Cu diffusion kinetics in (Cu, Ni)3Sn intermetallic compound nanolayers investigated by an Energy-Dispersive-X-ray-based permeation test

The Energy-Dispersive-X-ray-based permeation and oxidation test has been further developed by an improved theoretical analysis, in which chemical potential gradients rather than concentration gradients are employed. The developed test is able to characterize diffusion kinetics in diffusion barriers at the nanometer scale. The Cu flux coefficient in (Cu, Ni)3Sn intermetallic compound nanolayers was determined from the test to be 8.48 × 10− 15 mol·(m·s·J/mol)–1 exp(− 52.3 kJ·mol− 1/RT) in a temperature range of 250 °C–400 °C.