A model for the Kirkendall effect

Isotopic Selectivity in Ultrathin Langmuir−Blodgett Membranes of a Cross-Linked Cellulose Derivative

“…The Kirkendall experiment showed that copper (A) and zinc (C) in a brass diffusion couple had different diffusion coefficients through the displacement of an oxide impurity (B) located at the interface. This work fostered additional studies of the type A/B/C, where the “/” represents a distinct interface in trilayer geometries, to examine isotopic effects and void facilitated diffusion in metallic systems. , More recently, films of type A/B/C, where A and C are polymers and B is a vapor-deposited layer of gold particles, have been of interest. − In early studies, , displacement of the gold particles from their initial interfacial position during depth profiling experiments was taken as a sign that polymer interdiffusion could be attributed 4,5 to a compressible rather than incompressible 10 mechanism by including void transport across the interface. Subsequent experiments utilizing isotopic labeling on A/B films without markers were used to test various predictions for polymer dynamics following from the theory of reptation. − One basic assumption for eliminating the incompressible mechanism was that the gold particles are inert.…”

Polymer dynamics in hydrogenous systems by neutron reflectivity

“…Figure 5 shows that for each unit difference in the number of repeating units between polymer A and C, the membrane will move by 0.16 nm for the layer thicknesses used in this study. In this respect, the displacement of the interface is reminiscent of the Kirkendall effect experiment, in which oxide impurities present at the interface of a metallic diffusion couple allow one to track the position of the interface,22–24 and the use of vapor‐deposited gold marker experiments in polymer systems allows one to track the position of the interface 25–30. As similar results have been found for the air//dPS/IPCC/dPS//Si films, one may erroneously conclude that the IPCC membrane serves as nothing more than a sensitive marker for NR experiments.…”

“…NR has been used to measure the displacement of the membrane from its initial position during quench experiments. These systems share similarities with Kirkendall effect experiments in metallic systems22–24 and gold marker experiments in polymeric systems25–30 but also exhibit some significantly different effects 20, 21. New results for films of the type air//hPS/IPCC/hPS//Si are provided and are compared with prior results for the air//hPS/IPCC/dPS//Si and air//dPS/IPCC/dPS//Si systems.…”

“…In particular, the system air//hPS (39 k)/IPCC (5.7 nm)/dPS(40 k)//Si should possess equal tracer diffusion coefficients for hPS and dPS ( D hPS,tracer = D dPS,tracer ). Under these conditions, both the Kirkendall experiments22–24 and inert gold particles used in polymer systems25–28 would lead to a stationary interface. The fact that the IPCC membrane moves means that the membrane is not inert and that the phenomenon studied here is fundamentally different from classical marker experiments.…”

Grain Boundary Diffusion Parameters Determination Using A-Kinetics of Intermetallic Layer Formation

“…Morral, Son and Thompson [4] assumed that the concentration gradient at the Kirkendal plane can be approximated by an analytical expression for the concentration gradient at the Matano plane. They obtained:…”