Metallic coatings - Electroplated coatings of zinc-nickel alloys
1 Scope
This standard specifies the technical requirements and test methods for the electroplated coatings of zinc-nickel alloys with nickel content (mass fraction) of 5%~10% (low nickel) and 10%~17% (high nickel) on steel.
This standard is applicable to the electroplated coatings of zinc-nickel alloys on parts and components of automobile, aerospace, weapon and other products.
This standard is not applicable to:
——parts with tensile strength greater than 1,200MPa or Vickers hardness greater than 370HV;
——fasteners (bolts, nuts, etc.) with quality grade greater than 10.9;
——parts in contact with magnesium material.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3138 Metallic and other inorganic coatings - Surface treatment, metallic and other inorganic coatings - Vocabulary
GB/T 6461 Methods for corrosion testing of metallic and other inorganic coatings on metallic substrates - Rating of test specimens and manufactured articles subjected to corrosion tests
GB/T 6462 Metallic and oxide coatings - Measurement of coating thickness - Microscopical method
GB/T 9791 Chromate conversion coatings on zinc, cadmium, aluminium-zinc alloys and zinc-aluminium alloys - Test methods
GB/T 10125 Corrosion tests in artificial atmospheres - Salt spray tests
GB/T 12334 Metallic and other inorganic coatings - Definitions and conventions concerning the measurement of thickness
GB/T 13911 Designation for metallic coating and chemical treatment
GB/T 16823.3 Fasteners - Torque/clamp force testing
GB/T 16921 Metallic coatings - Measurement of coating thickness - X-ray spectrometric methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 3138 and GB/T 12334 and the following apply.
Foreword II
1 Scope
2 Normative references
3 Terms and definitions
4 Identification of coating
4.1 Identification methods
4.2 Examples of identification
5 Information to be provided by the purchaser to the electroplating manufacturer
5.1 Essential information
5.2 Additional information
6 Technical requirements of coatings
6.1 Appearance
6.2 Alloy proportion, thickness and corrosion resistance of the coatings
6.3 Bonding strength
6.4 Corrosion resistance
6.5 Friction coefficient
6.6 Prohibited and restricted substances
6.7 Heat treatment for removing hydrogen embrittlement
7 Test methods for coatings
7.1 Appearance
7.2 Alloy proportion
7.3 Thickness
7.4 Bonding strength
7.5 Corrosion resistance
7.6 Friction coefficient
7.7 Prohibited and restricted substances
Table 1 Symbol and meaning of identification and passivating film color of electroplated coatings
Table 2 Examples and descriptions of identification of the electroplated coatings of zinc-nickel alloys
Table 3 Alloy proportion, thickness and corrosion resistance of the electroplated coatings of zinc-nickel alloys
Table 4 Requirements for removing hydrogen embrittlement after electroplating the zinc-nickel alloys
