Pressureless Sintering and Properties of Silver Film for Electromagnetic Induction Heating

Silver films for electromagnetic induction heating were prepared on alumina ceramic through screen printing and pressureless sintering. The microstructure, mechanical properties and electrical properties of the silver films were characterized by SEM, four probe test and tensile test. The results indicate that the density of silver film is closely related to sintering temperature and glass frit content. With the increase of sintering temperature, the viscosity of the glass melt decreases, the silver particles are wetted and rearranged effectively, and a dense silver network forms through the sintering neck growth and further fusion. Meanwhile, with the increase of glass frit content, glass melt can not only promote the densification of silver particles, but also improve the adhesion strength of silver film and substrate. However, much glass melt blocks the contact between silver particles, thereby reducing the conductivity of the silver film. When the sintering temperature is 640 degrees C and the content of glass frit is 4wt%, the silver film owns good comprehensive properties. The sheet resistance reaches a minimum value of 2.26 m Omega/square, and the adhesion strength is high, reaching 14.64 MPa. The experimental results of electromagnetic induction heating show that the silver film with smaller sheet resistance has a faster heating rate.