Papers by Keyword: Plasma Spray Deposition

Abstract: The bulk nanostructured Co-P alloys were prepared by dynamic compaction and a plasma spray deposition techniques. The magnetic characteristics, such as the saturation magnetization, M₀, the Bloch constant, B, the local magnetic anisotropy field, H_a, the ferromagnetic resonance linewidth, ΔH, the coercivity, H_c, were investigated. A comparison between the magnetic properties of the Co-P alloys prepared by dynamic compaction and a plasma spray deposition techniques was carried out.

Abstract: Plasma spray deposition of hydroxyapatite (HA) coatings is a well established commercial process. When deposited on metallic substrates, these coatings have been shown to promote bone fixation and osteconductivity. A concern with current coatings is the formation of relatively large debris particles during resorption. The size of the debris is related to the particle size of the powder injected into the plasma during the deposition process. The use of solution precursors or dispersions of fine particle size powders as the feedstock for plasma spraying has been shown to produce submicron/nanocrystalline structured coatings from relatively inexpensive precursors. Nanocrystalline HA coatings may improve the resorption of the coating in the body, avoiding the irritant effect of large particles which may be seen in current thermal sprayed HA coatings. We have explored the use of sols prepared from several different precursors as the feedstock for the plasma spray deposition of HA coatings on Ti6Al4V substrates, employing statistical design of experiments to establish optimal deposition conditions. We report on the formation and the characteristics of the coatings as a function of the deposition parameters. The presence of different Ca-P crystalline and amorphous phases was assessed by X-ray diffraction analysis. The coating microstructure was characterized by scanning/transmission electron microscopy. The suitability of the technique to coat biomedical implants is discussed.

Abstract: The behavior of stoichiometric and near-stoichiometric NiAl at plasma spray deposition, without and with a bond coat, for coating layers realization on a low alloyed steel substrate has been investigated and is presented. In all variants, NiAl particle melting and their welding at the impact with substrate were observed. Furthermore, a relatively compact and adherent coating layer was formed and the NiAl was found to maintain its stability. These are all important factors for assuring the coating layer oxidation and corrosion resistance. Good results from the coating structure and adherence to the substrate points of view were obtained for the 45:55 Ni:Al composition, without a bond coat but adopting an Ar protective surrounding of plasma jet. The high resistance to corrosion of 45:55 NiAl composition was further validated through corrosion tests.