Effect of Hf and B incorporation on the SiOC precursor architecture and high-temperature oxidation behavior of SiHfBOC ceramics

Microstructural Regulation, Oxidation Resistance and Mechanical Properties of Cf/SiC/SiHfBOC Composites Prepared By Chemical Vapor Infiltration With Precursor Infiltration Pyrolysis

“…With the increase of PIP cycle times, the density of Cf/SiC/SiHfBOC composites increase gradually, while the porosity decreases gradually. The density of untreated Cf preform is 0.35 g/cm 3 , and its porosity is 85.73 %. The density of Cf/SiC preform is 0.50 g/cm 3 , and its porosity is 74.86 %.…”

“…The density of untreated Cf preform is 0.35 g/cm 3 , and its porosity is 85.73 %. The density of Cf/SiC preform is 0.50 g/cm 3 , and its porosity is 74.86 %. After the third PIP cycle times, the density of Cf/SiC/SiHfBOC composite was 1.02 g/cm 3 , and its porosity was 47.98 %.…”

“…With the emergence of hypersonic spacecraft, the requirements of thermal protection materials such as lightweight, strengthening-toughening, and oxidation resistance of thermal protection materials are increasing in the combustion chamber and tail nozzle of aerospace vehicles [1][2][3]. The thermal protection materials represented by ceramic thermal insulation tiles are difficult to meet the requirements of increasing the service environment temperature of hypersonic spacecraft [4][5][6][7].…”

“…It is found that the high-temperature stability of SiOC ceramics can be effectively improved by doping boron, nitrogen, zirconium, hafnium, and other elements. At present, a variety of precursor ceramics have been synthesized, such as SiBOC [11]、SiZrOC [12]、SiHfOC [12]、 SiAlOC [13]、SiBCN [14]、SiHfBOC [3]、SiBCNZr [14], etc. Continuous carbon fiber (or carbon fiber perform) reinforced ceramic matrix composites have excellent properties, such as low density [15], high toughness [16], high strength, and high reusability [17], especially the toughening property [18], which helps to solve the inherent brittleness of ceramic materials [19].…”

High-Temperature Properties and Applications of Si-Based Polymer-Derived Ceramics: A Review

“…Incorporating other elements, such as B [ 8 , 10 , 11 , 12 ], Al [ 13 , 14 , 15 ], Nb [ 16 ], Zr [ 4 , 17 , 18 ], Ti [ 19 , 20 , 21 ], or Hf [ 12 , 22 , 23 , 24 ], in the Si-C-N or Si-O-C systems may greatly enhance the thermostability of ceramic products by preventing or impeding the crystallization and phase segregation of the ceramic phases in inert or oxidizing environments [ 7 ]. Initially, at the crosslinking stage, B atoms may improve the formation of the crosslinking network and increase the yield and structural density of SiBOC [ 11 , 12 ]. Upon polymer-to-ceramic conversion, doped elements may form additional phases (e.g., TiO 2 , HfO 2 , ZrO 2 ) and lead to nanocomposite-like structures of metal-oxide/amorphous ceramics [ 25 ] or dissolve into and alter the amorphous phase (e.g., SiBOC, SiAlOC) which eventually segregate into additional phases (BN, Al 2 O 3 ) at higher temperatures.…”