This paper provides a summary of the status and potential of thermal spray activities in India. A meaningful indicator of the future growth of thermal spray technology in India is the rapid rise in the number of job shops that offer thermal spray coating services. The number of captive units meeting in-house coating needs has also increased markedly in recent years. These trends have in part been fueled by an increase in the number of home-grown Indian companies manufacturing spray systems, handling equipment, and performance evaluation test rigs. Research in areas such as cold gas dynamic spraying (CGDS) and solution precursor plasma spraying (SPPS) is also on the rise in India.

This paper deals with a comprehensive evaluation of the laser glazing or re-melting route as a possible means of specifically enhancing the performance of thermal sprayed WC-Co coatings. In the present study, a high-power continuous-wave 9kW CO 2 laser was utilized for laser treatment of plasma sprayed as well as detonation sprayed WC-Co coatings. The influence of the two most important laser-related variables, namely laser power and scan speed, on the properties of the laser-treated layers was investigated. Both mere surface densification by melting a thin top layer of the coating as well as melting of the entire portion of the coated layer were targeted during laser treatment. In each case, the laser treated coatings were fully characterized by optical microscopy, scanning electron microscopy, and microhardness measurements. In addition, the influence of laser processing on the elemental distribution, phase constitution and extent of defects in the treated layers was investigated. The tribological performance of the laser-glazed coatings was also evaluated and compared against the performance of their as-sprayed counterparts. The study has revealed significant differences between the response of plasma and detonation sprayed WC-Co layers when subjected to laser treatment. The potential of plasma-sprayed coatings to match the performance of the inherently superior detonation sprayed coatings by adopting laser glazing as a post-processing step has also been assessed.