Abstract
Abstract Almost full density (>99% theoretical density (ρth)) was achieved for ZrB2-20vol% SiC-Xwt.% Ta (X = 2,5, 5 and 10) composites after Spark Plasma Sintering (SPS) (Temperature: 1900 °C, Pressure: 50 MPa; Time: 3 min). The microstructure of ZrB2-based composites exhibited core-rim structure and it consists of major crystalline phases (ZrB2 core, (Zr, Ta)B2 rim, SiC), minor amounts of ZrO2 and (Zr, Ta)C solid solution phases. Both the specific weight (from 22.91 to 18.77 mg/cm2) and oxide layer thickness (401–195 μm) of ZrB2-20vol% SiC composites decreased with increasing addition of Ta after the isothermal oxidation at 1500 °C for 10 h in air. The cross-sectional microstructure of oxidized samples displayed presence of a stack of three distinctive layers, which includes thick dense SiO2 top layer, SiC depleted intermediate layer and unreacted bulk. The present work clearly demonstrated the advantage of tantalum addition in improving the oxidation resistance of ZrB2-20vol% SiC.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
