The erosion, corrosion, and stress corrosion cracking (SCC) of Ti-, Co-, Ni-, and Fe-base alloys specimens that were used in scale-control tests performed at the Salton Sea geothermal field were evaluated. Specimens were exposed to high-velocity, two-phase, 104{sup 0}C nozzle exhaust that was produced by expanding acidified hypersaline, highly mineralized brine to atmospheric pressure through converging-diverging nozzles. The exposed specimens were evaluated using surface profilometer traces, light microscopy, scanning-electron microscopy, and energy dispersive spectroscopy ananlysis. The observed degradation was attributed largely to synergistic effects of erosion, corrosion, and stress. A principal mode of degradation appeared to be the formation and growth of corrosion-assisted erosion cavities; it was proposed that surface repassivation kinetics play a key role in the development of these cavities. It was also suggested that scale deposits on the metal surface may either alter the mode of attack or act as protective barriers. It was concluded that, of the potential turbine-blade materials tested, the Ti-base alloys exhibited the best combination of resistance to erosion, corrosion, and SCC.

Two additional atmospheric sodium release tests were jointly conducted by ESG and ARL at INEL. These tests were conducted under very stable (Pasquill E and G) meteorological conditions where the natural humidity content was high (47 and 96% RH). Sufficient experimental data was obtained on Test 7 to quantitatively qualify the formation of Na/sub 2/CO/sub 3/ in the open atmosphere from primary sodium combustion products. These data show that a maximum concentration of approx. 60% Na/sub 2/CO/sub 3/ is reached with the plume 100 meters from the release point. This concentration increases slightly as the plume is dispersed beyond 2400 meters. The available particle fallout data is consistent with predictions.