Corrosion Behavior of CrN/AlSiN Multilayer Coatings on AISI 304 Stainless Steel in Aluminum Alloy Melt

摘要

In recent years, advances in coating deposition technologies have led to the development of nano-structured coating materials with unique properties. Among the many systems, Cr-Al-Si-N coatings have a variety of interesting properties such as the superhardness (～40 GPa), thermal stability with high-temperature oxidation resistance. These coatings were characterized as nanocomposites consisting of nanocrystalline CrN or CrAlN embedded in amorphous Si_3N_4 matrix. Nevertheless extensive discussion has been focused on the mechanical and thermal properties of Cr-Al-Si-N coating, the corrosion resistance at higher temperature is not reported yet. Therefore, the main target of this study is to evaluate the corrosion resistance of the CrN/AlSiN multilayer coating which was synthesized by cathodic arc deposition with Cr and Al88Si12 dual cathodes. The as-deposited coating was following conducted with heat treatment in nitrogen atmosphere at the temperature of 400°C, 600°C and 800°C for 1 hour, respectively. Microstructure of the heated films is analyzed by X-ray photoelectron spectroscope, X-ray diffractometer and scanning electron microscopy. The corrosion resistance of the heated CrN/AlSiN coatings was studied by dipping in the aluminum alloy melt for 3 hours. The results turned out that the better corrosion resistance of CrN/AlSiN multilayer coated stainless steel was obtained by post deposition annealing treatment in nitrogen at 400°C and 600°C if compared to that of the other samples.