中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 12 No. 3 June 2002 |
during milling of Cr powders
(School of Materials Science and Engineering,
Shandong University, Ji′nan 250061, China)
Abstract:The formation regularity of surface coating on milling balls during milling of C r powders was investigated, revealing that the plastic deformation of the balls surface plays an important role in the formation of coating and that the stronger affinity between the powders and the balls is a necessary pre-condition for the coating. The size of Cr powders, the coating thickness and the microhardness vary consistently with milling time during milling. At initial milling stage, t he powder size decreases, while the coating thickness and the microhardness increase, however, after milling for 24h, they all change slightly with prolonged milling, indicating a dynamic equilibrium between the powders cold welding and crashing, i.e. an almost equal rate for the powders attaching to and breaking off the milling balls.
Key words: coating;milling balls;plastic deformation;microhardness