1991 Volume 77 Issue 7 Pages 1003-1010
Effects of pretreatments such as argon ion bombardment and preheating of steel substrates on adhesion and formability of ion plated films were studied. The chromium film formed on the steel substrate with preheating at 200°C and argon ion bombardment (proper pretreatment) provided the excellent adhesion and formability compared with that formed without preheating or argon ion bombardment. The compositional depth profiles of chromium films on steels obtained by AES showed that the chromium film formed on the steel pretreated properly had no oxide and carbonaceous contamination at the interface, with much broader mixing zone than that of the chromium film formed without argon ion bombardment or preheating. It was suggested that the good adhesion of the chromium film formed on the steel with proper pretreatment was attributed to both the sputter cleaning effect before deposition and the formation of mixing zone.
The growth and orientation of the chromium films formed on the steels with various pretreatments were investigated using TEM. Plate-like grains grew epitaxially on the steel with proper pretreatment, whereas very small grains that didn't grow epitaxially were observed in the films formed with improper pretreatment. It was considered that the inferior formability of the chromium film formed without argon ion bombardment or preheating was caused by the high probability of the crack formation in grain boundaries among many small grains.
