Papers by Author: Kyun Tak Kim

Abstract: In this study, microstructure and wear behavior of thermally sprayed Fe-based alloy coatings were investigated. Fe-based alloy coatings were formed on a carbon steel substrate and then heat-treated at temperature of 700 oC for 20 minutes. Dry sliding wear tests were performed using the sliding speeds of 0.4 and 0.8 m/s, the applied loads of 3 and 6 N. Microstructure and wear behavior of as-sprayed and heat-treated Fe-based amorphous coatings were studied using a scanning electron microscope(SEM), transmission electron microscopy(TEM) and X-ray diffraction(XRD).

Abstract: SiC particulates reinforced Al matrix composites were fabricated by thermal spray process, and the dry sliding wear behavior against four different counterparts was investigated under a varying of the sliding speed and the applied load conditions. Al/SiC composites were fabricated by flame spraying, and the dry sliding wear tests were performed using the sliding speed of 0.4 m/s and 0.8 m/s at the applied load of 3 N. Sliding distance was kept at 1000 m for all the tests. Al2O3, ZrO2, Si3N4 and AISI 52100 balls were used as the counterparts. Wear tracks on the Al/SiC composites were investigated using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). It was revealed that wear behavior of Al/SiC composites was much influenced by counterpart materials.

Abstract: This study aims at investigating the effect of the sliding speed and the applied load on the dry sliding wear behavior of thermally sprayed Ni-based self-flux alloy coating. Ni-based self-flux alloy powders were flame-sprayed onto a carbon steel substrate and then these coatings were heat-treated at temperature of 1000 oC. Dry sliding wear tests were performed using the sliding speeds of 0.2, 0.4, 0.6 and 0.8 m/s and the applied loads of 5, 10, 15 and 20 N. AISI 52100 ball (diameter 8 mm) was used as counterpart material. Wear behavior of Ni-based self-flux alloy coatings was studied using a scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). It was revealed that microstructure and wear behavior of the Ni-based self-flux alloy coatings were much influenced by the sliding speed and the applied load.

Abstract: SiC particulates reinforced with Al matrix composites were fabricated using a thermal spray process. In addition, the dry sliding wear behavior was investigated using various sliding speeds and applied loads. Premixed Al and SiC powder was sprayed onto an Al6061 substrate by flame spraying, and dry sliding wear tests were performed under varying sliding speed and applied load conditions. Wear behavior of the composites were studied using a scanning electron microscope(SEM), X-ray diffraction(XRD) and a surface roughness tester.

Abstract: SiC particulates reinforced metal matrix composites (MMCs) were fabricated by two different processes, pressureless infiltration and thermal spray. 10, 20, 30, 40 and 50 vol% SiC reinforced Al matrix composites (AMCs) were fabricated by these two processes. For these AMCs, dry sliding wear tests were performed under a normal load of 3 N, a constant sliding speed of 0.2 m/s and sliding distance of 1000 m against an AISI 52100 ball. Microstructures and wear behavior were studied by means of scanning electron microscope (SEM) and electron probe micro-analysis (EPMA).