Mechanical properties of chromium-chromium sulfide cermets fabricated by self-propagating high-temperature synthesis

摘要

Metal sulfides are widely used in a variety of applications requiring high hardness and toughness. In this study, the microstructure and mechanical properties of chromium-chromium sulfide cermets are investigated. The chromium-chromium sulfide cermet was manufactured using self-propagating high-temperature synthesis, a process where the material is created under a self-sustaining combustion reaction between the chromium and sulfur. This type of synthesis allows the creation of near-net shape structures and offers the possibility of tuning material properties and material behavior by changing the composition of the reactant. Microstructural characterization was performed using optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy. The mechanical properties of the cermet (Young's modulus, fracture toughness, flexural strength, and microhardness) have been measured and related to morphology and chemical composition of the samples. Results show that dense cermets (about 7 % porosity) with specific structure have been obtained. Pure CrS has a significant hardness, but its toughness was insufficient for tool applications. However, we found that the density and fracture toughness of the cermets increase with the addition of Cr. The addition of Cr also improved the flexural strength and hardness of the cermet by 60 % and almost 38 %, respectively.