유성밀 프로세스와 밀링에너지

Abstract

Milling is a core fabrication process in powder technology. Especially the high-energy milling technology is being frequently used in energy-intensive process like mechanical alloying, mechanical activation and mechanochemistry, etc. Planetary ball mill is a representative highenergy mill together with shaker mill, stirred mill and vibration mill. Since milling condition strongly affects the property of milled powder materials, it should be controlled by changing the milling balls, the milling vial, the geometry of mill, and the rotation speed etc. to obtain an end product with desired characteristics. Milling with large, high density balls and higher rotation speed seems to provide materials with higher impact energy in comparison with small, low density balls and lower rotation speed. It is important to have an understanding the relationship between the milling process variables and the characteristics of final powder products. Many researchers have reported already their results and theories in such aspects. Attempts to modeling the ball mill process have been done in the last decades [1-14]. Burgio et al. [1] has established the fundamentals of mathematic model for determining the impact velocity of the ball and the energy transferred to powder. Padella [6] reported the results from experiments in which the energy transfer was intentionally controlled to form either intermetallic compound or amorphous phase of Pd-Si system. Research works to establish a milling map have pointed out the importance of determining which milling parameters have to be employed in order to obtain a particular final product. This paper reviews the theories of milling energy in planetary ball mill process based on the collision model.