Northwest Mettech, Vancouver, announces that its NanoFeed line of liquid and suspension feeders for the thermal spray industry has been developed to enable delivery of submicron powders to thermal spray torches. The powders are homogenously suspended in an easy-to-transport liquid medium, which is then delivered to the torch with a precisely controlled rate. Nanofeed units are available either standalone or integrated with a spray system.
Integration of Mettech’s Axial III plasma system with a NanoFeed suspension delivery device resulted in new technology, Axial III Suspension Plasma Spray (SPS). Axial III SPS is capable of producing a large variety of unique nanostructured coatings with characteristics completely different from those deposited from powders of the same chemistry.
Uniqueness of Axial III SPS derives from its axial injection principle. This form of injection is the only one that allows nano-size (<1µm) particles and droplets to enter the plasma plume.
One family of coatings where Axial III SPS has proven to be a viable alternative to existing technologies are thermal barrier coatings (TBCs) for high-temperature turbine components.
High end TBCs are generally produced by slow and very expensive vacuum process called electron beam physical vapor deposition (EB-PVD). Low end TBCs are thermally sprayed in atmosphere in the process called Atmospheric Plasma Spraying (APS). Axial III SPS produces TBCs with equivalent properties to that of EB-PVD coatings, but at much lower operating and capital costs, whereas Axial III APS can economically do the low end ones. Other areas of interest that can benefit from Axial III SPS are nano-ceramics and nano-cermets for power generation, fuel cells, and electronics.
