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2.5-Dimensional SiO2 fiber-reinforced Al2O3-SiO2 (SiO2f/Al2O3-SiO2) composites were prepared by the sol-gel method, using diphasic SiO2 sol as the precursor into which Al2O3 powders were added. Their antioxidative behaviors and flexural strengths at high temperature were tested and compared. In an oxidation atmosphere, the composites showed high oxidation resistance, with a flexural strength retention ratio of over 90.00% at 1200 °C. After oxidation at 1500 °C, the mass retention ratio and flexural strength were 97.49% and 65.0 MPa respectively. The oxidation resistance of SiO2f/Al2O3-SiO2 composites was higher than that of SiO2f/SiO2 composites. After high-temperature test, the flexural strength retention ratios of SiO2f/SiO2 and SiO2f/Al2O3-SiO2 composites were 86.18% and 94.80% respectively, and the latter had a flexural strength of 134.9 MPa. SiO2 f/Al2O3-SiO2 composites worked better than SiO2f/SiO2 composites did in the flexural strength test at 1200 °C. The mechanical performance degradation and mass variations of the composites during tests were closely associated with their microstructural evolutions.

Polymer infiltration pyrolysis (PIP) was used to prepare carbon fiber-reinforced silicon carbide (C/SiC) composites, and chemical vapor deposition (CVD) was employed to fabricate SiC coating. The oxidation behavior at 1700 °C and the flexural property at 1200 °C were tested. SiC coating exerted remarkable oxidation effects on PIP-C/SiC composites. In the absence of coating, PIP-C/SiC composites lost 29.2% of its mass, with merely 6.74% of the original flexural strength retained. In contrast, CVD-SiC coated PIP-C/SiC composites had the mass loss of 10.2% and the flexural strength retention ratio of 23.4%. In high-temperature tests, SiC coating played an important role in the flexural strength of PIP-C/SiC composites. The flexural strength of uncoated composites became 330.7 MPa, and that of coated ones reduced from 655.3 to 531.2 MPa.

Porous hydroxyapatite/tricalcium phosphate (HA/TCP) ceramic scaffolds with a uniform unidirectional pore structure were successfully fabricated by an ice-templating method by using Ca-deficient HA whiskers and phosphate bioglass. HA whiskers showed good dispersibility in the slurry and favoured the formation of interconnected pores in the scaffolds. Addition of bioglass powders enhanced the material sintering process and the phase transformation of Ca-deficient HA to β-TCP. Calcium-phosphate-based scaffolds with a composition from HA to an HA/β-TCP complex could be obtained by controlling the freezing moulding system and slurry composition. The fabricated scaffolds had a porosity of 75–85%, compressive strength of 0.5–1.0 MPa, and a pore size range of 130–200 µm.

Different simulated sintering atmospheres, such as conventional air, oxygen-enriched air, and oxy-fuel atmosphere were utilized to prepare ceramic specimens. The effects of sintering atmosphere and Al2O3 content on the microstructure and properties of the ceramic samples were investigated. Increasing the O2 concentration in the simulated sintering atmosphere enhanced the crystallization. An optimized microstructure, resulting in improved bending strength, Vickers hardness, and bulk density was obtained through an increased O2 concentration in the simulated sintering atmosphere. Compared to ambient air, oxygen-enriched air or oxy-fuel atmosphere showed superior sintering performances, leading to ceramics with better mechanical properties and denser microstructures. However, an increase in the Al2O3 content led to the degradation in the mechanical properties of the ceramics, mainly due to the blocking effect of AlO6 groups.