The microstructure, phase consistence and microhardness of thermal sprayed coatings were investigated. The tungsten and chromium carbide coatings and also composite NiCrSiB coating were analyzed. The microstructure of coatings were observed by using optical microscopy (MO), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Almost equiaxial carbide particles settled inside the surrounded material of coating were found. The cracks propagating thorough the particles and along boundaries between the particles and surrounded material were observed. This phenomenon was connected with the porosity of coatings. The decarburization process was detected in coatings by phase composition investigation using X-ray method. The decarburization process was the reason due to which beside initial Cr3C2 the Cr7C3 and Cr23C6 particles were found. In the tungsten coatings beside the initial WC carbides the W2Cones were found.
References
[1]
C. R. C. Lima and F. Camargo, “Thermal Spray 2003, Advancing the Science & Applying the Technology,” ASM International, 2003.
[2]
J. M. Guilemany, N. Espallargas, P. H. Suegama and A. V. Benedetti, “Comparative Study of Cr3C2-NiCr Coatings Obtained by HVOF and Hard Chromium Coatings,” Corrosion Science, Vol. 48, No. 10, 2006, pp. 2998-3013. doi:10.1016/j.corsci.2005.10.016
[3]
M. W. Richert, “The Wear Resistance of Thermal Spray the Tungsten and Chromium Carbides Coatings,” Journal of Achievements in Materials and Manufacturing Engineering, Vol. 47, No. 2, 2011, pp. 177-184.
[4]
H. Jianhong and J. M. Schoenung, “Nanostructured Coatings,” Materials Science & Engineering, Vol. A336, 2002, pp. 274-319.
[5]
G. N. Salaita and G. B. Hoflund, “Dynamic SIMS Study of Cr3C2, Cr7C3 and Cr23C6,” Applied Surface Science, Vol. 134, No. 1-4, 1998, pp. 194-196.
doi:10.1016/S0169-4332(98)00246-3
[6]
L.-M. Berger, S. Saaro, T. Naumann, M. Wiener, V. Weihnacht, S. Thiele and J. Suchanek, “Microstructure and Properties of HVOF-Sprayed Chromium Alloyed WC-Co and WC-Ni Coatings,” Surface and Coatings Technology, Vol. 202, No. 18, 2008, pp. 4417-4421.
[7]
G.-C. Ji, C.-J. Li, Y.-Y. Wang and W.-Y. Li, “Microstructural Characterization and Abrasive Wear Performance of HVOF Sprayed Cr3C2-NiCr Coating,” Surface and Coatings Technology, Vol. 200, No. 24, 2006, pp. 6749-6757.
doi:10.1016/j.surfcoat.2005.10.005
