力學(xué)性能及結(jié)構(gòu)的影響
( 1. 浙江大學(xué) 納米科學(xué)與技術(shù)中心, 杭州 310027;
2. 浙江東新密封材料有限公司, 樂(lè)清 325604)
摘 要: 采用溶膠凝膠法和機(jī)械共混法分別引入燒結(jié)助劑YAG（Y3Al5O12）和Al2O3+Y2O3制備復(fù)合粉體，經(jīng)過(guò)無(wú)壓液相燒結(jié)制備碳化硅陶瓷材料， 分析了燒結(jié)助劑引入方式對(duì)碳化硅陶瓷燒結(jié)、 性能及結(jié)構(gòu)的影響機(jī)制。 研究結(jié)果表明， 在1 950 °C燒結(jié)45 min時(shí)， 機(jī)械共混法制備的復(fù)合粉體可以獲得較好的燒結(jié)性能， 陶瓷具有較好的力學(xué)性能和顯微結(jié)構(gòu)， 而溶膠凝膠法制備的復(fù)合粉體則存在過(guò)燒。經(jīng)燒結(jié)工藝優(yōu)化， 溶膠凝膠法制備的復(fù)合粉體在1 860 °C燒結(jié)1 h后， 陶瓷可以獲得更優(yōu)的燒結(jié)性能、 力學(xué)性能及更理想的顯微結(jié)構(gòu)。 復(fù)合粉體中YAG相的提前形成及均勻分布促進(jìn)復(fù)合粉體的快速致密，降低燒結(jié)溫度， 改善陶瓷的力學(xué)性能及顯微結(jié)構(gòu)。 細(xì)晶、 裂紋偏轉(zhuǎn)和晶粒橋聯(lián)是碳化硅陶瓷的主要增韌機(jī)制。
關(guān)鍵字: 碳化硅；陶瓷； Y3Al5O12； 溶膠-凝膠法； 性能； 結(jié)構(gòu)
GAO Li-hua2, LI Xiang-yun2
（ 1. Center of Nano-Science and Nano-Technology, Zhejiang University,
Hangzhou 310027, China;
2. Zhejiang Dongxin Sealing Materials Co. Ltd., Yueqing 325604, China）
Abstract: SiC composite powders were respectively synthesized by sol-gel method and mechanical mixing method, and were pressureless liquid-phase sintered to prepare silicon carbide ceramic. The effects of adding methods on the sintering behaviour, mechanical properties and microstructure of silicon carbide ceramic were analyzed. The results show that at the sintering temperature of 1 950 °C, silicon carbide ceramic, with SiC/(Al2O3+Y2O3) composite powder by mechanical mixing method, possesses higher sintering properties, higher mechanical properties and more ideal microstructure than those with SiC/YAG composite powder by sol-gel method, and there exists over-sintering phenomenon in the SiC/YAG composite powder. After optimizing the process, silicon carbide ceramic, sintered at 1 860 °C with SiC/YAG composite powder by sol-gel method, can obtain excellent sintering and mechanical properties and perfect microstructure. Formation ahead of sintering and uniform distribution of YAG phase in composite powder can accelerate the densification, decrease sintering temperature and improve mechanical properties and microstructure of silicon carbide ceramic. The fine grains, crack deflexion and grain-bridging are main toughening mechanisms of silicon carbide ceramic.
Key words: silicon carbide; ceramic; Y3Al5O12; sol-gel method; property; structure
