A Reserrch On Low Thermal Conductivity Dielectric Layer Technology

Low thermal conductivity dielectric layer material could be used in aero engine turbine blade protection layer and other cutting-edge areas,and it could buffer external heat into the alloy substrate,so as to enhance the high temperature resistance and corrosion resistance properties of the substrate.The main work of this paper is as follows:(1)The surface of the silicon substrate was machined to form the surface of the trench,and the relationship between the ratio of etching and the thermal conductivity was studied,and analyzed the laws of decreased thermal conductivity with the increase of the etching area on the silicon wafer.(2)The surface of titanium sheet was electrolyzed by electrolytic anodic oxidation to form an oxide film with honeycomb structure on the surface.The change of thermal conductivity of the porous structure on titanium surface was studied.The results show that when the surface of the titanium sheet has a porous structure of the oxide film,the thermal conductivity of the sample will be significantly reduced,reducing the amplitude of up to 20%.(3)The surface of the titanium plate is etched to form a circular channel of a certain depth,width and distance,and a dielectric layer material is coated on the surface of the titanium plate so as to cover the annular channel and allow the air to be filled therein.The change of thermal conductivity in the interfacial layer with partial air is explored,and the thermal conductivity can be reduced by more than 60% by filling the interfacial layer with air.(4)The thermal conductivity of porous copper foams and nickel foams was studied and the change of thermal conductivity was analyzed.The results show that the thermal conductivity of the porous air structure can be reduced by more than 3 orders of magnitude.The introduction of a cavity structure in the dielectric layer or in the interface layer between the dielectric layer and the substrate by the use of the cavity or air having the lowest thermal conductivity has the effect of significantly reducing the thermal conductivity thereof.The relationship between the cavity content of different sample dielectric layers and its thermal conductivity,the greater the volume of the cavity,the lower the thermal conductivity of the performance.The research methods and conclusions of this paper provide a direction for finding low thermal conductivity dielectric layer materials.