Preparation And Application Of Pre-alloyed Powder For Diamond Tools

Pre-alloy powder has advantages of the low sintering temperature, high degree of alloying and easy to adjust the matrix composition. Now it is widely used in the preparation of diamond tools. Atomization comminuting process has been extensive application in industrial production due to its composition uniform, good technology controllability, sound repeatability of powder property, high efficiency, and low equipment investment. In this paper, the effects of flour milling technology on powder morphology and particle size distribution by adjusting the parameters of milling process were investigated. The effects of FCuZnSnNi proportion, sintering process parameters and oxygen content on segment hardness, bending strength and shear strength were analyzed. The main conclusions are as follows:1. During the atomization comminuting process, the powder morphology is mainly effect by the interfacial tension and viscosity of the molten alloy. While temperature and chemical composition are the primary factors effect the surface tension and viscosity of the molten alloy. When other conditions remain unchanged, the larger surface tension of molten alloy is, the more proportion spherical or near-spherical powder is.2. When other conditions are the identical, the smaller diameter of alloy flow is, the smaller powder particle size is. When atomization medium pressure and spray atomizer circumferential size are the same, the higher molten alloy superheat is, the smaller particle size is. The greater pressure of the atomization medium is, the smaller particle size is.3. With the increasing of FCuZnSnNi proportion, porosity of the matrix reduces, shear strength and bending strength increase at first, and then decrease later. When WFCuZnSnNi is 12%, the shear strength and bending strength reached the maximum, valuation are 511MPa and 738MPa, respectively.4. Appropriately increasing the sintering temperature or holding time can improve the alloying extent of the matrix and reduce the porosity. Meanwhile hardness, shear strength and bending strength of the matrix will be sharply improved.5. With the decrease of oxygen content, hardness, shear strength and bending strength of the matrix will be obviously improved.