INTERDIFFUSION OF AL AND CR THIN-FILMS

The interdiffusion of Al and Cr thin films from 659-726 K was investigated by measurements employing Auger electron spectroscopy (AES) and Ar ion beam sputtering. The only intermetallic phase observed at the Al-Cr interface of isothermally annealed couples was Al//7Cr. The rate constant measured for the parabolic-growth model dx/dt equals K/x of the Al//7Cr-layer thickness was K equals 1. 3 multiplied by 10**6 exp left bracket minus (262 kJmol** minus **1)/RT right bracket cm**2s** minus **1. The chemical interdiffusion coefficient D was calculated from compositional profiles of unannealed and annealed specimens by the Boltzmann-Matano solution to the interdiffusion of bimetallic, semiinfinite couples that form three phases. The interdiffusion coefficient was D equals 1. 3 multiplied by 10**6exp left bracket minus 240 kJmol** minus **1)/RT right bracket cm**2s** minus **1 at 6 at. % Cr.