A high powered YAG laser was applied to a carbon steels hardened surface with assistant gases such as air, oxygen, nitrogen, carbonic acid and argon. Effects of the assistant gas on the hardened zone were measured by hardness and microstructure. The structure of the hardened zone underwent complete martensitic transformation, and its hardness ranged from Hv 750-800. Under identical laser irradiation conditions, the hardened zone showed various values depending on the type of assistant gas, and the gas flow rate. Remelting took place in oxygen assistant gas. These results were due to the heat of oxidation and the exothermic reaction. The experimental results indicated that the hardened zone was affected by the cooling of the assistant gas as well as oxidation reaction.
Ta2O5 thin films were deposited under various sputtering conditions onto glass plates by RF magnetron sputtering apparatus. Sputtering conditions were directed by changing the RF power, O2 partial pressure and substrate-target distance. The effects of these sputtering conditions on the deposition rate and transmittance of films were investigated. Furthermore, the crystallinity and the ratio of oxygen to tantalum (O/Ta) of the films were investigated. The results showed that the deposition rate was affected by RF power, O2 partial pressure and substrate-target distance. On the other hand, the transmittance of films was only affected by O2 partial pressure, and the transmittance of the films which deposited at 0% O2 partial pressure was lower than that of the others in the short wave length area. O2 partial pressure was not found to effect the crystallinity of films, and the films which deposited at any O2 partial pressure were amorphous in structure. However, the ratio of oxygen to tantalum of films which deposited at 0% O2 partial pressure was smaller than that of films which deposited at the other O2 partial pressure.
Fine mechanical properties such as hardness and abrasion resistance are difficult to obtain for both the anodic oxide film and the base metal in sulfuric acid anodized coating. Age-hardening of Al-Cu alloys such as 2017 or 2024 are well known but we are not able to gain the fine properties of the anodic oxide film for these alloys. This report discusses the effect of heat treatment in subdividing and resolving soluble intermetallic compounds such as CuAl2, Mg2Si and Al2CuMg precipitated in a matrix of Al-Cu alloys to gain anodic oxide films with fine properties. By heating a matrix precipitating CuAl2, Mg2Si, Al2CuMg and other materials at optimum temperatures such as higher artificial aging temperatures but lower solution treatment before anodized coatings, these soluble intermetallic compounds are subdivided and resolved, and anodic oxide films are homogenuous and hard but the base metal is softened by heating so the next processes are given solid solution treatment and artificial aging. Through this processing, the strength of the base metal is recoverd in thermal refining such as T3 or T4 without the drop in hardness of films or the occurrence of cracks or peeling. Conclusions (1) The optimum temperature of heat treatment before anodized coating is about 400°C. (2) The abrasion and corrosion resistance of films are improved by this process. (3) Self-color anodized coatings such as gray or black are enable by this process.
In order to improve the adhesion between Ti oxide film and Pt film, a Ti layer has often been inserted as a thin interleaving glue layer. However, through heat treatment in an oxygen atmosphere, Ti diffusion and oxidation occur through the Pt films, and they influence the temperature coefficient of resistivity (TCR) of the Pt films. SEM, TEM and SIMS observation were used for the analysis of the behavior of the Ti atoms. It was found that the most of Ti atoms in the glue layer became oxidized and diffused onto the Pt surface, but the decrease in the TCR was at most a few percent. By changing the thickness of the glue layer, we found that 5nm is the most appropriate thickness of the Ti glue layer which enhances the adhesion and suppresses the deterioration of the TCR.
The dissolution rate of tungsten in an alkaline etching solution containing ferricyanide was studied. The cathodic reduction of ferricyanide was controlled by mass transfer under operating conditions, so the anodic dissolution of tungsten is also limited. The reaction rate was thus fairly proportional to the ferricyanide concentration, and was increased by solution agitation.
Aluminum foil of 99.99% purity was etched in a mixed aqueous solution of hydrochloric acid, sulfuric acid and aluminum chloride using 1, 5 and 10-Hz AC signals with controlled anodic potential and cathodic potential. The effect of frequency on the characteristics of AC etched aluminum foil was investigated. At a given cathodic potential, the anodic potential above which the AC etching takes place, and the anodic potential that gives the highest capacity, both shift toward the negative value with the increase of the frequency. At a given anodic potential, the cathodic potential that results in optimum etching shifts toward the negative value with the increase of the frequency. The length (L) of one side of the pit increases with the decrease of the frequency (f), and the relationships between the length and the frequency is found to be L ∝ f-0.78.
Aqueous precision cleaning systems are being replaced by 1, 1, 1-Trichloroethane washing as a way to clean vacuum parts for picture tubes. In these systems, oil-contaminated parts are transferred from bath to bath, while the detergent solution is constantly replenished and overflowed opposite the parts flow. Systems reach and remain at equilibrium so that the oil concentration and detergent concentration in each bath may be estimated in advance. Based upon the cleaning curves of parts obtained experimentally, practical equations which expressed the oil concentration were formed by considering the balance between the incoming and outgoing oil in the bath. This method was expanded in the case of using an oil separation device in the first bath. Based upon evaporation curves for detergent components in a laboratory test, practical equations for detergent concentration were also formed in the same way. Estimated concentrations shown roughly agreed with those in experiments.
Co-Zn alloy deposit was obtained from ambient-temperature molten-salt electrolytes, CoCl2-ZnCl2-BPC systems, and from organic-solvent added baths. The Co content in the Co-Zn alloy deposit was continuously controlled from 0 to 100wt% by controlling the bath composition and the current density. The morphology and the current efficiency of the Co-Zn alloy deposit were significantly improved by the addition of an organic solvent, i. e., propylene carbonate and ethyl alcohol, to the bath. The bath temperature could also be decreased from 130°C to 25°C by adding organic solvent. We assumed that the crystal structure of the Co-Zn alloy deposit changes from the binary phase of Zn and an intermetallic compound, Co5Zn21, to that of Co and an intermetallic compound with Co content in the deposit. We predict that the amorphous deposit of Co-Zn can be obtained from this molten-salt electrolyte.