DEPOSITION OF COATINGS ON SUBSTRATES

摘要

A process and apparatus are disclosed for the deposition of a layer of a first material onto a substrate of a second material. Powder particles of the first material are entrained into a carrier gas flow to form a powder beam directed to impinge on the substrate. This defines a powder beam footprint region at the substrate. The powder beam and the substrate are moved relative to each other to move the powder beam footprint relative to the substrate, thereby to deposit the layer of the first material. A laser is operated to cause direct, local heating of at least one of a forward substrate region and a powder beam footprint region. The laser is controlled to provide a spatial temperature distribution at the powder footprint region of the substrate in which the local temperature of the substrate is in the range 0.5Ts to less than Ts in a volume from the surface of the substrate at least up to a depth of 0.2mm from the surface of the substrate and not more than 0.25Ts at a depth of 1mm from the surface of the substrate, wherein Ts is the solidus temperature (in K) of the second material.