The Research On Phases Attained By Ball Milling Metal Powders In Solution

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 foucsed on the reactions in solid-solid and solid-gas systems,but few in the solid-liquid systems.Three systems were investigated by milling metal powders in distilled water. Based on the experimental results and the correlative chemistry theory,the phases formed in the process and its influenceable factors were studied.The significant results were enumerated as follows:As for the Mn-H2O system,5g pure Mn scraps(99.5%,-200mesh)and distilled water served as the starting materials were milled by high energy ball miller together with 200g steel balls as the milling medium.The experiments were conducted with the rotation speed of 380rpm.γ-Mn3O4 nanopowders were fabricated after milling some time and would experienced phase transformations if continue to be milled.The reaction would be accelerated if a little of HCl or MnSO4 was added while be decelerated if .a little of NaOH was added.Theγ-Mn3O4 phase with particl size between 20~100 nanometer was obtained after milling 1.5h when trace HCl was added.The oxygen added to the ball tin has little effect on the reaction.For the Zn-H2O system, 5g pure Zn scraps(99.5%,-200mesh)and distilled water served as the starting materials were milled together with 200g steel balls at the rotation speed of 380rpm. The ZnO and Zn(OH)2 powders on nanometer scale were generated after milling 20h and the Zn(OH)2 phase gradually transformed to ZnO with the milling time prolongation.But single phase ZnO couldn't be attained even after milling 90h.A bit of HCl added to distilled water slowered the reaction in evidence while a little of NaOH could accelerated the reaction and single phase ZnO was prepared after milling 40h. The oxygen added to the reaction system accelerated the reaction and single ZnO phase with average particl size below 30 nanometer was frabricated aftermilling 40h.The reaction speed will obviously improved when the the weight ratio of ball-to-material was 100 and single phase ZnO will be attained after milling 20h.For the Sn-H2O system, 5g pure Sn scraps(99.5%,-200mesh)and distilled water served as the starting materials were milled together with 150g steel balls at the...