Abstract: In order to harden the surface of workpieces having complex shapes without reviously applying absorption promoting surface layers, a mixture of inert gas and oxygen are supplied to the processing zone while the workpiece is exposed to laser radiation. The degree of absorption is maximized by adjusting at least one of the mixing ratio, the volume flow rate, and the processing temperature to conform to a nominal value.

Abstract: A device for plating two or more metal plates, strips, etc., by the absoron of laser energy. The device is fitted with beam-forming optics which form the laser radiation into a beam with a rectangular cross-section. The radiation source is a laser-diode array in which several laser diodes are disposed next to each other in the same plane to give bars which can be laid next to each other, as well as stacked one on top of each other, in any numbers. In order to homogenize the laser radiation produced by the array to give a rectangular cross-section, the device proposed is fitted with special optics such as a prism which converges in the shape of a wedge, a glass plate, with a rectangular cross-section, reflective boundary drives, etc. The rectangular cross-section beam heats the two surfaces of the metal plates being plated only locally, over limited areas and to small depths, to the plastic state.