Role of thermal spray in combating climate change

Abstract

Thermal spraying is a scalable surface engineering technique used to add or to restore functionality of a solid surface by applying a coating. Examples of this include protection against wear, erosion, abrasion, and heat. In a specific sense, thermal spraying is particularly used to deposit thermal barrier coatings (TBCs) which finds use in transportation, power generation and automotive sector. As being a surface technique, thermal spraying much like other surface coating techniques can avoid the use of excessive bulk materials and in turn offers longevity to the life of the component, so it already contributes to the reduction of global warming by virtue of avoiding the use of excessive scarce materials and improving fuel efficiency. In terms of its contribution to the cause of global warming, thermal spraying stands in sharp contrast to the energy-intensive processes such as melting, casting, extrusion and welding. With the rise of additive manufacturing, it is possible to use thermal spray to complement that process in many ways and “cold spray additive manufacturing” (CSAM) is already gaining popularity. The thermal spraying technique relies on using selective types of gases—hydrogen being one of them and few types of metals/alloys which are now classed as critical raw materials due to them being on the supply risk register. Efforts to consider recycling and reuse and to find alternatives to these are very timely to continue drawing the advantage of thermal spraying being a relatively green technique. In particular, the green energy initiatives and the drive to develop energy storage and battery technologies could challenge the supply of raw materials such as hydrogen gas and rare earth elements. This underlines the research and development need for alternate materials and processes to address the issue of climate change which is the major focal point of the COP 26 Summit at Glasgow in 2021. The combination of digital technologies and thermal spray coatings will reduce gas, powder and power consumption, which will make this manufacturing process even greener.