A study of the microstructure, wear and corrosion behaviour of high velocity oxygen fuel (HVOF) thermally sprayed coatings and self-standing forms, obtained with blends of Cr_3C_2-NiCr-NiCrBSi

摘要

The main conclusions of the present work are: 1. Coatings have been obtained with different mechanical blends of Cr3C2-NiCr and NiCrBSi. 2. Microstructure of the coatings consists on a dispersion of Cr3C2-NiCr particles in a matrix of NiCrBSi. The proportion of Cr3C2-NiCr and NiCrBSi in the coatings is proportional to the amount of these materials in the mechanical blend. 3. The bond between the particles of Cr3C2-NiCr and NiCrBSi in the coatings is mechanical. Diffusion phenomena have not been detected. 4. In all the cases, coatings have a compact structure with porosity levels between 2% and 3%. The oxide percentage is about 5%. 5. The microhardness of CrX coatings is bigger than that of the Cr3C2-NiCr and NiCrBSi coatings due to the hardening of the metallic matrix by the impact of solid particles of chromium carbide. 6. The wear resistance of CrX coatings depends on the content in NiCrBSi. The lower the content NiCrBSi the higher the wear resistance. 7. CrX coatings have better friction wear resistance than Cr3C2-NiCr and NiCrBSi coatings. 8. The corrosion resistance of the CrX coatings depends on the NiCrBSi content. The higher the NiCrBSi amount the higher the corrosion resistance.