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.