Preparation method of silicon-based ceramic core with high dimensional stability at high temperature

Abstract

The invention relates to a preparation method of a silicon-based ceramic core with high dimensional stability at high temperature, and the preparation method comprises the following steps of: (1) dividing quartz glass powder into coarse powder and fine powder according to particle size; (2) immersing part of the coarse powder into a nano oxide sol, stirring, mixing, drying, calcining, cooling andsieving to obtain oxide film coarse powder; (3) mixing the remaining coarse powder, the oxide film coarse powder, the fine powder and zircon powder; (4) adding a plasticizer after a mixer is heated up; after the plasticizer is melted, adding the mixed powder, stirring and mixing, pouring out and cooling; (5) placing in a slurry barrel of a hot die casting machine, heating, melting, stirring, injecting and pressing to prepare a green body; (6) placing the green body into a bowl body, covering with a filler, shaking up and vibrating; gradually raising the temperature of a roasting furnace to thefinal firing temperature, keeping the temperature and then cooling with the furnace. When the ceramic core prepared by the method of the invention is cast at high temperature, the reburning shrinkagetemperature of the core is improved, and the reburning shrinkage rate of the silicon-based ceramic core is reduced.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to a method for preparing a silicon-based ceramic core with high dimensional stability at high temperature. technical background [0002] The ceramic core is an adapter used to form the complex cavity structure of the casting in the investment precision casting process. It interacts with the external shell to ensure the dimensional accuracy of the wall thickness of the precision casting. Therefore, the surface quality and size of the cavity of the precision casting The accuracy is completely determined by the ceramic core; in the process of investment precision casting, the drastic change of the temperature environment requires the ceramic core to have good high temperature stability, so as to ensure that it will not occur due to sudden changes in the size of the core during the casting process. Fracture or collapse, resulting in blockage or deformation of the inner ca...

AI Technical Summary

Problems solved by technology

[0014] Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a method for preparing a silicon-based ceramic core with high dimensional stability at high temperature, wherein the surface of the matrix material quartz glass powder particles of the silicon-based ceramic core is subjected to nano-coating treatment, Fundamentally solve the problem of low sintering temperature of quartz glass, increase the refiring shrinkage temperature of the silicon-based ceramic core (or equivalently reduce the refiring shrinkage rate), and promote the nano-coating and quartz glass surface by increasing the sintering temperature The reaction of the devitrification layer produces a mullite hard phase; when the core is cast at high temperature, the hard product on the particle surface will hinder the movement of the viscous flow of the glass phase, thereby improving the quality of the silicon-based ceramic core. High temperature creep resistance is the purpose of high dimensional stability (including reburning shrinkage and high temperature creep resistance)

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