Effect of Magnetic Field, Heat Treatment and Dry Wear Analysis on Electroless Nickel Deposits

Abstract

This investigation reports the effect of magnetic field during coating on the mechanical properties of the electroless Ni–P deposits. Magnetic field strength has been varied between 0 and 3A. The heat treatment was found to be more responsive for the sintering temperature between 300 and 400 °C. Micro hardness of the electroless Ni–P deposits was measured with a diamond indenter. Magnetic method produced more hardness (above 1250 VHN) than the conventional method (below 1000 VHN). The amorphous phase to crystalline transformation happens at this range of sintering. The pin-on-disc wear tester was used to measure the wear resistance of the deposits. The coated sample has a maximum weight loss of 0.077 mg at the end of the wear test (after 35 min) and 0.052 mg for magnetic field sintered sample at the same condition. Subsequently, with respect to increase in sintering temperature, the weight loss found decreased from 0.077 to 0.051 mg for as coat to 350 °C, respectively. It is also noticed that, the specific wear rate is 0.062 (kg/Nm3) for magnetic field sintered sample and 0.119 (kg/Nm3) for conventional sample. The characteristics of deposits produced in presence of magnetic field were found to be superior from those produced using conventional deposition techniques. Magnetic field has doubled the performance than the conventional techniques. Enhancements in properties were correlated with modified crystallinity and the conversion of Ni–P in to possible phosphides in the presence of magnetic field.