Research On Preparation And Electrical Performance Of SiAlCN Via Polymer-derived Ceramic Method

Aerospace and other defence industry are often involved with high temperature,strong electromagnetic interference and other extreme work environments, how to realize instantaneous, accurate physical perception and measurements under this condition, has troubled the scientific community and industry for many years.Meanwhile, enormous demands have been proposed to sensor materials in this application backgrounds.As the representative of modern ceramic materials, PDCs-Si becomes an ideal material for electronics, information, aerospace and other high-tech fields’ key component, because of its properties, which contains high temperature resistance, corrosion resistance, low density, high hardness.Firstly, this paper starts from Si Al CN precursor synthesis, linear polysilazane and alumium isopropoxide containing C=C, Si-H bond are chosen as raw material which are synthesized under inert gas protection and strict controlled water oxygen values. Further more, the precursor are characterized by analyzing the specific reaction mechanism during the synthesis. And on the basis of this, curing and crosslinking of precursor produce reaction. Cured product of precursor at different temperatures and times are characterized by analyzing the reaction curing type and crosslinking mechanism.Subseq-uently, the heat treatment temperature rise above 1000℃, TG test is carried on to get resin cracking process.Secondly,based on the synthesis,the preparation of bulk materials has been mainly studied.On the basis of commonly used dry pressing method,the preparation process is optimized by adding cold isostatic process which could eliminate the inner pressure gradient caused by one-way dry pressing to obtain a more uniform and dense body.Under certain heating rate,ceramic body is sintered,and contrastive analysis of the character-istics of the sample obtained by the traditional dry processing method and optimized method is carried out.By applying XRD,XPS,FT-IR,拉曼and other analytical testing method,ceramic process is characterized to obtain the law of microsco-pic organizational structure changing along with temperature and to explain the influence and microstucture evolution by the aluminum element content.Finally, the electrical properties of PDCs-Si Al CN have been studied. The mechanism and law of the crystalline and amorphous sample conductivity which varies with temperature is explained. Meanwhile, the effects of aluminum on electrical properties are studied.By charactering the synthesis, crosslinking, curing and cracking process of PSCs-Si Al CN precursor, ceramic process is studied and the conductive mechanism isexplained. It’s of great significance to the development of ceramic material used for sensor.