Synthesis And Characterization Of Potycrystalline Diamond Compact With High Thermal Stability

Polycrystalline diamond compact is a new type functional material, polycrystallinediamond layer by metal or non-metal binder bonds on cemented carbide. Hard alloy substrateand diamond powder abrasive after assembled sintering under high temperature and highpressure. The PDC has high wear resistance, high thermal conductivity and high hardness ofpolycrystalline diamond, as well as hard alloys with high toughness, weldability and strength.Application areas include oil drilling, coal mining, manufacturing cutting tools, geologicaldrilling etc..Traditional synthetic polycrystalline diamond compact structure has been improved.(1)in the synthesis chamber, dolomite instead of pyrophyllite;(2) the use of salt instead of CBNas a high-pressure reactor and pressure transmission medium; and (3) Instead of thetraditional metal foil structure, using three metal cup.In this paper, by using a hinge type domestic six face presser6x600T, polycrystallinediamond composite sheet for successful method using Co and Si powder melt infiltrationcatalytic synthesis of growth type Φ19mm diameter drilling. Determine the synthesis processfor the synthesis of pressure5.5-7GPa, synthesis temperature1650℃-1750℃, synthesistime was10min.Using XRD, EDX, SEM, DSC-TG analysis method, the residual stress andmicrostructure of polycrystalline diamond composite with high thermal stability were studied.At the same time, Raman analysis, residual stress, the heat resistance and hardness propertiesof PDC were tested.Polycrystalline diamond composite of high thermal stability made TGA-DTA analysis.Conventional PDC initial oxidation temperature is probably about780℃, the initialoxidation temperature polycrystalline diamond composite of high thermal stability isprobably about820℃. Higher than conventional PDC is probably about40℃.Mechanism for the synthesis of polycrystalline diamond composite of high thermalstability is analyzed. Compared to conventional PDC，the structure of new designed PDC was changed from the previous two-layer structure into a three-layer structure by infiltrationinto both sides of the permeation side. Silicon carbide and diamond strong chemical bondingoccurs at the interface grow into high thermal stability dia-SiC bonded structure model.