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Mechanism of Al-Si codeposition on In738LC through single-step diffusion process

Nikzad, S ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1504/IJSURFSE.2017.082942
  3. Abstract:
  4. The out-of-pack cementation method was applied to coat the Nickel-based super alloy IN738LC with Si-modified aluminide. Different mixtures of the pack containing pure Al, Si, alumina powders as an inert filler, and NH4Cl as a halide salt activator were used for co-deposition at 950 and 1,050°C. The results showed although the amount of subhalide vapour pressures of Al and Si were equal at 1,050°C, Al atoms diffused only after Si atoms had been deposited. Before heat treatment, the coating thickness formed by the pack containing 2.3 wt.% Al was 6 μm more than that containing 3.5 wt.% Al. After heat treatment, thickening coatings formed within the pack containing 2.3 wt.% Al was less than that obtained in the other pack containing 3.5 wt.% Al. This study suggests that increasing the depositing temperature will increase the thickness at a constant composition of the pack powder. Copyright © 2017 Inderscience Enterprises Ltd
  5. Keywords:
  6. Co-deposition ; Si-modified aluminide coating ; Alumina ; Aluminum coatings ; Coatings ; Deposition ; Heat treatment ; Silicon ; Silicon alloys ; Thickness measurement ; After-heat treatment ; Aluminide coating ; Co deposition ; Constant composition ; Depositing temperature ; Diffusion process ; Nickel- based superalloys ; Pack-cementation method ; Aluminum
  7. Source: International Journal of Surface Science and Engineering ; Volume 11, Issue 1 , 2017 , Pages 1-11 ; 1749785X (ISSN)
  8. URL: https://www.inderscienceonline.com/doi/abs/10.1504/IJSURFSE.2017.082942