Oxidation of Refractory Metals as a Function of Pressure, Temperature, and Time: Tungsten in Oxygen

Abstract

By regarding the kinetics of oxidation of tungsten as occurring by the consecutive reactions: W + O~ --> WO~; WO~ + %O~ -> WO~(~); WO~(~) 1/n (WO~),~v~p) and by expressing the rate in terms of conventional chemical kinetic quantities, it is shown that the results of three investigations may be correlated in the temperature range 500~176 and pressure range 0.0013-20.8 atm of oxygen. A good approximate form for the rate of attack of metallic tungsten above 700~ is shown to have the form: Rate = d(m/A)/dt -~ 5.89 X 10 ~ exp (--12,170/T) P~/'~ mgw/cm ' hr, where T is expressed in ~ and P in atmospheres of oxygen.

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