Do You Know The Inspection Method For Spring Surface Cleanliness?

The metal surface coating and organic coating of the spring should meet the requirements of dense, uniform and consistent coating (plating) layer, and firm bonding with the substrate. In most cases, the occurrence of peeling, bubbling or blooming of the coating layer, as well as local lack of coating layer in the coating (plating) layer, is due to the surface cleanliness before metal coating (plating). Compared with organic solvent coatings, spring metal surface coating treatments using water as a solvent, such as electroplating, anodizing, phosphating, and water-based coating, are more sensitive to organic pollution on the metal surface. Even single molecule layer pollutants may lead to the failure of the entire process. Therefore, the cleanliness of the material surface after pre-treatment is crucial
Method: 1. Visual and optical methods
Oil stains on bright metal surfaces can be observed with the naked eye and with the help of a magnifying glass or optical microscope. Its disadvantage is that the passive oxide film and extremely thin oil stains on the metal surface cannot be detected. The above methods are ineffective for rough and dull metal surfaces, but they can be determined by wiping the surface with clean and white cotton, cloth, or paper, and then observing whether it is clean
2. Surface tension method
Based on the influence of surface oil stains on its surface energy, the surface energy of metals is determined by whether they are soaked in a series of test solutions with different surface tensions, and the cleanliness of their surfaces is determined accordingly. If a series of solutions ranging from 80% acetic acid and 20% water (V/V, the same below) to 1% ethanol and 99% water are prepared, their surface tension correspondingly increases from 24.5 × 10-5N/CM increased to 66.0 × 10-5N/CM.
3. Paint method