Synthesis of boride coating on steel using high energy density processes: Comparative study of evolution of microstructure

Ultrahard titanium diboride (TiB2) coatings are deposited on plain carbon s teel substrate using two high energy density processes, viz. pulsed electro de surfacing (PES) and laser surface engineering (LSE). These two processes are entirely different in physical nature and hence result in dissimilar m icrostructures. Ln the present investigation, a comparative study has been made between the evolved microstructures. Both processes produced a surface layer which is adherent and metallurgically bonded to the substrate. PES p roduced relatively thinner and less uniform coating than LSE process. The P ES coating was, however, homogeneous and very fine grained. The laser-assis ted coating was "composite" in nature with TiB2 particles embedded in Fe ma trix. Mechanical characterization of these coatings has been performed usin g microhardness measurements. (C) Elsevier Science Inc., 1999. All rights r eserved.