Abstract: The present invention is a process for forming protective films on an alloy substrate by: oxidizing an alloy comprising iron and chromium in an oxygen containing atmosphere, said alloy containing from about 5 to about 15 wt % chromium, at a temperature of from about 200.degree. C. (473.degree. K.) to about 1400.degree. C. (1673.degree. K.), more preferably 300.degree. C. (573.degree. K.) to 600.degree. C. (873.degree. K.) wherein the partial pressure of oxygen in said oxygen containing atmosphere is above or equal to the dissociation pressure of Fe.sub.3 O.sub.4 and FeO below or equal to the dissociation pressure of Fe.sub.2 O.sub.3 within the specified temperature range, and for a time sufficient to effect the formation of a film comprising iron-chromium oxide (FeCr.sub.2 O.sub.4) spinel on the surface of said alloy. In a further embodiment, the film may additionally contain Silicon.

Abstract: A method and a sensor to measure the sulfur activity in sulfur-containing environments are disclosed. The active component is a non-stoichiometric metal sulfide foil or film. In the case of a thin sulfide film, a ceramic substrate is employed for improved mechanical rigidity. The electrical conductivity of the sulfide is related to the sulfur activity of the process stream to which it is exposed.

Abstract: A method for joining bimetallic tubulars and a bimetallic tubular weld configuration which ensures both a continuous corrosion resistant inner lining across the joint as well as the required mechanical strength.