ELECTRODEPOSITED AND ELECTROLESS Ni-P MULTILAYER ALLOY COATING

摘要

A new kind of terrace multilayer amorphous Ni-P alloy coating came into being by using a new plating technique. This technique completed the whole electroless and electroplated process in the same kind of bath by altering the temperature and electric field continuously. The coating made by this technique is a dual or tri-layer coating whose inner-section was electroless or electrodeposited layers. This paper studied the cross-section of this terrace coating by scan electron microscope (SEM) and Energy Dispersive spectroscope (EDS). The results show the pinholes in the coating were covered mutually, and therefore the porosity of coating was lowered efficiently. The result of EDS proves the periodic fluctuating about content of phosphorous took place on this kind of coating along the deepness of coating,which strengthens the role of electrochemical protection. In the end, an experiment of salt-spray was executed to test the anti-corrosion capability, it indicates that this multilayer coating of 15μm thickness has the same anti-corrosion ability with an electroless coating of 60μm thickness.