This geothermal corrosion program is to determine why geothermal brines are so corrosive to economical iron-base alloys. Geothermal resources that can be developed with iron-base alloys will have a significant economic advantage over geothermal sites that would require extensive use of expensive alloys. Data developed in this program will be used to guide selection and design of near-term plants. The program objectives are: O To clarify corrosion factors important to materials selection for geothermal power plants. O To establish a set of brine composition and temperature limits for carbon steels in geothermal brines and report final results by the end of FY 1978. The program involves tests of many materials in high pressure equipment where a wide variety of brine chemistries can be studied. The validity of these lab tests is checked by field tests in actual geothermal brine