Study On Preparation And Thermal Insulation Performance Of Nano Aerogel Thermal Insulation Coating

This paper is aimed at the huge energy loss caused by the backwardness of thermal insulation materials in the petrochemical,aerospace,ship and construction fields in my country,and the problem of SiO₂ aerogel is limited due to the shortcomings of infrared transmittance and high thermal conductivity at high temperature.Inorganic powder and refractory fiber are selected as the main heat insulating fillers,and the reinforcing fiber is used as the reinforcing phase.Aerogel,opacifier,binder,and foaming agent are sequentially added,and the nano aerogel heat insulating coating is prepared by mechanical stirring.The infrared transmission properties of several infrared opacifiers and the particle size and microscopic morphology of TiO₂ infrared opacifiers were studied.The influence of SiO₂ aerogel,TiO₂ infrared opacifiers and foaming agents on the performance and microscopic morphology of thermal insulation coatings was studied to determine the best formulation of the coating.The results show that:SiO₂ aerogel is uniformly dispersed in the thermal insulation coating matrix,and many microporous structures are formed on the coating surface;TiO₂ as an opacifier can effectively shield infrared radiation;foaming agent can increase the porosity of thermal insulation coatings,hinder heat transfer,and reduce Thermal conductivity,effectively improve the thermal insulation performance of the coating.The 25nm rutile TiO₂ has the lowest infrared transmittance at high temperature,the highest mass spectral attenuation coefficient in the 4?12?m band,and the strongest resistance to thermal radiation.When the mass ratio of SiO₂ aerogel to 25nm rutile TiO₂is 1:1,the aerogel insulation coating has the lowest infrared transmittance and thermal conductivity and the best overall performance.In the specific implementation process,the inner layer needs to be coated with an infrared shielding layer,and the outer layer is coated with aerogel thermal insulation coating.The design ideas and preparation schemes of thermal insulation coatings with gradient pore structure are proposed.The dry density,compressive strength,and thermal conductivity of thermal insulation coatings decrease with the increase of SiO₂aerogel or blowing agent.With the gradual increase of coating thickness and heat source temperature,the coating thickness has an effect on the thermal insulation effect of thermal insulation coatings.The gain effect is getting smaller and smaller.When the addition amount of SiO₂aerogel and 25nm rutile TiO₂ is 7.0%,and the addition amount of blowing agent is 0.9%,the overall performance of nano aerogel coating is the best,and the thermal conductivity is only 0.034 W/(m·K)at 70?and 0.047W/(m·K)at 350?,with thin layer,high efficiency and excellent thermal insulation performance.