The effect of oxygen concentration in the furnace and annealing time on the gloss of pickled pure titanium was studied to stabilize the gloss of pure titanium for construction manufactured by the continuous annealing and pickling line (APL). The gloss of pickled pure titanium annealed in 3% O2 was lower than that annealed in 5% or 10% O2. When the oxygen concentration was low, fine scale formed that was difficult to remove by dipping in a molten salt bath and thus difficult to pickle, lowering gross. Gloss was low when annealing time was short, and grain growth did not occur sufficiently, increasing the number of peaks of pickled pure titanium on the surface. Applying these findings to APL operation made it possible to control precisely the gloss of pure titanium for construction.
We studied the effects of stannous ion concentration, flow rate, and current density on limiting current density, tinplate appearance, bright current-density-range, morphology, and orientation of deposited tin crystal, using a laboratory circulation cell and phenolsulfonic-acid-based baths. We found that (1) limiting current density increased and bright current-density-range broadened with increasing flow rate and stannous ion concentration, (2) the maximum bright current-density-range was near the limiting-current-density and increased with increasing flow rate and stannous ion concentration, (3) the minimum bright current-density-range increased slightly with increasing flow rate and stannous ion concentration, (4) fine tin crystals less than 1μm in diameter were closely deposited in the bright current-density-range, but coarse tin crystals of diameter more than 1μm were deposited below the range and many dendritic crystals were deposited above the range, (5) the iron exposure value (IEV) decreased with increasing current density, then increased, and over the current density of the lowest IEV at a low stannous ion concentration of 20g/L, the value increased greatly and increased slightly at a high stannous concentration of 50 or 80g/L, (6) the preferred orientation of tin deposited under the bright current-density-range was (100), but the (100) orientation decreased and (101) orientation increased with increasing the current density. In the bright current-density-range, the preferred orientation of deposited tin was (101).
The deposition mechanism of self-deposition coating system for steel substrates has been investigated. The first stage of the self-deposition reaction is steel oxidation by iron (III) fluoride. The second stage reaction is resin emulsion coagulation and deposition on the steel surface by neutralizing the negative charged emulsion with positive charged iron (II) ions generated in the first stage. To demonstrate the effects of iron (II) and iron (III) ions, equilibrium calculation and simulation in concern with resin emulsion coagulation with iron (II) fluoride have been conducted. As the results, iron (III) fluoride existed as a fluoride complex with nocharge in the coating bath and did not contribute to discharging the resin emulsion. On the other hand, iron (II) fluorides in coating bath exist as hexaaqueous complexes with positive divalents, and effectively discharged the emulsion. The remarkable defference in the stability consants of iron fluorides between iron (II) and iron (III) ions consists of the self-deposition coating system.
Interference coloring of anodized aluminum is the result of a sophisticated electrolytic process of anodizing, anodic pore widening (pore modification), metal electrodeposition into modified pores, and final reanodizing (or not). Due to this sequence, the anodic film consists of four layers differing in optical property and thickness. This investigation was made by regarding a portion consisting of metal deposits and oxide as a single uniform layer in the anodic film with a complex reflective index specified by that of metal and the volume fraction of metal to oxide to propose a comprehensive optical model for interference color. In this model, variables affecting color other than the reflective index are thickness of both the metal deposit layer and oxide between the deposit and base aluminum, which depend on electrolysis conditions. The model was studied for several interference colors produced in different electrolyses and found to be in good agreement.
A YAG laser was used to surface-harden electroless Ni-P alloy plating on an aluminum alloy substrate. The relationship between laser irradiation and tribological properties was evaluated by a dry friction and wear test. Laser irradiation at 500W and beam scanning of 50mm/s produced harder surface film without heat damage to the aluminum alloy substrate by rapid heating and cooling of the laser. The laser-hardened film had the highest wear resistance in the dry friction and wear test.