( 武漢理工大學(xué) 材料復(fù)合新技術(shù)國家重點實驗室， 武漢 430070)
摘 要: 采用熱壓n(TiC)∶n(Ti)∶n(Si)∶n(Al)=2∶1∶1∶0.2的混合粉末制備了高純度、 固溶有鋁的Ti3SiC2。研究了該材料在1100℃和1200℃空氣中的循環(huán)氧化行為。 結(jié)果表明， 含鋁Ti3SiC2的循環(huán)氧化可以分為氧化層的形成、致密和穩(wěn)定。 40次循環(huán)后， 試樣表面形成6~10μm的致密氧化膜， 其主要由固溶的鋁所形成的α-Al2O3組成， 并含少量的SiO2和TiO2。 這種致密氧化膜有利于提高Ti3SiC2的氧化性能。熱應(yīng)力計算表明， 氧化層內(nèi)部存在很大的壓應(yīng)力。
關(guān)鍵字: Ti3SiC2；循環(huán)氧化； 熱應(yīng)力； 動力學(xué)
（ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China）
Abstract: The cyclic oxidation behavior of Ti3SiC2 sintered by hot pressing with the start powder mixture of n(TiC)∶n(Ti)∶n(Si)∶n(Al)=2∶1∶1∶0.2 was investigated. The results indicate that the oxidation of Ti3SiC2 with the solute Al follows a three-step rate law at 1100℃ and 1200℃ for 40 cycles, i.e. formation, densification and stabilization of the oxide layers. The oxide scales, with the thickness of 6-10μm, consisting of α-Al2O3, and little SiO2 and TiO2, make the samples have excellent oxidation resistance. The approximate calculation results indicate that a large compressive stress occurs in the oxide scale.
Key words: Ti3SiC2; cyclic oxidation; thermal stress; kinetics
