A method for microwave hot-press sintering of polymer-precursor-derived SiCN-based ceramic materials

By employing a three-stage gradient heating and pressurization coordinated control strategy, the problem of thermal runaway in microwave hot pressing sintering was solved, achieving efficient and uniform densification of SiCN-based ceramics and obtaining high-performance ceramic materials.

CN122102706APending Publication Date: 2026-05-29ZHENGZHOU UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
ZHENGZHOU UNIV
Filing Date
2026-03-05
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

In the existing technology, during the microwave hot pressing sintering of PDC-SiCN-based ceramics, the dielectric constant and dielectric loss increase with the pyrolysis temperature, which leads to an enhanced microwave absorption capacity of the material. This causes local energy accumulation and uneven temperature distribution, resulting in thermal runaway and affecting the densification and microstructure uniformity of the material.

Method used

A three-stage gradient heating and gradient pressurization coordinated control strategy is adopted. By using a "fast-medium-slow" heating rate and a "low-medium-high" pressurization rate, the dielectric properties of PDC-SiCN-based ceramics are matched to prevent local energy accumulation and temperature unevenness, thereby achieving uniform densification of the material.

Benefits of technology

It effectively suppressed thermal runaway, achieved high densification and uniform microstructure of SiCN-based ceramics, improved yield and performance stability, and had clear process parameters and good repeatability.

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Abstract

The application discloses a microwave hot-pressing sintering preparation method of polymer precursor converted SiCN-based ceramic material and belongs to the technical field of high-performance ceramic material preparation. The method comprises the following steps: firstly, pre-pyrolyzing a polymer precursor and preparing ceramic powder; and then, loading the ceramic powder into a wave-transparent high-temperature-resistant mold and performing microwave hot-pressing sintering. The core of the method is to execute a gradient temperature rising and gradient pressure increasing cooperative control program matched with the evolution law of the dielectric property of the material. In the sintering process, a specific "fast-medium-slow" three-section type temperature rising strategy is adopted, medium-speed and slow-speed temperature rising is adopted in the temperature interval in which the dielectric constant and dielectric loss of the material are improved, so as to balance the microwave energy input and heat conduction; meanwhile, a "low-medium-high" gradient pressure increasing strategy is adopted, so as to cooperatively promote densification. The method effectively inhibits the "thermal runaway" phenomenon in the microwave sintering process, realizes uniform and efficient densification of the polymer precursor converted SiCN-based ceramic on a conventional equipment, obtains high-density and high-performance ceramic material, and has good process stability and high repeatability.
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