Wear parameter optimization for CrN/TiAlSiN coating using novel BWM integrated TODIM decision-making approach

In the present work, TiAlSiN thin film with CrN interlayer deposited on hardened DAC-10 tool steel was subjected to wear test against tungsten carbide (WC) counterbody. Taguchi and multi-objective decision-making (MODM) method were used to optimize and evaluate the relative effect of four independent wear parameters, namely temperature (T), sliding distance (S_v), applied load (L), and sliding distance (S_d) on the wear responses such as wear rate (WR), friction coefficient (COF), surface roughness (Ra), wear depth (WD), and hardness (Hv). The coated surface was characterized to evaluate its topography, and structural make-up using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-Ray diffractometry (XRD). Based on the wear test results, novel BWM (best–worst method) 'integrated TODIM (Tomada de Decisao Interativa Multicriterio) was used to optimize the wear parameters. The optimized wear parameters were T = 100 °C, S_v = 0.05 m/s, L = 5 N, and S_d = 2000 m giving desirable wear (or output) responses (WR = 5.67 × 10^–8 mm³ Nm⁻¹, COF = 0.51, Ra = 5.4 µm, WD = 0.67 µm and Hv = 2781). The robustness of the proposed optimization method was analyzed using sensitivity analysis as well. Finally, the worn coated surface and counterbody was investigated to understand the wear mechanism with the combination of wear parameters designated as best alternative (optimized wear parameters), and the worst alternative. Micro-delamination and micro-plowing dominated the wear mechanism against the best alternative whereas wear test with worst alternative resulted in adhesion, heavy delamination, and plowing on the coated surface.