| 플라즈마 용사 Al2O3 코팅의 특성에 미치는 CrO3 봉공처리의 영향 |
| 조경식, 이현권, 권정철1 |
금오공과대학교 신소재시스템공학부
1제일윈텍(주) |
| Influence of CrO3 Sealing Treatment on Properties of Plasma Sprayed Al2O3 Coating |
| Kyeong-Sik Cho, Hyun-Kwuon Lee, Jeong-Cheol Kwon1 |
School of Advanced Materials & System Engineering, Kumoh National Institute of Technology
1Top Win Tech Co. |
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| ABSTRACT |
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Plasma sprayed ceramic coatings inherently contain pores and usually also cracks. Post-treatment of the plasma sprayed coatings is a way to close the connected pores and cracks. In this study, post-sealing treatment in plasma sprayed $Al_2O_3$ coatings was employed to overcome the reduction of coating properties. $Al_2O_3$ plasma thermal spray coating was made on aluminum alloys plate, $CrO_3$ post coating and heat treatment at $550^{circ}C$ was carried out in order for final $Cr_2O_3$ to be saturated through phase transformation. Chromia sealing began at the fine defect in coated microstructure, while larger pores were permeated later. The increase in concentration and treatment frequency of sealing solution resulted in the decrease of porosity of coating layer, while cracks occurred partially after the third treatment. After twice treatment of 10M $CrO_3$ solution, microhardness and breakdown voltage of $Al_2O_3$ coatings were found to increase by ${fallingdotseq}$ 50% and ${fallingdotseq}$ 390% respectively than without post-treatment. |
| Key words:
Plasma thermal spray coating, $Al_2O_3$ spray coating, $CrO_3$ sealing treatment |
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