可陶瓷化EPDM绝热材料的烧蚀特性及陶瓷化机理OA北大核心CSTPCD

The characteristics of carbonized layer in thermal insulation are closely related to its ablation resistance.Through characterization and analysis of structure and composition of carbonized layer of ceramicable EPDM insulation after oxygen-acetylene ablation,the correlation among different parameters of linear ablation rate of insulation layer and carbonized layer was obtained,and the formation mechanism of carbonized ceramic-like layer was analyzed.The results show that when the content of ceramifiable sili-cone resin filler is 35～40 phr,the carbonized layer possesses denser structure,higher hardness,smaller porosity and more ceramic products,which effectively improve the ablative resistance of EPDM insulation layer.There is a strong correlation between the linear ablation rate of the insulating layer and structure,composition of the carbonized layer.The formation of ceramic-like carbonized layer structure can be divided into four stages:thermal decomposition of polymer,chemical vapor deposition of small molecules,in-situ formation of SiC on ablated surface,filling and bonding of molten SiO2 in carbonized layer.Finally,a kind of Si—O—C composite ce-ramic structure is formed.