  Thermal spraying has been present for over a century, being greatly refined
and optimised during this time, becoming nowadays a reliable and cost-efficient
method to deposit thick coatings with a wide variety of feedstock materials and
substrates. Thermal sprayed coatings have been successfully applied in fields
such as aerospace or electricity production, becoming an essential component of
today's industry. To overpass the traditional capabilities of those coatings,
new functionalities and coherent responses are being integrated, opening the
field of functional and smart coatings. The aim of this paper is to present a
comprehensive review of the current state of functional and smart coatings
produced using thermal spraying deposition. It will first describe the
different thermal spraying technologies, with a focus on how different
techniques achieve the thermal and kinetic energy required to form a coating,
as well as the environment to which feedstock particles are exposed in terms of
temperature and velocity. It will then deal with the state-of-the-art
functional and smart coatings applied using thermal spraying techniques, with a
discussion on the fundamentals on which the coatings are designed, the
efficiency of its performance and the industrial applications, both current and
potential. The inherent designing flexibility of thermal sprayed functional and
smart coatings has been exploited to explore exciting new possibilities on many
different fields. Applications such as anti-bacterial and anti-fouling
coatings, superhydrophobic surfaces, electrical and heating devices for
functional coatings and self-healing, self-lubricating and sensors for smart
coatings are here presented and discussed. All these exciting developments pave
the way for the numerous applications that are to come in the next decade,
making the field of thermal sprayed coatings a unique opportunity for research.
