Oleic Acid As Grinding Aid And Surface Antioxidant For Ultrafine Zirconium Hydride Particle Preparation

ZrH2 is brittle and easy to grind into ultrafine particles, which can be further thermally dehydrogenated to produce fine metal zirconium powder. However, surface oxidation of ZrH2 usually occurs during the grinding process. In this study, oleic acid was employed as a grinding aid and surface antioxidant for ultrafine ZrH2 preparation by wet ball milling in ethanol solution. With the addition of oleic acid, the particle size (d(50)) of ZrH2 after milling was reduced from 9.10 to 3.21 mu m, and the surface oxygen content decreased from 21.65% to 13.11%. The zeta potential of the ZrH2 surface was positive and the oleate anion was adsorbed on the ZrH2 surface by electrostatic adsorption. Oleic acid acted as a grinding aid, improving the grinding efficiency of ZrH2, and also as a coating film protecting ZrH2 from surface oxidation. Ultrafine ZrH2 particles with high purity can be manufactured by the proposed wet ball milling process, which has great potential for practical industrial production. The approach based on surfactant addition to improve the grinding efficiency and surface protection could also be applied for the preparation of other ultrafine materials using wet ball milling.