Effect of Plate-like Alumina Seed Amount on Microstructure and Properties of Alumina Ceramics
ZHU Li-hui1, LIU Wei2, LI Tai-chang2, HUANG Qing-wei3
1. School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China; 2. Zhongzhou Branch China Aluminum Co., Ltd., Jiaozuo 454174, Henan, China; 3. Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
Abstract：The effects of plate-like alumina seed amount on the microstructure and properties of alumina ceramics prepared by pressureless sintering were studied,when plate-like alumina single crystal particles were used as seeds and CaO-Al2O3-SiO2(CAS) were used as additives.The additions of both α-Al2O3 platelets and CAS lead to the development of elonged grains.More and more elonged grains are formed with the increase of seed addition.However when 60%(mass fraction) seeds are added,the size of elonged grains decreases in spite of more elonged grains.The relative density and hardness of alumina ceramics are hardly affected by the addition of plate-mike alumina seeds,but the fracture toughness increases first and then decreases with the increase of seed addition.When 30% seeds are added,the fracture toughness reaches a maximum(6.5MPa·m1/2).Compared with the sample without the addition of seeds,the fracture toughness increases by 25%.
 SONG H,COBLE R L.Origin and growth kinetics of platelike abnormal grains in liquid-phase-sintered alumina[J].Journal of the American Ceramic Society,1990,73(7):2077-2085.  HORN D S,MESSING G L.Anisotropic grain growth in TiO2-doped alumina[J].Materials Science & Engineering A,1995,195A(1-2):169-178.  TARTAI J,MESSING G L.Anisotropic grain growth in α-Fe2O3-doped alumina[J].Journal of the European Ceramic Society,1997,17(5):719-725.  WU Y Q,ZHANG Y F,HUANG X X,et al.Microstructural development and mechanical properties of self-reinforced alumina with CAS addition[J].Journal of the European Ceramic Society,2001,21(5):581-587.  YOSHIZAWA Y,TORIYAMA M,KANZAKI S.Preparation of high fracture toughness alumina sintered bodies from Bayer aluminum hydroxide[J].Journal of the Ceramic Society of Japan,1998,106(12):1172-1177.  XIE Zhi-peng,LU Ji-wei,LIU Tong,et al.Fabrication of high toughness alumina with elongated grains[J].Journal of Materials Science Letters,2001,20(15):1425-1427.  谢志鹏,高立春,李文超,等.晶种诱导长柱状晶生长规律与高韧性氧化铝陶瓷材料[J].中国科学,2003,33(1):11-18.  刘彤,谢志鹏,陆继伟,等.长柱状晶高韧性氧化铝陶瓷的制备与性能研究[J].材料工程,2001,(8):14-17.  XIE Z P,LU J W,HUANG Y,et al.Influence of α-alumina seed on the morphology of grain growth in alumina ceramics from Bayer aluminum hydroxide[J].Materials Letters,2003,57(16-17):2501-2508.  BRANDON D,CHEN D,CHAN H.Control of texture in monolithic alumina[J].Materials Science & Engineering A,1995,195A(1-2):189-196.  BECHER PAUL F.Microstructural design of toughened ceramics[J].Journal of the American Ceramic Society,1991,74(2):255-269.