Carbon nanotube-nano polycrystalline diamond composite material and preparation method thereof

Abstract

The invention belongs to the technical field of composite materials, and relates to a carbon nanotube-nano polycrystalline diamond composite material and a preparation method thereof. Raw materials comprises by mass, 10-30% of carbon nanotubes (CNTs), with the balance being onion-like carbon (OLC). The preparation method comprises the following steps: mixing the two raw materials of OLC and CNT according to different mass ratios; and filling a hard alloy die with the CNT and OLC mixture obtained after mixing, and pre-pressing under 400-600 MPa; then putting the pre-pressed sample into a mold and performing high-temperature and high-pressure sintering under 7-25 GPa at 1800-2200 DEG C, performing heat preservation for 5-60 min, then cooling and performing pressure relief to obtain the composite material. The CNT is adopted to balance the internal pressure loss of the sintered body, the sintering condition is reduced, the problem that the sintering condition is high when OLC is adopted as a raw material to prepare the polycrystalline diamond sintered body is solved, and the high-hardness carbon nano tube-nano polycrystalline diamond composite material is obtained.

Description

technical field [0001] The invention belongs to the technical field of composite materials, and relates to a carbon nanotube-nanometer polycrystalline diamond composite material and a preparation method thereof. Background technique [0002] Polycrystalline diamond (PCD) has high hardness and wear resistance, it overcomes the shortcomings of single crystal diamond anisotropy and {111} crystal plane dissociation damage, and is widely used in aerospace, electronics, construction, gemstones 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, an...

AI Technical Summary

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]

[0004] However, the synthesis of PCD using carbon nano-onions (OLC) as a precursor requires extremely high pressure and temperature conditions (P≥18GPa, T≥2300°C), high requirements for equipment, high cost, and the maximum size of synthetic PCD is less than 3mm , it is difficult to apply