Assessment of End-of-Life Behavior of the Surface Modification to Improve Cavitation-Erosion Resistance in the Mercury Target at the Spallation Neutron Source

Technical Report · Fri Jun 01 04:00:00 EDT 2007

DOI:https://doi.org/10.2172/931799· OSTI ID:931799

Pawel, Steven J ^[1]

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1. ORNL

The cavitation-erosion resistance of the Kolsterised{reg_sign} layer on annealed or cold-worked substrates of 316LN stainless steel has been examined in mercury using a vibratory horn technique and extended exposure periods intended to expose 'end-of-life' performance characteristics. The Kolsterised{reg_sign} layer tends to remain protective--as evidenced by modest steady-state weight loss and surface roughness increases, only isolated pitting, and limited wetting by mercury--until the protective layer has been thinned by general erosion to about 15-20 {micro}m. Prior to that amount of erosion, the cavitation-erosion resistance of both types of specimens appears defined by the properties of the protective layer. However, after thinning to such a degree, initial breakdown of the protective layer is characterized by increases in both the surface roughness and the number/depth of individual pits across the surface at a rate that is strongly dependent on the substrate condition, with annealed substrates significantly more prone to damage. However, even as the protective properties of the Kolsterised{reg_sign} layer decrease, both weight change and profile development as a function of sonication time suggest a gradual reversion to cavitation-erosion behavior similar to that of untreated substrates.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 931799
• Report Number(s): ORNL/TM-2007/063; KC0204019; ERKCSN2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BREAKDOWN
MERCURY
MODIFICATIONS
NEUTRON SOURCES
PERFORMANCE
ROUGHNESS
SPALLATION
STAINLESS STEELS
SUBSTRATES
TARGETS