Corrosion and arc erosion in MHD channels

Technical Report · Mon Apr 01 04:00:00 EST 1991

OSTI ID:5475938

Rosa, R J; Pollina, R J

The objective of this task is to study the corrosion and arc erosion of MHD materials in a cooperative effort with, and to support, the MHD topping cycle program. Materials tested in the Avco Research Laboratory/Textron facility, or materials which have significant MHD importance, will be analyzed to document their physical deterioration. Conclusions shall be drawn about their wear mechanisms and lifetime in the MHD environment with respect to the following issues; sulfur corrosion, electrochemical corrosion, and arc erosion. The impact of any materials or slag conditions on the level of power output and on the level of leakage current in the MHD channel will also be noted, where appropriate. Two phenomena that can effect the analysis of slag leakage current have been investigated and found significant. These are: (1) transverse current along the slag layer in the insulator walls of an MHD duct, and (2) electrode surface voltage drops. Both tend to reduce the value inferred for average plasma conductivity and increase the value inferred for axial leakage current. These two effects in combination are potentially capable of explaining the high leakage inferred. Corrosion on the water side of metal MHD duct wall elements has been examined in CDIF and Mark 7 generators. It appears to be controllable by adjusting the pH of the water and/or by controlling the dissolved oxygen content.

• Research Organization: Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG22-88PC88928
• OSTI ID: 5475938
• Report Number(s): DOE/PC/88928-T4; ON: DE91016829
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300103* -- MHD Generators-- Materials
Components
& Auxiliaries
36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
CHEMICAL REACTIONS
COAL-FIRED MHD GENERATORS
COPPER ALLOYS
CORROSION
CURRENTS
DIRECT ENERGY CONVERTERS
DOCUMENT TYPES
ELECTRIC CURRENTS
HYDROGEN COMPOUNDS
LEAKAGE CURRENT
MHD CHANNELS
MHD GENERATOR CDIF
MHD GENERATORS
OXYGEN COMPOUNDS
PH VALUE
PROGRESS REPORT
SLAGS
TUNGSTEN ALLOYS
TUNGSTEN BASE ALLOYS
WATER