Chemical Conversion Films

Chemical Conversion Films (phosphating treatment, blackening treatment)

▪ Phosphating treatment is a process that when iron and steel parts are chemically treated in phosphate solution which contains Zn, Mn, Ca, Fe or alkali metals, a layer of insoluble phosphate film will form on the surface. Currently the phosphating treatments can be divided into Mn-phosphating and Zn-phosphating.

▪ Blackening treatment is high-temperature alkali oxidation treatment, commonly called bluing or dye blackening.

Process performance and application

▪ The blackening process does not affect the dimensional precision of part, and there is no risk of hydrogen embrittlement. Sealing treatment on surface of blackened ordinary iron or steel can dramatically improve its abrasion resistance. This process is widely applied in protection and decoration of  machines, electronic devices and precision instruments.

▪ The phosphating treatment is widely applied to the pretreatment of painting and electrophoresis as it dramatically improves the corrosion resistance of part and easily combines with matrices. In addition, as the part possesses relatively high hardness and thermal stability on surface, it is also used in abrasion reduction and lubrication. Therefore, it is widely applied to surface modification treatment of low, medium and high carbon steel.

Examples of products

Examples of products