Invited Speaker

Prof. Keke Chang (Research Fellow)

Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences Zhengzhou University

Email: changkeke@nimte.ac.cn

Title: High-Temperature Corrosion Mechanisms of Ni-Based Alloy Coatings Serving in Harsh Marine Environment

Profile:

Keke Chang is a Professor at Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences. He obtained his doctoral degree at Materials Chemistry, RWTH Aachen University. His research focuses on theoretical design and surface/interface manipulation of materials for harsh environment. He has published 125 papers in peer-reviewed journals, which have been cited ~4500 times. He is a Member of Scientific Group Thermodata Europe and serves on the Early-Career Editorial Boards of Surface & Coatings Technology, Friction, and Materials Research Letters. His contributions have been recognized by several awards, including the Spriggs Phase Equilibrium Award from the American Ceramic Society, the Best Paper Award (1st Place) from Journal of Materials Informatics, and the Outstanding Contribution Award from Materials Research Letters.

Abstract:

Marine equipment operating in harsh thermal-salt environments often suffers rapid degradation, as conventional Ni-based alloy coatings lose their protective Cr₂O₃ scale under the combined effects of high temperature and NaCl. Targeting applications under such aggressive conditions, we designed a series of NiAlYX (X = Si, Ta, Nb, Ti, Mo) alloy systems based on phase diagram calculations. Through multiscale theoretical modeling and experimental validation, we systematically revealed the evolution of oxide scale structures after oxidation at 750 °C for 168 hours. The results show that NiAlYSi forms a dense and stable oxide scale comparable to NiAlYCr, demonstrating superior oxidation resistance. In contrast, alloys containing Ta, Nb, Ti, or Mo tend to develop a thicker NiO outer layer and deeper oxidation zones, exhibiting reduced corrosion resistance. Furthermore, by constructing a high-temperature salt-reaction system and employing in-situ gas detection, we found that NaCl reacts rapidly with Cr, forming volatile chlorides that disrupt the protective oxide layer. Combined with thermodynamic and first-principles calculations, we elucidate the underlying damage mechanism of hot-salt corrosion. This work provides theoretical guidance for the compositional optimization of Ni-based alloy coatings adapted to harsh marine environments.