Oxidation Resistance Optimization of TiC/Hastelloy Compo-sites by Designing Composition

Abstract:

TiC/Hastelloy composite has been proposed as one of promising intermediate temperature solid oxide fuel cell interconnects, and the oxidation resistance is one key property for its application. TiC/Hastelloy composites with 50vol% and 58vol% metal matrix were prepared by reactive infiltration method. Results show that high metal content results in the increase in Cr content, which optimizes the oxidation resistance of TiC/Hastelloy composites by promoting formation of continuous Cr₂O₃ layer to inhibit external diffusion of Ni and Ti. The content of Ti and Ni oxides in oxide scale obviously decreases. The mass gain reduces from 2.03 to 0.55 mg·cm^-2. Meanwhile, in order to inhibit the migration of Cr, Co is extra introduced into the composites with 58vol% metal. During the oxidation process, Co and Fe (in metal matrix) show high external diffusion rate through Cr₂O₃, and generate in-situ CoFe₂O₄ layer outmost the oxide scale.

Key words:solid oxide fuel cell;interconnect;TiC/Hastelloy composites;oxidation resistance