Method for preparing porous chromium carbide by reactive sintering process
Release time:
2021-11-16 10:04
Source:
The invention relates to a porous carbide preparation method, in particular a porous chromium carbide preparation method and its reaction sintering. Porous ceramics have significant properties such as low density, wide porosity range, good high temperature stability, low thermal conductivity, high permeability, and low specific heat capacity. Therefore, they are widely used in many places, including catalytic carriers, filters, bioreactors, Batteries, gas sensors, gas separation devices, thermal insulation materials, capacitors, shock absorbers, heaters, heat exchangers, molds and surgically implanted organs. With the emergence of more and more new porous materials, they are becoming more and more important to our modern scientific and technological life. So far, many inorganic materials (oxides, carbides, etc.) It has been used to prepare porous ceramics.
It is an object of the present invention to provide a method for reducing chromium oxide to chromium carbide at a relatively low temperature using an atmospheric reduction method, and to provide a novel method for preparing a porous chromium carbide material. According to the technical scheme of the present invention, it is a method for preparing porous chromium carbide by using a reaction sintering process. First, an embryo body of a required shape is prepared, that is, the chromium oxide powder is uniformly ground in a ball mill, mixed and stirred with a binder PEG-400 (polyethylene glycol) according to the weight fraction, and cold isostatically pressed into a ceramic embryo body of a specific shape in a special mold (such as a cylinder, cube, hexagon, etc.) made by the manufacturer.). The porous ceramic is then sintered in a vacuum tube furnace filled with a carbon reducing atmosphere. The invention relates to a method for preparing porous chromium carbide by using a reaction sintering process, which comprises the following steps: adding chromium oxide powder to aluminum oxide balls, grinding for 10 hours to uniformity, adding a binder PEG-400, mixing evenly, and mixing The uniformly mixed powder is pressed into an embryo body by cold isostatic pressing in a mold, the embryo body is placed in a vacuum tube furnace, sintered under 150 for 1 hour, and then heated to 1000 sintering for 2 hours; the mixed gas is introduced and sintered at 1000-1300 for 10-20 hours to obtain a macroporous chromium carbide ceramic block material. In order to prevent the oxidation of porous chromium carbide at high temperatures, argon protection should be introduced during the cooling process. The invention can obtain various shapes of large-hole chromium carbide block materials by means of green dense sintering, and the large-hole chromium carbide block material has strong operability and controllability on the microstructure of porous materials, is simpler than the traditional method, is easy to form, and is suitable for the industrial preparation of porous ceramics.
Compared with the prior art, the present invention has the advantages that: macroporous chromium carbide bulk materials of various shapes can be obtained by dense sintering method, which is simpler and easier to form than traditional methods; by controlling the green compact pressing process and sintering Parameters, macroporous ceramics with specific porosity and pore size can be prepared as required, and the microstructure of porous materials has strong operability and controllability. The device is simple, controllable and low cost, which is suitable for the industrial preparation of porous ceramics. This idea has guiding significance for the development of porous ceramic preparation technology.
Chromium carbide
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