成型压力对冷等静压-烧结法ITO靶材孔隙缺陷的影响

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1 Volume 25 Number 9 The Chinese Journal of Nonferrous Metals September (2015) ITO ( ) ITO ITO ( ) ITO 4 MPa 20 MPa 200 MPa 15~45 μm 1.09% 0.2% ITO 12 MPa 12 MPa ITO 12 MPa ITO MPa ITO 59.3% ITO 99.1% ITO TF12 A Effects of forming pressures on pore defects in ITO target prepared by cold isostatic pressing-pressureless sintering LIU Zhi-hong, CHEN Wei, LI Yu-hu, LIU Zhi-yong (School of Metallurgy and Environment, Central South University, Changsha , 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 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 (Indium tin oxide ITO) ITO [1 2] ITO [3 5] ITO (NCET ) (2012M521544) lyh_csu@163.com

2436 2015 9 ITO NADAUD [6] TiO 2 ZrO 2 SiO 2 ITO 1% TiO 2 99% ITO KIM [7] ITO 25 MPa 300 MPa 50% 90% IWASA [8] ITO ITO 120

15 g/cm 3 ) 99% ITO ITO ITO [13 15] ITO ITO ITO ITO ( ) ITO 1 1.1 ITO In 2 O 3 SnO 2 9:1 20.05 m 2 /g 1.

$2 XRD pattern of ITO granules 1 ITO XRF Table 1 XRF analysis result of ITO granules (mass fraction, %) Mg Al Ti Ni Cu Zn$

2 ITO NADAUD [6] TiO 2 ZrO 2 SiO 2 ITO 1% TiO 2 99% ITO KIM [7] ITO 25 MPa 300 MPa 50% 90% IWASA [8] ITO ITO 120 min 75% 91% KIM [9 10] ITO [11] SiC SiC 200 MPa [12] 4.6 GPa 60% (ITO 7.15 g/cm 3 ) 99% ITO ITO ITO [13 15] ITO ITO ITO ITO ( ) ITO ITO In 2 O 3 SnO 2 9: m 2 /g 1.95 g/cm 3 ITO SEM XRD XRF ITO 60 μm 2 ITO In 2 O 3 SnO 2 1 ITO XRF 1 ITO SEM Fig. 1 SEM image of ITO granules 2 ITO XRD Fig. 2 XRD pattern of ITO granules 1 ITO XRF Table 1 XRF analysis result of ITO granules (mass fraction, %) Mg Al Ti Ni Cu Zn Sr Fe Pb Ca Gd As Si Total ITO %( ) ITO 1.2 ITO 42 mm ITO 25 g Y79 4~24 MPa

3 25 9 ITO min LDJ ~250 MPa 30 min h h ITO ITO ITO Rigaku-TTR X (Cu K α = Å) ITO METTLER TOLEDO PL204 ITO S4 PIONEER X ITO JSM 6360LV ITO Quantachrome PoreMaster ITO 3 SEM MPa SEM 3 SEM Fig. 3 SEM images of fracture surfaces of green bodies after mould pressing at different pressures: (a) 4 MPa; (b) 8 MPa; (c) 12 MPa; (d) 16 MPa; (e) 20 MPa; (f) 24 MPa

4 MPa ITO SEM Fig. 4 SEM images of fracture surfaces of ITO green bodies obtained by mould pressing at different pressures and then cold isostatic pressing at 200 MPa: (a) 4 MPa; (b) 8 MPa; (c) 12 MPa; (d) 16 MPa; (e) 20 MPa; (f) 24 MPa 3 4 MPa ITO ITO ( 3(a) ) 12 MPa ITO 4 12 MPa 200 MPa ITO 20 MPa 200 MPa ITO SEM ITO ITO ITO ITO

5 25 9 ITO 2439 [16] ITO 5 4 MPa 20 MPa 200 MPa 5 20 MPa 4 MPa 200 MPa MPa 4 MPa 20 MPa 1~15 μm 15~45 μm 20 MPa 2 Table 2 Pore size distributions of ITO green bodies obtained under different pressure combinations between mould and cold isostatic pressing Mould pressing pressure/ MPa Cold isostatic pressing pressure/ MPa Total porosity Pore size distribution/% 1 15 μm zone μm zone ~45 μm 3 4 SEM 5 4 MPa 20 MPa 200 MPa Fig. 5 Pore size differential distribution curves of ITO green bodies obtained by mould pressing at 4 MPa and 20 MPa respectively, as well as by further cold isostatic pressing at 200 MPa MPa MPa SEM MPa 7 24 MPa MPa MPa 100 MPa 2 24 MPa 100 MPa 250 MPa 1~15 μm 15~45 μm 1.12% 1.08% 0.23% 0.26% 8 ITO SEM ( 8 ) 4 MPa 200 MPa ITO ( 8(a)) 24 MPa ( 8(b) (c)) ITO

6 MPa SEM Fig. 6 SEM images of fracture surfaces of green bodies obtained by mould pressing at 24 MPa and then by cold isostatic pressing at different pressures: (a) 100 MPa; (b) 150 MPa; (c) 200 MPa; (d) 250 MPa ITO ITO ITO 7 Fig. 7 Pore size differential distribution curves of green bodies obtained at different cold isostatic pressures MPa 9 4 MPa 24 MPa 46.6% 52.9% 200 MPa 56.5% 58.6%

7 25 9 ITO U [17 18] 12 MPa 12 MPa ITO ( 3(b)) MPa Fig. 9 Effects of mould pressing pressures on relative densities and density gradients of green bodies obtained by mould pressing or by mould pressing plus cold isostatic pressing at 200 MPa 8 ITO SEM Fig. 8 SEM images on morphological evaluation of porosity defect resulted by dimpled ITO granule under different combination treatment between mould and isostatic pressing pressures: (a) Mould pressing at 4 MPa and isostatic pressing at 200 MPa; (b) Mould pressing at 24 MPa and isostatic pressing at 100 MPa; (c) Mould pressing at 24 MPa and isostatic pressing at 200 MPa 20 MPa ( 3(e) 3(f)) 20 MPa 4 MPa ( 5) SHINOHARA [19] MPa MPa 250 MPa 57.9% 59.3% 3~8 ITO 11 SEM MPa 200 MPa

8 MPa Fig. 10 Relative densities of green bodies obtained by mould pressing at 24 MPa and then by cold isostatic pressing at different pressures 3 24 MPa 250 MPa 99.1% ( 1 μm) 3~8 ITO 10 μm 5~10 μm [20 21] SHINOHARA [22] ABE [23] 11 SEM Fig. 11 SEM images of fracture surfaces of sintered ITO targets under different pressure combinations between mould pressing and cold isostatic pressing: (a) Mould pressing at 8 MPa and isostatic pressing at 200 MPa; (b) Mould pressing at 16 MPa and isostatic pressing at 200 MPa; (c) Mould pressing at 24 MPa and isostatic pressing at 100 MPa; (d) Mould pressing at 24 MPa and isostatic pressing at 150 MPa; (e) Mould pressing at 24 MPa and isostatic pressing at 200 MPa; (f) Mould pressing at 24 MPa and isostatic pressing at 250 MPa

9 25 9 ITO Table 3 Relative densities of sintered ITO targets under different pressure combinations between mould pressing and cold isostatic pressing Mould pressing pressure/mpa Cold isostatic pressing pressure /MPa Relative density/% ITO 3 1) ITO 3 2) ITO 12 MPa ITO 4 MPa 20 MPa 15~45 μm 1.97% 1.5% 200 MPa 15~45 μm 1.09% 0.2% 3) 24 MPa 100 MPa 250 MPa 1~15 μm 15~45 μm 1.12% 1.08% 0.23% 0.26% 4) ITO 24 MPa 52.9% 250 MPa 59.3% 99.1% REFERENCES [1] HAMBERG I, GRANQVIST C G. Evaporated Sn-doped In 2 O 3 films: Basic optical properties and applications to energyefficient windows[j]. Journal of Applied Physics, 1986, 60(11): [2] COX P A, FLAVELL W R, EGDELL R G. Solid-state and surface chemistry of Sn-doped In 2 O 3 ceramics[j]. Journal of Solid State Chemistry, 1987, 68(2): [3] WEN S J, CAMPET G, PORTIER J, COUTURIER G, GOODENOUGH J B. Correlations between the electronic properties of doped indium oxide ceramics and the nature of the doping element[j]. Materials Science and Engineering B, 1992, 14(1): [4] GNEHMAN B L, JONSSON S, RUDOLPH T, SCHERER M, WEIGERT M, WERNER R. Influence of manufacturing process of indium tin oxide sputtering targets on sputtering behavior[j]. Thin Solid Films, 1992, 220(1): [5] ISHIBASHI S, HIGUCHI Y, OTA Y, NAKAMURA K. Low resistivity indium-tin oxide transparent conductive films. II. Effect of sputtering voltage on electrical property of films[j]. Journal of Vacuum Science & Technology A, 1990, 8(3): [6] NADAUD N, NANOT M, BOCH P. Sintering and electrical properties of titania- and zirconia-containing In 2 O 3 -SnO 2 (ITO) ceramics[j]. Journal of the American Ceramic Society, 1994, 77(3): [7] KIM B C, LEE J H, KIM J J. Effect of forming pressure on densification behavior of nanocrystalline ITO powder[j]. Journal of the European Ceramic Society, 2007, 27(2): [8] IWASA K, ISOBE T, SENNA M. Enhanced densification of indium-tin oxide ceramics for sputter target through wet mechanochemical processing[j]. Solid State Ionics, 1997, 101: [9] KIM S M, SEO K H, LEE J H, KIM J J, LEE H Y, LEE J S. Preparation and sintering of nanocrystalline ITO powders with different SnO 2 content[j]. Journal of the European Ceramic Society, 2006, 26(1): [10] KIM S M, LEE J H, KIM J J. Reaction-sintering behavior of nanocrystalline indium tin oxide with varying SnO 2 content and particle size[j]. Scripta Materialia, 2007, 56(4): [11],,. SiC [J]., 2000, 28(3): HUANG Zheng-ren, JIANG Dong-liang, TAN Shou-hong. Crushing behavior of SiC granule prepared by spray pelletization during compaction[j]. Journal of the Chinese Ceramic Society, 2000, 28(3): [12],,,.

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untitled 20 1 2010 10 Vol.20 Special 1 The Chinese Journal of Nonferrous Metals Oct. 2010 1004-0609(2010)S1-s0127-05 Ti-6Al-4V 1 2 2 (1. 710016 2., 710049) 500~1 000 20 Ti-6Al-4V(TC4) TC4 800 TC4 800 TC4 TC4 800