Ceramic material sintering furnace and isostatic pressing field-controlled spark pulse sintering method

Abstract

The invention discloses a ceramic material sintering furnace and an isostatic pressing field-controlled spark pulse sintering method, namely isostatic pressing and spark pulse field controlled sintering for short. The isostatic pressing and spark pulse field controlled sintering is characterized by comprising preparation of a ceramic blank, an isostatic pressing and spark pulse field controlled sintering furnace, processing of a ceramic sintering body, and an isostatic pressing and spark pulse field controlled sintering method, wherein the isostatic pressing and spark pulse field controlled sintering furnace comprises a lower furnace body, a thermocouple, an upper furnace body, an electrode plate, an bench insulator, an electrode lead, a graphite packing, a control electric field, a rubber seal cartridge, an insulating ring adaptor, a pressure gauge, a gas cylinder, a gas valve, a compressor, a gas inlet, a gas outlet, an impulse current generator, a sintering controller and fixing support feet, the isostatic pressing and spark pulse field controlled sintering method enables the transfer and direction of the heat energy, pressure and electromagnetic field of macroscopic and microcosmic ceramic materials to tend to be uniform due to the application of the discharge plasma pulse currents and alternating electromagnetic fields on the blank and the comprehensive action of gas isostatic pressing, the ceramic material is uniformly and isotropously sintered in the microcosmic crystal lattice, the grain boundary and the dot matrix, so that the various performances of the sintered structural ceramic material are improved.

Description

technical field [0001] The invention relates to the technical field of manufacturing superhard and wear-resistant ceramic materials, in particular to a ceramic material sintering process and technical equipment, in particular to a ceramic material sintering furnace and an isostatic pressure field-controlled plasma sintering method. Background technique [0002] With the rapid development of the electronics industry and the aerospace industry in recent years, there are more and more manufacturers of ceramic parts. In particular, superhard wear-resistant ceramic materials are developing faster. However, the raw material formula, manufacturing process, molding and sintering methods of superhard wear-resistant ceramic materials play a key role in the quality and performance of superhard wear-resistant ceramic materials. . According to different product structures, specifications, precision and performance, the commonly used molding methods in the prior art include: compression ...

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Problems solved by technology

[0006] Pressureless sintering: simple high-temperature sintering method, the disadvantage is that there is no external force, and the pure body internal heat energy has a macroscopic and microscopic influence on the ceramic material; the disadvantage is that the densification of pulling out gas and crystal lattice and grain boundary rearrangement is not enough

Hot pressing technology has a history of decades. It was first used in the preparation of tungsten carbide and tungsten powder dense parts, and now it has been widely used in the production of ceramics, powder metallurgy and composite materials; the disadvantage is: the pressure applied mechanically, the pressure applied It has directionality, and the macroscopic pressure directionality leads to uneven microscopic structural pressure, which makes the performance uniformity of the sintered body poor

Using gas or liquid as the pressure medium, the material (powder, green body or sintered body) is subjected to uniform pressure in all directions during the heating process, and the densification of the material is promoted by the combined action of high temperature and high pressure; the disadvantage is: through gas or The liquid exerts pressure on the workpiece. The pressure of the gas or liquid is isotropic and equal, but the gas or liquid exerts the same pressure on the surface of the workpiece. As the structure and thickness of the workpiece change, the workpiece The pressure felt by various parts of the interior and different structural shapes is completely different, which means that the surface of the workpiece is subjected to the same pressure, but inside the workpiece or at different depths, the internal or microscopic pressure generated by the same pressure on the surface The pressure is completely different, so pure hot isostatic pressing is sintering under the same external pressure and the same external heat; it will inevitably cause the inhomogeneity of the internal micro-morphology of the sintered body, which will also lead to the performance of ceramic materials. Defects on

The main feature of this technology is the use of bulk heating and surface activation to achieve ultra-fast densification and sintering of materials; the disadvantage is that the sintered product will have uneven performance along the direction of the electric field, and the distribution of the magnetic force lines of the electric field will produce an area for the ceramic material. property difference; using microscopic plasma heating, the microstructure lacks the pressure effect; the applied discharge or pulse current has strong directionality or polarity, and a current channel or flash circuit phenomenon will be formed in the green body, making the overall sintered body microstructure Poor uniformity, resulting in differences in the overall performance or directionality of the sintered body

[0012] In summary, the existing sintering methods do not have the effect of realizing the isotropy and uniformity of the entire sintered body of the workpiece in terms of the application and transfer of pressure and the generation and transfer of heat. Therefore, the sintered ceramic material , of course there will be different degrees of defects in various macro and micro performances; there is still room for technical improvement in the directional control of pressure and heat energy

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