1 Range
This standard specifies technical requirements and test methods for electroplating of intermetallic tin-nickel alloys consisting of approximately 65%(mass ratio) tin and 30%(mass ratio) nickel.

This standard applies to electroplating of tin-nickel alloys on steel and other metal products, which can prevent corrosion of the base metal under different conditions of use.

This Standard does not apply to:

a) tin-nickel alloy coating on threaded parts;

b) tin-nickel alloy coatings on unworked and formed sheets, strips or wires or on parts formed from them;

c) tin-nickel alloy coating on the spring coil;

d) Tin-nickel alloy coatings on steel with tensile strength greater than 1000Mpa(or corresponding hardness), because such steel is prone to hydrogen embrittleness after electroplating (see 8.2);

e) Tin_Nickel alloy thin surface coating mainly used to change the surface tone of the parts and give the parts a decorative appearance.

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

2 Reference Standards
The FOLLOWING standards CONTAIN provisions which, by reference in this standard, constitute provisions of this standard. All versions shown are valid at the time of publication of this standard. All standards are subject to revision and parties using this standard should explore the possibility of using new versions of the following standards.

Metal coating coating thickness measurement anodic dissolution Coulomb method (IDTIS 02177:1985)

Test method for Adhesion strength of metallic coatings (electrodeposited and chemically deposited) on metallic substrates (eqvIS02819:1980)

Light industrial products — Test method for thickness of metal coatings and chemically treated coatings — beta ray backscattering method (IDTIS 03543:1981)

Method for microscopic measurement of cross-sectional thickness of metal and oxide coverings

Metal and other non-organic coverings — Sulfur dioxide corrosion test under normal condensation conditions (eqvIS06988:1985)

Metal coating electrodeposited nickel layer (eqvIS01658:1988)

Metal and other inorganic coverings – Definitions and general rules for thickness measurement (eqvIS020 “:1990)

Procedures for sampling inspection of electrodeposited metal covers and related finishing counts (eqvIs04519:1980)

Metal cover thickness measurement: X-ray spectral method (eqvIs03497:1990)

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

3 Definitions
The following definitions are used in this standard.

3.1 The main surface

Some SURFACE OF THE WORKPIECE THAT HAS BEEN PLATED OR IS TO BE PLATED, ON WHICH THE COATING IS IMPORTANT TO THE APPEARANCE AND/OR PERFORMANCE OF THE WORKPIECE, AND ALL REQUIREMENTS SPECIFIED IN THE STANDARD SHALL BE SATISFIED.

3.2 Basic measurement surface refe initial ncearea

An area on a major surface in which a specified number of single measurements are required.

The MATERIALS THAT THE DEMANDER SHALL PROVIDE TO THE ELECTROPLATING MANUFACTURER
4.1 Heart needs information

The Demander shall provide the following information to the electroplating manufacturer:

a) No. Of this national standard;

b) properties of the base metal (see Chapter 5);

c) Use condition number (see 7.1) or coating classification number (see 7.2);

d) specify the main surface of the workpiece to be plated, such as marked with drawings or provided with suitably marked samples;

e) Sampling and inspection requirements (see Chapter 6);

f) unavoidable corner traces and other acceptable coating defects on the workpiece (see 10.1);

g) Bonding strength test method used (see 10.3).

4.2 Supplementary Information

When necessary, the Demander shall also provide the following supplementary information:

a) requirements for heat treatment (see Chapter 8);

b) Porosity test requirements (see 10.5);

Special requirements for the bottom coating (see Chapter 9);

d) Samples that can indicate the appearance requirements of the coating (see 10.1);

Special pre-processing requirements;

f) Special packaging requirements for self-plated parts.

Note: The Demander shall propose the contents stipulated in 4.1 and, if necessary, the contents stipulated in 4.2. Only the compilation of this standard is presented

It is not enough without these contents.

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

5. Matrix
This STANDARD does not REQUIRE THE surface condition, appearance or surface roughness of the substrate prior to plating (see Appendix B(Appendix B)). But because the substrate surface quality is too poor to make the coating can not meet the appearance and (or) performance requirements, can not be considered electroplating production quality is not required.

6 Sample shot
When it is necessary to check whether the tin-nickel coating meets the requirements specified in Chapter 10 of this standard, the sampling inspection shall be carried out according to the sampling method specified in GB/T12609, and the acceptance level shall be agreed between the supplier and the demander.

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

7 Classification
7.1.Use condition numbers

The use conditions are divided according to the following use environment, and the use condition number indicates the severity of the use condition:

4 especially harsh as used in outdoor harsh corrosion conditions;

3 as harsh as typical outdoor temperature conditions;

2 Medium as used in indoor slightly condensed conditions;

1 As slightly as used in indoor dry atmosphere conditions.

note

1 See 10.2, where guidelines for the relationship between condition numbers and minimum thickness are given.

When the use of condition number or layer classification number is specified, it should be noted that the tin-nickel layer is brittle and easy to bruize (see Appendix B).

7.2 Coating classification number

The coating grade number consists of three parts, the first two parts of which are separated by a short slash, such as :fbc

Where :a represents the chemical symbol of the matrix metal (or the main component in the alloy matrix);

b A indicates the chemical symbol of the substrate metal (or the main component in the alloy substrate), followed by

The minimum thickness of the bottom coating is expressed as a number in µm. If there is no bottom coating, it can be omitted (see 4.2c).

One represents the chemical symbol of the coating composition, snNi, followed by a number representing the minimum thickness of the coating, in µm.

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

For example :Fe/Cu2.5SnNi10

The classification number indicates that the base metal is steel, the bottom coating is copper coating at least 2.5µm thick, and the tin-nickel coating is at least 10µm thick.

Heat treatment of steel
8.1 Stress relief before plating

The deep cold deformation work hardening steel parts should be heat treated at a temperature of 190~220℃ for 1h before electroplating. To relieve stress.

After carburizing, flame quenching or high-frequency induction quenching and subsequent grinding of some steel, with the above conditions will damage its performance, can be replaced by a lower temperature to eliminate stress, such as 130~150℃, the processing time is not less than 5h.

8.2 Eliminate hydrogen embrittance after plating

Since the diffusion of hydrogen through the tin-lead coating is very slow, heat treatment to eliminate hydrogen emittance is not required after plating.

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

Requirements for the bottom coating
For any of the following reasons, it is necessary to electrocoat some substrate materials:

a) Guarantee the bond strength (see B2.2 and B2.3 in Appendix B);

b) improve and f erosion.

The choice of an undercoat or undercoat system should be made with care that it should not bring undesirable performance. Avoid the use of high stress nickel if hydrogen embrittance occurs in the base material or the plated parts.

For conditions 2, 3 or 4, in addition to the specified tin-Ni alloy coating thickness (see 10.2), a copper, nickel, copin-tin alloy or tin bottom coating of a minimum local thickness of 8µm is required for steel and iron-based alloys, which is necessary to maintain good appearance and bond strength.

If an undercoat is specified, its performance (see B2 in Appendix B) and minimum local thickness (see 10.2) shall be specified by the Demander.

The thickness of A single substrate or multiple substrates shall be measured using the appropriate method specified in Appendix A(Standard Appendix) A1.1.

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

10 Requirements for coating
10.1 Appearance

During visual inspection, there should be no visible defects on the main surface of the plated part, such as blistering, pinholes, roughness, cracks or partial no coating, and no stains or discoloration.

The Demander shall specify acceptable and unavoidable marks on the joints and allowable defects on non-primary surfaces.

If necessary, the demander shall provide or approve samples that show the appearance requirements of the coating.

10.2 Thickness

The tin-nickel coatings are classified by thickness and the minimum thickness value for each condition number (see 7.1) is specified in Table 1 (see B1 in Appendix B).

Within the basic measurement plane on the main surface, the thickness of any part that can be angled out by A 20mm diameter ball is measured using the appropriate method given in Appendix A. The minimum thickness of the coating shall meet the requirements specified in Table 1. In the case of the main surface area of the workpiece equal to or greater than 100mm2, the minimum thickness in the table should be regarded as the local thickness minimum. In the case of the main surface area of the workpiece is less than 100mm2, the minimum thickness in the table should be regarded as the average thickness minimum.

For printed circuit boards with electroplated vias, the minimum coating thickness requirement applies not only to any position on the main surface that can be reached by a 20mm diameter ball Angle, but also to the surface inside the vias. (See A0.2.4 in Appendix A).

Thickness of coating

When the thickness measurement is in dispute, the arbitration method specified in A0.2 in Appendix A shall be used.

10.3 Strength of bond

ISO 2179-1986 Metal coating Tin-Nickel alloy electroplating

Note: This test may have adverse effects on the mechanical properties of the specimen. Therefore, the sample after the thermal shock test should not be used for other tests.

If the purchaser stipulates the test bonding strength, the 1.12 thermal shock test method in GB/T5270_1985 is used for the test. The test temperature of different matrix metals is specified in Table 1 of GB/T5270-1985. The heating time is 1h.

10.4 Porosity

If the Demander specifies porosity measurement, coatings with a minimum thickness of 10µm or greater shall be tested using the method in GB/T9789. The number of test cycles shall be agreed upon by the supplier and the purchaser, and the test results shall be graded according to the provisions of Appendix C of GB/T9798-1997, Metal coverings with a non-anode base metal coverings — an accelerated corrosion Test — an evaluation method for the results. Porosity is considered unsatisfactory if any of the following occurs:

a) Coatings with thickness equal to or greater than 25µm have a grade of less than 9 after testing;

b) The coating thickness in the range of 10~25µm is less than the required value of the demander after the test.