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GB/T 17462 — 1998
This standard is equivalent to ISO2179:1986. This standard makes the following modifications and supplements to IS0 2179:
- Add the guiding element "metallic coating" in the name of the standard, and omit the original supplementary element "specifications and test methods" to make the subject clearer and more prominent;
- Omit the introduction, and put its contents in the notes of the relevant chapters;
- Add the "not applicable to the nickel-plated thin surface coating mainly used to change the surface color of parts and give the parts a decorative appearance" in Chapter 1;
- Omit the original standard reference IS0 2859 in Chapter 2, because another reference standard 1S0 4519 already contains the content of the reference standard to avoid duplication;
- Add the meaning of "basic measuring surface" in Chapter 3;
- Add the "basic measuring surface" in Chapter 1, Chapter 5, Chapter 10 and A1.1. Some necessary supplements have been made to make the expression more complete and clear. Appendix A of this standard is the appendix of the standard, and Appendix B is the appendix of the suggestion. This standard was proposed by the State Bureau of Machinery Industry: This standard is under the jurisdiction of the National Technical Committee for Standardization of Metal and Non-metallic Coverings. The responsible drafting unit of this standard: Wuhan Institute of Material Protection. The main drafters of this standard: Ye Luqi, Xie Ruibing, Li Feng. He Lixin. JianxinwmGB/Tt7462-1998
ISO Foreword
ISO (International Organization for Standardization) is a worldwide federation of national standards bodies (ISCs) and member bodies. The work of formulating international standards is generally carried out through ISO technical committees. If each member body is interested in a topic determined by a technical committee, it has the right to make a statement to the committee. Governmental and non-governmental international organizations associated with ISO International organizations can also participate in this work. The draft international standard adopted by the technical committee shall be sent to the member groups for approval before being adopted as an international standard by the ISO Council. According to the IS0 procedure, at least 75% of the member groups participating in the voting shall approve it to be passed. International Standard ISO2179 was developed by IS0/TC107 Technical Committee for Metallic and Other Non-Organic Coatings: This second edition cancels and replaces the first edition (i.e. 1S02179:1972), which is a technical revision of the first edition. Registrants should note that all international standards will be revised. Therefore, unless otherwise stated, the other international standards referenced in this international standard are their latest versions.
1 Scope
National Standard of the People's Republic of China
Metallic Covering Tin-Nickel Alloy Electroplating
Metallic coatings-Electropiaied coatings of tin-nickel alloysGB/T 17462 - 1998
eq ISO 2179:1986
This standard specifies the technical requirements and test methods for the electroplating of tin-nickel alloys, an intermetallic compound consisting of approximately 65% (mass ratio) tin and 30% (mass ratio) nickel.
This standard is applicable to tin-nickel electroplated coatings on steel and other flat products. The electroplated coating can prevent corrosion of the base metal under different service conditions.
This standard does not apply to:
tin-nickel alloy coatings on threaded parts;
h) tin-nickel alloy coatings on unprocessed sheets, strips or wires, or parts made from them1;
tin-nickel alloy coatings on spring coils;
d) nickel-nickel alloy coatings on steel with a tensile strength greater than 100 MPa (or corresponding hardness), which is susceptible to hydrogen generation after electroplating (see 8.2);
e) nickel-nickel alloy thin surface coatings used to change the color of the surface of parts and give them a decorative appearance. 2 Referenced standards
The texts contained in the following standards constitute the provisions of this standard through reference in this standard. The version indicated is valid at the time of publication of this standard. All standards are subject to revision, and parties using this standard should consider the possibility of using the latest version of the following standards. CB/T4955.-1997 Thickness of metal coating - Coulometric method with anodic solution (IDT ISO 2177:1985) GB/T5270-1985 Test method for adhesion strength of metal coating (electrodeposited layer and chemically deposited layer) on metal substrate (E9V 150 2818:1980)
GB/T59311986 Thickness test of metal coating and chemically treated layer of light industrial products - Force method - Ray backscattering method (IDT [0 A543.1981)
GB/6462-19863 Thickness of metal and oxide coating - Microscope measurement method (EG150) 1463:1982) GB/T 9789--1988
Metal and other non-organic coatings - Sulfur dioxide corrosion test under normal condensation conditions (RV TS0 6988:1985)
GB/T 9798
Metal coatings and electrodeposited coatings (EG1S1658:1988) GB/T 12334-1990 Definitions and general rules for thickness measurement of metals and other inorganic coatings (E9V (S0 206411990)
CB/T 12G09-1950 Sampling procedure for electrodeposited metal coatings and related finishes by counting (ISO 519:1980) X-ray spectroscopic method for thickness measurement of metal coatings (C4VIS0) 3197:1990) (5 169211997
Approved by the State Administration of Quality and Technical Supervision on August 12, 1998 and implemented on July 1, 1999
3 Definitions
This standard adopts the following definitions.
3.1 Significant surface GB/T 17462—1998
Some surface of a workpiece that has been plated or is to be plated, on which the coating is important to the appearance and (integrity) performance of the workpiece, and should meet all the requirements specified in the standard.
3.2 Reference area An area on a significant surface where a certain number of single measurements are required. 4 Information that the purchaser should provide to the electroplating manufacturer 4.1 Necessary information The purchaser should provide the following information to the electroplating manufacturer: a) Number of this national standard: h) Properties of base metal (see Chapter 1); h) Condition of use number (Condition 7.1) or coating grade number (see 7.2); e) Sampling and inspection requirements (see Chapter 2); f) Unavoidable contact marks and other acceptable coating defects on the workpiece (see 10.1); g) Adopted bonding strength test method (see 10.3). 4.2 Supplementary information
When necessary, the purchaser shall also provide the following supplementary information:) Requirements for heat treatment (see Chapter 8)
h) Requirements for porosity test (see 10.5);) Special requirements for the bottom coating (now Chapter 9); d) Samples that can show the appearance requirements of the coating (see 10.1); e) Special pre-treatment requirements:
f) Special packaging requirements for plated parts.
Note: The purchaser shall provide the requirements specified in 4.1 and, if necessary, the requirements specified in 4.2. It is not enough to only provide the number of this standard without these requirements.
5 Substrate
This standard does not make any requirements for the surface state, appearance or surface roughness of the substrate before electroplating (see 2.1 in Appendix R (Suggested Appendix)). However, if the coating fails to meet the appearance and (or) performance requirements due to the poor surface quality of the substrate, it cannot be considered that the electroplating production quality does not meet the requirements. 6 Sampling
When it is necessary to check whether the tin-nickel inlay method meets the requirements specified in Chapter 1 of the wood standard, the sampling inspection shall be carried out according to the sampling method specified in B/12609. The acceptance level shall be agreed upon by the supplier and the buyer. 7 Classification
7.1 Use condition number
The use conditions are divided according to the actual use environment, and the use condition number indicates the severity of the use conditions: 4 Particularly severe: : Such as use in severe corrosion conditions outdoors; 3
Severe: Such as use in typical outdoor overflow conditions GB/T 17462--1998
2 Moderate - such as use in indoor conditions with slight condensation; 1 Mild - such as use in indoor dry atmosphere conditions. NOTES
1 See 10.2, which gives guidance on the relationship between the use of the part number and the minimum thickness. 2 When the use of the part number or the bond layer size is specified, it should be noted that the tin-nickel bond layer is brittle and easily damaged by magnetism (see Annex B). 7.2 Coating Classification Number
The coating classification number consists of two parts.The first two parts are separated by a short slash, as shown in the table: a/h.
where: a-… represents the chemical symbol of the base metal (or the main component of the alloy base); h represents the chemical symbol of the base metal (or the main component of the alloy base); followed by a number representing the minimum thickness of the base, in μm, if the base is not a base (see 4.2c)); c represents the chemical symbol of the coating composition SnNi, followed by a number representing the minimum thickness of the coating, in μm. For example; Fe/Cu 2.5 SnNi 10
This grade number indicates that the base metal is steel, the bottom coating is a copper coating of at least 2.5μm thick, and the tin-nickel coating is at least 10um thick. 8 Heat treatment of steel
8.1 Stress relief before electroplating
Deeply cold-deformed and hardened steel parts should be heat treated at a temperature of 190-220G before electroplating to relieve stress. For some steels that have been carbon-coated, flame-rate quenched or high-frequency induction-rate quenched and then milled, the above treatment will damage their performance and can be replaced by lower temperatures to relieve stress. For example, 130-~150 (, treatment The treatment time is not less than 6h. 8.2 Elimination of hydrogen embrittlement by electroplating
Since the diffusion of hydrogen through the tin-lead coating is very slow, it is not appropriate to perform heat treatment to eliminate hydrogen embrittlement after electroplating. 9 Requirements for the bottom coating
For some base materials, it is necessary to electroplate the bottom coating for any of the following reasons: a) to ensure bonding strength (see B2.2 and 32.3 in Appendix B); b) to improve corrosion resistance.
When selecting the bottom coating or bottom coating system, it should be noted that it should not bring about adverse performance. If it causes hydrogen embrittlement in the base material or the plated parts, the use of high-stress nickel should be avoided.
For use conditions No. 2, 3 or 4, in addition to the specified tin-nickel alloy coating thickness (see 10.2), a copper, nickel, copper-tin alloy or tin base coating with a minimum local thickness of 8um is required for steel and iron-based alloys. This base coating is necessary to maintain good appearance and adhesion.
If a base coating is specified, its properties (see Appendix B1B2) and minimum local thickness (see 10.2) shall be specified by the party. The thickness of the single-base coating or multi-layer base coating shall be as specified in A1.1 of Appendix A (Standard Appendix). 10. Requirements for the key layer
10.1 Appearance
When inspected by daylight, there should be no visible defects on the main surface of the plated part, such as blistering, pinholes, roughness, cracks or local absence of coating, and there should be no stains or discoloration.
The purchaser shall specify the acceptable unavoidable contact marks and the defects allowed on non-main surfaces. If necessary, the purchaser shall provide or approve samples that may indicate the appearance requirements of the coating: 10.2 Thickness
The nickel coating shall be divided into thicknesses and listed in Table 7. The leaf specifies the minimum thickness value (see B1 in Appendix B) corresponding to each service condition number (see 7.1).
Service conditions
GB/T 17462-1998
Table 1 Coating thickness
(Grading number)
SnNi 25
SnNi15
SnNi 10
SnNi 5
Minimum thickness -1
1For secondary applications where the bulk properties of the tin-plated coating are utilized only and corrosion resistance is secondary, the lower thicknesses specified in Table 1 may be used (see Appendix BDI).
2Under very special circumstances, a bond coat of greater than specified in the table may be used + average thickness (see Appendix BDI).
Measure the thickness of the bond coat at any point in the main surface that can be contacted by a 20 mm diameter ball using the appropriate method given in Appendix A. The minimum thickness of the bond coat shall be as specified in Table 1. Where the main surface area of the component is equal to or greater than 100 mm, the minimum thickness in the table shall be regarded as the minimum average thickness. Where the main surface area of the component is less than 100 mm, the minimum thickness in the table shall be regarded as the minimum average thickness. For printed velvet boards with keyholes, the minimum coating thickness requirement applies not only to any position on the main surface that can be contacted by a small ball with a diameter of 2) 1 μm, but also to the surface inside the through hole (A0.2.1 in Appendix A). When there is a dispute over the thickness measurement, the arbitration method specified in A0.2 in Appendix A should be used. 10.3 Bond strength
Note: This test may have an adverse effect on the mechanical properties of the test piece. In this regard, the specimen after the thermal test shall not be subjected to other tests. If the purchaser specifies the test of bonding strength, the thermal shock test method in 1.12 of GB/T 5270-1985 shall be used for the test. The test temperature for different base metals is specified in Table 1 of GB/T 5370-1985. The heating time is 1 hour. After the test, there shall be no signs of separation of the coating from the substrate.
10.4 Porosity
If the purchaser specifies the determination of porosity, the polysemy degree is 10 μl or 1C μl. The coating shall be tested by the method specified in GB/ 978. The number of test cycles shall be agreed upon by the supplier and the buyer: and the test results shall be graded according to the provisions of Appendix C of GB/T 9798-1937. The porosity shall not meet the requirements if any of the following conditions occurs: 1) The coating with a thickness of 25 μm or more has a grade less than 9 μm after the test; 2) The coating with a thickness of 1 μm to 25 μm has a grade less than 9 μm after the test. 3) The coating with a thickness of 1 μm to 25 μm has a grade less than 9 μm after the test. 4) The coating with a thickness of 1 μm to 25 μm has a grade less than 9 μm after the test. 5) The coating with a thickness of 1 μm to 25 μm shall not meet the requirements. A0 Introduction
A0.1 Conventional method
GB/T 17462 — 1998
Appendix A
(Difficult Appendix)
Measurement of coating thickness
As long as the specimens specified in this appendix are used correctly, all the methods given in this appendix can be considered to have sufficient accuracy. Taking into account factors such as coating thickness, part shape, part size, coating composition and wall material, the conventional test force method selected should be the method that can produce the most reliable results expected.
In individual cases, other methods that have been proven to be equivalent or better than the test methods given in this appendix may also be used. A0.2 Arbitration method
A0.2.1 General requirements
In controversial cases, the arbitration method should be selected based on the specific circumstances of A0, 2.2--A0.2.4. A0.2.2 For local thickness greater than 9μm
, the microscopic method of heat determination in A1.1 shall be used.
A0.2.3 Local thickness less than 9um
If the substrate is copper, copper alloy, nickel or steel, the surface of the coating is smooth enough, and the electrolytic wave does not leak out of the electrolytic probe, then the coulometric method specified in A1.1 shall be used for measurement. The microscope method specified in A1.2 shall be used for measurement. Note: The bottom layer shall be measured by the coulometric method, and the nickel alloy plating shall be removed step by step. The coulometric method shall be used to measure the thickness of the nickel-plated alloy coating on the through-hole of the printed circuit board. A0.2.4 The thickness of the nickel-plated gold coating on the through-hole of the printed circuit board shall be measured by the microscope method specified in A1.1. The microscopic section shall be parallel to the axis of the hole, and shall be perpendicular to the surface of the coating or the bottom layer to be measured (see GB/T6462).
A1 Partial thickness measurement
A1.1 Microscope method
The method specified in GB/T6462 is adopted. This method includes the protective coating procedure, that is, the copper protection with a plating thickness of not less than 10um is adopted.
The accuracy tolerance of this method is ±0.8μm or when the thickness is less than 25um, the accuracy tolerance is ±% of the thickness. A7.23 X-ray backscattering method
The force method specified in GBT931 is adopted. This method requires the instrument operation accuracy to achieve the measurement value of the coating thickness to be accurate to within 10% of its true value; this accuracy is determined by the unit mass of the coating, the atomic number of the matrix metal and the change of the alloy composition. A1.3 X-ray spectrometry
The method specified in GB/T16921+ is adopted. This method requires the instrument and operation accuracy to achieve the measurement value of the coating thickness to be accurate to within 10% of its true value. The value is accurate to within 10% of its true value.
A1.4 Coulometric method
Use the method specified in GB/T 4955. This method generally has an accuracy of less than 10%. When this method is used as an arbitration method, the electrochemical density of the nickel alloy is calculated based on the density of the nickel alloy equal to 8.82% g/cm, the alloy composition is 65% (by weight) and the percentage (mass ratio). It can also be calculated using the alloy composition and density measured directly. A2 Measurement of average thickness
Because there is no feasible method for chemical decomposition of tin-nickel coatings, the weight method is usually not used to measure the average thickness of the electroplating layer, but the arithmetic average of several local thickness measurements on the main surface is taken as the average thickness measurement value (see CB/T 12334). These instructions remind users to pay attention to:GB/T 17462 — 1998
Appendix B
(Guided Appendix)
Guided Tips
) If certain energy dissipations of tin-dart alloys may lead to improper use of this bond layer: b) Properties and preparation of the substrate:
c) Electroplating practice.
B1 Properties of the coatingWww.bzxZ.net
The electroplated nickel-containing gold is a single-frame metastable alloy compound, and its molecular formula is similar to SnVi: Although this alloy will not be oxidized below 8cO (, but a phase change will occur when the temperature is increased. There is a maximum safe upper operating temperature of about 300 when there is a suitable base coating. This coating is hard (about 750Hv) and has a tendency to deform after plating: This coating should not be used for parts that are subjected to deformation and exposure, when appearance is the most important requirement. White nickel alloy is relatively stable, and the coating thickness should not be greater than 25! μm. The brightness of the cast nickel alloy coating is closely related to the surface state of the base metal. As the coating thickness increases, the brightness tends to decrease (see B2.). Except for some strong In addition to acidic environments, tin-nickel alloy coatings are easily exposed to the air to form a passivation film and have good corrosion resistance. The potential of tin-nickel coatings is more positive than that of most base metals, which makes the corrosion process of the base metal under the plated holes more serious. Therefore, the coating has better corrosion resistance. Its porosity must be low, and a coating thickness greater than the thickness specified in the element (for example, 5 μm) can be required.
In some applications where the low friction coefficient or high wear resistance of tin-nickel alloy coatings is required, the porosity of the coating is a minor factor; if lubricating oil is required during use, the presence of gaps will also affect lubrication. Unlike plating, tin-nickel coatings will not experience product growth or morphological changes, but if the conditions are not right, it will precipitate.
Although factors other than coating thickness may affect coating porosity, the thickness values given in the coating thickness classification number can still help to predict porosity.
B2 Properties and standards of substrate materials
B2.1 Surface condition
The surface condition of the coating depends in part on the surface condition of the substrate material. B2.2 "Difficult to clean" bulk materials
Some bulk materials, such as phosphor bronze, beryllium bronze, nickel-iron alloys, rolled or rolled alloys, are difficult to perform a complete chemical pre-cleaning due to the natural oxide film on their surfaces. If a copper base layer with a minimum local thickness of 2.5 μm is pre-plated, it will be beneficial to improve the bonding strength of the coating. B2.3 Aluminum, magnesium and zinc alloys || tt||These alloys are very susceptible to damage by dilute acids and alkalies, so special pretreatment is required before the silver-nickel alloy coating is electroplated, that is, a layer of copper-silver alloy or nickel base coating of equivalent order (19~25un) needs to be deposited. B3 Electroplating practice
B3.1 Coating thickness requirements
Unless otherwise specified in GB/T 12334, it should be noted that the thickness of the deposited layer specified in this standard is the minimum local thickness rather than the average thickness. The average thickness that should be achieved to meet the given minimum local thickness requirement on the main surface will depend on the geometry of the plated part and the plated stopper, and the placement of the cathode and anode that are closely related to both. When rolling plating, especially rolling small parts, the deviation of the coating thickness conforms to the normal (Gaussian) distribution law.
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