A new slurry infiltration method to enhance the wear resistance of bulk graphite with development of reinforced graphitic composites including SiC or Si3N4 hard particles

Abstract

Bulk graphite blocks are infiltrated by a Si slurry method to form composites of graphite containing SiC or Si3N4 reinforcements, in order to enhance the wear resistance of the graphitic structure. The microstructure of the SiC reinforcements includes nuclei grains and whiskers, while the microstructure of the Si3N4 reinforcements is a mixture of fine grains, grains of blade- and needle-like morphology. The wear rate of the SiC- and Si3N4-reinforced graphitic block is 77.7 and 42.8 μm3/Nmm, respectively, as measured using an unlubricated pin-on-disc test. These values are ~ 55% and 75% lower than the wear rate of the reference graphite (174 μm3/Nmm). The coefficient of friction of the composites is as low as the coefficient of friction of the reinforcement-free graphite, showing values of ~ 0.17.