抄録
The author investigated the diffusion of Cu, Mn, Ni, Fe, Zn, Si and Mg into aluminium which are commonly added as aluminium alloys.
As to the experimental process, each cylinder of 50mm in height and 20mm in diam. made from these diffusing elements or alloys with aluminium was contacted closely with an aluminium disc of 10mm in height and 20mm in diam. Next thus prepared samples were placed in the Tammann tube or mild steel crucible of 150mm in depth and 20mm in diam., so as to let the aluminium disc go upwards, and downwards in the case that it's specific gravity is greater than that of the diffusing elements. The melting for diffusion was carried out by a nichrome resistance furnace, and held for 1·5 hours at a constant temperature. Then samples for chemical analysis were sucked up with an aspirator from the top or bottom of the molten alminium discs.
The diffusion coefficients were calculated by the following equation.
where ψ is the probability integral; h, the thickness of aluminium disc; D, the diffusion coefficient; t, the time of diffusion; CM. the concentration of diffused element at the upper or lower surface of the molten aluminium disc; and CMo, the concentration of diffusing element in the cylinder.
From the experimental results, the author found that Si has the greatest, Mg, Mn and Ni the smallest, and Cu, Zn intermediate diffusion coefficient, except Fe of which coefficient is small at a low temperature and great at a high temperature, whilst he could not find a definite law between the diffusion coefficient and the properties of each element.
