Corrosion mechanism of Ti2AlC MAX phase coatings under the synergistic effects of water vapor and solid NaCl at 600 °C

In-situ reaction synthesis Al2O3 overlay modified 7YSZ TBC for NaCl hot corrosion

Corrosion behaviour of AlN ceramics in LiF-LiCl-LiBr-Li molten salt at 500 °C

The present study was done to investigate the microstructure and erosion–corrosion behavior of Inconel 625 coating. 270 µm thick coating was successfully deposited on alloy-76 with cold spray coating process, and from microstructure analysis, it is found that coating is dense, smooth and hard with porosity less than 1%. Surface porosity was further reduced to less than 0.5% by burnishing process. Corrosive tests were performed in the actual working plant of medical waste incinerator for 10 cycles of total 1000 h at 900 °C. Coated samples performed better as compared to bare alloy mainly because of formation of chromia-rich protective surface scale layer which had resisted the penetration of corrosive species toward the substrate. Erosion–corrosion rates in mils per year (mpy) are 108.29, 43.45 and 30.69 for bare alloy-76, Inconel 625 coated and burnished-625 coated alloy-76, respectively. Active oxidation mechanism has been noticed in case of bare alloy in corrosive incinerator environment. Cold spray coated Inconel 625 microstructure is suitable for application in erosive–corrosive high temperature environment.

Microstructure of Ni-Cr-Based Coating for Corrosive Conditions

Analysis of cold spray‐coated boiler‐tube material in a chlorine‐based corrosive environment at 900°C

The pyrochemical reprocessing faces challenges in the selection of suitable materials for the fabrication of the container in electro-refining process. Yttria stabilized zirconia (YSZ) coating was considered as a promising material in this application, but the performance of YSZ coating in NaCl-KCl molten salt must be improved. In the present work, metal-organic decomposition (MOD) method was put forward to deposit an Al2O3 overlay on the top surface of sprayed YSZ coating. The corrosion behavior of the YSZ coatings with and without Al2O3 overlay in molten NaCl-KCl eutectic salt was investigated by immersion test. The results showed that the sprayed YSZ coating suffered severe corrosion and a NiO corrosion product formed on the coating surface. Meanwhile, a transformation of ZrO2 from a non-transformable tetragonal (t′) phase to a monoclinic (m) phase emerged. In contrast, the surface morphology of the YSZ coating with Al2O3 overlay remained almost unchanged. No corrosion product or new phase was formed. These results proved that the Al2O3 overlay prepared by the MOD method can significantly improve the corrosion resistance of YSZ coating.

Lei Zhang

Papers

Influence of Al2O3 overlay on corrosion resistance of plasma sprayed yttria-stabilized zirconia coating in NaCl-KCl molten salt

Corrosion resistance of TaSiCN coatings in NaCl-KCl molten salt