Effect of carburizing and annealing processes in improving the Ni/WC–Co adhesion strength:

Heat treatment processes have a positive impact in improving the adhesion strength of different interlayer/substrate materials. However, information regarding the effect of these processes in enhancing the adhesion strength of an electroplated nickel interlayer on tungsten carbide substrate for diamond deposition is lacking. In this study, the effect of carburizing and annealing process conditions in enhancing the adhesion strength of the electroplated nickel interlayer was investigated. The heat treatment processes were designed and modeled by the design of experiments technique. The heat-treated specimens were characterized by the field-emission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. The adhesion of the interlayer before and after the heat treatment was assessed by the scratch test. The results show that the adhesion of the electroplated nickel interlayer was remarkably improved by both processes. The mathematical models for predicting the adhesion strength of the carburized and annealed nickel interlayer within the specified ranges were developed. The maximum adhesion strength of 30 N was obtained from the nickel interlayer annealed at the highest process condition of temperature and time.