蓝宝石单晶炉隔热屏内胆损坏机理  

Damage mechanism of inner heat shield of sapphire single crystal furnace

作　　者：廖彬彬[1] LIAO Bin-bin(Zhuzhou Cemented Carbide Group Co.,Ltd.,Zhuzhou 412000,China)

机构地区：[1]株洲硬质合金集团有限公司,株洲412000

出　　处：《粉末冶金技术》2021年第3期229-233,共5页Powder Metallurgy Technology

基　　金：国家重点研发计划专项资助项目(2017YFB0305600)。

摘　　要：通过研究金属钼(Mo)在真空环境下蒸发速率和饱和蒸气压与温度的关系,探讨了蓝宝石单晶炉Mo隔热屏内胆的损坏机理。结果表明,蓝宝石单晶炉的核心工作温度在2100℃以上,每炉的高温阶段时间超过120 h,隔热屏内胆在高真空环境下产生蒸发,由电子显微结构可以看到Mo片表面疏松、多孔,厚度逐渐变薄、剥落,失去隔热作用。利用金属高温环境下的蒸发速率、饱和蒸气压和工作时间推算出金属因蒸发而造成的厚度变化公式,由公式测算出来蓝宝石单晶炉的隔热屏内胆变薄的趋势与实际使用寿命相吻合。由于金属钨(W)的熔点比钼更高,利用该公式可以测算出W在蓝宝石单晶炉最严苛的工作条件下几乎不会蒸发变薄,是一种理想的隔热屏内胆替代品。The relationships of the evaporation rate,the saturated vapor pressure,and the working temperature of Mo in vacuum environment were investigated,and the damage mechanism of Mo inner heat shield in sapphire single crystal furnace was discussed.In the results,the core operating temperature of the sapphire single crystal furnace is above 2100℃,the high temperature period of each cycle is more than 120 h,and the inner heat shield evaporates in the high vacuum environment.It can be seen from the microstructure that the surface of Mo sheet is loose and porous,and the sheet thickness gradually becomes thin and peels off,losing the heat insulation effect.The formula of the thickness change due to the metal evaporation is deduced from the evaporation rate,the saturated vapor pressure,and the working time at high temperatures.The thickness change trend on the inner heat shield of sapphire single crystal furnace calculated by the formula coincides with the actual service life.Since the melting point of W metal is higher than that of Mo metal,it will hardly evaporate and become thinner under the most severe working conditions in the sapphire crystal furnace according to the calculation results by the formula.Therefore,W is an ideal substitute of the inner heat shield.

关 键 词：蓝宝石 隔热屏 MO 真空 蒸发 

分 类 号：TG146.41[一般工业技术—材料科学与工程]