Dual heating mode flash sintering method combining current heating with radiant heating

Abstract

This invention relates to a method for preparing block material from powdery material by sintering. The method is a rapid sintering method by combination of electric heating and radiation heating. The electricity / radiation power ratio is (5-30):1. The radiation heater / mold height ratio is (1-3):2. Samples with diameters greater than 30 mm are heated through combination of electric heating and radiation heating at a heating rate of 100-800 deg.C / min; the heat preservation time is 3-15 min. After heat preservation, electric heating and radiation heating terminated, and the samples are naturally cooled. The method can be used to prepare samples with uniform inner structure and diameters greater than 30 mm, and has such advantages as short sintering time and low energy consumption.

Description

technical field [0001] The invention relates to a sintering method for preparing bulk materials from powder materials, in particular to a rapid method for preparing dense bulk materials (including ceramics, ceramic matrix composite materials, metals, metal matrix composite materials, ceramic / metal composite materials, etc.) Sintering method. Background technique [0002] The most effective preparation method of bulk materials such as ceramics and ceramic matrix composites is through the preparation of raw material powder, molding, sintering and subsequent processing, and the sintering process is the most critical step in the entire preparation method, which is largely This determines the final performance of the prepared material. With the development of raw material powder preparation technology, people have obtained a large number of ultrafine powders with excellent performance, and hope to prepare bulk materials with the same excellent performance. The focus of the whole...

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Problems solved by technology

[0003] There are many ways to sinter powder materials. The commonly used sintering methods are ① pressureless sintering, ② pressure sintering, ③ hot pressing sintering, ④ hot isostatic pressing sintering, ⑤ microwave sintering, ⑥ electric current (including pulse, direct current, alternating current) Sintering, etc., the characteristics of each sintering method are obvious: ① and ② methods cannot directly apply pressure to the sample, so it is difficult to obtain dense materials for most new materials; ③ and ④ methods can obtain dense bulk materials, but The sintering time is long, the energy consumption is high, and the cost is high; ⑤ and ⑥ The two methods heat up quickly and can prepare bulk materials in a short time, but microwave sintering is difficult to apply pressure while heating up, and it is difficult to obtain completely dense materials. At the same time, there is also the weakness that the uniform temperature zone is small, and large-sized samples with uniform structure cannot be prepared. The current sintering method can apply a certain mechanical force while rapidly heating up, and it is easy to obtain dense bulk materials, so it is becoming more and more widely used. application

[0004] The current sintering method is widely used in the preparation of ceramics, ceramic composite materials, metals, metal / ceramic composite materials, etc., and many bulk materials with excellent performance have been prepared, but more and more users find that this method prepares bulk materials. There is a fatal weakness in the material: when the diameter of the prepared bulk material exceeds 30mm, the inhomogeneity of the internal structure of the material will inevitably appear in the sample

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