Laser-Welded Steel Foils with Sapphire Substrates

A nanosecond pulsed laser was used to weld stainless steel foils of 10 lm thickness to the sapphire substrates. The microstructure of the bonded interface was studied. Both materials were partially ablated under the influence of the laser beam. An inhomogeneous distribution of the steel and sapphire along the bonded interface is observed. The electrical resistance of the steel foil was measured before and after laser welding, showing that the weld slightly increases the electrical resistance but still keeps the values acceptable for electrical contacts.