Microstructures and Properties of Fe–Co–Cu Pre-Alloyed Powder for Geological Diamond Bits

Abstract

For geological diamond bits Fe–Co–Cu alloys are the a generation of metal matrix. In this paper, the Fe–Co–Cu pre-alloys with various chemical compositions were synthesized using the co-precipitation method, which were subsequently sintered at different temperatures. The structural, thermal and properties of the powders and its sintered materials were characterized by various techniques. X-ray diffraction studies indicated that solid solutions were formed for the alloys during co-precipitation process. Microstructures of these pre-alloyed powders exhibited that the sintering process was facilitated by the irregular shapes, interconnected fine particles as well as the large surface areas. The thermal effects of the pre-alloyed powders were explored by differential scanning calorimetry. The optimal sintering temperature for each pre-alloyed powder was determined by the mechanical analysis. Scanning electron microscopic results show that the composition ratio of Fe and Cu had a significant impact on the microstructures of the sintered materials, and the 65%Fe-20%Cu-15%Co alloy reached the best surface coverage over the diamond bits. The drilling performances for various pre-alloyed powders were verified by micro-drilling experiments. Those results suggested that the 65%Fe-20%Cu-15%Co alloy exhibited the optimal performance for application in geological diamond drilling bits.