THE EFFECT OF THERMAL ANNEALING ON THE ADHERENCE OF AL2O3-FILMS DEPOSITED BY LOW-PRESSURE, METAL-ORGANIC, CHEMICAL-VAPOR-DEPOSITION ON AISI-304

Thin alumina films, deposited at 280 degrees C by low-pressure, metal-organic, chemical-vapor deposition on stainless steel, type AISI 304, were annealed at 0.17 kPa in a nitrogen atmosphere for 2, 4, and 17 hr at 600, 700, and 800 degrees C. The effect of the annealing process on the adhesion of the thin alumina films was studied using a scanning-scratch tester, type SST-101, developed by Shimadzu. The best mechanical properties were obtained with unannealed samples. After thermal annealing the critical load decreased proportional to annealing time and/or temperature. This effect was probably due to the presence of a high thermal stress and to preferential segregation of sulfur near the oxide-alloy interface.