Wear resistance of iron oxide thin films

• Published in: Journal of applied physics 1988-04, Vol.63 (8), p.3275-3277
• Main Authors: Chen, Mao-Min, Lin, Judy, Wu, Tsai-Wei, Castillo, Gilbert
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.340810

Magnetite films (Fe3O4) were reactively sputtered onto (100) silicon substrates in an Ar+O2 gas environment from a target containing Fe and 0.75 at. % Os. The films were then oxidized in air to form γ-Fe2O3. The wear resistance of the films was evaluated using an oscillatory wear tester and a contact start/stop tester with IBM 3380 type of sliders. Magnetite films exhibited poor durability independent of the deposition substrate temperature and oxygen partial pressure. Upon oxidizing the magnetite films in air at elevated temperatures, the wear resistance increased. For fixed deposition conditions, the wear resistance of the film increased with oxidation temperature. However, too high an oxidation temperature will transform the film into α-Fe2O3, which is antiferromagnetic material. For a fixed oxidation temperature of 300 °C, the wear resistance of the film increased with increasing deposition substrate temperature. Durable γ-Fe2O3 thin film can be produced by depositing 1000-Å-thick film at 325 °C and subsequently oxidizing the film at 300 °C. A visible wear track was detected only after 16 000 contact start/stop cycles for γ-Fe2O3 film media without additional layers of overcoat or lubricant in ambient environment. The friction coefficient was low and remained stable with sliding cycles. The dependence of friction coefficient of the film on deposition conditions will be discussed.