Coating of meso-porous metallic membranes with oriented channel-like fine pores by pulsedlaser deposition

Abstract

There is increasing demand to functionalize meso- and nanoporous materials by coating andmake the porous substrate biocompatible or environmentally friendly. However,coating on a meso-porous substrate poses great challenges, especially if the poreaspect ratio is high. We adopted the pulsed laser deposition (PLD) method to coatNi3Al-based meso-porous membranes, which were fabricated from a single-crystal Ni-basedsuperalloy by a unique selective phase dissolution technique. These membranes were about250 µm thick and hadchannel-like pores (∼200 nm wide) with very high aspect ratio. Two different coating materials, i.e. diamond-likecarbon (DLC) and titanium, were used to coat these membranes. High energy C or Ti ions,produced in the plasma plume by the PLD process, penetrated the channel-likepores and deposited coatings on the pore walls deep inside the membrane. Thethickness and the quality of coatings on the pore walls were examined using thedual-beam system. The coating thickness, of the order of 50 nm, was adherentto the pore walls and was quite uniform at different depths. The carbon andthe Ti deposition behaved quite similarly. The preliminary experiments showedthat the PLD is an adequate method for coating fine open cavities of complexgeometry. Simulations based on stopping and the range of ions in matter (SRIM)calculations helped in understanding the deposition processes on pore walls at greatdepths.