Adhesion of evaporated aluminium films with underlayers of nickel, cobalt and chromel

Abstract

Thin layers of nickel, cobalt and chromel are evaporated under vacuum on to glass microscope slides and used as underlayers for aluminium films. Adhesion measurements are used to investigate ageing effects which are shown to depend upon temperature as well as the nature and thickness of the underlayer. Results are shown to be due to intermetallic compound formation at the interface causing a type of age-hardening which may result in either decrease or increase in the measured adhesion according to the compound formed and the condition of ageing.