Thermal spray coatings are widely used in many applications, and the adhesion effect at the coating/substrate interface plays an important role during the service life. The thermal spraying coating and substrate is primarily combined by a mechanical seizure effect. In this work, a strategy to generate interfacial metallurgical bonding is proposed. Plasma spraying with wire feeding was adopted to increase the size of sprayed particles, and metallurgical bonding was clearly formed between deposited particles and the substrate (304 stainless-steel and 7075 aluminum alloy). Interface reaction can be found at both NiAl/7075 and NiAl/304 interfaces. Typical Al-Al3Ni eutectic phase with higher microhardness was formed at NiAl/7075 interface. The adhesive strength of the coatings was significantly improved to 82.67 ± 3.96 MPa and 64.45 ± 2.84 MPa, respectively, for NiAl coating on 304 and 7075 substrates through tensile adhesion tests (TAT) without surface roughening pretreatment. This technique shows a promising aspect of the application of thermal spray coatings.

A series of catalytic coatings consisting of MnO_x-CeO₂ and TiO₂ support were prepared by atmospheric plasma spraying, which was aimed at the application of selective catalytic reduction (SCR) of NO_x. The effect of the load of active component on the coating was firstly studied. The results showed that all the coating presented the highest catalytic activity at approximately 350 °C and the coating with the composition of 20MnO_x/5CeO₂/TiO₂ (wt%) achieved the most powerful performance. The coating was then prepared on a wire-mesh structure substrate, which can be easily assembled as a gas filter. The results showed that the specific surface area was greatly increased resulting in the significant improvement of the catalytic activity of the coating. This strategy offered a promising possibility of removing NO_x and particulate fliting simultaneously in industrial applications.