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Cast iron is commonly used in numerous engineering applications due to its excellent damping quality and its lower cost. However, this material suffers from metallic wear due to presence of graphite in the austenite matrix (Akdogan & Durakbasa, 2008; Muthazhagan et al., 2014; Praveen et al., 2015; Rajkumar & Aravindan, 2011). The removal of graphite form the austenite takes place due to interfacial tangential motion between sliding surfaces. There are two available solutions to combat of surface degradation problems. One is the replacement of bulk material with a material having high wear resistance and another is to provide a protective layer on the surface of the component to be protected. The latter is the suitable solution as it is easy to deposit the high wear resistance material with economical techniques and thus saves the cost incurred in the replacement of bulk material. There are many coating techniques available include thermal spray coatings, claddings and hard facing etc. (Davis, 2004; McCune et al., 1995; Pawlowski, 2008; Singh, 2009; Vasudev et al., 2017). These methods of coating are very cheap and even easy to perform and having no safety issues associated with them. Thermal spray coating is an emerging technique used for the deposition of the material on the substrate in molten or semi-molten state. The desired properties can be achieved by using this technique as almost all the engineering materials can be deposited by this method. Amongst the all thermal spray processes high velocity process is widely used for the deposition of nickel based alloys and cermets coating (Kaur et al., 2008; Sidhu et al., 2005). In the recent past years, this process has emerged in the field of surface engineering for its excellent coating characteristics against wear and corrosion protection(Bala et al., 2017; Hardwicke & Lau, 2013) This process involves high velocity up to 1000m/s and temperature range of 3000°C and thus the materials even, having high melting points can be deposited with this process. According to the requirement among the several nickel based powders, Alloy-718 is the most preferred because at high temperatures around 650°C, it shows good resistance against abrasive and erosive wear. During the sliding of lathe beds the temperature at the interface rises up to 300°C due to friction and sometimes due to improper lubrication (Bala et al., 2011; Delaunay et al., 2000; Kumar, Singh, Singh, & Joshi, 2015; Ramesh et al., 2011; Wang et al., 2002). An attempt has been made by the authors to review the critical use of cast iron in glass manufacturing industry. It has been found that the cast iron loses its strength at high temperature range due to oxidation of iron and graphite present in it (Brand et al., 2004; Cable, 1999; Callister et al., 2017; Choi & Park, 2000; Cingi et al., 2002).
In the present research work, Alloy-718 powder was chosen due to its extensive properties to resist wear, high temperature corrosion and it also provides creep resistance(Sidhu & Prakash, 2003; Yan et al., 2009). The novelty of the current study is that the conventional available Ni-Cr coatings have been replaced by superalloy Alloy-718. This material is used in the coating of various parts in steam turbines to provide creep and wear strength. As the cast iron applications are mainly subjected to abrasive and erosive wear along with high temperatures, the Alloy-718was selected as a coating feedstock powder. The HVOF thermal spray procedure was selected due to its capability to spray nickel based alloys with minimum porosity and higher mechanical bonding of powder to the substrate.