In general, it had been well known that the energy efficiency of grinding process decreases with decrease of produced particle size or with increase of grinding time or with increase of input energy.
In this study, we defined the size reduction energy as the elastic strain energy which is stored up to fracture in the solids. The relationship between particle size and fracture energy or impact velocity required for fracture quantitative based on the single particle crushing was referred.
As a result, it was found that the increase of probability of collision between particles and grinding media is effective for ultrafine grinding. The above has been verified experimentally by the ball milling.
