Thermal electrochemical, and plasma oxidation of Ti-50Zr, Cu-50Zr, Cn-50Ti, and Cu-33Ti-33Zr alloys

The three main methods for oxidation of metallic substrates, thermal, anodi c and plasma have been applied to a copper, titanium, and zirconium alloy a nd its corresponding binaries (Cu-33Ti-33Zr, Cu-50Ti, Cu-50Zr and Ti-50Zr). Polished polycrystalline samples of these alloys were examined before trea tment, after vacuum thermal annealing at 100 degreesC and heating in 20 mTo rr oxygen at 100, 200, and 300 degreesC. ISS depth profiles were taken of s elected samples. The "least-noble" component oxides first, but at high temp eratures and with plasma oxidation the ''noble" component segregates to the surface. A comparison of the resulting structures on the ternary and binar y alloys with different oxidation methods is used to explore the physico-ch emical processes during oxidiation. Results from these three methods are di scussed in terms of physical/chemical parameters that influence the chemica l nature and structure of the resulting oxides, The electrochemical process es that occur during the materials reaction with a chosen environment are u sed to discuss the physical and chemical mechanisms involved. Intrinsic (th ermal and plasma oxidation) and extrinsic (electrochemical oxidation) elect ric fields are shown to influence the chemical and structural nature of the resulting oxide structures. The influence of transport phenomena is discus sed.