不同粉液比对GI-Ⅱ型渗透陶瓷相关性能的影响

Influence of powder/liquid ratio on the viscosity of alumina slurry, shrinkage and strength of melt-infiltrated ceramic

目的 :研究用于制作复合体骨架的氧化铝粉浆的粉液比对渗透陶瓷复合体相关性能的影响。方法 :配制粉液质量比 4∶ 1、5∶ 1、6∶ 1、7∶ 1、8∶ 1的氧化铝粉浆两份 ,其中一份加入增塑剂 ,据旋转法测试粉浆粘度。制作氧化铝坯体 ,在 112 5℃下烧结 2 h形成氧化铝预制体 (preform) ,再在 112 5℃下玻璃熔融渗透 6 h完成复合。测试复合体三点抗弯强度和收缩率。结果 :7～ 8∶ 1的粉浆粘度较高 ,加入增塑剂可以降低 ;4～ 7∶ 1粉液比组强度较高达到 376 .7～ 397.6 MPa,而 8∶ 1组强度偏低仅 32 1.5 MPa;各粉液比组的试件线性收缩率介于 0 .2 6 %～ 0 .34% ,无统计学差异。结论 :4～ 7∶ 1粉液比有利于粉浆涂塑操作 ,不明显影响 GI- 型渗透陶瓷收缩率和三点抗弯曲强度。

砄bjective:To investigate the influence of different ratio of alumina powder to liquid on slurry viscosity and relative properties of final composite. Methods:Two groups of slurry of alumina were prepared with powder/liquid ratio of 4∶1, 5∶1,6∶1, 7∶1 and 8∶1 respectively.The slurry in one group prepared with each ratio was mixed with plasticizer. After ultrasonic vibrating, the slurry viscosity values were measured on LVDV ⅢBrookfield Rheometer. Beam like adobes slip cast with the slurry with those powder/liquid ratios were sintered at 1 125 ℃ for 2 hours to fabricate preforms. The preforms were then infiltrated by melt glass at 1 125 ℃ for 6 hours. The beam strength was obtained according to three point flexural test. Length of the beams before sintering and after infiltration were measured to evaluate shrinkage.Results:The viscosity was significantly lowered with the decrease of powder/liquid ratio, addition of plasticizer to slurry obviously reduced the viscosity, especially with ratio 7～8∶1. Although the strength values of the slurry with powder/liquid ratios of 4～8∶1 indicated no statistical difference, the mean strength value of slurry with the powder/liquid of 8∶1 was relatively low while that in other groups reached 376.7 MPa to 397.6 MPa. The shrinkage rate of the composite ranged from 0.26% to 0.34% and the mean of all groups was (0.31%± 0.11 )%. Conclusion: Powder/liquid ratio of 4～7∶1 does not significantly influence slurry viscosity, shrinkage and strength of the composite. It's advisable to avoid high viscosity of slurry resulting from powder/liquid ratio of 8∶1.