Micro-nano polycrystalline diamond composite material and preparation method thereof

Abstract

The invention discloses a micro-nano polycrystalline diamond composite material and a preparation method thereof. The micro-nano polycrystalline diamond composite material comprises the following components: carbon nano onions and micron diamond, wherein the mass percent of the micron diamond is 20-50wt.%, and the balance is the carbon nano onions; and the Vickers hardness of the micro-nano polycrystalline diamond composite material ranges from 30 GPa to 200 GPa. The preparation method comprises the following steps: carrying out annealing treatment on detonation nano diamond powder to preparecarbon nano onions; adding micron diamond crystal grains for mixing, wherein the mass percent of the micron diamond is 20-50wt.%; a mixture formed by the micron diamond and the carbon nano onions is filled into a WC hard alloy die to be pre-pressed, the pre-pressing pressure is 400-600 MPa, and pre-pressing is conducted for 10-30 s; and a pre-pressed sample is put into a mold for high-temperatureand high-pressure sintering, and the micro-nano polycrystalline diamond composite material is prepared. The Vickers hardness of the micro-nano polycrystalline diamond is nearly one time higher than the Vickers hardness of a common PCD, and the performance of the micro-nano polycrystalline diamond is obviously improved.

Description

technical field [0001] The invention relates to the technical field of composite materials, in particular to a micro-nano polycrystalline diamond composite material and a preparation method thereof. Background technique [0002] At present, polycrystalline diamond (PCD) has high hardness and wear resistance, which overcomes the shortcomings of single crystal diamond anisotropy and {111} crystal plane dissociation damage, and is widely used in aerospace, electronics, construction , gem processing, oil drilling and geological exploration and many other fields. [0003] Wang Mingming and others used nano-onion-carbon as raw material to synthesize polycrystalline diamond using a six-sided top press at 2-6GPa / 1000-1600°C / 1-6min. The block is dense and the Vickers hardness reaches HV45. ~61GPa, the grain size of the sintered body is less than 20nm, which overcomes the defect that the weak phase reduces the performance of PCD in the PCD synthesized by the existing technology, and ...

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Problems solved by technology

However, the closed and continuous carbon shell restricts the sliding of the (002) plane, which leads to the generation of stress, and the formation of twin diamonds is the result of cumulative stress release [Tang Hu, Nano-polycrystalline diamond synthesis and carbon nano-onion high temperature Research on the mechanism of high-pressure phase transition [D]. Qinhuangdao: Yanshan University, 2018]

The synthesis of PCD using carbon nano-onions (OLC) as a precursor requires extremely high pressure and temperature conditions (P≥18GPa, T≥2300℃), high requirements for equipment, high cost, and the maximum size of synthetic PCD is less than 3mm, which is difficult application

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