APPLICATIONS OF COMMINUTION TECHNIQUES FOR THE SURFACE MODIFICATION OF POWDER MATERIALS

This paper reviews a new method for surface modification to cover particle surface with fine particles mechanically in a dry phase by making use of comminution techniques. First, the relation of comminution process with surface modification technology is discussed, and the advanced machines developed in Japan to treat core particles surface with fine particles based on grinding principles are introduced. Then, the details of the composite process of core/fine particles with these machines are explained. In the second section, the effects of the controlling factors on the composite process such as mechanical actions, treating temperature and atmosphere are discussed. The third section deals with the conditions of combinations of core/fine particles acceptable to this method, and it is demonstrated that this method has a great feasibility to fabricate composite particles by the combination of various kinds of core/fine particles. The scale-up of these machines is explained in the fourth section, and a typical example is introduced. The last section summarizes the applications of the composite particles fabricated by this method to create various kinds of new materials, which include the application for surface modification technology. The applications of this method are shown to expand for other types of processing such as rounding particles and mixing different kinds of powder materials precisely. Furthermore, it is also explained that this method can fabricate composite particles inside which different kinds of components are dispersed.