Effect of Graphite Additives on TO and TNO Ceramic Sintering Properties and Mechanical Properties

• Main Authors: Szu-Yung Chuang, 莊汜甬
• Other Authors: 李景恆
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/wpw323

碩士 === 國立虎尾科技大學 === 材料科學與綠色能源工程研究所 === 103 === A transparent conductive oxide (transparent conducting oxide, TCO) material is mainly used as indium tin oxide (tin-doped indium oxide, ITO) because of its excellent electrical conductivity (10-3 ~ 10-4Ωcm) and visible transmittance (80 % or more), but there are also many problems. For instance, indium is toxic and expensive because it is rare element. There is a dwindling crisis so the academic industry is actively developing alternative materials. There have been papers indicating that titania-doped niobium oxide (niobium-doped oxide, TNO) plated film is also made of good light transmitting property and conductivity, but related studies are exploring Properties for the parameters of sputtering film. There are few studies on the impact of target properties and the subsequent film coating system. In this study, TNO and TiO2 are doped with a small amount of graphite, in order to explore the sintered density, microstructure, crystal structure and electrical properties of the target, and understand the mechanical properties through the material hardness and bending strength. Experimental results show that TO and TNO doped 1mol% and 3mol% graphite are in the lowest resistivity after sintered at a temperature of 1200 ℃. The best argument of resistivity, which is 1.7 × 10-2Ωcm, is TNO-3C. It’s true that doping graphite may increase the oxygen vacancies and enhance carrier mobility, but it will also result in decreased density, causing holes which will reduce carrier mobility. After the two effects cancel each other out, the resistance will lower slightly, indicating that doping graphite has a positive impact on resistance. In the crystal structure, TO will change its stoichiometry after sintered in oxygen-deficient atmospheres, causing Ti8O15 and Ti9O17 crystal structure to form. TNO is rutile crystal structure because Nb2O5 will completely solid dissolve in TiO2. In the mechanical nature, doping graphite leads to density decrease and indirectly reduces the hardness of TO and TNO. Due to differences in crystal structure, the hardness of TO ceramic values higher than that of TNO, but the Flexural strength of TNO is superior to that of TO ceramics.