SiC whiskers: A strategy to modify the high-temperature performance of laminated ZrB2–SiC ceramics

Abstract

With SiC whisker and SiC particle as interface layers, ZrB2–SiC–SiCw (LZ-Sw) and ZrB2–SiC–SiCp (LZ-Sp) laminated ceramics were prepared by tape casting and hot pressing. Fracture behaviors and accompanying microstructural changes were studied in the range from 20 to 1500 °C. At 20 °C, both LZ-Sw and LZ-Sp exhibited excellent flexural strengths in parallel direction of 607 ± 58 and 568 ± 46 MPa, respectively. From 20 to 1500 °C, the flexural strength of LZ-Sw was always higher than that of LZ-Sp. From 1200 to 1500 °C, the flexural strength of LZ-Sw declined relatively slowly while that of LZ-Sp dropped sharply. At 1500 °C, the flexural strength of LZ-Sw reached 361 MPa in the parallel direction, 66.4% higher than that of LZ-Sp (217 MPa). The superior high-temperature performance of LZ-Sw was caused by porous interface layers composed of SiC whiskers and ZrB2 particles, which reduced the enrichment of the glassy phase and avoided grain-boundary sliding.