The Kinetics of the Reactions of Beryllium with Oxygen and Nitrogen and the Effect of Oxide and Nitride Films on its Vapor Pressure

A systematic study of the reaction of beryllium with oxygen is made over the temperature range of 350° to 950°C. The experimental data may be fitted by the parabolic rate law except for the initial period of the reaction. A plot of gives an energy of activation of 50,300 calories per mole. A comparison of this rate data with other metals and alloys shows that vacuum‐treated beryllium has the smallest parabolic reaction rate constant at 900°C of any metal or alloy that we have studied. The reaction with nitrogen is studied over the temperature range of 600° to 925°C. The data may be fitted by the parabolic rate law. A comparison with the oxygen reaction shows that the rate of reaction is somewhat smaller. A plot of gives an energy of activation of 75,000 calories per mole. No reaction is observed with hydrogen over the temperature range of 300° to 882°C. A study of the vapor pressure of beryllium and the influence of oxide and nitride films is made using the Langmuir method. Excellent agreement is found for the vacuumtreated specimens with the recent results of Holden, Speiser, and Johnston. Oxide films exert a strong effect in reducing the vapor pressure, the effect varying as the square root of the oxide thickness. A film of 99 micrograms per cm2 lowers the vapor pressure 100‐fold.