Atmospheric Corrosion Laboratory Test of Automotive Components
November 2, 2020
To control the corrosion of wheels and chassis parts, it is necessary to understand the interaction between materials, electroplating methods, and the relative effectiveness of various protective measures and technologies. In the laboratory, the corrosion influence factors are repeatedly and accurately controlled. The laboratory corrosion test is used for the development of corrosion control technology, the certification of production materials and the quality certification after production.
■ Salt spray test
The salt spray test conforms to the standard ASTM B117. The salt water is sent to an atomizing nozzle through the siphon principle, and combined with compressed air in the nozzle to produce very small droplets floating in the test chamber until it settles on the sample
■ Cycle test
The salt spray tests did not repeat the actual atmospheric corrosion because they always kept the specimen completely wet. Materials exposed to the environment undergo periodic wet and dry phases. The transition between wet and dry conditions accelerates corrosion and changes the chemical structure of corrosion products.
■ Automobile corrosion test method
In the automotive industry, the trend in corrosion testing methods is to include controlled relative humidity cycles between approximately 50% and 95%. The linear conversion is designed to improve repeatability and reproducibility, while slowing down the drying process, reaching the peak corrosion rate in a longer period than in the traditional wet/dry test, and controlling the relative humidity below and above 76%.