A Novel S i ₃ N ₄ – S i C Ceramic Used for Volumetric Receivers

S i ₃ N ₄ – S i C composite ceramics used for volumetric receivers were fabricated by pressureless sintering of micrometer S i C , S i ₃ N ₄ , andalusite, and other minor additions powders. Mechanical, thermal expansion, thermal conductivity, and thermal shock resistance properties were tested at different sintering temperatures. The best sintering temperature of optimum formula A 2 is 1360°C, and the bending strength reaches 79.60 Mpa. And moreover, its thermal expansion coefficient is 6.401 × 10 ⁻⁶ /°C, thermal conductivity is 7.83 W/(m K), and no crack occurs even subjected to 30 cycles thermal shock with a bending strength increase rate of 4.72%. X ‐ray diffraction results show that the phase constituents of the sintered products mainly consist of S i C , S i ₃ N ₄ , mullite, and quartz. Microstructure that is most appropriate and exhibits maximal thermal shock resistance was detected using SEM . The porosity of S i ₃ N ₄ – S i C ceramic foam prepared from formula A 2 is 95%, which provides a rapid and steady action for the receiver. The evaluation of the present foam shows that S i ₃ N ₄ – S i C ceramic composite is a good candidate for volumetric receivers.