Nanomaterial Deposits Formed by DC Plasma Spraying of Liquid Feedstocks

Abstract

An experimental system consisting of an axial feed plasma gun, a variable-rate liquid delivery system, a liquid atomizer-feeder, and a substrate movement and control system was designed and assembled for preparing nanograined ceramic deposits. Sprayed deposits were produced with different spray and sol feed parameters and investigated in both the as-sprayed and heat-treated conditions. Assprayed deposits were predominately hydroxide phases and were strongly adherent to the substrates. Postspray heat treatment at 873 K led to conversion of the alumina and zirconia deposits to ␥-alumina and tetragonal zirconia phases, respectively. Subsequent heat treatment at 1273 K resulted in densification of the deposits and formation of high-temperature phases. A small increase in the grain size was observed with heat treatment, but the specimens still retained nanosized grains.

Suspension Plasma Spraying: Process Characteristics and Applications

“…Also, the minimum thickness of the coatings is limited to about 10 lm, as at least several piled up splats should form the coating. Here, the use of liquid feedstock as solutions or suspensions yields a higher flexibility, even nanophase materials can be processed or synthesized within the process (Ref [1][2][3]. Molten droplets with a diameter of a few hundred nanometres to a few micrometers can be generated.…”

Microstructure and polarization of La0.8Sr0.2MnO3 cathode deposited by alcohol solution precursor plasma spraying

“…In SPPS, metal nitrates are used as the raw materials for the starting precursor. Karthikeyan et al [28,29] argued that in this process a series of physical and chemical reactions of precursor droplets are involved. After solution precursor droplets are injected into the plasma jet, the liquid droplets are accelerated by the jet and heat transfer from the jet to the droplet leads to evaporation of the solvent, condensation of the precursor, chemical reaction and synthesis, nucleation and growth of the grains and densification of the particles.…”

Optimization of Dielectric Properties of Suspension Plasma Sprayed Hydroxyapatite Coatings

“…Tomaszek et al [5]. The technology of suspension spraying has been studied recently as a part of efforts aiming at development of nanostructural coatings [6]. One of the first tested applications was heat insulating part of thermal barrier [7,8].…”