Al2O3短纤维增强薄型瓷质陶瓷的试验研究

Experimental Study of Thin Porcelain Tile Reinforced by Al_2O_3 Short Fiber

以小长径比Al_2O_3短纤维为增强体制备增强薄型瓷质陶瓷,研究Al_2O_3短纤维掺量对其吸水率、素坯和成品弯曲强度、断裂功、物相和显微结构的影响,并对其增强增韧机理进行了分析.结果表明:在增强薄型瓷质陶瓷配合料中,Al_2O_3短纤维的最佳掺量(质量分数)为1.5%,其素坯的弯曲强度比基质陶瓷素坯高6.2%,达到1.76MPa,烧成后其吸水率(质量分数)为0.45%,弯曲强度比基质陶瓷高16.90%,达到81.84 MPa,断裂功比基质陶瓷增加35.8%,达到670.22J/m2.在1 200℃的烧成过程中,Al_2O_3短纤维的主晶相由θ-Al_2O_3转变为α-Al_2O_3,促进了基体中二次莫来石的析出,从而使弯曲强度提高.断裂功的增加源于裂纹在Al_2O_3短纤维与基体界面发生偏转和界面脱黏,也得益于二次莫来石和Al_2O_3短纤维中大量纳米晶界对裂纹扩展能量的吸收.

Thin porcelain was reinforced by using Al2O3 short fibers with low aspect ratio as reinforcement.The influence of addition of Al2O3 short fibers on water absorption,bending strength of green body and sintered body,fracture work,phases and morphologies of the specimens as well as mechanism of reinforcement and toughening were studied.The results show that the optimal Al2O3 short fibers content in the raw powder mixture of porcelain is 1.5%（by mass）,at which the water absorption of sintered body is 0.45%（by mass）and the bending strength of green body and sintered body is 1.76 MPa and 81.84 MPa which is6.2% and 16.90% higher than that of porcelain matrix respectively.Especially,the fracture work of sintered body rises to 670.22 J/m2,which is 35.8% higher than that of porcelain matrix.The major phase of fiber turns fromθ-Al2O3 toα-Al2O3 which promotes secondary mullite during sintering at 1 200℃,leading to reinforcement effect.The fracture work increases significantly due to crack deflection and debonding of interface between fiber and matrix.Meanwhile,the secondary mullite and large amount of nano grain boundaries in Al2O3 short fibers also attribute to energy consumption for crack propagation.