(中南大学冶金与环境学院，长沙 410083)
摘 要: 孔隙缺陷是影响ITO靶材密度及其均匀性的主要原因。研究冷等静压-常压烧结法制备ITO靶材中孔隙的形成机理及其在成型中的变化过程，分析成型压力(模压和冷等静压)对生坯及靶材孔隙缺陷及相对密度的影响。结果表明：尽管模压压力远低于冷等静压压力，但模压过程对ITO生坯中孔隙缺陷的消除具有重要影响；当模压压力由4 MPa提高到20 MPa时，生坯经200 MPa冷等静压后，孔径在15~45 μm区间的孔隙率由1.09%降低为0.2%。实验所用ITO颗粒的屈服压力约为12 MPa。当模压压力小于12 MPa时，生坯中的ITO颗粒仅发生压缩形变；而当其大于12 MPa时，ITO颗粒破碎，致使生坯致密化，从而消除孔隙缺陷。在模压和冷等静压压力分别为24和250 MPa条件下，ITO生坯相对密度达59.3%，烧结后ITO靶材相对密度高达99.1%。
关键字: ITO靶材；成型压力；孔隙缺陷；形成机理
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:Pore defects are the primary cause that affects the density and uniformity of ITO target. The formation mechanism of pores, as well as their evaluation in the forming process, were studied in ITO target preparation by cold isostatic pressing-pressureless sintering. The effects of forming pressures in mould and cold isostatic pressing on pore defects and relative densities of ITO green body and sintered target were investigated. The results show that even though the pressure in mould pressing is much less than those in isostatic pressing, mould pressing has a significant impact on the elimination of pore defects. As the pressure in mould pressing increases from 4 MPa to 20 MPa, the porosity of sizes between 15-45 μm in the green body decreases from 1.09% to 0.2% after cold isostatic pressing at 200 MPa. The yield pressure of ITO granules used in this study is about 12 MPa. When the pressure in mould pressing is lower than 12 MPa, ITO granules in the green body only suffer from compressive deformation; while the pressure is larger than 12 MPa, ITO granules in green body are crushed in mould pressing, resulting in the densification of ITO green body, therefore eliminating the pores. Under pressures of 24 MPa in mould pressing and 250 MPa in isostatic pressing, respectively, the relative density of obtained ITO green body reaches 59.3%, and after pressureless sintering, the relative density of the obtained ITO target reaches up to 99.1%.
Key words: ITO target; forming pressure; pore defect; formation mechanism
