Investigating the Oxidation Resistance of HfCZrCTiC Composite at 1200 °C: The Role of Nano Carbon Black and Silicon

Introduction and Objectives: The HfCZrCTiC composite is part of the family of ultra-high temperature ceramics used in heat shields for spacecraft, furnace linings, supersonic aircraft components, and nuclear reactor components. The purpose of this research is to investigate the effect of nanocarbon black and silicon on the oxidation resistance of HfCZrCTiC composite.Materials and Methods: Four composites, including HfCZrCTiC, HfCZrCTiC containing nano carbon black, HfCZrCTiC containing silicon, and HfCZrCTiC containing nano carbon black and silicon simultaneously were sintered at 2000 °C by spark plasma method. The oxidation process was carried out using differential thermal analysis (DTA) and thermal gravimetry analysis (TGA) at a temperature of 1200 °C. Microstructural evaluation and phase identification were done using a scanning electron microscope and X-ray diffraction.Results: The results showed that the weight changes for HfZrTi, HfZrTi-C.Bn, HfZrTi-Si and HfZrTi-C.Bn-Si samples were obtained to be 13.5%, 16.9%, 12.9%, and 7%, respectively. In addition, the results of differential thermal analysis (DTA) revealed that in the samples of HfZrTi, HfZrTi-C.Bn, HfZrTi-Si and HfZrTi-C.Bn-Si, the starting temperature of oxidation occurred at 480 °C, 400 °C, 500 °C, and 580 °C, respectively, indicating the lower the starting temperature of oxidation, the higher the weight changes.Conclusion: It was found that in HfZrTi and HfZrTi-C.Bn samples, the detected phases after oxidation included hafnium oxide, zirconium oxide, and titanium oxide. These phases along with silicon oxide were identified in HfZrTi-Si and HfZrTi-C.Bn-Si samples.