Synthesis of powders and films using a new laser ablation technique

Abstract

A novel method to produce powders and films from ceramic targets is presented. It is shown that the laser spark atomizer (LINA-SPARK™), LSA, combines the advantages of operating at atmospheric pressure and ambient temperature to produce highly uniform films with a web-like structure which can be deposited at relatively high deposition rates (ca. 1 μm·min⁻¹). The preparation of powder particles and coating starting from commercial ceramic specimen (Al₂O₃) is investigated. Highly agglomerated nanopowders and homogeneous mesoporous coatings forming a web-like structure are prepared using this new technique. The formation of the nanoparticles is explained following a liquefaction process which generates an aerosol, followed by the cooling/solidification of the droplets which results in the formation of a smoke. The general dynamic of both the aerosol and the smoke favors the aggregation process and micrometer-sized fractal-like particles are formed. The laser spark atomizer can be used to produce highly mesoporous thick films. The porosity can be modified by the carrier gas flow rate thus enabling for a control of the microstructure of the coatings which make these nanoparticulate thick films suitable candidates for application in membrane technology, catalysis and lithium ion batteries. ZrO₂ and SnO₂ nanoparticulate thick films are also synthesized successfully using this new process with quite identical microstructure.