纳米η-Al_2O_3无压烧结制备单相氧化铝陶瓷
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摘要
采用99%纳米η-Al_2O_3为原料,无压烧结制备单相氧化铝陶瓷,通过TG-DSC、XRD和SEM等手段对试样进行分析和表征,并测试其力学性能。结果表明:纳米η-Al_2O_31084.8℃时转变为α-Al_2O_3,转变温度小于理论转变温度;晶型转变释放的能量能够降低氧化铝陶瓷的烧结温度,1550℃时试样的相对密度达91.48%,显气孔率为2.45%,断裂韧性较高。由于η-Al_2O_3的密度小于α-Al_2O_3,无压烧结时试样发生晶型转变产生体积收缩,致密性较低,直接用η-Al_2O_3制备致密的单相Al_2O_3陶瓷较为困难。
The single-phase Alumina ceramic was prepared useing 99% nanometer η-Al_2O_3 via pressureless sintering. The specimen were investigated via TG-DSC,XRD,SEM etc,the mechanical properties were tested. The results show that the nanometer η-Al_2O_3 transform to α-Al_2O_3 at 1084. 8 ℃,the transition temperature is lower than the theoretical transition temperature. The energy release by crystal transition can reduce the sintering temperature of alumina ceramic,the relative density of the specimen is 91. 48%,the apparent porosity of the specimen is 2. 45%,and it has high fracture toughness at 1550 ℃. Due to the density of η-Al_2O_3 is less than α-Al_2O_3,the specimen appears large volume shrinkage during crystal transition. The densification of the specimen prepared using 99% nanometer η-Al_2O_3 via pressureless sintering is low,it is diffcult to prepare the compact single-phase Alumina ceramic with nanometer η-Al_2O_3 via one-step pressureless sintering.
The single-phase Alumina ceramic was prepared useing 99% nanometer η-Al_2O_3 via pressureless sintering. The specimen were investigated via TG-DSC,XRD,SEM etc,the mechanical properties were tested. The results show that the nanometer η-Al_2O_3 transform to α-Al_2O_3 at 1084. 8 ℃,the transition temperature is lower than the theoretical transition temperature. The energy release by crystal transition can reduce the sintering temperature of alumina ceramic,the relative density of the specimen is 91. 48%,the apparent porosity of the specimen is 2. 45%,and it has high fracture toughness at 1550 ℃. Due to the density of η-Al_2O_3 is less than α-Al_2O_3,the specimen appears large volume shrinkage during crystal transition. The densification of the specimen prepared using 99% nanometer η-Al_2O_3 via pressureless sintering is low,it is diffcult to prepare the compact single-phase Alumina ceramic with nanometer η-Al_2O_3 via one-step pressureless sintering.
引文
[1]孙跃军,荀冬雪,刘民.纳米氧化铝粉体制备方法与工艺的研究进展[J].中国材料进展,2017,36,(6):455-460.
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[7]JO H,JUNG H,PARK J,et al.Surface modification ofη-Al2O3by Si O2impregnation to enhance methanol dehydration activity[J].Bulletin of the Korean Chemical Society,2017,38(3):307-312.
[8]NIIHARA K,MORENA R,HASSELMAN D P H.Evaluation of KIC of brittle solid by the indentation method with low crack-to-ident ratios[J].J.Mater Sci.Lett.,1982,1(1):13-16.
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[10]陈玮.α-Al2O3形成过程显微结构演变及其调控[D].长沙:中南大学,2010.
[2]LI Jiang,PAN Yubai,LIU Jue,et al.Hot-pressed sintering of fine-grained Alumina ceramics[J].Journal of the Chinese Ceramic Society,2009,37(2):271-274.
[3]LH N J,SIMO L,FALLER C A,et al.A review of two-step sintering for ceramics[J].Ceramics International,2016,42(11):12556-12572.
[4]殷剑龙,王修慧,张野.烧结助剂对高纯氧化铝陶瓷致密化过程的作用[J].稀土,2014,35,(5):16-20.
[5]SUN R J,SHEN S G,ZHANG D F,et al.Hydrofining of coal tar light oil to produce high octane gasoline blending components overγ-Al2O3andη-Al2O3supported catalysts[J].Energy Fuels,2015,29(11):7005-7013.
[6]FARAJIMOTLAGH M,POURSALEHI R,ALIOFKHAZRAEI M.Synthesis mechanisms,optical and structural properties ofη-Al2O3based nanoparticles prepared by DC arc discharge in environmentally friendly liquids[J].Ceramics International,2017,43(10):7717-7723.
[7]JO H,JUNG H,PARK J,et al.Surface modification ofη-Al2O3by Si O2impregnation to enhance methanol dehydration activity[J].Bulletin of the Korean Chemical Society,2017,38(3):307-312.
[8]NIIHARA K,MORENA R,HASSELMAN D P H.Evaluation of KIC of brittle solid by the indentation method with low crack-to-ident ratios[J].J.Mater Sci.Lett.,1982,1(1):13-16.
[9]GITZEN W H.Alumina as a ceramic material[J].The American Society,1970,9:11-27.
[10]陈玮.α-Al2O3形成过程显微结构演变及其调控[D].长沙:中南大学,2010.