The electroplating of copper using a gel electrolyte has been studied. The suitable condition to gelate the high concentration electrolyte solution by gelatin was found. Using the gel electrolyte, it is easy to fix and remove the electrolyte on/from the metal surface. The influences of pH and chloride concentration on copper deposition using gel electrolyte were investigated by the cathodic polarization curves and surface observation. Finally, pattern electroplating using gel electrolyte was performed.
The gas bubbles are evolved in the horizontal electroplating cell, so that the surface uniformity and other properties of electroplated steel sheet are affected by the current density distribution in the direction of net movement of gases. In the electroplating industry, it is essential to know and control the current density distribution. In this study, in order to clear the behavior of gas evolved in the horizontal electroplating cell, the effects of the liquid velocity and average current density on the current density distribution in the horizontal parallel electrolysis cell were experimentally investigated. Gas holdup in horizontal electrolysis cell increases in the direction of liquid flow, causing a corresponding variation in the ohmic resistance between electrode and electroplated steel sheet. The resulting non-uniformity in current density distribution and the increase in overall resistance in the horizontal electroplating cell are characterized by the modified equation of Tobias equation derived for vertical electrolysis cell. The experimental results of effect of gas evolution on current density distribution in the horizontal electrolysis cell were simulated by the model calculation modified by considering the gas holdup, which is effective for electrolysis evolving large amount of gas bubbles.
The preparation of Hydrophobic TiO2 by the wet coupling treatment method was investigated using compounds of the alkyltrimethoxysilane series. Additionally, wet treatment of TiO2 using preliminarily treated n-PTMS and n-BTMS solutions was examined for the effectiveness of the use of preliminarily treated silane coupling agent in the wet process. The main results obtained are as follows : (1) The adsorption amount of n-PTMS dissolved in pure water onto TiO2 treated by the wet method was negligibly small, resulting in an M value that indicated the degree of hydrophobicity was zero. In contrast, M values of TiO2 treated by the wet method using i-BTMS, n-BTMS and n-HTMS increased with the increase in elapsed time. However the increase in carbon number resulted in the acceleration of increase of M values, causing an increase in maximum M value. A large amount of fixed ATMS does not necessarily signify maximum M value. (2) The maximum M value of TiO2 treated by the wet method using different pH solutions containing n-BTMS appeared to be 60%. Retention time required to increase of M value was shortened according to the sequence of pure water, pH 9.0, pH 4.0 and pH 3.3, and this finding suggested that the sequence was directly related to hydrolysis and condensation reaction rates of n-BTMS in those solutions. The amount of n-BTMS required to provide sufficient hydrohobicity to TiO2 at pH value, under which coupling treatment proceeds quickly, is larger than for slower treatment. The minimum amount of fixed n-BTMS providing maximum M value to TiO2 was found to be about 1 mg per 1 g TiO2, which was 27% of the theoretical amount of n-BTMS addition. In aqueous ammonia solution of pH 10.0, n-BTMS exhibits white turbidity to form an emulsion. Using this emulsion, wet coupling treatment of TiO2 proceeds quickly compared to those at lower pHs. (3) Wet treatment of TiO2 using preliminarily treated n-PTMS or n-BTMS was able to provide hydrophobicity faster than that using n-BTMS solution without preliminary treatment.
Flattened diamond crystals can be synthesized on polycrystal gold plate by hot-filament chemical vapor deposition (HFCVD) at atmospheric pressure. The ratio of the size of the top face and the height is 20 : 1 or more. Spraying the reaction gas onto the substrate is effective for synthesis of flattened diamond crystal. By spraying the reaction gas onto the substrate, sub-micron crystals on the substrate migrate. Then, they collide with each other, and twins are formed. The preferential growth of the side face that has the re-entrant corner occurs. Finally, flattened diamond crystals are formed. Moreover, the quality of all the diamond crystals including flattened diamonds can be improved by spraying the reaction gas. The probability of synthesis of flattened diamond crystal is 50% on HFCVD when spraying the reaction gas at 13 kPa.
We investigated the electrochemical behavior on the boron-doped conductive diamond electrode in HNO3 aqueous solution containing Pb2+ ions. The anodic oxidation led to the formation of a PbO2 deposit on the diamond electrode. In HNO3 solution containing less than 10 μM (M=mol/l) Pb2+ ions, a clear cathodic current peak was observed on the diamond electrode in the cathodic potential scan after holding the potential at 1.80 V vs. SCE. On both the platinum and glassy carbon electrodes, it was difficult to detect a cathodic current peak exactly in the same solution because of the large background current of these electrodes. The proportional relation between the magnitude of the cathodic current peak and the concentration of Pb2+ ions (1-10 μM) in coexistence of Cu2+ and Fe3+ ions was obtained by use of diamond electrodes pretreated with cathodic reduction and anodic oxidation in HNO3 solution. The diamond electrode also showed high ability to scavenge Pb2+ ions from the solution.
The urethane derivative of hydroxyapatite including triethoxyisilyl group was synthesized by causing hexamethylene diisocyanate to act on hydroxyapatite particles in DMF at 40℃ in the presence of dibutyltin dilaurate (IV) catalyst, followed by adding of 3-aminopropyltriethoxysilane. The triethoxysilyl group in this compound was hydrolyzed in ethanol by adding water and acetic acid at 70℃ to prepare the precursor suspension solution. A glass plate coated by being dipped in this suspension solution was heat-treated at 200℃. The observation by SEM on the surface of glass plate thus obtained was found that the glass was coated by finely dispersed hydroxyapatite particles.
It was confirmed that the rust formation on Iron surface by the dissolved oxygen in water was accelerated under the applied strong magnetic field (10T). Acceleration originates from the convection induced by the change of diffusion of the paramagnetic oxygen molecule by the high gradient of magnetic field formed around the iron. The possibility of the control of iron rust formation was indicated by the magnetic field.