Graphite and ceramic composite material and preparation method thereof

Abstract

The invention provides a graphite and ceramic composite material and a preparation method thereof. The graphite and ceramic composite material is prepared by compounding a porous graphite framework and ceramic; the graphite and the ceramic are alternatively and uniformly distributed; the volume fraction of the porous graphite framework is 30 to 70%, and the balance amount is ceramic. The preparation method comprises the following steps of firstly, utilizing the porous graphite framework which is quickly prepared by a selective laser sintering forming technique, carbonizing, and coating the ceramic coating; utilizing a gel injection molding forming technique to fill the ceramic material, freeze-drying under the vacuum condition, discharging glue, and sintering at high temperature, so as toobtain the graphite and ceramic composite material. The graphite and ceramic composite material prepared by the preparation method has the characteristics that the heat conductivity is low, and the strength is high; the chemical stability is good, the heat expansion coefficient is low, the anti-thermal vibration ability is excellent, and the high-temperature metal liquid impact can be endured fora long time; after secondary mechanical cutting processing, the graphite and ceramic composite material can be repeatedly used for multiple times, and can replace the traditional water glass sand type; the graphite and ceramic composite material can be matched with the graphite casting in the production of steel castings.

Description

technical field [0001] The invention relates to a graphite ceramic composite type and a preparation method thereof, belonging to the technical field of forming and manufacturing of non-metallic materials. Background technique [0002] Graphite molds are usually machined from high-strength and high-density synthetic graphite. Graphite molds have high thermal conductivity (generally between 60~150W / m·k), strong chilling ability, good mechanical properties, low thermal expansion coefficient, good chemical stability and thermal shock resistance, and can be used for Secondary cutting process, repeated use many times. Castings produced by graphite molds not only have good surface quality, stable dimensional accuracy, and good mechanical properties of castings, but also have high production efficiency and low production costs. As a mold for continuous casting or semi-continuous casting, graphite casting molds are mostly used in the production of castings such as zinc alloy, coppe...

AI Technical Summary

Problems solved by technology

[0004] However, as an auxiliary sand mold in graphite casting molds, water glass sand molds have the following disadvantages: First, water glass sand molds cannot withstand the impact of high temperature molten steel above 1550°C for a long time, that is, sand cleaning and re-core making are required for each casting mold or modeling, the process route is complicated and lengthy; secondly, due to the constraints of the current technological level, the recovery and reuse rate of sodium silicate sand is low (about 25%), and waste sand needs to be stacked in a special site. As solid waste, it is harmful to the surrounding environment Thirdly, the sodium silicate sand mold is a loose and porous material, and its mechanical properties are poor (when the residual moisture is 0.5%, its compressive strength is about 0.8MPa, and its tensile strength is only 0.01MPa). Therefore, low-strength sand molds are extremely susceptible to damage, it is impossible to restore the shape through secondary cutting and other technological measures to achieve synchronization with the graphite mold, so as to achieve the purpose of repeated use

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