zinc alloys
Coating composition
Zn/Cu Ni35d Tr r
Zn/Cu Ni25d C mc
Zn/CuNi25d Crmp
Zn/C11 Ni35p Ct r
Zn/Cu Ni25p Ct mp
Zn/Cu Ni25 Ct mc
7n/C Ni35h Cr mr
2n/CuNi35h Cr mp
2n/Cu Ni25d Cr r
Zn/Cu Ni2d Cr mc
2n/Cu Ni20d Cr mp
7n/Cu Ni25p Cr r
Zn/Cu Ni20p Cr me
Zn/cuVi20p (rmp
Zn/Cu Nissb Gt 1
Zn/Cu Ni25b Cr mc
mp
7n/Cu Ni15h Cr 1
Zn/cu Ni8h Cr 1
11 Service case numbers are 3,2,1 Attached, sometimes nickel may be substituted for nickel, and chromium may be substituted for chromium by ruthenium or chromium chromium. When the service condition number is 2, nickel or ruthenium may be substituted for nickel. It is not specified that a coating thicker than that of service condition number 1 shall be used for service condition number 1. Service condition
Coating grade number!
Zn/Cu20 Ni30d C1 r
Zn/Cu20 Ni20d Cr mc
7n/Cu20 Ni20d Cr mp
Zn/Cu20 Ni30p Cr 1
Zn/Cu20Ni20p Crmc
Zu/Cu20 Ni20p Cr np
Zn/Cu20 Ni30h Gt mr
Zn/Cu20 Ni30l, CrImp
7n/Cu15 Ni20d Tr r
Zu/u15 Nilsd Cr mc
Zn/Cu15 Nt15d Ce mp
Zn/Cu15 Ni20p Cr r
Zn/c1b Ni15p Ce inc
Zn/Cu15 Ni:5p Cr my
Zu/Cu21 Nis0b Cr r
Zn/Cu20 Ni20h Cr me
2n/tu30 Ni2nh (r mp
Zn/tu?o Ni10h Cr r
In Table 2.4, the bond layer series with service condition number
1 is the same as
1) When the service condition number is 3.2 and 1, Yuejin can be used instead of h Inlay: Use nickel or chromium to replace chromium. When the service condition number is 2, it can be replaced by nickel.
Table 3 Nickel + chromium plating on copper or copper alloy
Service case number
Plating compensation grade number 1
Cu/Ni30d Cr:
Cu/Ni25d Cr mc
t'u/Ni25d Cr mp
Ku/Ni3up Gr r
Cu/Ni25p Crinc
tu/Ni25p Cr tup
Cu/Niscb Ct tmc
Ch/Ni30h Cr mp
Cu/Ni26d Ct T
Service Case No.
GB/T 9797
End of Table 3)
Coating Grade No.\
Cu/Nob Cr
Cu/Ni5b Cr r
Cu/Ni3b Cr tt||Al/Ni25d Cr mr:
Al/Ni25d Cr mp
Al/Ni35d (r 1
Al/Ni30p Ce ine
A1/Ni30p tr mr:
Al/Ni25d Cr mp
Al/Ni35d (r 1
Al/Ni30p Ce ine
A1/Ni30p tr mr:
Al/Ni25d Cr mp
Al/Ni35d (r 1
Al/Ni30p Ce ine
A1/Ni30p Cr mp
Al/Ni20h (.rr
Al/silohGr
[）奈「In addition to the specified nickel base layer, a copper base layer may also be added. For some alloys and some applications, adding copper may be more appropriate. 2 Service condition number 2-1 can be used, d or nest instead of nickel - n or mp instead of r chrome, 6
Heat treatment of steel parts
If it is required that the steel parts need to be reversely heat treated before and (or) after bonding (see 1.2.1), the heat treatment should be carried out in accordance with the corresponding specifications recommended in Appendix A of (GH/T9798-1997).
Requirements for coating
7.1 Appearance
There should be no obvious bonding defects on the main surface of the plated parts, such as blistering , pores, roughness, cracks, missing bond areas, spots or changes. The degree of permissible sensitive layer defects on non-main surfaces and the location of unavoidable tooling marks on the main surface shall be specified by the manufacturer: 7.2 Thickness and type of coating
-General provisions
The corresponding coating thickness and type of the specified service condition number shall correspond to the classification number in Table 1 to Table 4. The minimum thickness requirement for the surface metal bond layer on the main surface that can be contacted by a ball with a diameter of 20III shall be specified. The manufacturer also specifies the thickness requirements that other surfaces should meet. The coating thickness measurement method is shown in 9.1. 7.2.2 Thickness of copper coating
GB/T 9797-1997
The minimum thickness of copper coating in copper + nickel + chromium coating is shown in Table 113 and Table 213. The minimum thickness of copper coating in nickel + chromium coating on zinc alloy is 8μm (see Table 2A). Note: All the mirror layers listed in Table 2A are plated on a copper base layer with a thickness of at least 10 μm [see 5.2b> and 7.2.2]. In order to allow the low-current areas of non-main surfaces of complex-shaped parts to have a sufficiently thick layer, the minimum thickness of the copper layer on the main surface may be increased to 10~12. 7.2.3 Thickness and type of nickel coating
7.2.3.1 Nickel coating thickness
The total minimum thickness of the nickel coating shall comply with the provisions of the coating grade number (see 5.2) 7.2.3.2 Type of nickel coating
The type of nickel coating is represented by the following symbols: h--full bright nickel deposition;
-dark nickel or semi-bright nickel with mechanical polishing; p
dark satin nickel or semi-bright nickel without mechanical polishing; d-dark or satin nickel, the relevant requirements are shown in Table 5. Table 5 Requirements for double or triple nickel layers
Parallel length ratio
Second (casting layer type)
Bottom (s)
Middle layer (commercial sulfur) h)
Sulfur content:
%tmim)
-0. 04 and +20. 15
1) The test method for elongation is shown in (Appendix 1 of GB/T58197). Thickness (percentage of total nickel layer thickness) "
" 2) The sulfur content of the nickel layer is to determine the type of plating used. There is no simplified method to determine the sulfur content of the nickel layer, but according to any method specified in Appendix 1 of GB/T57081097, using a specially prepared test column, it can be accurately measured. 3) According to the provisions of G3612, the thickness of the prepared layer is broken, polished and soaked, and the thickness ratio and type of the layer are determined by microscope to identify the change. 7.2.4 Type and thickness of chromium layer
7.2.4.1 Type of chromium layer
The type of chromium layer is indicated by the symbol after the chemical symbol Cr: Crr
indicates conventional chromium.
indicates microcracked chromium. When measured by the method specified in Attachment A (Standard Attachment), there should be more than 250 cracks per centimeter of length in any direction of the plated part, and a closed network should be formed on the entire surface. indicates microporous chromium. When measured by the method specified in Attachment A, there should be at least 10 cracks per square centimeter of area of the plated part. 000 pores (dead spots).
NOTE: This type of chromium is obtained by depositing chromium on a nickel layer containing a continuous layer of non-conductive particles of chromium. This coating is applied to the surface of the alloy. 7.2.4.2 The thickness of chromium is specified as follows:
Conventional pattern, Cr r - minimum thickness, 3 μm. Microcrack pattern, Cr mc, minimum thickness, 0.3 μm (see Notes 1 and 2). Microporous pattern, Cr mp - minimum thickness, 0.3 μm (see Note 2). Microporous pattern, Cr mp.5 - minimum thickness, 0.5 mm (see Note 2). NOTE
! Sometimes, in order to obtain the required crack pattern, the thickness of the microporous pattern is significantly greater than the above specified, about 0.8 mm. After a period of use, the gloss may be lost, which is not acceptable in some applications. The minimum thickness of microporous and microcrack patterns in Table 1 is increased to 0. 5μm can reduce the tendency of gloss and fire. 7.3 Joint strength
GB/ 9797-: 1997
The coating and the body and each group of coatings should be well bonded and can pass the corresponding test specified in 9.2. 7.4 Corrosion resistance
The coating should be free of pores and can pass the test of the specified service condition number specified in 9.3, and be rated according to Appendix C of GB/T9798-1997, and its minimum qualified rating should be 9. 8 Sampling
The sampling procedure of GB12609 is selected. The acceptance level should be specified by the purchaser. 9 Test method
9.1 Thickness
The total thickness of the coating and the thickness of each group of coatings should be measured at any part of the main surface that can be contacted by a ball with a diameter of 20mm. The coulometric method specified in GB/T455 can measure the thickness of the chromium layer, the total nickel layer sequence, the copper layer and the thickness of the copper alloy base layer of known composition. The X-ray spectrometry method specified in GB/T16921 can measure the thickness of the chromium layer. It can also be used to measure the thickness of the bottom nickel layer before nickel plating. The microscope method specified in GB6462 can be used to measure the thickness of each nickel layer with a minimum thickness of 10μm, and can also measure the thickness of copper or copper alloy and gold plating (see 7.2.2). The STEP test method can also be used to determine the strip thickness of double and triple nickel mirror layers and the electrochemical relationship between the layers. The STEP method test can be used to produce parts, so it has been widely evaluated and has become a part of the national standard of some companies. There is still controversy about the optimal value of the potential difference between the layers to ensure good protection of bright nickel and semi-bright high-gold, but the company has set this potential difference to not less than 11251mV. This standard adopts 151456 equivalent to the decision to define this test method as a revised version of the standard, but no STEP method manuscript that can be accepted by this international standard has been proposed. Users of this standard are welcome to conduct this test and make compensation for the results, which will further improve the quality of the product. If properly calibrated, the magnetic method specified in GBT13711 can measure the total thickness of the nickel plating layer of b, d, s or P on zinc alloy copper alloy and steel with known composition. Other thickness measurement methods with a proven measurement error within 10% can also be used. In case of dispute, the coulometric method is used to measure the thickness of the nickel layer and the thickness of the nickel layer less than 10 μm, and the microscopic method is used to measure the nickel layer and the thickness of the bottom layer less than or equal to 10 mm.
9.2 Bonding strength
Test the bonding strength of the coating according to the thermal shock test or chain knife test specified in GB5270. After the test, there should be no separation between the forging layer and the body, and between the coating and the coating.
9.3 Corrosion resistance
The plated parts shall be subjected to corrosion test according to Table 6, and the test duration shall correspond to the service condition number of the plated parts. Any special test shall be specified by the belt manufacturer. Table 6 Correspondence between corrosion test and service part number Duration of American system scrap corrosion test
Base metal
Zinc alloy
Service condition number
CASS test
(GB/T 10125)
CORR test
ASS test
(GB 6465)
(GR/T10125)
British metal
Zinc alloy
Copper or copper containing gold
Aluminum or lead alloy
Service condition number
GR/T 9797—1997
Table 6 (End)
CASS test
(GR/T 10125)
Extracted test characteristics
CORR test
(GB 5465)
ASS test
(G/T 10125)
1When the base metal is copper or copper alloy, the test duration is shorter than that of steel, zinc alloy or aluminum alloy. This is because the nickel coating on the pin or alloy is thinner than that on steel, zinc alloy or alloy under the same service conditions. When the coating penetrates, the slow corrosion of the pin alloy proves that the use of these thinner and less corrosion-resistant bonding layers is appropriate. 2The horizontal line indicates that there is no test requirement.
3When the service condition is zero, there is no corrosion test requirement. The several corrosion tests specified in G3/T10125 provide a set of means to control the continuity and quality of the coating. It is assumed that there is little correlation between the test duration and the service life of the key parts. After the plated parts have undergone appropriate corrosion tests, they should be inspected and rated in accordance with the provisions of Appendix B of GB/T9798-1997 (see 7.4). 9.4 Ductility bzxZ.net
When tested according to the method specified in Appendix B of GB/T9798-1997, the elongation of the + nickel layer cannot be lower than the provisions of 7.2.3 9.5 Continuity of chromium coating
Microcracks and micropores The density of cracks or pores in the key layer should meet the minimum requirements specified in 7.2.4.1. The method for measuring the continuity of the coating is shown in Appendix A (Standard Appendix).
A1 Scope
GB/T9797-1997
Appendix A
(Standard Record) | |tt||Measurement of pore density and crack density in chromium coating This appendix specifies the method for measuring the pore density and crack density of chromium coating on product parts. A2 Principle
On a representative surface of the plated part, copper is deposited under specified conditions by cathode. Copper is only deposited on the nickel layer exposed by the discontinuous chromium layer. The pore density and crack density of the chromium layer are calculated based on the number of copper points deposited on a certain area or the number of cracks on a certain length. A3 Apparatus
General laboratory equipment:
Electrode: used to deposit copper on the cathode test piece: Solution: copper sulfate (CuSO4*511,0) 200g/L. sulfuric acid (HS0),) 20g/L. During the whole electroplating process, the temperature is maintained at 18~24r. The cathode current density is 30A/m.
A4 Procedure
A4.1 Preparation of test pieces
Prepare the test pieces as follows.
Insulate all unplated edges and copper wires in contact with the cathode rod of the plating tank with insulating varnish, and immerse and clean them in a hot alkaline degreasing solution at a temperature not exceeding 65°C until the surface is evenly wetted. The cleaning effect will be better if you use a soft brush to gently scrub. Rinse thoroughly in running water and then immerse in a sulfuric acid solution of about 5% for 5 to 10 seconds. If the test is carried out several days after the chromium deposition, before the copper deposition, immerse the sample in a nitric acid solution for 4 minutes. The concentration of nitric acid is 1u~-20g/L. The solution temperature is about 65°C. This treatment helps to reveal cracks or pores.
44.2 Measurement
The test piece is charged and inserted into the sugar (A3).
On the treated test piece, copper is deposited at a cathode current density of 3UA/m\cathode for a time of about 1~5min and a temperature of [8~24°C. Copper is only deposited on the nickel bottom layer exposed by the discontinuity of the chromium layer (pores and cracks). Take a close look at the test piece, wash it with cold water first and then with hot water, and dry it in the air (do not use compressed air). Do not wipe the part of the test piece where pores or cracks need to be counted.
Count the number of copper points deposited on the test piece and the number of cracks shown by the known length of the deposit to estimate the number of discontinuities in the chrome plating. The counting can be done with a metallographic microscope with a scaled mirror or with a microscopic film taken from a representative area of the test piece.
Appendix B
(Suggestive Appendix)
Examples of service conditions corresponding to various service condition numbers Examples of service conditions corresponding to service condition numbers are as follows: Service condition number 4
Extremely severe narrow external corrosion conditions:
9797--1997
Service condition number 3
3—Typical outdoor temperature conditions
Service condition number 2—
An indoor area where condensation may occur:
An indoor area with mild and dry air;
Service condition number 1
Service condition—
Purely decorative environment1 Preparation of test pieces
Prepare the test pieces as follows.
Insulate all unplated edges and the copper wire in contact with the cathode rod of the plating tank with insulating varnish and clean them by immersion in a hot alkaline degreasing solution at a temperature not exceeding 65°C until the surface is evenly wetted. A gentle scrubbing with a soft brush will provide better cleaning results. Rinse thoroughly in running water and then immerse in a solution of about 5% sulfuric acid for 5 to 10 seconds. If the test is to be carried out several days after the deposition of chromium, immerse the sample in a nitric acid solution for 4 minutes before the deposition of copper. The concentration of nitric acid is 1u~-20g/L. The solution temperature is about 65°C. This treatment helps to reveal cracks or pores.
44.2 Measurement
Put the test piece into the sugar (A3) with an electric charge.
On the treated test piece, copper is deposited at a cathode current density of 3UA/m\, and the electroplating time is about 1~5min-temperature [8~24℃. Copper is only deposited on the nickel bottom layer exposed by the discontinuity of the chromium layer (pores and cracks). Take a fine test piece, wash it with cold water first and then with hot water, and dry it in the air (do not use compressed air). Do not wipe the parts of the test piece where pores or cracks need to be counted.
Count the number of copper points deposited on the test piece and the number of cracks shown by the known length of the deposit to estimate the number of discontinuities in the chromium plating layer. The counting can be done with a metallographic microscope with a scale mirror, or with a microscopic film taken from a representative area of the test piece.
Appendix B
(Suggestive Appendix)
Examples of service conditions corresponding to various service condition numbers Examples of service conditions corresponding to service condition numbers are as follows: Service condition number 4
Extremely severe narrow external corrosion conditions:
9797--1997
Service condition number 3
3—Typical outdoor temperature conditions
Service condition number 2—
An indoor area where condensation may occur:
An indoor area with mild and dry air;
Service condition number 1
Service condition—
Purely decorative environment1 Preparation of test pieces
Prepare the test pieces as follows.
Insulate all unplated edges and the copper wire in contact with the cathode rod of the plating tank with insulating varnish and clean them by immersion in a hot alkaline degreasing solution at a temperature not exceeding 65°C until the surface is evenly wetted. A gentle scrubbing with a soft brush will provide better cleaning results. Rinse thoroughly in running water and then immerse in a solution of about 5% sulfuric acid for 5 to 10 seconds. If the test is to be carried out several days after the deposition of chromium, immerse the sample in a nitric acid solution for 4 minutes before the deposition of copper. The concentration of nitric acid is 1u~-20g/L. The solution temperature is about 65°C. This treatment helps to reveal cracks or pores.
44.2 Measurement
Put the test piece into the sugar (A3) with an electric charge.
On the treated test piece, copper is deposited at a cathode current density of 3UA/m\, and the electroplating time is about 1~5min-temperature [8~24℃. Copper is only deposited on the nickel bottom layer exposed by the discontinuity of the chromium layer (pores and cracks). Take a fine test piece, wash it with cold water first and then with hot water, and dry it in the air (do not use compressed air). Do not wipe the parts of the test piece where pores or cracks need to be counted.
Count the number of copper points deposited on the test piece and the number of cracks shown by the known length of the deposit to estimate the number of discontinuities in the chromium plating layer. The counting can be done with a metallographic microscope with a scale mirror, or with a microscopic film taken from a representative area of the test piece.
Appendix B
(Suggestive Appendix)
Examples of service conditions corresponding to various service condition numbers Examples of service conditions corresponding to service condition numbers are as follows: Service condition number 4
Extremely severe narrow external corrosion conditions:
9797--1997
Service condition number 3
3—Typical outdoor temperature conditions
Service condition number 2—
An indoor area where condensation may occur:
An indoor area with mild and dry air;
Service condition number 1
Service condition—
Purely decorative environment
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