Preparation And Properties Of High Power LED Heat Sink With Aluminum Nitride Ceramic Substrate Metallization

Recently,researchers focus on obtaining high thermal conductivity and high adhesion strength for heat-release substrates of high-power LED.The aluminum nitride ceramic substrate surface was quickly coated by settlement method with tungsten powder.The surface metallization on aluminum nitride ceramic substrate was realized by a laser scanning method at room temperature.The influences of laser scanning times,scanning speed,metal tungsten powder addition and particle size on the properties of the substrate were investigated after metallization.The metallic substrate surface and interface microstructure were investigated by electron microscope.The composition and phase of surface and interface of the metallic substrate were observed and analyzed by energy spectrum analysis and X-ray diffraction.The bonding strength of aluminum nitride and metal tungsten was tested by the mechanical equipment,and thermal conductivity of aluminum nitride and metal tungsten was tested.The interaction mechanism between laser and material was studied.The results showed that aluminum nitride surface formed the dense metal tungsten layer when adding the mass to 1 g and the particle size to 3-5 microns of tungsten metal powder and heating process selection for laser scanning 1 time,scanning speed of 50 mm/s.The particle size distribution of tungsten metal was uniform on the aluminum nitride ceramic surface.The laser beam is used to transfer some of the energy to metal tungsten and ceramic substrate.The aluminum nitride ceramic substrate and the metal tungsten layer were closely connected by a layer of solidified material formed by melting.The mass transfer between them was through diffusion,sputtering and chemical reactions,the reactions were beneficial to the combination of metal and ceramic;the shear strength of metal tungsten layer with aluminum nitride ceramic substrate can reach 62.5 MPa,and the thermal conductivity of surface metallization on aluminum nitride ceramic is 114.37 W/(m·K).The connection of ceramic and metal provides a broad application prospect for the heat dissipation of high-power electronic devices.