Spark Plasma Sintering as a Cladding Method to Produce In Situ Ni-TiC Nanocomposite Clad Layer

摘要

In situ Ni-TiC nanocomposite was cladded on steel substrate by spark plasma sintering (SPS) method. Reactive powder was prepared by mechanical alloying (MA) of a mixture of Ni, Ti and C elemental powders using a high energy planetary ball mill. Powders and compacted samples were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). Results show that, by the selection of appropriate conditions, a metastable Ni-Ti-C powder could be obtained with the nominal composition Ni(Cr)-32wt.%Ti-8wt.%C. Resultant powder was consolidated on steel substrate by SPS and the microstructure was investigated. XRD results showed the occurrence of an in situ reaction during SPS which led to the formation of TiC nanoparticles in the matrix. SEM revealed an adherent interface of clad layer and the substrate. Microhardness measurement testing showed a hardness of about 1200 VHN and the wear resistant of in situ Ni(Cr)-TiC nanocomposite was excellent according to sliding wear test results.