논문 해외 국제전문학술지(SCI급) Simultaneous coating of Si and B on Nb–Si–B alloys by a halide activated pack cementation method and oxidation behaviors of the alloys with coatings at 1100 C
- 학술지 구분 국제전문학술지(SCI급)
- 게재년월 2015-09
- 저자명 Jingchang Cheng a , Seonghoon Yi a,⇑ , Joon Sik Park b
- 학술지명 Journal of Alloys and Compounds
- 발행처명 ELSEVIER
- 발행국가 해외
- 논문언어 외국어
- 전체저자수 3
홈페이지
논문 초록 (Abstract)
Phase formations during Si and B co-deposition by a halide activated pack cementation on Nb–Si–B alloys and the oxidation behaviors of the alloys were investigated together with diffusion pathway analysis. Coatings comprising Nb-borides and Nb-silicides were successfully fabricated on the surfaces of α-Nb, T2 single-phase and Nbss + T2 two-phase alloys at 900 °C, respectively. For the coating process, powder mixtures with different Si to B ratios of (12.5:12.5) and (18.75:6.25) were used, respectively. Regardless of the Si to B ratio in the powder mixture used, the coating layers were identified as NbB2/NbSi2/Nb5Si3/substrate. The diffusion pathway followed the mass balance and showed one route regardless of the compositions of powder mixtures used in this study. The sequential oxidation product layers of the α-Nb and the T2 single phase alloy were identified as borosilicate/NbO2/NbB2/NbSi2/α-Nb and (borosilicate + 3Nb2O5⋅B2O3)/Nb2O5/NbB2/NbSi2/T2, respectively. The diffusion pathway for the oxidation reaction was proposed using a schematic quaternary isothermal diagram.