Abstract:

In order to improve the comprehensive properties of zirconia products,specimens prepared with aggregates of different density were designed:65 mass% fused dense zirconia particle,45 mass% fused dense zirconia particles plus 20 mass% fused zirconia bubble,and 65 mass% fused zirconia bubble.After mixing,hydraulic pressing,drying,and firing at different temperatures (1 650,1 720 and 1 800 ℃) for 6 h,the cold crushing strength,the cold modulus of rupture,the thermal conductivity,the linear expansion rate and the hot creep resistance of the prepared specimens with the total amount of ZrO₂+HfO₂+Y₂O₃≥99.0% were tested,and the phase composition and the microstructure were analyzed.The results show that:1)the composite properties of the specimen using 45 mass% fused dense zirconia particles plus 20 mass% fused zirconia bubble as aggregates are the best;the cold crushing strength,the cold modulus of rupture and the creep resistance do not decrease significantly while the apparent porosity increases and the thermal conductivity decreases,and the linear expansion change rate is also small;the cold crushing strength,the cold modulus of rupture and the creep resistance of the specimen with 65 mass% fused zirconia bubble as aggregates decrease significantly,although the apparent porosity increases further and the thermal conductivity decreases further;2) the optimum firing condition is at 1 720 ℃ for 6 h.

Key words: fused zirconia, zirconia bubble, high purity zirconia products, thermal conductivity

摘要：

为了提高氧化锆制品的综合性能,设计了配料组成中骨料分别为65%(w)的电熔氧化锆致密颗粒、45%(w)的电熔氧化锆致密颗粒加20%(w)的电熔氧化锆空心球、65%(w)电熔氧化锆空心球三种骨料密度不同的试样,经混料、液压成型、烘干后,分别在1 650、1 720和1 800 ℃保温6 h制成w(ZrO₂+HfO₂+Y₂O₃)≥99.0%的高纯氧化锆试样,然后检测试样的常温耐压强度、常温抗折强度、热导率、线膨胀率和高温压蠕变率,并分析试样的相组成和显微结构。结果表明:1)以45%(w)的电熔氧化锆致密颗粒加上20%(w)的电熔氧化锆空心球为骨料的试样的综合性能最优,在显气孔率增大、热导率减小的同时,其常温抗折强度、常温耐压强度和抗蠕变性并未显著降低,热膨胀性变化也很小;以65%(w)电熔氧化锆空心球为骨料的试样,虽然显气孔率进一步增大,热导率进一步减小,但其常温抗折强度、常温耐压强度和抗蠕变性均显著降低。2)最佳烧成条件为1 720 ℃保温6 h。

关键词: 电熔氧化锆, 氧化锆空心球, 高纯氧化锆制品, 热导率