摘要 |
A process for producing a phosphate coating, wherein a sludge, which is an impurity component other than inevitable impurities contained in a phosphating bath, is removed and the object is electrolyzed in order to enhance the capability of chemical conversion coating and provide a high-quality conversion coating. This process serves to form a satisfactory phosphate coating on whatever metallic material and can provide a phosphate coating having a large thickness which has not been available in the prior art. |