层状ZrB2-SiC-G陶瓷在1300℃下的抗氧化性及其残余强度的研

采用流延-层叠-热压的方法制备了不同石墨界面层的层状ZrB₂-SiC-G超高温陶瓷, 研究其在1300℃下氧化0.5~10 h的氧化行为以及氧化时间对室温残余强度的影响, 观察了增重量随氧化时间的变化, 并对其物相和形貌进行了分析。结果表明, 石墨界面层中添加40vol% ZrB₂和10vol% SiC制备的层状ZrB₂-SiC-G超高温陶瓷, 室温弯曲强度为670 MPa, 断裂韧性为13.7 MPa·m^1/2, 氧化10 h后弯曲强度仍达429MPa, 断裂韧性仍达10.25 MPa·m^1/2, 优异的残余强度是由于表面形成了致密的SiO₂玻璃层而阻止了材料内部被氧化。

Oxidation Resistance and Residual Strength of Laminated ZrB2-SiC-G Ceramics at 1300

The laminated ZrB₂-SiC-G ultra high temperature ceramic with different graphite interface layers were successfully prepared by tap-casting-stacking-hot press. The oxidation behavior at 1300℃ for 0.5-10 h and the influence of oxidation time on residual strength at room temperature were studied. In addition, the gain weight along with the change of oxidation time was observed, and phase and morphology were analyzed. The results show that the laminated ZrB₂-SiC-G ultra high temperature ceramic prepared by adding 40vol%ZrB₂ and 10vol% SiC in the graphite interface layer obtains the best mechanical properties with room temperature flexural strength of 670 MPa and the fracture toughness of 13.7 MPa·m^1/2. After 10 h oxidation, the flexural strength is still up to 429 MPa, and the fracture toughness is still up to 10.25 MPa·m^1/2. The excellent residual strength is attributed to the formation of a dense glass layer of SiO₂ on the surface which prevents the internal material from being oxidized.