Integrity Assessment of High-Performance Thin-Film Coated Materials by Meso-mechanics

点击翻译按钮获取中文摘要

he durability of coated materials with higher performances should be adequately evaluated prior to their applications. This work aims at the establishment of procedure to estimate the durability of such materials. In the present work, the borosilicate glass was coated with ceramic films by the radio-frequency (RF) magnetron sputtering method, and mechanical properties of coated glass materials were investigated. At first, mechanical properties of materials coated with single ceramic film, alumina (Al_2O_3), silicon carbide (SiC) or titan nitride (TiN) were investigated. It was found that the strength properties are improved by coating ceramic materials on glass. As for the strength properties, TiN coated glass is superior to Al_2O_3 and SiC coated ones, though it was suggested that the surface properties of TiN coated material should be improved in its application. A new procedure to estimate the strength of coated materials was proposed by incorporating relative hardness and roughness with sputtering time. The strength in experiments was well estimated by using the proposed procedure. The possibility of a two-layer coating using Al_2O_3-SiC was also examined as a processing for the improvement. The measurements of surface roughness and porosity of coating film revealed that relatively smooth and dense coating films were formed under the sputtering condition adopted in this work. Thicker film was found to be harder because of the avoidance of effect due to softer glass substrate. Higher RF output power resulted in harder film. The bending strength was reduced by longer time of sputtering as well as porosity of coating film. By comparison with glass materials coated with single ceramics and the glass substrate, it was clarified that the strength and hardness of coated glass materials were improved by two-layer coating.