“…In recent years, Ultra-High-Temperature Ceramic (UHTC) materials, including zirconium or hafnium diborides or carbides, are assuming an increasing importance in aerospace research because of their high temperature capabilities, with melting points above 3500 K, high temperature strength and oxidation resistance at service temperatures exceeding 2300 K. Some of these materials proved to be very interesting to develop aerospace components working in harsh environments [6,7,8]. The use of single-phase materials, without secondary phases, is not sufficient because they are characterized by low fracture toughness, low thermal shock resistance and lack of damage tolerance [9]. To improve their properties UHTCs composites with SiC or other Silicon based ceramics, in the form of particles, short fibers or whiskers have been developed with better tolerance and thermal shock resistance in aggressive chemical environments [10,11].…”