Parametric optimization of wt.% Y₂O₃ modified chromium-aluminide coatings using utility concept-based Taguchi approach

Abstract

Purpose

The purpose of this paper is to obtain a single setting (optimal setting) of various input parameters of pack cementation process, i.e. halide salt activator, powder of master alloy and wt% of Y₂O₃ to obtain a single output characteristic as a whole namely resistance of hot corrosion for T91 steel.

Design/methodology/approach

The multi-criterion methodology based on Taguchi approach and utility concept has been used for optimization of the multiple performance characteristics namely hot corrosion rate K_P1, K_P2 and K_P3 for pack cementation coated T91 steel in chlorine and vanadium environment.

Findings

All the three pack cementation parameters, namely, halide salt activator, powder of master alloy and wt% of Y₂O₃ had a significant effect on the utility function based on analysis of variance for multiple performances. The percentage contribution of halide activator (1.54 percent), master alloy powder (4.66 percent) and wt% Y₂O₃ (93.79 percent). The results indicated the beneficial influence of yttrium on the chemical stability of the protective layer in presence of chlorine and vanadium environments. The optimal parameter settings obtained in this study is A2B2C1, i.e. halide salt activator (NaCl), powder of master alloy (92Cr-8Al) and 1wt% of Y₂O₃.

Research limitations/implications

The outcome of this study shall be useful to explore the possible use of the developed coating for high temperature components. Unfortunately, the pack cementation was normally limited by the diffusion and reaction kinetics involved, which has a detrimental effect on the mechanical properties of work pieces. Therefore, reducing pack cementation temperature is required for widespread application of the pack coatings.

Social implications

Pack coating at optimum conditions can be used for surface coating technologies to economically improve high temperature oxidation, corrosion resistance of components.

Originality/value

The multi-criterion methodology based on Taguchi approach and utility concept has been used for first time for parametric optimization of wt% Y₂O₃ modified chromium- aluminide coatings for T91 steel.

Citation

Hussein, A.K. (2017), "Parametric optimization of wt.% Y₂O₃ modified chromium-aluminide coatings using utility concept-based Taguchi approach", Multidiscipline Modeling in Materials and Structures, Vol. 13 No. 3, pp. 448-463. https://doi.org/10.1108/MMMS-04-2017-0020