原始粉BET,CIP压力与烧结温度对ITO靶材微观结构及结瘤情况的影响

Microstructure of ITO Target and Impact of Nodulation by BET,CIP Pressure and Sintering Temperature

以不同比表面积(BET)气化In2O3和SnO2粉(In2O3/SnO2=9:1)为原料,使用模压辅助冷等静压(CIP)成型的方法制备出铟锡氧化物(ITO)坯体,又在不同温度条件下烧结制得ITO靶材。研究了原始粉BET,CIP压力与烧结温度对靶材微观结构及结瘤的影响,结果表明:BET更大的A配方粉末烧结活性更高,在较低的烧结温度即可致密,而微观结构致密性的提高有利于防止靶材结瘤;当CIP压力由285 MPa提高至400 MPa,坯体各方向收缩率明显增加,且相对密度由64.90%提高至70.23%,CIP压力继续提高至500 MPa,坯体密度不再继续增加,稳定在70%左右;在1540℃常压氧气氛烧结20 h后,CIP压力为285 MPa和400 MPa的靶材相对密度均超过99.8%,晶粒尺寸均在4~10μm,但前者含少量尺寸在2μm以下的微孔,而后者微观致密性更好、晶内小微粒尺寸更大,且溅射后未出现结瘤;在1575℃常压氧气氛烧结20 h后,CIP压力为285 MPa和400 MPa的靶材相对密度均超过99.8%,均未出现微孔缺陷,但靶材晶粒尺寸均偏大,范围大致在4~17μm,其中400 MPa靶材出现了更多数量的异常大晶粒;当CIP压力均为400 MPa时,1575℃烧结靶材结瘤偏多,而1540℃烧结靶材未出现结瘤。

Indium tin oxide(ITO)green body was prepared by molding assisted cold isostatic pressing(CIP)with gasified In2 O3 and Sn02 powder(In203/SnO2=9:1)of different Brunner Emmet Teller(BET)and ITO target was prepared under different temperature conditions.The effect of raw powder BET,sintering temperature and the maximum CIP pressure on the microstructure and nodulation of ITO target was studied.The results showed that Formula A powder with bigger BET had higher sintering activity and could be compacted at lower sintering temperature,while the improvement of microstructural compactness was beneficial to prevent nodulation of target materials.When the pressure of CIP increased from 285 MPa to 400 MPa,the shrinkage of the green body increased obviously in all directions and the relative density increased from 64.90%to 70.23%.When the CIP pressure continued to increase to 500 MPa,the relative density of the green body no longer increased and kept about 70%.After sintering at 1540 for 20 h in normal oxygen atmosphere,the relative densities of ITO targets of 285 MPa and 400 MPa were both over 99.8%and the grain sizes were 4~10μm,but the former contained a small amount of micro-pores below 2μm while the latter had a better micro density and larger size of intra-granular particle and no nodules appeared after sputtering.After sintering at 1575 for 20 h in normal oxygen atmosphere,the relative densities of ITO targets of 285 MPa and 400 MPa were both over 99.8%and no micro-porous defects were found in both of the two,but the grain sizes of the targets were large with range of approximately 4~17μm and more abnormal large grains were found in the target of400 MPa.When the CIP pressure was 400 MPa,the sintered target at 1575 had more nodules,while the sintered target at 1540℃had no nodules.