The present disclosure provides a thermal spray system and method that utilizes an exothermic reaction. The exothermic reaction creates substantial heat and provides increased diffusion and bonding between different components of the wire alloy during coating and solidifying. The disclosed exothermic reaction creates greater diffusion of boron and carbon within the coating, increases bond strength between different components and/or solidified droplets or splats of the coating, and increases bonding strength between the coating and the substrate. The resulting coating provides greater homogeneity of the coating chemistry and fewer micro-cracks. The exothermic reaction may be created by a particular alloy composition (such as powdered elements within a cored wire) that creates and maintains a higher droplet temperature. The exothermic reaction may be created by the use of an oxidizer and a fuel, such as iron oxide and aluminum, as well as other reactive elements causing an exothermic reaction.