1. Coating Thickness Measurement
Standard Requirements: Decorative chrome plating is usually ≥0.2μm, while functional chrome plating (such as hard chrome) requires ≥10μm, specifically according to GB/T 11379-2008 or design specifications.
Measurement Methods:
X-ray fluorescence (XRF): Non-destructive testing, accuracy ±0.1μm.
Magnetic/Eddy current thickness gauge: Suitable for iron-based or non-ferrous metal substrates, portable but requires calibration.
Microscopic cross-section method: Destructive testing, highest accuracy (±1μm).
2. Coating Uniformity Assessment
Multi-point measurement: Use a thickness gauge to measure at different locations on the workpiece (e.g., flat sections, corners), thickness variation should be ≤10%.
Visual inspection: Visual inspection or white light imaging comparator to check color difference and gloss (decorative plating requires ≥80GU).
3. Adhesion Test
Cross-cut test (GB/T 9286): After cross-cutting, tape peeling test, coating peeling area ≤5% is considered qualified.
Thermal shock test: Rapid cooling after heating to 250℃, no blistering or peeling of the coating.
4. Hardness and Wear Resistance
Microhardness test: Chrome plating hardness should be ≥800HV (hard chrome).
Reciprocating wear test: Simulates actual wear conditions to evaluate coating durability.
5. Corrosion Resistance Verification
Salt spray test (GB/T 10125): Neutral salt spray test ≥96 hours without red rust (decorative chrome plating).
Nitric acid stripping method: Immersion in 90℃ nitric acid, no bubbles within 30 seconds indicates sufficient density.
6. Porosity and Defect Detection
Vacuum test method: Detects porosity through pressure changes. Ultrasonic/X-ray inspection: Used to detect cracks or pores within the coating.
