Synthesis of carbon nanocoils was carried out by the simple apparatus based on hot-filament CVD at catalyst temperatures below 450ºC. Copper was vacuum evaporated onto the nickel particles formed by scratching the poly-crystal nickel plate with sandpaper. These particles were used for the catalysts for synthesis of nanocoils. Heating was not performed at all for forming these particles. Ethanol as a carbon source was introduced into the chamber with argon gas. Synthesis was performed at atmospheric pressure. Carbon nanocoils could be synthesized at temperatures above 400ºC. The yield of nanocoils in total carbon fibers is about 80% at 400ºC. The diameter of these products decreases with the decrease of diameter of catalyst particles.
During the heat treatment of 0.3mass%Si-1mass%Mn-0.07mass%P ultra low carbon hot-rolled steel, readily oxidizable elements such as Si, Mn and P were internally oxidized and a depletion layer of these elements was formed at the steel surface region. The amounts of Si and Mn selective surface oxidation of the cold-rolled steel were remarkably suppressed after recrystallization annealing. By this heat treatment of the hot-rolled steel, the galvannealing rate of the galvanized steel was accelerated to a rate equivalent to that of mild steel. As a result, the galvannealing temperature of the galvannealed steel could be lowered and the anti-powdering properties of the galvannealed steel were remarkably improved. The reasons for acceleration of the galvannealing behavior and the improvement of the anti-powdering properties, were considered as follows : 1) The amount of Si and Mn selective surface oxidation, which acted as a barrier for the Fe-Zn galvannealing reaction, was suppressed. 2) The amount of solute P, which delays the Fe-Zn galvannealing reaction, was reduced. 3) The reduction of galvannealing temperature brings about the suppression of the Γ and Γ1 phases formed at the higher temperature, those unfavorable for anti-powdering properties.
Anodizing of magnesium was studied in sodium metasilicate with ortho-Cresol-4-sulfonic acid aqueous solution. A gray-colored anodic oxide film was obtained in 3.0mol·dm−3 sodium metasilicate-0.25mol·dm−3 o-Cresol-4-sulfonic acid aqueous solution at constant current density of 1000A·m−2 for 6.0×105C·m−2 at 278K. This film mainly consisted of magnesium, silicon, and oxygen and contained small amounts of carbon and sulfur. In the wear test using #800 SiC waterproof abrasive paper, this anodic oxide film showed almost the same wear resistance as that obtained in 2.0mol·dm−3 sodium metasilicate aqueous solution. However, in 0.86mol·dm−3 NaCl solution at 308K, the former without sealing showed higher corrosion resistance than the latter with sealing. Moreover, its corrosion resistance was further improved by the sealing treatment in boiling distilled water.
Applications have been investigated in recent years for newly designed electromagnetic radiation absorption materials as measures to restrict electromagnetic radiation from small-sized electronic equipment such as EMC and SAR. The materials obtained so far have focused on flattening metallic powder mechanically and distributing it in resin to form a structure that absorbs unnecessary electromagnetic radiation. In this report, we examine a material that aims to confine as much electromagnetic radiation as possible without absorbing it (μ'>μ") as a countermeasure for SAR. We thought that decreasing the eddy current was required to control absorption, and (making particle size minute is effective) to decrease the eddy current. The minute magnetic powder was obtained by the electroless plating method (Titanium Redox Method). The electromagnetic absorption property of a sheet within which this powder was distributed in resin was confirmed, with a frequency μ'>μ", to exceed 1GHz.