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Metallic coatings--Review of porosity tests

Basic Information

Standard ID: GB/T 17720-1999

Standard Name:Metallic coatings--Review of porosity tests

Chinese Name: 金属覆盖层 孔隙率试验评述

Standard category:National Standard (GB)

state:in force

Date of Release1999-04-08

Date of Implementation:1999-09-01

standard classification number

Standard ICS number:Mechanical manufacturing>>Surface treatment and coating>>25.220.40 Metal coating

Standard Classification Number:Comprehensive>>Basic Standards>>A29 Material Protection

associated standards

Procurement status:eqv ISO 10308:1995

Publication information

publishing house:China Standards Press

other information

Release date:1999-04-08

Review date:2004-10-14

Drafting unit:Wuhan Institute of Materials Protection

Focal point unit:National Technical Committee for Standardization of Metallic and Non-metallic Coverings

Publishing department:State Administration of Quality and Technical Supervision

competent authority:China Machinery Industry Federation

Introduction to standards:

This standard reviews published methods for revealing porosity and discontinuities in coatings. The various tests described in this standard are based on the use of appropriate reagents to react with the substrate exposed at the discontinuity of the coating to form observable reaction products. GB/T 17720-1999 Review of porosity tests for metallic coatings GB/T17720-1999 Standard download decompression password: www.bzxz.net
This standard reviews published methods for revealing porosity and discontinuities in coatings. The various tests described in this standard are based on the use of appropriate reagents to react with the substrate exposed at the discontinuity of the coating to form observable reaction products.


Some standard content:

CB/T17720—1999
This standard is equivalent to 1S010308:1995 Comments on the porosity test of metal interlayers
This standard makes the following changes to 1S010308:1995: - "7.20 Porosity test" and the names of the method mentioned in the text are changed to "α-isobutylphenol test". - Appendix 1 In order to conform to Chinese habits, the arrangement method of checking the Chinese names of the base materials and the Chinese names of the covering layers in the order of the first Chinese pinyin letters is adopted. This is a non-essential difference compared with 1S010308. This standard deletes the "bacteria test" under the copper covering layer on the zinc substrate in Appendix F, and adds the "cadmium sulfide test" under the palladium, platinum, gold, and chromium covering layers on the silver substrate in Appendix F and the "alizarin test" under the chromium covering layer on the aluminum substrate. Appendix A of this standard is the appendix of the standard, and Appendix B, Appendix C, Appendix D, Appendix E, Appendix F and Appendix G are all indicative appendices. 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 drafting unit of this standard: Wuhan Institute of Material Protection. The main authors of this standard: Jiang Xinbi, Zhu Jingsheng, Yang Fangming: GB/T17720-1999
ISO Foreword
ISO (International Organization for Standardization) is the national standardization organization ( ISO is a worldwide federation of member bodies. The work of preparing international standards is normally carried out through technical committees of ISO. Member bodies have the right to make representations to the committee on a subject identified by a technical committee. International organizations, governmental and non-governmental, in liaison with ISO may also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all aspects of international electrotechnical standardization. Draft international standards prepared by technical committees are sent to member bodies for approval before being adopted as international standards by the ISO Council. According to ISO procedures, at least 75% of the voting members must approve them for approval. International Standard ISO10308 was prepared by Technical Committee SC7, Corrosion Testing Subcommittee of ISO/TC107, Metallic and Other Inorganic Coatings. Appendix A is an appendix to the standard, and Appendix B to Appendix G are suggestive appendices. 1 Scope
National Standard of the People's Republic of China
Comment on Porosity Test of Metallic Coverings
Metallic This standard reviews the methods for revealing porosity and discontinuities in coatings published to date and is applicable to top coatings such as aluminum, anodized aluminum, brass, chromium, cobalt, copper, gold, steel, lead, nickel, nickel-selenium, nickel-cobalt, nickel-iron, nickel-phosphorus, palladium, platinum, ceramic or porcelain, silver, copper, saw-lead, chain-brocade, pot-zinc, zinc, and aluminum, plated-copper, brass, copper, iron, Kavar (NiFeCo) alloy, magnesium, brocade, inlay-code, inlay-phosphorus, phosphorus-copper steel, silver, steel, saw-lead and zinc alloy substrates, as well as palladium conversion films and phosphate conversion films (including related organic titanium) on metal substrates. The tests described in this standard are based on the formation of observable reaction products using appropriate reagents acting on the substrate exposed at the discontinuity of the coating.
1 The holes are generally perpendicular to the surface of the coating, but may also be oblique to the surface of the coating; they are often graphical or may be torsionally shaped, see Appendix C (Informative Appendix).
2 The size of the holes varies from submicroscopic, that is, invisible under an ordinary microscope, to microscopic, that is, visible at 10 to 1000 microns, to macroscopic, that is, visible to the naked eye.
3 Porosity can be clearly shown by staining the surface of the coating. 4 Porosity in the coating is not always harmful, for example, microcracks and micropores are not necessarily cracks or small holes. 5 The result of the porosity test is expressed as the number of pores per square meter of surface. It is related to the specific test method used in the test and the effective multiple used in the inspection. It is a relative value.
2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T 3138-1995 Terminology of metal bonding and chemical treatment and related processes (neq ISO 2079, 1981 and ISO 2080: 1981) GB/T 6461-1986 Rating of electroplated specimens after corrosion test of metal coatings on the substrate as a cathode (eqy IS0 4540: 1980)
GB/T 6465-1986 Corrosion test of metals and other non-organic covering layers (CORR test) (eqv IS0 4541.1978)
GB/T 8752-1928
Inspection of discontinuity of thin anodic oxide films on anodized aluminum and aluminum alloys | Sulfuric acid test (idt ISO 2085:1986)
GB/T9789-1988
Metal and other non-organic coatings - Sulfur dioxide corrosion test under normal condensation conditions (eqv 150 6988.1985)
GB/T 9797--1997
Rust + chromium and steel electrodeposition layer (eq[501456:1988) GB/T10125--1997Artificial atmosphere corrosion test Salt spray test (eqISO92271990) GB/T 11379-1989
Metal coating - Chrome electrodeposition for industrial wall (ne9IS061581984) CB/T 12305.2—1990
Metallic coatings Test methods for gold and gold alloy electroplated coatings Part 2: Environmental testing Approved by the State Quality and Technical Supervision Bureau on April 1, 1999 and implemented on September 1, 1999
GB/T 17720—1999
(eqvISO 4524-2:1985)
Metallic coatings Test methods for gold and gold alloy electroplated coatings Part 3: Electrolytic imaging test of porosity GB/T 12305.3—1990
(eqyISO 4524-3.1985)
GB/T 12332—1990
Metallic coatings Nickel electroplated coatings for use on plastics (eqv1504526:1985) GB/T126091990
Metallic coatings Copper + nickel + chromium electroplated coatings on plastics (eqvIS0 4525:1985) GB/T 17721 1999
Porosity test Iron reagent test (eIS010309:1994) Metallic body coatings
Watch cases and accessories Gold alloy coatings Part 2, Determination of fineness, thickness and corrosion resistance IS0 3160.2-1992
ISO 45271987
Technical requirements and test methods for autocatalytic nickel-phosphorus coatings ISO 4538—1978
3 Definitions
Metallic coatings TAA test This standard adopts GB/T 3138 and the following definitions. Discontinuities
Cracks, micropores, pits, scratches or other openings on the surface of the coating that expose the discontinuity of the underlying metal. For details on discontinuities in the coating, see Appendix D (suggestive Appendix) and Appendix G (suggestive Appendix) in the references 1] 4 Principle
The porosity test results are expressed as the final products of the chemical reaction, some of which appear in the original place and others appear on the paper or in the gel coating. The observation results are expressed according to the test method and the test items determined by the purchaser. It can be observed visually or with a 1C-fold microscope, or by using magnified photographs or microscopic magnified photographs. See references 1], [2, [3], [5 and [6] in Appendix G (see also Appendix A (Standard Appendix) Porosity Test Table and Appendix D Classification of Discontinuities of Metallic and Other Inorganic Coatings). 5 Common Features of Porosity Tests
Porosity tests are different from corrosion tests and aging tests that specifically involve test time. They are basically short-term tests. A good porosity test process must clean, depolarize and activate the exposed base metal and etch it daily so that the corrosion products it produces are sufficient to fill the pores and reach the surface of the coating. Ideally, this etching should not react with the surface of the coating, and the reaction time must be limited, especially for thin coatings, because the dripping action will corrode the substrate in all directions, which will cause the bottom of the coating to erode, resulting in the observed results. When the corrosion product dissolves in the reagent, a precipitate indicator can be used to form a reaction product (see Appendix E (Suggested Appendix) Porosity Test Method Classification). 6 Test Specimens
Porosity tests are generally destructive and are used to evaluate the quality of substrate coating (plating) processing. Therefore, it is generally not allowed to have a separate test specimen.
7 Specific porosity tests
7.1 Alizarin test
7.1.1 Scope
Applicable to chromium (including Cu/Ni/Cr and Ni/Ni/Cr), cobalt, copper, nickel, nickel-boron, nickel-cobalt, nickel-iron and nickel-phosphorus layers on aluminium substrates: 7.1.2 Summary of method
The specimen is treated with sodium hydroxide, sodium alizarin sulfonate and acetic acid under specified conditions. The red grain spots generated indicate porosity. The test procedure is detailed in ISO 4527. See also Appendix G for references [9], [31] and [37]. 7.2 Alizarin test
7.2.1 Scope
GB/T 17720—1999
Applicable to chromium (including Ni/Ni/Cl), cobalt, vanadium, darton, nickel-cobalt, vanadium-iron and quenched-phosphorus layers on aluminium, magnesium or zinc alloy substrates. 7.2.2 Method Summary
The test specimen is treated with potassium hydroxide and 1-aminoaldehyde-2-dicarboxylate under specified conditions. The red marks or spots produced indicate porosity. The test procedure is detailed in Appendix G of the reference literature [13]. 7.3 Cadmium sulfide test
7.3.1 Scope
Applicable to metallic chromium (including Ni/Ni/Cr), gold, palladium, platinum and layers on brass, brass, copper, phosphorus copper and silver substrates. 7.3.2 Method Summary Www.bzxZ.net
The filter paper is soaked in a cadmium oxide solution and then treated with sodium sulfide to precipitate sulfide on the filter paper. The test procedure is detailed in GB/12305.3.
7.4 Copper sulfate (Preece) test
7.4.1 Scope
Type A is applicable to zinc layers on iron, steel or iron-based alloy substrates. Type B is suitable for thin anodic oxide films with a thickness of less than 5 μm on aluminum alloy substrates. 7.4.2 Summary of the method
The specimen is immersed in a copper sulfate solution, and the aluminum alloy and iron alloy substrates are immersed in solutions of different compositions. The light red marks or spots indicate the pores of the coating on the iron substrate, and the black marks or spots indicate the pores of the coating on the lead alloy substrate. For details of the test procedure, please refer to the reference [38] and GB/T8752 in Appendix G.
7.5 Copper sulfate
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