Effects of hexagonal boron nitride and sintering temperature on mechanical and tribological properties of SS316L/h-BN composites

In this work, hexagonal boron nitride (h-BN)-embedded 316L stainless steel (SS316L/h-BN) composites were prepared using a conventional powder metallurgy process. In order to produce self-lubricating composites, various amounts of h-BN (10, 15 and 20 vol%) were incorporated. Effects of h-BN content and sintering temperature on the mechanical and tribological properties were of primary interest. The results suggested that an increase in h-BN content reduced the hardness of the composites, but that the hardness could be improved by increasing the sintering temperature. Addition of h-BN up to 20 vol% improved the friction coefficient of the composites. At a sintering temperature of 1250 degrees C, h-BN transformed into a boride liquid phase, which formed a eutectic during cooling and exhibited a deterioration effect on lubricating film formation of the h-BN, resulting in an increase in the friction coefficient of the composites. The specific wear rate was greatly reduced when the composites were sintered at 1200 degrees C. The lowest friction coefficient and specific wear rate in the composites could be found under the experimental conditions used in this work when using 20 vol% of h-BN at a sintering temperature of 1200 degrees C. (C) 2012 Elsevier Ltd. All rights reserved.