Preparation And Performance Of Heat-resistant And Ablation-resist Inorganic Particles Modified Carbon/phenolic Composites

Thermal Protection Material?TPM?,which is used for Thermal Protection System?TPS?,is the key material in the guarantee of the shuttle's operation and use.As a reliable solution to normal operation of aircraft,ablation heat is most widely applied.Carbide type ablative thermal protection materials can be applied to flight environment where heat flux density is varying or not precisely calculated.Its structure is relatively simple,which can meet the particular requirement in the thermal environment by increasing or decreasing the thickness of the thermal protection material.One typical material is carbon/phenolic composites?C/Ph?.However,due to the oxidation under high temperatures,the traditional carbon/phenolic composites?C/Ph?can not meet the higher and higher requirement of the thermal protection of high performance new aircraft.Thus,how to restrain the carbon element's thermal oxidation incarbon/phenolic composites?C/Ph?of becomes not only the key point of improving the ablation performance of carbon/phenolic composites?C/Ph?,but also a hot issue in the research of advanced resin thermal protection material.In this article,the author by using the physical blending-presoak material-laminated process produced the carbon fiber reinforced phenolic composites which was able to form a compact inorganic coating in the process of the ablation under high temperature.By adding ultrafine inorganic solid particles into the resin matrix in order to improve the high temperature oxidation resistance and high temperature carbon residue rate of the resin matrix,the ablation performance of carbon/phenolic composites can be improved.Compared with modified phenolic resin with chemical method and changing the carbon fiber arrangement,inorganic solid particles modified carbon/phenolic composites for ablation performance improvement is more significant and easy to use.In the more demanding ablative thermal environment,ultrafine inorganic particle modification of carbon/phenolic composites can rely on the existing mature process of polymer matrix composites to achieve the ablation resistance under high temperatures.According to the sedimentation and reunion phenomenon in the blending of ultrafine inorganic solids particles and phenolic resin,twain-80 is used as the surface active agent to enhance the dispersion of inorganic solid particles in resin.By using this mixed solution to infiltrate carbon fiber woven fabric to make the presoak material,the author uses laminated molding to produce ZrSi₂-muscovite powder modified carbon/phenolic composites and carried out a detailed research on the process and performance of the solid particle-modified resin and composite material.The article mainly analyzed the influence on of ZrSi₂ particles during the curing process,high temperature resistance,the ablation performance,insulation performance and the ablative mechanismof phenolic resin and carbon/phenolic?C/Ph?composites.On this basis,the author chose the muscovite powder as the second phase particles to improve the interlaminar shear performance of ZrSi₂ modified carbon/phenolic composites after high temperature pyrolysis.By optimizing the ratio of components,inorganic particles modified carbon/phenolic composites with highly ablation resistance was eventually produced.According to the study,ZrSi₂ particles will not affect the curing reaction of phenolic resin,but they will generate ZrO₂ and SiO₂ with the reaction of the pyrolysis gas such as CO,CO₂ and H₂O under high temperatures.The reabsorption of pyrolysis gas generating solid products,which on the one hand could improves activation energy of the thermal cracking reaction of phenolic resin and high-temperature carbon residue rate,on the other hand could improves the structural integrity of the pyrolysis products of modified phenolic resin.The two hands will establish a good foundation to improve the ablation resistance of the polymer matrix composite under high temperatures.By this way,the oxyacetylene ablation performance of carbon/phenolic?C/Ph?composites has been greatly increased.And its oxyacetylene ablation mechanism has been changed in a certain degree.As for the pure carbon/phenolic?C/Ph?composites,there were only carbon fibers on the surface of the sample after oxyacetylene ablation,and the ablation rate of resin is greater than the carbon fibers.Due to the the asymmetry ablation rates of the resin and fibers,the pure carbon/phenolic?C/Ph?composites has a body ablation under the oxyacetylene flame.Adding a certain amount of ZrSi₂ particles has played an important role in the protection of phenolic resin matrix.The continuous ZrO₂-SiO₂ protective layer was formed on the surface to inhibit the oxidation reaction of resin matrix.From the microstructure of the surface after ablation,the ablation of matrix basically was equal to that of the fibers.The ablation behavior of ZrSi₂ modified carbon/phenolic composites has changed from body ablation into surface ablation.In order to further improve the ablation resistance of ZrSi₂ modified carbon/phenolic laminated composites,the author introduces muscovite powder as the second phase particles into the composites.Muscovite powder melt,flowed and transfered mass under high temperatures,which can effectively improve the interface bonding on the surface of the resin and carbon fiber.The interlaminar shear performance of ZrSi₂ modified carbon/phenolic composites after pyrolysis under high temperatures was improved,thus it was beneficial to further reducing the linear ablation rates of the composites.