Papers by Keyword: Metal Surface Treatment

Abstract: Our main purposes were to establish ultraviolet-ray aided machining (here after reffered to as U-RAM) and clarify the chemical and mechanical polishing mechanism. The inner/outer surfaces of small cup-type nickel tube is strongly required to polish, simultaneously. The present study deals with the new development of simultaneous polishing technology and the verify of polishing phenomena that uses a photocatalyst and a cathilon (a luminous dye: Cathilon Brilliant Flavine; hereafter referred to as cathilon) excited by an ultraviolet ray (hereafter referred to as UV). Measurements and observations clarified that TiO₂ of 0.18-μm grain size polished chemically/mechanically the outer surface using cathilon, and cathilon chemically polished the inner surface of small cup-type nickel tube, simultaneously. Further measurements indicated that the chemical erosion roughened the inner surface, when cathilon increased from 2.5, 5 to 20wt%. An increase of TiO₂ to 20wt% at 20wt% of cathilon did not result the flatter surface. Aluminum oxide does not provide the polishing ability due to the poor photocatalyst effect compared with TiO₂.

Abstract: Fabrication of self-assembled film used 792(silane coupling agent), citric acid, boric acid and triethanolamine as the main materials. Through orthogonal experiment and the single factor analysis experiment, the optimum technological conditions are 792 10mL·L^-1, citric acid 24g·L^-1, boric acid 8g·L^-1, triethanolamine 7.5mL·L^-1, temperature 20~21°C, time 10min. Simulated sea water (3% Sodium chloride) is applied to measure the effects of the film. The results show that the processing is simple, tank liquor is stable, and film is uniform, dense and colorless.

Abstract: In this study we selected polyethylene glycol (400), triethanolamine, silane coupling agent and glycerol as the main raw material, and systematically studied the chemical adsorption film technology on the steel surface by taking one step. Under the optimum conditions ( polyethylene glycol (400) was 10mL/L, triethanolamine was 40mL/L, silane coupling agent was 10mL/L, glycerin was 15mL/L, the pH was 10, the time was 12min, and temperature was 45°C), we characterized the chemical adsorption film by SEM, XPS and IR. The results showed that the treatment process was simple, the tank liquor was stable, the chemical adsorption film was dense, uniform. This adsorption membrane resistance to corrosion and coating adhesion was superior to the traditional phosphating process.

Abstract: The main purposes of this study were to lessen the deformities in the machined surface, to make the crystal grains on the machined surface appear, and to apply this machining at the micrometer level instead of at the nanometer level. The present study targets the development of a polishing technique that uses a photocatalyst and a luminous dye (Cathilon Brilliant Flavine; hereafter referred to as cathilon) excited by an ultraviolet ray. Nickel (hereafter referred to as Ni) was polished chemically and mechanically at the sub-micrometer level under an ultraviolet-ray irradiation. Measurements clarified that TiO₂ of 0.1 μm grain size mechanically polished the Ni, and cathilon chemically polished Ni. A flat surface was attained on the Ni by chemical and mechanical polishing using both the TiO₂ and cathilon, when they were irradiated by an ultraviolet ray. Further measurements indicated that the corrosion of Ni surface became large under an ultraviolet-ray excitation. The eroded trace was large when cathilon is rich. Though much TiO₂ tends to roughen Ni surface, the flat surface was obtained in the case of much TiO₂ and much cathilon due to both equivalent influences.

Abstract: This study targets the development of a polishing technique that uses a photocatalyst and a fluorescent substance excited by an ultraviolet ray. Nickel (hereafter referred to as Ni) was polished chemically and mechanically at the micrometer level under ultraviolet-ray irradiation. Measurements clarified that TiO2 of 0.1-μm grain size, at which size the excitation by the ultraviolet ray was less influential, mechanically polished the Ni. Cathilon (a luminous dye) chemically polishes Ni. The corrosion of the Ni surface became large under ultraviolet-ray excitation. A flat surface was attained on the Ni by chemical and mechanical polishing using both the TiO2 and cathilon, when was irradiated by an ultraviolet ray.

Abstract: The aim of this study was to optimize the surface treatment and to accelerate the osteoinductivity of porous bioactive titanium implant. Previous studies have reported that sodium removal with hot water treatment converts sodium titanate on the surface of an alkali-treated titanium plate into titania with a specific structure, which has better bioactivity than sodium titanate. We developed a dilute hydrochloric acid (HCl) treatment for porous titanium, which removed sodium from the complexly shaped porous structure more effectively than conventional hot water treatment. Three types of surface treatments were applied: (a) alkali and heat treatment, (b) alkali, hot water, and heat treatment (conventional treatment), and (c) alkali, dilute HCl, hot water, and heat treatment (Na-free treatment). The osteoinductivity of the materials implanted in the back muscles of adult beagle dogs was examined at three, six, and twelve months. Na-free porous bioactive titanium exhibited the highest osteoinductivity, and bone formation was observed within three months. This study showed that sodium removal has a significant positive effect on the osteoinductivity of the porous bioactive titanium implant.

Abstract: Porous bioactive titanium implant was produced by plasma-spray method and succeeding chemical and thermal treatment. This porous titanium implant possess a porosity of 40% and complex interconnective porous structure. Mechanical property of porous titanium was characterized for compressive and 4-point bending properties, as well as compressive fatigue. Bone tissue response and biocompatibility of porous bioactive titanium implant was evaluated by in vivo osteoconductive model. Ultimate compression strength and bending strength were 280 and 101 MPa. Bone ingrowth showed significant increases in treated implant, while in these untreated porous titanium implant, bone ingrowth seemed to decrease with time. These results suggest that porous bioactive titanium is a candidate for clinical applications under load-bearing conditions.

Abstract: . An investigation of wear and bioconductivity characteristics of oxidized Ti-29Nb-13Ta- 4.6Zr is presented. Experimental results showed that oxidation treatment at 400oC for 24h in air results in the formation of a hard layer on the surface of the alloy, which greatly benefits its wear resistance. Calcium phosphate (Ca-P) phase was found to grow on the oxidized and alkali treated Ti-29Nb-13Ta-4.6Zr alloy samples when they were immersed in a protein-free simulated body fluid or fast calcification solution.