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혼합조건에 따른 철분말 소결체의 특성 변화에 관한 연구
김한삼 ( Han-sam Kim ),최태규 ( Tae-kyu Choi ),박종성 ( Chong-sung Park ) 한국고등직업교육학회 2002 한국고등직업교육학회논문집 Vol.3 No.4
The microstructure and mechanical characteristics of sintered materials composed oi Fe-xwt.%P with mixing times had been studied. The Fe+xwt.%P(x = 0.25, 0.5, 0.75,1) powders were sintered for 2 hours at 940°C. Before sintering of the powders, each of powder composition was worked into ball-mill machine for 12, 24, and 48 hours. The shrinkage of preform increased with phosphorus amount and mixing time during sintering. Pores and Fe<sub>3</sub>P facet type phase in the grain boundary and grain of sintered materials were observed by means of scanning electron microscope. Amounts of pores and the size of Fe<sub>3</sub>P phase decreased with increase of the mixing time. The hardness of sintered materials depended upon the content of phosphorus and the mixing time of powder. The hardness increased with the increase of phosphorus content and mixing times.
플라즈마 용사된 WC-12%Co 피복층의 접합강도에 관한 연구
이의길,김한삼,Chr 대한용접접합학회 2000 대한용접·접합학회지 Vol.18 No.5
The development of new spraying processes has increased the demand for high quality protective coatings. Many thermal spraying processes have been developed to obtain coatings for a wide spectrum of materials and substrates. The plasma spray process was used to deposit coatings of WC-12%Co powders on mild steel substrate, and the characteristics of as-sprayed and vacuum heat treated coatings have been investigated. The variations of microhardness and bond strength in WC-12%Co coatings after heat treatment under vacuum circumstance have been investigated. The effects of phases and morphologies of WC-12%Co coatings have been investigated by utilizing X-ray diffraction and scanning electron microscopy, respectively. The microhardness and bond strength of the coatings were increased with increasing the temperature in the temperature range of $700^{circ}C~1000^{\circ}C$. The bond strength was obtained 49 MPa after vacuum heat treatment at $1000^{\circ}C$.