Document 44dR9x6rJNqo4vNywZ4a4oMOV

SILVERMAN-HUSAIN--NITROGEN OXIDE-ARC WELDING 143 oxides which are in the highest state, presumably in the form of nitric acid mist, and possibly carried on small submicron iron particles as nitrates. Nitrogen trioxide, NOs or -hexoxide, N206, can exist, but little is known about them.11 It is possible that nitric acid can be formed in an electric arc in the presence of water vapor; hence it is not improbable that this is formed from welding gases. 3 O Oz Chart 4.--Total oxides, nitric oxide, nitrogen dioxide, nitrogen trioxide and total fume con centrations during and after arc welding with coated electrodes. Recirculation of cabinet' air from 60 to 180 minutes. x , 11. Since its absorption spectrum has been obtained, NOs is more nearly a substantiated com pound than a hypothetical intermediate (Johnston, H. S., and Yost, D. M.: The Kinetics of the Rapid Gas Reaction Between Ozone and Nitrogen Dioxide, J. Chem. Phys. 17^386, 1949).