高温型Mo-Al_2O_3金属陶瓷的研制

Development of the High Temperature Mo-Al_2O_3 Cermet

将Mo与Al2O3粉体按摩尔比为0.3、0.4、0.5配料,混合均匀后通过粉末冶金法制成3种Mo-Al2O3金属陶瓷试样。在1800℃,2h氢气气氛中烧结后,试样的气孔率随Mo含量的增加呈降低趋势,而强度呈增加趋势。同时,随Mo含量增加,金属陶瓷中Al2O3的晶粒尺寸减小,Mo的形态从以弥散状为主转变为以连续状为主。研制的高温型Mo-Al2O3金属陶瓷测温套管(金属与陶瓷摩尔比为0.4)在真空或N2保护条件下测量高温合金熔液温度时,平均使用寿命达到100次。

The Mo and Al2O3 powders were prepared and mixed evenly with a mole ration of 0.3, 0.4 and 0.5 respectively and then three kinds of Mo-Al2O3 cermets samples were fabricated by the powder metallurgy method. When the samples was sintered in hydrogen for two hours at 1800 ℃ the porosity of the samples has a tendency of decrease with increasing of Mo content, whereas the strength of the samples has the tendency of increase. Meanwhile the average grain size of Al2O3 in the cermets is decreased with increasing of Mo content The morphology of Mo is transformed from mainly dispersive structure to continuous structure. When the developed protective pipe of thermocouple made by the Mo-Al2O3 cermets was used to measure the temperature of superalloy melts under the condition of vacuum or with the protection of nitrogen, its mean service life reached 100 times.