Effect of Annealing Temperature on Electrochemical and Mechanical Properties of STS with Titanium Carbonitride Composites Synthesized By Spark Plasma Sintering

Stainless steel-titanium carbonitride based composites were fabricated and analyzed to utilize for bipolar plate in fuel cells. In order to study the size effect of the titanium carbonitride on mechanical and corrosion resistance properties of the composites, micro and nanosize titanium carbonitride powders were used. Stainless steel-carbonitride composites were prepared by spark plasma sintering and subsequently annealed at different temperatures up to 1100 °C to improve the morphological and mechanical properties. Various properties of the obtained samples were compared before and after annealing. It was shown that after the heat treatment, mechanical properties of the stainless steel-carbonitride composites were improved due to the diffusion of titanium carbonitride particles into stainless steel. Addition of microsized titanium carbonitride powders was found to be effective to improve the mechanical properties of the composite such as microhardness and compressive strength. However, addition of nanosized titanium carbonitride powders led to increasing of corrosion resistivity of the composite. Physical properties, such as thermal and chemical stability of the obtained composite samples were investigated by microhardness tester, potentiostat, field emission-scanning electron microscope, EDX and X-ray diffraction.