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SiC-ZrC composite powders were synthesized by carbothermal reduction method using starch as carbon source, zirconium dioxide as zirconium source, and silica sol as silicon source. The effects of reaction temperature on the phase composition and microstructure of SiC-ZrC composite powders were investigated. The reaction process was thermodynamically analyzed and calculated, and the synthesis mechanism of SiC-ZrC composite powder was analyzed. The synthesized powder samples were characterized and analyzed by X-ray diffraction, scanning electron microscopy, and other testing methods. Results show that the optimum reaction condition for the synthesis of SiC-ZrC composite powders is at 1550 ̊C-1600 ̊C for 1.5 h. High temperature and low pressure are beneficial in conducting the synthesis reaction. The SiC-ZrC composite powders synthesized by calcining at 1550 ̊C and holding for 1.5 h are mainly composed of a certain amount of whiskers, spherical particles, floc particles, and other structures. Moreover, their grain size is small (100-200 nm). The powder samples synthesized at 1600 ̊C produced a larger number of whiskers. The length of the whiskers was mostly 10 μm, the arrangement was complex and irregular, and a diverse microstructure was formed.

SiC-TiC composite powders were synthesised through carbothermal reduction under an argon atmosphere by using silica sol, starch, and TiO₂ as the raw materials. The influences of the starch dosage and holding time on the synthesis of SiC-TiC composite powder are discussed in detail. The samples were characterised using an X-ray diffractometer (XRD), an integrated thermal analyser (TG-DTA), a scanning electron microscope (SEM), and an energy spectrometer (EDS). The results showed that the SiC-TiC composite powders were completely synthesised after holding at 1550 °C for 3 h when the amount of excess starch was 5 wt% and after holding at 1550 °C for 2 h when the amount of excess starch was 10 wt%-20 wt%. The morphological characteristics of the powder samples with 5 wt%-15 wt% excess starch calcined at 1550 °C for 2 h were mainly flake particles, spherical particles, irregularly shaped particles and elongated whiskers. Conversely, no whiskers were found in the powder samples calcined at 1550 °C for 2 h when the amount of excess starch was 20 wt%.

Using aluminum hydroxide (Al(OH)₃) and aluminum nitrate (Al(NO₃)₃.9H₂O) as aluminum sources and highly active glucose (C₆H12O₆) as a carbon source, we synthesized ultrafine AlN powder through carbothermal reduction-nitridation. Then, we explored the effects of aluminum sources, reaction temperature, holding time and other reaction conditions on the phase composition and micromorphology of the synthesized AlN powder. Result showed that AlN powder and different proportions of Al₂O₃-AlN composite powder can be prepared by controlling reaction temperature or holding time. Under the conditions of this experiment, Al(OH)₃ more beneficial as an aluminum source for carbothermal reduction-nitridation than Al(NO₃)₃.9H₂O. The optimum reaction conditions for the synthesis of single-phase AlN powder with Al(OH)₃ as aluminum source were holding time of 3 h and temperature of 1450 °C. The powder sample synthesized under this reaction condition is mainly composed of flaky, short-rod, and irregularly shaped fine particles with sizes ranging from 50 nm to 100 nm.