Innovative fabrication of Ti–48Al–6Nb porous coating by cold gas spraying and reactive sintering

A Ti–48Al–6Nb porous microfiltration coating was fabricated by cold gas spraying (CGS) followed by reactive sintering. The porous coating possesses a porosity of 20.0% and interconnected pore structure. The skeletons in the coating were consisted of typical γ-TiAl/α2-Ti3Al fully lamellar microstructure, and firmly bonded with substrate. Uniform pores in the range of 0.5–3 μm were formed, attributing to the diffusion reactions and skeletons growth during the reactive sintering process. The bending strength and gas permeability of the supported coating with a thickness of 604.4 μm, are 89.33 MPa and 5.39 × 10− 13 m2, respectively. The porous coating has high permeability and sufficient strength for microfiltration applications in kinds of extreme environments.

► An effective approach for fabrication of Ti-48Al-6Nb porous coating.
► The average pore size of coating is 1.8 μm, and the porosity is 20.0%.
► Phase transformation is followed with the pore formation.
► The coating has sufficient strength and permeability for microfiltration.