Microstructure and characterizations of one-step forming TiC/Ni₃Al–Ni₃Al multicoating on 316L stainless steel

Abstract

In this paper, in situ TiC/Ni₃Al–Ni₃Al multicoatings were fabricated on 316L stainless steel substrate by one-step forming technology. The phase constitutions and microstructure of multicoatings were observed through X-ray diffraction, scanning electron microscopy and three-dimensional laser scanning, and their performances were studied by microhardness, wear, salt spray corrosion, cavitation erosion, thermal oxidation and hot corrosion tests. The results showed that TiC/Ni₃Al–Ni₃Al multicoatings and 316L powder metallurgy stainless steel substrate were formed simultaneously with metallurgical bonding by one-step forming technology. Compared with 316L stainless steel, the formed TiC/Ni₃Al–Ni₃Al multicoatings with higher hardness presented a better wear resistance, especially at elevated temperatures. Meanwhile, TiC/Ni₃Al–Ni₃Al multicoatings possessed excellent abilities to resist the corrosion and oxidation, including the salt spray corrosion, cavitation erosion and hot corrosion. The good performance of the multicoatings was attributed to the formation of continuous phases of TiC–Ni₃Al without pores and excellent metallurgical bonding interface.

Keywords:

• Powder metallurgy
• Interface
• Composite
• Steel
• Coating

Acknowledgements

This work is supported by Natural Science Foundation of Jiangsu Province, China (grant no. BK2012250), the Opening Foundation of Jiangsu Province Material Tribology Key Laboratory, China (grant no. Kjsmcx201302), and Research Fund Jiangsu Province Key Laboratory of High-end Structural Materials (grant no. hsm1303).