氧化锆纤维对氧化硅陶瓷型芯性能的影响

Influence of Zirconia Fiber on Properties of Silica Ceramic Cores

为提高硅基陶瓷型芯的综合性能,将不同含量的氧化锆短纤维添加至以锆英粉为矿化剂的型芯基体粉料中,通过热压注法制备氧化硅陶瓷型芯,研究型芯收缩率、显气孔率和力学性能的变化,并观察试样断面微观形貌。结果表明,当氧化锆纤维掺入量从0增加到5%,陶瓷型芯试样的室温和1550℃高温抗弯强度先上升后下降;当氧化锆纤维掺入量为1%时,室温和1550℃高温抗弯强度最好,分别为18.64MPa和28.06MPa,与未纤维强化的陶瓷型芯试样对比,分别提升15.84%和13.46%;氧化锆纤维掺入量为1%的陶瓷型芯试样的收缩率为0.89%,显气孔率为30.4%,高温变形量为0.71mm。分析认为,氧化锆纤维掺入量较高导致纤维的完整性被破坏且出现团聚现象、对基体起割裂作用是陶瓷型芯试样综合性能变差的主要原因。

In order to improve the comprehensive performance of silicon-based ceramic core,zirconia fibers with different contents were added to the core matrix powder with zirconia powder as mineralizing agent,and silicon oxide ceramic cores were prepared by hot pressure injection method.The variations of the core shrinkage,porosity and mechanical properties with different zirconia fiber incorporation amounts were studied,and the micro morphologies of the sample sections were observed.The results showed that when the zirconia fiber incorporation increased from O to 5%,the room temperature and high temperature flexural strength at 1550℃ of the ceramic core specimens first increased and then decreased.When the zirconia fiber incorporation amount was 1%,the bending strength at room temperature and at 1550℃ was the best,which were 18.64 MPa and 28.06 MPa,respectively,which increased by 15.84%and 13.46%compared with unfiber-reinforced ceramic core samples.The shrinkage rate of the ceramic core specimen with zirconia fiber incorporation amount of 1%was 0.89%,the apparent porosity was 30.4%,and the high temperature deformation was o.71 mm.It is concluded that the high amount of the zirconia fiber content led to the destruction of fiber integrity and agglomeration,and the cutting effect on the matrix,which is the main reason for the deterioration of the comprehensive performance of the ceramic core samples.