(中南大學冶金與環(huán)境學院，長沙 410083)
摘 要: 孔隙缺陷是影響ITO靶材密度及其均勻性的主要原因。研究冷等靜壓-常壓燒結法制備ITO靶材中孔隙的形成機理及其在成型中的變化過程，分析成型壓力(模壓和冷等靜壓)對生坯及靶材孔隙缺陷及相對密度的影響。結果表明：盡管模壓壓力遠低于冷等靜壓壓力，但模壓過程對ITO生坯中孔隙缺陷的消除具有重要影響；當模壓壓力由4 MPa提高到20 MPa時，生坯經200 MPa冷等靜壓后，孔徑在15~45 μm區(qū)間的孔隙率由1.09%降低為0.2%。實驗所用ITO顆粒的屈服壓力約為12 MPa。當模壓壓力小于12 MPa時，生坯中的ITO顆粒僅發(fā)生壓縮形變；而當其大于12 MPa時，ITO顆粒破碎，致使生坯致密化，從而消除孔隙缺陷。在模壓和冷等靜壓壓力分別為24和250 MPa條件下，ITO生坯相對密度達59.3%，燒結后ITO靶材相對密度高達99.1%。
關鍵字: ITO靶材；成型壓力；孔隙缺陷；形成機理
（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
