电磁感应加热银膜的无压烧结及其性能研究

Pressureless Sintering and Properties of Silver Film for Electromagnetic Induction Heating

通过丝网印刷在氧化铝陶瓷基体表面,无压烧结制备电磁感应加热银膜,并通过SEM、四探针测试法和拉伸测试法表征银膜的微观形貌、力学性能和电学性能等。结果表明,银膜的致密性与烧结温度和玻璃粉含量密切相关。随着烧结温度升高,玻璃熔体粘度降低,有效润湿银颗粒,使其紧密重排,并通过烧结颈的生长进一步融合形成致密银网络。随着玻璃粉含量增多,玻璃熔体既有效提高银颗粒的烧结致密化,又改善银膜与基体的结合强度,但较多的玻璃熔体会阻隔银颗粒之间的接触,降低银膜的导电性。当烧结温度为640℃、玻璃粉含量为4%(质量分数)时,银膜具有良好的综合性能,其方阻达到极小值,为2.26 mΩ/□,结合强度较高,达到14.64 MPa,电磁感应加热实验结果表明,方阻越小的银膜的感应升温速率越快。

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℃and the content of glass frit is 4 wt%,the silver film owns good comprehensive properties.The sheet resistance reaches a minimum value of 2.26 mΩ/□,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.