Material Damage in a Volcanic Environment

Abstract

Field testing of materials at White Island was undertaken to asses the corrosion performance of metals and alloys under the severe corrosive conditions encountered in geothermal volcanic environments. Metallic materials were tested in six different types of sites in the volcanic environments, of which the maximum temperature was 230?C. This paper reports preliminary results for these exposure tests. In a high-temperature fumarolc, nickel-base alloys containing more than molybdenum and titanium alloys showed excellent tance with corrosion rates less than 0.05 mmiy, but lower-alloy matcrials were severely corroded. In the nickel-base alloys molybdenum played a key role in enhancing resistance to corrosion. The corrosion rate increased linearly with decreasing molybdenum content in the range from 3% to Nickel-base alloys containing less than molybdenum were corroded at rates of to 2 mmiy greatcr than carbon and steels. In a low-tcmperaturc ( I 08?C) fumarole, duplex stainless steels showed good resistance, with rates less than 0.04 which was comparable with the nickel-base alloys containing more than molybdenum.