Fabrication of Textured Nb ₄ AlC ₃ Ceramic by Slip Casting in a Strong Magnetic Field and Spark Plasma Sintering

Abstract

Textured Nb 4 AlC 3 ceramic was successfully fabricated in a strong magnetic field followed by spark plasma sintering. The optimized suspension parameters for slip casting were determined to be 20 vol% Nb 4 AlC 3 and 2 wt% polyethyleneimine dispersant of powder in deionized water. After texturing in a strong 12 T magnetic field followed by cold isostatic pressing, the relative green densities were 50.4% and 58.7%, respectively. A dense Nb 4 AlC 3 sample was obtained by sintering at 1450°C under a pressure of 30 MPa in vacuum. X‐ray diffraction analysis revealed that the preferred orientation of Nb 4 AlC 3 grains parallel to the magnetic field direction was along the c ‐axis. The Lotgering orientation factors on the textured top surface (TTS) and textured side surface (TSS) were determined to be f (00 l ) =0.59 and f ( hk 0) =0.64, respectively. The layered texture microstructure contributed to laminar transgranular and intergranular fractures. The indentation response on the TTS showed isotropy and that on the TSS revealed anisotropy.