Segregation of molten salt on chromizing in thermal diffusion process

Abstract

The segregation of thermal diffusion salt bath chromizing process was analyzed. The experimental chromizing ingredients were prepared by the four groups A, B, C, and D. In order to study the segregation status of this case, the cooling molten salt in the crucible was removed by drilling from the heart core of molten salt. The core of molten salt was analyzed by X-ray fluorescence spectroscopy and XRD. Through the analysis, we can conclude that the Cr element deposited in the bottom was 4.51 times than the top. Chloride added to the molten salt will reduce segregation. Meantime we proposed some measures to overcome the segregation problem.

Keywords

segregation / thermal diffusion process / chromizing

References

[1] Liu X.J., Wang H.C., Li Y.Y. Effects of Rare Earths in Borax Salt Bath Immersion Vanadium Carbide Coating Process on Steel Substrate[J]. Surface&Coatings Technology, 2008, 202: 4 788-4 792.

[2] Liu X.J., Wang H.C., Li D.W., Wu Y.X. Study on Kinetics of Carbide Coating Growth by Thermal Diffusion Process [J]. Surface & Coatings Technology, 2006, 201: 2 414-2 418.

[3] Wu Y.X. Study on Thermal Diffusion on Cold Extrusion Die [D], 2006 Wuhan Wuhan University of Technology

[4] Liu X.J. Study on Vanadium Carbide Coating on Die Steels by Thermal Diffusion Process [D], 2007 Wuhan Wuhan University of Technology

[5] Sen S. The Characterization of Vanadium Boride Coatings on AISI 8620 Steel [J]. Surface & Coatings Technology, 2005, 190: 1-6.

[6] Herrera Y., Grigorescu I.C., Ramirez J., DiRauso C., Staia M.H. Micro Structural Characterization of Vanadium Carbide Laser Clad Coatings [J]. Surface & Coatings Technology, 1998, 108–109: 308-311.

[7] Aghaie-Khafri M., Fazlalipour F. Vanadium Carbide Coatings on Die Steel Deposited by the Thermoreactive Diffusion Technique [J]. Journal of Physics and Chemistry of Solids, 2008, 69: 2 465-2 470.

[8] Sen U. Wear Properties of Niobium Carbide Coatings Performed by Pack Method on AISI 1040 Steel[J]. Thin Solid Films, 2005, 483: 152-157.

[9] Saduman Sen. A Stuay on Kinetics of CrxC. Coated High. Chromium Steel by Thermo-Reactive Diffusion Technique [J]. Vacuum, 2005, 79: 63-70.

[10] Wang H., Qu P., Zhang Ying. Study on Corrosion Resistance and Oxidation Resistance of Materials Used in Borax Bath [J]. Material & Heat Treatment, 2010, 40(4): 27-33.

[11] Wang H., Wang H., Wang Xiao. Ni60-SiC Coating Prepared by Plasma Spraying, Plasma Re-melting and Plasma Spray Welding on Surface of Hot Forging Die [J]. Journal of Wuhan University of Technology-Materials Science Edition, 2011, 26(4): 715-718.

[12] Wang H., Wang H., Pan Chenggang. Vanadium Carbide Coating Growth on Die Steel Substrate in Borax Salt Bath [J]. Journal of Wuhan University of Technology-Materials Science Edition, 2010, 25(4): 600-603.

[13] Wang Hongfu. Research on TD Technology Several Key Issues [D], 2010 Wuhan Wuhan University of Technology