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황석훈 ( Suk Hun Hwang ),김정환 ( Jung Hwan Kim ),오용준 ( Yong Jun Oh ) 대한금속재료학회 ( 구 대한금속학회 ) 2009 대한금속·재료학회지 Vol.47 No.5
Co nanoparticles on silica substrates were fabricated by inducing a thin-film dewetting through two different processes-furnace annealing and pulsed-laser annealing. The effects of annealing temperature, film thickness and laser energy density on dewetting morphology and mechanism were investigated. Co thin-films with thicknesses between 3 to 15 nm were deposited using ion-beam sputtering, and then, in order to induce dewetting, thermally annealed in furnace at temperatures between 600 and 900℃. Some as-deposited films were irradiated using a Nd-YAG pulsed-laser of 266 nm wavelength to induce dewetting in liquid-state. Films annealed in furnace agglomerated to form nanoparticles above 700℃, and those average particle size and spacing were increased with an increase of film thickness. On the laser annealing process, above the energy density of 100 mJ/cm2, metal films were completely dewetted and the agglomerated particles exhibited greater size uniformity than those on the furnace annealing process. A detailed dewetting mechanism underlaying both processes were discussed. (Received January 7, 2009)
구리를 함유하지 않은 친환경 자동차 브레이크 패드의 마모 특성에 관한 연구
김기봉,양상선,이성주,황석훈,김신욱,김용진,Kim, Ki-Bong,Yang, Sangsun,Lee, Seong-Ju,Hwang, Suk-Hun,Kim, Sin-Wook,Kim, Yong-Jin 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.1
The friction characteristics of Al-Fe alloy powders are investigated in order to develop an eco-friendly friction material to replace Cu fiber, a constituent of brake-pad friction materials. Irregularly shaped Al-Fe alloy powders, prepared by gas atomization, are more uniformly dispersed than conventional Cu fiber on the brake pad matrix. The wear rate of the friction material using Al-8Fe alloy powder is lower than that of the Cu fiber material. The change in friction coefficient according to the friction lap times is 7.2% for the Cu fiber, but within 3.8% for the Al-Fe alloy material, which also shows excellent judder characteristics. The Al-Fe alloy powders are uniformly distributed in the brake pad matrix and oxide films of Al and Fe are homogeneously formed at the friction interface between the disc and pad, thus exhibiting excellent friction and lubrication characteristics. The brake pad containing Al-Fe powders avoids contamination by Cu dust, which is generated during braking, by replacing the Cu fiber while maintaining the friction and lubrication performance.