Preparing method for gradient hard alloy with surface rich in graphite phase

Abstract

The invention discloses a preparing method for a gradient hard alloy with the surface rich in graphite phase. The preparing method is characterized in that firstly, heat preservation is conducted for 2-4 h at the temperature ranging from 550 DEG C to 750 DEG C, and a hard alloy raw blank removing a forming agent is formed, wherein the porosity of the hard alloy raw blank ranges from 25% to 40%; then, the three substances including amorphous Si-C-O wrapping TiH2 core / shell structure powder, a multi-wall carbon nano tube and Na2CO3 are mixed according to the weight percent of 1:2:1, and then a hydrogen-containing carburizing medium is prepared, wherein the outer diameter is smaller than 8 nm, the length is smaller than 30 microns, and the specific surface area is larger than 350 m<2> / g; then, the raw blank is embedded in the hydrogen-containing carburizing medium and is compacted under the pressure of 5-15 MPa; and finally, liquid phase sintering is conducted, and the gradient hard alloy with the surface rich in graphite phase is prepared. The preparing method solves the problems that in the existing technology, grain growth is serious, the carburization time is long, and efficiency is low; and in the sintering process, the gradient hard alloy with the surface rich in graphite phase is prepared in the sintering process.

Description

technical field

[0001] The invention relates to a preparation method of cemented carbide, in particular to a preparation method of gradient cemented carbide whose surface is rich in graphite phase, and belongs to the field of hard materials. Background technique

[0002] Cemented carbide has the characteristics of high strength, high hardness, high elastic modulus, wear resistance, corrosion resistance, low thermal expansion coefficient and high chemical stability. It is known as "industrial teeth" and is widely used as cutting tools and drilling tools , wear-resistant parts, etc. In order to improve its friction and wear performance, carburizing treatment can be carried out on the surface to make the surface rich in graphite phase, so as to obtain a good anti-friction effect.

[0003] CN105331868A discloses a preparation method of gradient structure WC-Co cemented carbide. The invention uses the WC-Co cemented carbide billet with a porosity of 15-40% and uniform distributi...

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