Mechanical Properties and Oxidation Behavior of Nb-Ru Alloy Coatings Prepared by DC Magnetron Sputtering

• Main Authors: Hsiu-Nuan Chu, 朱秀暖
• Other Authors: Yung-I Chen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/24838048023766863950

碩士 === 國立臺灣海洋大學 === 材料工程研究所 === 101 === Due to the rapid development of optoelectronic products, it causes the dependence on precision machining and molding tec hnology aspheric optical glass surge. In Glass molding proce ss, the main point is the nature of the glass molding die co ating, of which high hardness, high temperature resistance, good adhesion and inertness with the glass material are basi c requirements. The present glass molding die coating common ly uses metal films. In this study, Nb–Ru alloy coatings by sputtering are prepared to explore the feasibility of Nb–Ru alloy coating in high temperature glass molding such as hard ness, phase stability, oxidation behavior and other charact eristics. There are four parts in this study, first, Nb–Ru alloy coat ings with titanium interlayer were fabricated by magnetron sputtering on Si wafer. The composition and structure of Nb –Ru alloy films are manipulate through input power and subs trate-holder rotation speed. The structural characteristics and oxidation mechanism for Nb–Ru alloy coatings under the d ifferent control parameters are studied. Whether changing th e power or substrate-holder rotation speed the coatings exhi bit layered structure with a columnar grain. Second, annealing process was conducted at one percent of O2 -Ar from 400 to 600℃ for 30 minutes. Through TEM, the Nb-ri ch’s laminated period is 76.4 nm due to the formation of oxi des. Due to the different thickness when changing the substr ate-holder rotating speed, the phase structure will change N b–Ru cycle of each layer in the same composition. When 1% of O2-Ar under 600°C heat treatment temperature in 30 minutes, the increasing of Ru component will decrease the content of oxygen into the alloy coatings, and it will also affect the reaction speed of O and Nb. Nb0.08Ru0.92(R5) hardness values up to 19.9 GPa, and Young's modulus as 313 GPa in the mechan ical properties of hardness and Young's modulus. Third, changing the oxygen partial pressure in 50 ppm O2-N2 and controls the heat treatment temperature in 30 minutes, i n order to study the oxidation mechanism of the Nb–Ru alloy coatings. When the heat treatment temperature increased from 400 to 600℃, and oxygen content of the coatings will increa se, but not necessarily in the surface oxide layer depending on the type of the alloy coatings composition. Under TEM ana lysis of Ru-rich sample, only a small amount of oxygen enter the alloy coatings, calculated a laminated period of 8.8 nm, but no oxide layer appears, and while Nb: Ru component is 1: 1, the unoxidized region and the oxide regions respectively to 9 nm and 13 nm in a laminated period. In Ru-rich content Nb0.08Ru0.92, with increasing heat treatment temperature, Ru phase remains unchanged, but Nb2O5 oxidation temperature up to 600℃, which is due to the Ru barrier of O into the film with reduce Nb reaction. Fourth, oxidation kinetics experiments up to 8 hours are con ducted through TGA at 350 to 600℃. The Nb–Ru alloy coatings have slow oxidation rate and therefore reflect linear kineti c curve at a low temperature. From the result that the kp va lue in increases with temperature, the faster is the rate of oxidation under elevated temperature.