Soldagem & Inspeção
Print version ISSN 0104-9224
GRAF, Karin and D'OLIVEIRA, Ana Sofia Clímaco Monteiro. PTA hardfacing of Nb/Al coatings. Soldag. insp. [online]. 2012, vol.17, n.2, pp. 158-165. ISSN 0104-9224. http://dx.doi.org/10.1590/S0104-92242012000200009.
Hardfacing is widely applied to components yet the majority of the welding techniques available restrain the variety of hard alloys that can be deposited. Plasma Transferred Arc hardfacing offsets this drawback by using powdered feedstock offering the ability to tailor the chemical composition of the coating and as a consequence its properties. The high strength and chemical inertia of aluminide alloys makes them very suitable to protect components. However, the strong interaction with the substrate during hardfacing requires analysis of each alloy system to optimize its properties and weldability. This work analyzed coatings processed with a cast and ground Nb40wt%Al alloy and the effect of Fe and C on the coatings features. It confirmed that sound Nb aluminide coatings can be processed by plasma Transferred arc hardfacing and will have a strong interaction with the substrate, which determines the final microstructure and properties of coatings. Final remarks point out that during Nb-Al coating tailoring the interaction with the substrate has to be considered at the early stages of design process.
Keywords : Aluminides; hardfacing; coatings; PTA; Nb/Al.