The 1932/1933 experiments of Grube-Jedele revealed their discovery that 0–100at% diffusion penetration curves could generate monotone composition-variant interdiffusion coefficients, . Grube-Jedele templated a smoothed infinite couple sectionally and sequentially curve via a set of constant  error-function curves with local 2- and 3-point matching. The first and second derivatives created a monotone sequence of coefficient values. This was detailed in processing Grube-Jedele curves; remarkably revealing, as with constant , that the variable  obtained generated a √t penetration dependence. This finding was later verified analytically via Ginzburg-Landau’s 1950 variational-quantum, lattice-dynamics requirement that  lay outside of the Fickian second derivative. The Ginzburg-Landau and Grube-Jedele procedures and analyses were supported in 1947 by Smigelskas and Kirkendall’s experimental discounting of Boltzmann’s 1897 purely mathematical theorem.

Confirmation of the Grube-Jedele Procedure in Processing Interdiffusion Data in Binary Alloys. A.Perovic, J.S.Kirkaldy: Metallurgical and Materials Transactions A, 2011, 42[1], 1-3