Application of phosphating plus immersing in hard film antirust oil as dual surface modification in corrosion prevention of workpiece made of bonded neodymium-iron-boron

The anticorrosion coating process applicable to the workpieces made of bonded Nd-Fe-B was established by combining phosphating with immersing in antirust oil. Salt-fog tests and damp-hot corrosion tests were conducted to evaluatethe corrosion resistance of the workpieces made of bonded Nd-Fe-B after being treated by phosphating and immersing in antirust oil. It wasfound that the bonded Nd-Fe-B workpieces after phosphating plus immersing in the antirust oil, the dual-surface modification, showed significantly increased corrosion resistance,and the process established would have promising application in the corrosion prevention of metallic workpieces.