Fabrication of ZrC/ZrO2 composite continuous fibers with a radial gradient using pack carburizing

Abstract As a polycrystalline fiber, continuous zirconia (ZrO2) fiber used at high temperatures will cause grain coarsening and strength degradation due to grain growth. In order to suppress the grain coarsening, zirconium carbide (ZrC) and carbon were introduced into ZrO2 continuous fibers by pack carburizing, and ZrC/ZrO2 composite fibers with a radial gradient were subsequently prepared. Due to the pinning effect of ZrC or carbon on the grain boundary, the movement of the grain boundary is limited. The composite fibers obtained in an argon atmosphere at 1400 °C exhibited fine grain, compact micromorphology, and a tensile strength of 784 MPa. The formation process of the composite fiber was accomplished by the interaction of external graphite carbon and internal residual carbon with ZrO2. This work provides a simple and economical method for preparing carbide composite fibers.