Effect of P Addition on the Thermal Stability of Nanocrystalline Ni-Co-Fe-P Coatings

Abstract

The thermal stability of nanocrystalline Ni-Co-Fe-P coatings with phosphorus content up to 3.38 wt% prepared by pulsed electrodepostion was studied using XRD, TEM and DSC. It is found that multi-component alloying does improve the thermal stability of nanocrystalline coatings due to a “solution drag effect”. For nanocrystalline Ni-40.41%Co-6.16%Fe-1.63%P coating, P-atoms segregate the grain boundaries during annealing which leads to a higher thermal stability. While due to the higher initial P-concentration in Ni-30.1%Co-2.15%Fe-3.38%P, saturation of P and precipitation occurs earlier leading to a slightly lower stability.