Resistance to weather of the bolosilicate, lead, and phosphate enamels, used as building material, was examined by comparing the results obtained from the weather meter test with those from the exposition-to-weather test.
1. The enamels of borosilicate system was eroded in a shorter time both in the weather meter test (exposition to ultra-violet rays) and in the exposition-to-weather test.
2. The enamels of lead and phosphate systems showed a higher resistance to efflorescence both in the weather meter test and in the exposition-to-weather test.
The resistance to acid of the enamels of lead system, however, was lower than those of phosphate system. The latter, therefore, is more recommendable for a building material such as panelling.

View full abstract

Since wettability of lead-tin solder, which affects soldering operation and strength etc., was studied by measuring “static contact angle” defined by the authors in the last paper, a standardization of testing method of organic soldering fluxes by the contact angle has been tried by the further experiment.
The electric furnace, in which the solder drops on a test specimen were melted, was newly improved to make “the standard error of contact angle of solder drops melted in it” smaller than that reported previously.
In order to study the effets of organic fluxes for the wettability of lead-tin solder, the various factor finding experiments and the statistical analyses were made. As a result, it was found that the standard error became 3°in this case as opposed to 10°in the last case and the effect of organic fluxes and their blending formulae could be recognize by using “static contact angle.”

View full abstract

Zinc plating from cyanide baths was studied. Experiments were performed mainly at 30°C and without agitation, using sodium baths and potassium baths. Results are as follows:
With an increase in temperature, total Zn content and total OH content, and with a decrease in total CN content, the cathodic current efficiency at identical current density increased and cathodic polarization decreased. Higher current efficiency and lower cathodic polarization were obtained in potassium baths than in sodium baths. Anodic passivation was observed at lower current density in potassium baths than that in sodium baths. The specific conductivity increased with an increase in free alkali content, and 1.2-1.3 times higher value was obtained in potassium baths compared with corresponding sodium baths. In potassium baths, the range of current density for the lustrous deposit was more limited than in sodium baths. Throwing power was also discussed.

View full abstract