Abstract
The present study discusses the formation of a conductive film from noble metal nanoparticles on a stainless steel substrate for use in the manufacture of electrical components, such as connectors. The proposed method consists of on-demand dispensing with nanoparticle paste followed by a brief preheating and laser sintering. The major results obtained are as follows: the laser sintering formed a gold film with a diameter of 0.8 mm and a thickness of 0.3-1.0 μm on the stainless steel substrate without any surface pretreatment; a laser with a wavelength of 915 nm enabled instantaneous sintering within one second in air; the laser-sintered gold nanoparticle film had such a high adhesion to the substrate that no separation occurred after 90°-0.5R bend-peel tests; the high adhesion was attributed to the interdiffusion of gold, iron, chromium and nickel in the course of sintering; primary sintering of the preheated gold nanoparticles at 523 K for 60 s with a small amount of solvents, and secondly sintering from the substrate side proceed simultaneously, making possible efficient sintering of the nanoparticles as well as high adhesion to the substrate; the laser-sintered gold film possessed a very good electrical property.
