Atmospheric Photochemistry

Atmospheric Sulfidation of Copper Alloys: II . Alloys with Nickel and Tin

“…Sulfidation ol nickel and tin metals.--The susceptibilities of unalloyed nickel and tin to sulfidation were examined by exposing samples of the metals to the corrosive environment for periods of as long as 3 weeks, i.e., to a total exposure of ~1500 ppm 9 h. Such an exposure is equivalent to approximately a century of reduced sulfur exposure in a typical environment or to approximately 10 yr in an extremely corrosive environment (2). The surfaces of these samples did not undergo degradation visible to the naked eye during that period, nor was any sulfur detectable by SEM/EDXA techniques.…”

“…With gas turbine powered ships, the possibility of zinc contamination of the fuel causes concern, since zinc has been reported to produce intergranular corrosion in nickel-based superalloy turbine blades (1). However, Canadian Navy ship gas turbines have burned zinc-contaminated fuel, with ZnSO4 being formed on the hot section blades, with apparently little harm (2). Canadian studies indicate, in fact, that 2.5-5.0 weight percent (w/o) additions of ZnSO4 inhibit hot corrosion in aggressive 90 w/o NaeSO~-10 w/o NaC1 melts at 900~ (2).…”

Absolute OH quantum yields in the laser photolysis of nitrate, nitrite and dissolved H2O2 at 308 and 351 nm in the temperature range 278?353 K

“…This requires the knowledge of the ambient concentrations in tropospheric droplets. The data for NO3 and H202 may be taken from the compilation by Graedel and Weschler (1981), where aqueous phase concentrations of nitrate between 5 x 10 -5 and 1 × l0 -6 mol/1 for urban (Graedel, 1980) and rural (Likens et al, 1979) situations, respectively, are given. For H202 the corresponding quantities are 3 x 10 -6 mol/1 (Kok, 1980) and 3 x l0 -7 mol/1 (Kelly et al, 1979;Bufalini et al, 1979).…”