COATING BY LASER-SURFACE TREATMENT

The application of optical engineering in industrial processing is gai ning greater acceptance. The range of surface treatment processes avai lable goes all the way from transformation hardening, annealing, shock hardening and bending (as processes which do not involve melting) to processes which involve melting such as surface melting, surface alloy ing, surface cladding and those processes which involve some form of p hotochemistry such as laser chemical vapour deposition, laser physical vapour deposition and stereolithography. One of these processes, lase r cladding, has been recently extended at University of Liverpool to p rovide a technique of rapid alloy scanning whereby variable compositio n laser clad tracks can be laid down by the laser thus giving the whol e range of compositions in the alloy system in a single sample. Evalua tion of specimens of this type can be carried out by a range of micro testing techniques including corrosion testing procedures. Laser surfa ce treatment processes available for the production of corrosion resis tant surfaces are reviewed. These include surface melting, surface all oying and surface cladding procedures. Consideration is then given to the new variable composition laser melt track technique with particula r reference to the rapid prototyping of corrosion resistant alloys.