Study On Rapid Preparation And Properties Of A New Type Of High Temperature Resistant And Heat Insulation Composite Board

The significance of heat insulation materials is mainly to reduce heat loss,improve fuel utilization efficiency,and ensure the safety of labor production environment.Traditional thermal insulation materials have many deficiencies,such as poor mechanical properties,easy to absorb moisture and decay,and high cost,which cannot guarantee the performance requirements of thermal insulation materials for civil industrial production and military equipment.Based on the relevant heat transfer theory,this paper designs and develops a new type of high temperature resistant heat insulation composite board.Adhesive technology is adopted,which is made of graphite/ceramic composite thermal insulation material,aluminum silicate fiber paper and flexible graphite paper layer-by-layer bonded by high-temperature glue,in order to achieve high temperature resistance,light weight,high compression resistance and low thermal conductivity Rate and good sealing performance of a new type of high-temperature-resistant thermal insulation composite board.The main research contents are as follows:Analyze the heat transfer principle and the influencing factors of the material's thermal conductivity under natural conditions.According to the Fourier equation,the theoretical model of the thermal conductivity of the multilayer composite board is derived,and further the theoretical model of the thermal conductivity of the new high temperature resistant thermal insulation composite board.In order to ensure that the thermal conductivity of the new high-temperature heat-resistant composite board is less than 1.0W/m·K,it is calculated that the thermal conductivity of the graphite/ceramic composite thermal insulation material needs to be less than 2.075W/m·K,and the new high-temperature heat-resistant thermal insulation composite is calculated 6 different combinations of boards.Based on selective laser sintering to prepare graphite/ceramic composite thermal insulation materials,the effects of vacuum pressure impregnation and hot-press curing post-treatment processes on their comprehensive properties were compared.The study found that the density of the sample can reach 1.24g/cm3with the vacuum pressure dipping route,and the compressive strength and thermal conductivity are 12.25MPa and 3.43W/m·K,respectively.Taking the hot pressing curing route,when the thickness of the SLS sample is 12mm,its density is 1.23g/cm3,and the compressive strength and thermal conductivity are 11.76Mpa and 5.14W/m·K,respectively.Comparing the two process routes,it is found that when the sample density is equivalent,the compressive strength of the sample when the vacuum pressure dipping route is taken is slightly greater than that of the hot press curing route,and the thermal conductivity is significantly lower than that of the hot press curing route.As a post-treatment process,vacuum pressure impregnation route is preferred.At this time,the density and thermal conductivity of the graphite/ceramic composite thermal insulation material still cannot meet the requirements,so the expandable graphite is added as a pore-forming agent and added to the previous formulation.The study found that the density,compressive strength and thermal conductivity of the sample decreased with the increase of the amount of expandable graphite added.Compared with the decrease in thermal conductivity(52.8%),the decrease in compressive strength(29.6%)was smaller.When the amount of expandable graphite is1%,the sample density is 1.02g/cm3,the compressive strength is 10.92MPa,and the thermal conductivity is 1.89W/m·K,which meets the performance requirements of graphite ceramic composite insulation materials.Adopting the bonding process,the graphite/ceramic composite heat insulation material,aluminum silicate fiber paper and flexible graphite paper are successively bonded through high temperature adhesive to prepare a new type of high temperature resistant heat insulation composite board.The density of the new high-temperature heat-insulation composite board under different combination structures showed a slight downward trend,between 0.808?1.079g/cm3;the compressive strength remained basically unchanged,between 11.01?11.56MPa;the thermal conductivity coefficient showed a downward trend Because of the existence of interfacial thermal resistance,the actual thermal conductivity of the thermal conductivity of the new high-temperature heat-resistant composite board is lower than the theoretical thermal conductivity;the compression rate and rebound rate have been declining.Comparing the comprehensive performance of the 6 combination forms of the new high temperature resistant heat insulation composite board,the comprehensive performance of combination form 2~#is found to be the best and selected as the best combination form of the new high temperature resistant heat insulation composite board.High temperature resistance(1500?),the density is 1.016g/cm3,the compressive strength is 11.49MPa,the thermal conductivity is 0.61W/m·K,the compression rate is8.2%,and the rebound rate is 45%.