Processing and Properties of Ultra-Fine Quaternary Cu-Based Pre-alloyed Powder for Diamond Tools by Co-precipitation Process

In this paper, the preparation of pre-alloyed powder and its effect on the properties of metal-bonded diamond tools were systematically studied. A co-precipitation process was used to prepare ultra-fine quaternary Cu-based pre-alloyed powder. The optimal parameters of preparing the precursor powder were precipitation temperature of 50 ℃ and reactant concentration of 1 mol/L. After the precursor powder was calcined and reduced by hydrogen, ultra-fine Cu-based pre-alloyed powder with an average particle size of about 0.55 μm was obtained and its main components were Cu, Fe, Ni, Cu–Sn, and Fe₃Ni₂. Furthermore, the mechanical properties of the bulks with pre-alloyed powders and the elemental metal powder mixture of equivalent composition were investigated. The results demonstrated that the mechanical properties of sintered bulks, including relative density, hardness and flexural strength, were improved using pre-alloyed powder. The optimal hardness and flexural strength values of the bulks with pre-alloyed powder were 110 HRB and 1056 MPa, respectively, which were 10.0% and 24.8% higher than those of the mixed powder matrix (100 HRB and 846 MPa). With the addition of diamond particles, the maximum flexural strength of the bulks reduced to 882 MPa, which was still 24.1% higher compared to the mixed powder matrix (711 MPa). In addition, the cutting ability of the diamond saw blade with pre-alloyed powder was superior to that with the elemental metal mechanical mixing powder.