Papers by Keyword: Titanium Substrate

Abstract: Laser surface cladding is a material processing technique to overlay the precursor material with the substrate to form a sound chemical and metallurgical bonding. Recently, laser cladding technique has been introduced in the bioceramic coating field. This paper presents a new technology to obtain bioceramic composite coating on Ti6Al4V substrate by Nd-YAG laser cladding. The microstructures of the mixed powders and cladding layer were investigated by scanning electron microscopy, and the compositions were analyzed by electron diffraction spectroscopy. The phases of the mixed powders and cladding layer were clarified by X-ray diffraction technology. Composite coating including HAP,Ca₂P₂O₇,Ca₃(PO₄)₂ and calcium titanates was successfully obtained by Nd-YAG laser cladding with pre-depositing mixed powders of CaHPO₄·2H₂O and CaCO₃ directly on Ti6Al4V substrate. The average grain size of the mixed powders is 3μm from the image analyse software. The most important parameter that affected the completion of laser cladding was the scanning speed.

Abstract: The synthesis of platinum nanoparticles by reduction of H2PtCl6 with ascorbic acid has been studied. By high-resolution electron microscope and XRD analyses, the resultant nanoparticles have been found to be pure platinum of fcc structure. Their sizes were observed to increase with the increases chemical reductive with 24h. Then, platinum nanoparticles directly attached to Ti plates(Pt nanoparticles/Ti) were successfully fabricated. In this method, platinum nanoparticles could be grown on the Ti surface via the one-step immersion into the growth solution containing PtCl62- and ascorbic acid. The attached and grown platinum nanoparticles were spherical having an agglomerated nanostructure composed of small nanoclusters. The present Pt nanoparticles/Ti may be promising for a new type of electrode material.

Abstract: Carboxyl multi-walled carbon nanotubes (MWCNTs) as the second phase in the hydroxyapatite(HA) composite coatings on Ti substrate, produced by a sol–gel route, were developed for biomedical applications. The crystallization of hydroxyapatite phase was investigated with X-ray diffraction(XRD) and the microstructure of the obtained composite coatings were studied by scanning electron microscopy (SEM). Bonding strength between coating and substrate were also investigated. The surface of the composite coatings were dense and uniform. The coatings had good adhesion to the substrate. As-prepared HA-MWCNTs composite coatings combining the osteconductive property of HA and the excellent mechanical property of MWCNTs will provide a promising material for potential bone replacements.

Abstract: We report the preparation of quasi-arrays of aluminum nitride nanocones via chemical vapor deposition on nitriding treated titanium substrate at 800 °C through the reaction between AlCl3 vapor and NH3/N2 gas. The field emission measurement exhibits a fine electron emission with the turn-on field of 10.7 V/mm, which is quite smaller than the turn-on field of 41.3 V/μm for aluminum nitride nanocones deposited on silicon wafer in our previous works. The reduction of turn-on field is attributed to the formation of a layer of conductive tiannium nitride on titanium substrate during the nitriding treatment.

Abstract: Lead-free piezoelectric (Bi1/2Na1/2)TiO3 (BNT) films were deposited on 1 mm thick pure titanium(Ti) substrates by a hydrothermal method. Tensile tests were performed to quantitatively assess the adhesion strength between BNT films and Ti substrates. Ti substrates were pretreated by chemical polish and mechanical polish respectively prior to BNT film deposition. In the tensile test, the behavior of BNT film exfoliation was investigated by the replica method. The critical Ti substrate strain inducing BNT film exfoliation was determined by the aid of finite element analysis (FEM). In this study, the results revealed that BNT film exfoliations were caused by the strain of Ti substrate, and the mechanical polish pretreatment improved the adhesion of BNT film to Ti substrate.

Abstract: The effect of surface states of substrate and additives on copper electrodeposition for thin film applications was investigated. Titanium substrate states were mechanically and chemically moderated and several additives such as Arabic gum, hydroxyl ethyl cellulose, and chlorine were used during electrodeposition process under a constant current condition with current density of 500 mA/cm2. Results obtained using SEM, X-ray, and AFM for early stage of copper nucleation and growth revealed that substrate conditions and additives appear to be effective in producing uniformly-distributed copper nuclei and their subsequent growth in a regulated manner of surface leveling. The shape of copper nuclei was clearly affected by the surface state of the substrate. It seems to be related with dislocations produced on the titanium cathode during surface moderating. Hardness, growth direction, and resistivity of copper deposits changed with the kind of additives.