Thermal spray is one of the most widely used coating techniques to improve wear, surface
fatigue or corrosion properties. In the atmospheric plasma spray (APS) process, a powdered material
is melted by hydrogen and argon combustion and is propelled at high speed onto the target substrate.
The high impact energy of the particles produces a dense and resistant coating layer. Mechanical
and surface properties of the obtained coating depend on various spraying parameters, such as
gas flow, traverse speed and spraying distance, among others. In this research, the influence of
these manufacturing parameters on the thickness, hardness and resistance of the coating obtained
from a Ni-Al alloy sprayed onto an aluminum alloy substrate was studied. In order to analyze the
effect of these parameters on the coating properties, an extensive experimental program was carried
out. A metallographic analysis, hardness and strength measurements were carried out using the
small punch test to locally study the mechanical properties of the coating surface. The design of
experiments and the response surface methodology facilitate the assessment of the optimal set of
spraying parameters.
