What is surface treatment?

In the working process of parts, due to the wear, corrosion and fatigue of their surfaces, they have caused very amazing economic losses. Therefore, our technical workers use physical, chemical, mechanical and other methods to change the structure of the surface of the components, that is, surface treatment , To obtain the required performance to improve the reliability of the product or extend its life. In addition, surface treatment can also give full play to the potential of the material, save energy, and reduce production costs. Therefore, the designer should fully and reasonably choose various surface treatments when designing parts and components.

Today, I will introduce the expression methods of plating, chemical and electrochemical treatment layers of common metals, including: zinc plating, copper plating, nickel plating, cadmium plating, oxidation, phosphating, passivation, etc., according to GB/T13911- 1992.

  1. Various symbols used in metal plating and chemical surface treatment methods

1) Symbols for matrix materials (commonly used matrix materials) Material name symbols Iron, copper, Fe Cu, aluminum, aluminum alloy Al, zinc, zinc alloy, Zn, magnesium, magnesium alloy Mg, titanium, titanium alloy Ti, plastic PL (international abbreviation) Metal material chemical element symbol representation : The chemistry of alloy materials with their main components.

  • Coating method processing method symbol: method name symbol (English abbreviation) electroplating Ep Ap electrochemical treatment Et chemical treatment Ct

3) chemical and electrochemical treatment name symbol processing name symbol oxidation phosphating a. electro-galvanized bright chromate Process C1A b. Electro-galvanized rainbow chromate treatment C1B (bleached type) commonly used c. Electro-galvanized rainbow chromate treatment C2C (rainbow type) d. Electro-galvanized dark chromate treatment C2D (symbol-C; grade 1, 2; type: ABCD).

  1. Representation method of metal plating and chemistry and electrochemistry (marking on the drawing)
  • Metal plating method: Example:

Example 1. Fe/Ep.CuN15bCy 0.3mc. 10μm, bright nickel 15μm, micro-crack chromium 0.3μm)

Example 2. Fe/Ep.Zn7.C2C 7μm, rainbow chromate treatment level 2 Type C) (Rainbow type)

Example 3. Cu/Ep.Ni5bCr0.3r (copper, electroplated bright nickel 5μm0.3μm)

Example 4.Fe/Ep.Cu20.ApNi10Cr0.3cf 20μm, electroless nickel plating 10μm, electroplating no cracks Chromium 0.3μm)

Example 5.PL/EP.Cu10bNi15bCr0.3r (plastic, electroplated bright copper 10μm, bright nickel 15μm, ordinary chromium 0.3μm)

  • Examples of chemical and electrochemical treatment methods:

Example 1. AI/Et·A·clBK) (Aluminum, electrochemical treatment, anodized, black)

Example 2. Fe/ct·MnPh (Copper material, chemical treatment, manganese phosphate treatment)

  1. Coating treatment layer indication symbol Feature name symbol
Bright b
Semi-bright s
Dark m
Double layer d
Normal r


  1. Post-processing symbol: Post-processing name symbol


Coloring CI
Emulsion E
Coating Pt
Black Bk
Brown BN
Red RD
Orange OG
Yellow YE
Green GN
Blue (light blue) BU
Purple(Purple red) VT
gray (blue gray) GY
white WH