Parameter optimization of high energy ball milling process for TiO2 powder using the Taguchi method

The Taguchi method's robust design was applied to investigate the effect of main high-energy ball milling (HEBM) parameters – milling time (MT), ball-to-powder weight ratio (BPWR), and milling speed (MS) - on the TiO₂ crystallite size (CS). The experiment used the L₁₆(4³) orthogonal array (OA). The as-received and milled powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The CS of TiO₂ varied between 3.48 and 73.70 nm depending on the HEBM conditions. The optimum milling parameter combination was determined by using the analysis of signal-to-noise (S/N) ratios. Based on the S/N ratio ana-lysis, optimal HEBM conditions were found to be MT 100h, MS 400rpm, BPWR 50:1. The analysis of variance (ANOVA) was used for indicating the significance of each milling parameter and their effect on CS. Statistical analysis by S/N and ANOVA established that the MT is the most influential parameter, followed by MS and BPWR. The results of the parameter optimization experiment were validated by a confirmation test at a 90% confidence level. The confirmation test showed that there is a good agreement between the experimental and statistical data.