Laser surface engineering of steel for hard refractory ceramic composite coating

Laser surface modification technique is applied to deposit ultrahard ceramic (TiB(2)) coating on 1010 steel. A uniform, continuous and crack free coating with a metallurgically sound interface is obtained. Coating is "composite" in nature comprising TiB(2) particles and Fe in the laser melt zone. Polygonal and needle shaped boride particles are uniformly distributed in the laser melted zone. The interfacial microstructure consists of cellular dendrites and fine equiaxed dendrites. Metastable phase(s) such as Fe(x)B(y) and Ti(m)B(n) are also observed which is a characteristic feature of non-equilibrium synthesis by laser energy. Laser melt zone has a high hardness. However, hardness is not uniform in the layer. (C) 1999 Elsevier Science Ltd. All rights reserved.