Effect of surface roughness and plasma current to adhesion of Cr3C2-NiCr coating fabricated by plasma spray technique on 16Mn steel

The life time and quality of thermal spray coatings are strongly influenced by the technological parameters of the coating process and characteristics of the coated surface. In this paper, 16Mn steel substrates of different surface roughness are coated by Cr3C2-NiCr using a plasma spray technique. The adhesion of the coating to the substrate has been studied in relation to the roughness of the substrate and the plasma current of the spraying process. The results showed that the adhesion of the Cr3C2-NiCr coating to 16Mn steel substrate is strongly influenced by the roughness and the current intensity. The range of substrate surface roughness and current intensity at which the Cr3C2-NiCr exhibited high adhesion to the steel substrate are discussed in this paper.

Microstructure and Property of Novel γ-Fe/ (Cr, Fe)7C3 Lamellar Eutectics Reinforced Composite Coating

γ-Fe/(Cr, Fe)7C3 lamellar eutectics reinforced the composite coating was deposited onto the 16Mn steel surface to enhance its surface hardness and wear resistance. The microstructure, phase composition, microhardness as well as wear resistance of the cladding coating were explored. Results indicated that the coating showed the dense and defect-free metallurgical bonding with the substrate and mainly consisted of (Cr, Fe)7C3, γ-Fe/(Cr, Fe)7C3 lamellar eutectic, B4C and carbon fibers. (Cr, Fe)7C3, B4C and carbon fibers were tightly embedded in the γ-Fe/(Cr, Fe)7C3 lamellar eutectics matrix. The microhardness and wear resistance of the coating compared with that of the substrate were highly improved by nearly 5 and 3 times, respectively.

Application of Taguchi Method and Anova Techniques to Maximize HVOF Spraying to WC-12Co

The purpose of this study was to achieve a low-porosity HVOF (High velocity Oxygen Fuel) spray cover and to determine the effect of spray parameters on the porosity of the coating. The spray parameters studied include: Powder feed rate (A); Spray distance (B); Oxygen/Propane ratio to porosity of WC-12Co coating on 16Mn steel. Taguchi method and ANOVA (Analysis of variance) technique were used to optimize and analyze the effect of spray parameters. The results showed that the optimum spray parameters with A = 26 g/min, B = 0.2m, C = 5 for porosity smallest. Factor A has the greatest influence on porosity, followed by B and C. The experimental result is then compared to optimal results and the error is only 4.2 %. Hence, one can say that the optimal results are reliable and Taguchi method - ANOVA technique proved to be an effective solution to the optimization problem. Parameters for a WC-12Co coating with improved porosity on 16Mn steel substrate have been identified.