Abstract
The processing and properties of HfB2-20 vol%SiC ultra high temperature ceramics were examined. Dense billets were fabricated by hot-pressing raw powders in a graphite element furnace for 1 h at 2200°C. Specimens were then tested for hardness, mechanical strength, thermal properties and oxidation resistance in a simulated re-entry environment. Thermal conductivity of the current materials was found to be less than previous work had determined while the strength was greater. Oxidation testing of two flat-face models was conducted, at two conditions, for two 10-min durations each. It was concluded that passive oxidation of SiC plays a role in determining the steady-state surface temperatures below 1700°C. Above 1700°C, temperatures are controlled by the properties of a thick HfO2 layer and active oxidation of the SiC phase.
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
