Oxide Films Formed on Titanium, Zirconium, and Their Alloys with Nickel, Copper, and Cobalt

Abstract

The electron diffraction technique is used to study the structures of the oxides which form on the metals, titanium and zirconium, and on the alloys, 50 Ti-Ni, 70 Ti-Ni, 28 Ti-Cu, 20 Zr-Cu, 60 Zr-Co, and 70 Zr-Ni, in the temperature range 300°to 700°C.The structures found are plotted on existence diagrams as functions of time and temperature. Attempts are made to correlate the structures obtained with thermodynamic data reported by other workers. The oxides occurring on titanium and zirconium are titanium dioxide (rutile) and the monoclinic modi-THE determination of the structures of the surface oxides resulting from a gas-metal reaction is one of the important factors in understanding the mechanism of the reaction. If these determinations are carried out in a consistent and systematic manner in regard to time, temperature, and gas pressure, a good deal of information may be obtained concerning the relative importance of the formation and diffusion of the several metal ions or the formation and diffusion of the oxygen ion, atom, or molecule through the oxide film. In addition, it may be possible to check on the thermodynamic predictions of possible oxide structures formed on the metal or alloy as well as reactions between the oxides in the film.The authors (9, 11) have presented electron diffraction investigations of the oxides which form on iron, cobalt, nickel, chromium, copper, tungsten, and molybdenum. This communication reports a similar study on titanium and zirconium and their alloys with nickel, copper, and cobalt.Titanium and zirconium are reported (13) to react with hydrogen, nitrogen, and oxygen at elevated temperatures. Neither metal forms tarnish films in air and both metals are considered protective up to 500°C. The corrosion resistance of both metals

Phase Diagrams of the Titanium-Aluminum, Titanium-Chromium-Iron, and Titanium-Oxygen Alloy Systems

“…The incipient melting temperature for a 25 weight per cent oxygen alloy, corresponding to the theoretical composition TiO, was determined to be 17600C, which is in very close agreement with a previously reported melting point of 1750*C (30). d. X-ray diffraction studies X-ray diffraction studies were undertaken to determine the structure of the intermediate phase TiO and, by means of the parametric method, to check certain points on solubility boundaries as established by metallographic observations.…”

The hydrogen permeability of Cu–Zr binary amorphous metallic membranes and the importance of thermal stability

“…Hickman et al found that between 573 K and 773 K only copper oxides can form in Zr 20 Cu 80 [42]. Both reports by Sen et al [42] and Hickman et al [41] agree with our observations. Also, it is possible that the surface composition of the as-cast membranes is different than the bulk composition.…”

Stress-Corrosion Cracking of Titanium Alloys

“…Tomashov et al 30 found the air-formed film thickness to be 18.9 A after several days exposure. Other workers 31 ' 32 found thicknesses from 12 A to U5 A. Andreeva 33 using an ellipsometric technique found the oxide thickness immediately after interaction of titanium with air at room temperature to be [12][13][14][15][16] A thick. After 70 days the thickness was 50 A.…”