Singularity in Pure Zinc at High Temperatures

Precise measurements of the temperature dependence of the electrical resistance of pure zinc were made without any imaginable disturbance, and no anomaly was found in the range from room temperature to the melting point. The study of quenching effect on the specific gravity showed, contrary to the result by Bingham, also no anomalous change. It was concluded that pure zinc had no singularity at high temperatures

Study on the Transformation of Zinc by Electric Resistance in Connection with Eutectic Phenomena

Accurate measurements of the electric resistance of zinc were made by the potentiometer method in the range of temperature from room temperature up to 350℃. The anomalous changes were observed at the temperatures, 170, 200, 230 and 320℃. The first two temperatures were explained respectively to be the eutectic temperatures of the solders, Pt-Sn-Zn and Sn-Zn systems, used to solder the potential lead and the specimen ; 230℃ to be the temperature of second separation in the former solder ; 320℃ to be the eutectic temperature of the alloy, Pd-Zn system formed in the specimen. From a conception explaining the eutectic phenomenon, 170°, 200°and 320℃ were considered to be anomalies of zinc itself

Exact Solutions of Two Ideal Cases in Grain Boundary Diffusion Problem and the Application to Sectioning Method

Exact solutions of grain boundary diffusion based on the two mathematical conditions assumed for the surface source are discussed for the purpose of application to the experiments by means of sectioning method. It is concluded that the result obtained by either of these solutions is in effect unaffected by possible deviations from the ideal condition, and one of them, the "instantaneous source" solution, is the most successful one in analyzing the problem. The expression for the solutions can be transformed to another type of expression more appropriate to the grain boundary diffusion, and some discussions and numerical evaluations of these solutions over a more extensive range of parameters than previous are given

Diffusion of Iron Group Elements in Silver

The diffusion coefficients of nickel and cobalt into silver has been measured as a function of temperature by the tracer and lathe sectioning techniques. The results obtained were expressed as follows : D=(21.9)・exp(-54, 800/RT)cm^2/sec for nickel D=(104)・exp(-59, 900/RT)cm^2sec for cobalt. Taking into consideration the result by Mullen for the diffusion of iron into silver, the activation energy of diffusion of the first transition elements increases slowly from Cu to Ni and after showing a sharp maximum at cobalt, decreases suddenly at iron. Such behavior is different in the case of copper, in which a flat maximum is found at nickel. Also the frequency factor shown in the above expression is fairly large when compared with copper. It is pointed out here that the solid solubility limits of the first transition metals in silver are extremely small when compared with copper, which has some influence on the result of measurement of the activation energy as well as the frequency factor in the case of silver