Method for preparing metal impregnation carbon/graphite material

Abstract

A method for preparing metal impregnation carbon / graphite material is as follows: 60 to 70wt% of calcined coke, 25 to 35wt% of artificial graphite powder and 5 to 10wt% of natural graphite powder are fully and evenly mixed in a mixer and preheated to 120 to 150 DEG C, thus obtaining mixed filler; binder pitch of the softening point of 90 to 120 DEG C and the residual carbon rate of 48 to 55wt% isheated and melted, then the mixed filler is added, and the mixed filler and the binder pitch are mixed for 1 to 3h at the temperature of 120 to 150 DEG C, after mixing, sheet rolling is carried out for 6 to 10 times at the temperature of 120 to 150 DEG C, and the thickness of the rolled plate is less than 1mm, after cooling, the rolled plate is smashed to less than 200Mu m, thus preparing the final pressed powder; the pressed powder is molded and pressed at 60 to 100MPa and then is put into a carbonization furnace at inert atmosphere and heated to 1300 to 1350 DEG C at the heating rate of 5 to 10 DEG C / h, and the constant temperature is kept for 1 to 2h at the highest temperature; and the material is naturally cooled to less than 100 DEG C and is taken out of the furnace, thus obtaining the material. The method has the advantages of high mechanical strength, small aperture and uniform distribution.

Description

technical field [0001] The invention belongs to a method for preparing a carbon / graphite matrix material for impregnating metal. Background technique [0002] Carbon / graphite materials have good self-lubricating properties, small friction coefficient, and low linear expansion coefficient, so they are widely used as mechanical seal materials in industry. However, the bulk density of general carbon / graphite materials after carbonization and sintering is small (1.4-1.5g / cm 3 ), low strength, loose structure (internal opening rate of 20-30%), it is difficult to be used as a mechanical seal material for high PV (pressure and speed) value conditions. If this kind of material is used as the matrix, other molten metal materials are immersed into its open pores by high temperature and high pressure to form a firm network structure, which can greatly improve its compactness, strength and wear resistance. The metal-impregnated carbon graphite material has high mechanical strength (it...

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Problems solved by technology

[0003] Studies have shown that for metal-impregnated carbon / graphite materials, the ideal distribution state of metal in the carbonaceous body is a uniform distribution of fine mesh structure, which can not only effectively improve the densification and reinforcement effect on the carbonaceous body, but also facilitate Improve the friction and wear properties of materials; but in terms of impregnation, it is not like impregnating carbonizable organic matter, the more impregnation, the better. This is because the friction coefficient of metal is generally large, although the impregnation is too large, it can better improve the material. The strength and impermeability of the material, but the friction coefficient of the material is greatly increased, and its tribological properties are reduced; in addition, due to the large thermal expansion coefficient of the metal, the friction coefficient is high, and the immersed metal must be evenly distributed on the substrate in a fine mesh. Carbon can effectively improve the tribological properties of the material

If the metal immersed in the carbon / graphite matrix is ​​unevenly distributed or has a local aggregation state, the molten metal will form uneven internal stress in the matrix carbon during the cooling and solidification process and greatly increase the local friction coefficient of the composite material, which will also cause Its tribological performance is greatly reduced; in addition, due to the large friction coefficient in the localized metal area, the instantaneous temperature rise of the friction surface is very high under high rotation conditions, and the friction wear is serious, which makes the surface finish of the friction pair worse, further making the friction As the coefficient increases, the tribological performance deteriorates, resulting in increased friction time imbalance and wear, and the leakage phenomenon becomes more and more serious, which eventually leads to the sealing failure of the sealing element