The Research On Phases Attained By Ball Milling Metal Powders

The reaction milling which is based on the principles of mechanochemistry theory takes more and more important part in developing new materials. The present researches have been foucs on the reactions in solid-solid and solid-gas systems, but few in the solid-liquid systems. In solid-liquid system, metal is milled in organic solvent, studies on metal milled in inorganic solvent are even fewer.Taking comparison with mechanical alloying, this paper investigates the rule of reactions of titanium, titanium dioxide, ferrum and ferric oxide milled in neutral water. The experimental is as follow:1. In the Ti-H2O system, titanium is milled in distilled water, with the ratio of balls and raw material of 60:1, rotate speed of the mill of 370rpm. After 90h milling, solid solution of ferrum and titanium has been found. The surplus ferrum may be that stripped off from the milling balls. Lattice parameter of ferrum increased by 1.12% with the products being refined to 80-100nm. Under the same conditions above but changing pH value of water with hydrochloric acid or sodium hydroxide to 3 and 11 respectively, it is showed that the pH value doesn't influence the formation of products but the speed of the reactions. Speed of reaction is highest in neutral solution, followed by acid and that of alkaline is the slowest.2. As to titanium oxide-ferrite oxide and titanium-ferrum system, raw material is milled in distilled water, with the ratio of balls and raw material, rotate speed of the mill of 300rpm. The result shows that the titanium oxide has entered into the lattice of ferrite oxide, with the existence of little titanium oxide and ferrite oxide, while in ferrum-titanium oxide system, it is indicated that the two are hard to react with each other, with the appearance of a little FeTiO3. Products in the systems above are all uniform in distribution and nanometer in scale, to the level of 20-100 nm.3. Mechanical alloying technology is adopted inα- Fe₂O₃-TiO₂, Fe-Ti, Fe-TiO₂ system respectively for comparison, and the experimental is as follow: as toα- Fe₂O₃-TiO₂ and Fe-TiO₂ system, FeTiO3 can be produced with a small amount of ferrum. In terms of ferrum-titanium system, titanium is pushed into the lattice of ferrum which is tended to become amorphous. Products created by mechanical alloying are 0.1⁰.5μm on average of scale.