Production of Chromium Boride Layers on Carbon Steel with Conversion Treatment: Chromium Deposition + Diffusion Annealing

Abstract

The present study has been conducted in order to obtaining chromium boride layers on carbon steel using a conversion processing comprising the following steps: boriding treatment in order to increase the amount of boron atoms in the steel surface, deposition of a thin layer of pure chromium using electrolytic method, and finally an annealing treatment for boron diffusion and formation of boride layer until complete transformation of chromium layer. Depending on the method used (chromium deposition followed by boriding or boriding followed by chromium deposition) and the holding time, the partial or complete conversion is obtained as a result of the diffusion process. The role of the annealing temperature on transformation rates of chromium into chromium boride films was investigated. It is shown that for 1 h at 900• C, the chromium layer is totally transformed. The scanning electron microscopy analysis and X-ray diffraction showed the presence of CrB and CrB2 chromium borides in addition of FeB and Fe2B iron borides.

Femtosecond Pulsed Laser Deposition of Chromium Diboride-Rich Thin Films

“…Using these experimental data and the Joensson and Hogmark approach [27], the intrinsic film hardness was found to be 21 ± 4 GPa, in which thickness was 200 nm. This value is somewhat higher than the Vickers hardness for the CrB2bulk material, where the latter was [16][17][18][19][20] GPa [3,6,8,9]. This is likely due to the nanocrystalline nature of the 500 °C deposited film.…”

“…Chromium diboride thin films have been already deposited by several techniques including thermal evaporation process [11], magnetron sputtering in different configurations [4,6,9,[12][13][14][15][16], chemical vapor deposition [17] and conversion treatment [18]. The results indicate that in some cases the films were boron-defective [9,11,14,15] while in others showed a brittle behavior [6, 12,13] or…”

“…needed particular requirements for the experimental apparatus [4]. In the case of the layers produced by conversion method, a mixture of CrB and CrB 2 was obtained [18]. On the other hand, Pulsed Laser Deposition (PLD) is not only a quite simple physical deposition technique which, in general, does not require a post annealing treatment or the presence of a buffer gas, but it has already been successfully applied to the production of metal borides thin films.…”

Boriding Treatment of Low Alloy Steels: Effect of Holding Time and Temperature

“…In order to improve the performance of mechanical parts notaby tools, shafts and, gears certain surface treatment should be used. Boriding treatment is particulary applied to iron alloys to ameliorate their surface behaviors by producing hard iron borides films [1][2][3][4]. Boriding treatment can be released by solid, liquid, or gaseous methods.…”