Microstructural regulation, oxidation resistance, and mechanical properties of Cf/SiC/SiHfBOC composites prepared by chemical vapor infiltration with precursor infiltration pyrolysis

Abstract

To further improve the oxidation resistance of polymer derived ceramic (PDC) composites in harsh environments, Cf/SiC/SiHfBOC composites were prepared by chemical vapor infiltration (CVI) and precursor impregnation pyrolysis (PIP) methods. The weight retention change, mechanical properties, and microstructure of Cf/SiC/SiHfBOC before and after oxidation in air were studied in details. Microscopic analyses showed that only the interface between the ceramics and fibers was oxidized to some extent, and hafnium had been enriched on the composite surface after oxidizing at different temperature. The main oxidation products of Cf/SiC/SiHfBOC composites were HfO2 and HfSiO4 after oxidation at 1500 °C for 60 min. Moreover, the weight retention ratio and compressive strength of the Cf/SiC/SiHfBOC composites are 83.97% and 23.88±3.11 MPa, respectively. It indicates that the Cf/SiC/SiHfBOC composites should be promising to be used for a short time in the oxidation environment at 1500 °C.

Formation mechanism and roles of oxygen vacancies in melt-grown Al2O3/GdAlO3/ZrO2 eutectic ceramic by laser 3D printing

“…For example, the microstructures of the directionally solidified Al 2 O 3 /Y 3 Al 5 O 12 and Al 2 O 3 /GdAlO 3 eutectic composites nearly maintain unchanged even after annealed at 1700 for 1000 h, and their flexural strengths are ℃ almost constant during the annealing process [2,3]. Besides, oxide ceramic possesses unpaired oxidation resistance, as compared with other ceramics such as SiC [6][7][8][9]. As a result, these exciting performances make the oxide eutectic composite one of the most promising candidates for new generation of hightemperature structural materials applied in the fields of aerospace and power generation system.…”

Molten salt synthesis and antioxidation property of SiC‐coated mesocarbon microbeads

“…The experimental results illustrate the conspicuous improvement of antioxidation property of MCMB particles by SiC coatings. During the test, the oxidation reactions as following could take place in MCMB and SiC coating 33–35 : $$$$\begin{equation}{\rm{C(s)}} + {{\rm{O}}_{\rm{2}}}{\rm{(g)}} \to {\rm{C}}{{\rm{O}}_{\rm{2}}}{\rm{(g)}}\end{equation}$$$$ $$$$\begin{equation}{\rm{SiC(s) + 2}}{{\rm{O}}_{\rm{2}}}\left( {\rm{g}} \right) \to {\rm{C}}{{\rm{O}}_{\rm{2}}}\left( {\rm{g}} \right) +{\rm{Si}}{{\rm{O}}_{\rm{2}}}\left( {\rm{s}} \right)\end{equation}$$$$ $$$$\begin{equation}{\rm{SiC(s)}} + \frac{{\rm{3}}}{{\rm{2}}}{{\rm{O}}_{\rm{2}}}\left( {\rm{g}} \right) \to {\rm{CO}}\left( {\rm{g}} \right) +{\rm{Si}}{{\rm{O}}_{\rm{2}}}\left( {\rm{s}} \right).\end{equation}$$$$…”

Zr‐doped SiOC ceramics fibers and the high‐temperature thermal performance

“…Regarding to this problem, polynary ceramics through introducing metal elements exhibited improved properties compared to conventional silicon containing ceramics. Zr, Hf, Ti, and other metal elements were commonly regarding as reinforcing agents to enhance the high temperature performance especially the thermal stability, antioxidation and other unique properties such as wave adsorption and catalysis 14–17 . Zr was one of the most commonly used elements as metal inorganic and organic salts were easily accessible, which enhances their potential for bulk materials, coatings or fibers.…”