Investigation of high temperature wear resistance of electroless nickel coating with different contents of phosphorous

In this article, it has been attempted to investigate and compare the wear behavior of 4 types of electroless nickel-phosphorous coating (with 4, 5, 9, and 12 wt % P) at 250A degrees C. Changes of the phosphorous deposition were controlled through the manipulation of pH in plating bath. All samples were heated at 400A degrees C for an hour under argon gas atmosphere. Later on, after the heat treatment, the coating structures were investigated via X-ray diffraction test. Moreover, the hardness and wear behavior of coatings over sliding distance of 1000 meters were measured via Vickers micro-hardness measurement and pin-on-disk test with 10 N load, respectively. Additionally, the worn surface was investigated through SEM. The results illustrated that the higher the phosphorous proportion, the longer the amount of intermetallic phases, and the lower the coating wear. It has been determined that the highest and lowest wear resistance happened in Ni-3.5% P coating and Ni-12% P coating respectively.