Arc-sprayed titanium anode for cathodic protection of reinforcing steel in coastal concrete bridges

Conference · Wed Jan 01 00:00:00 EST 1997

OSTI ID:900813

Cramer, Stephen D; Covino, Jr, Bernard S; Holcomb, Gordon R; Bullard, Sophie J; Collins, W K; Govier, R D; Wilson, Rick D; McGill, G E ^[1]

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1. Oregon Dept. of Transportation

Stable operation of cobalt (Co) catalyzed thermal-sprayed titanium anodes for cathodic protection (CP) of bridge reinforcing steel was maintained in accelerated tests for a period equivalent to 23 years service at Oregon Department of Transportation (ODOT) bridge CP conditions. The Co catalyst migrated into the concrete near the anode-concrete interface with electrochemical aging. The titanium anode had a porous heterogeneous structure composed of alpha -Ti containing interstitial O and N, and a fcc phase thought to be Ti(O,N). Splat cooling rates were estimated to be on the order of 10 to 150 K/s, well below those that would lead to rapid solidification. Composition gradients within individual splats resulted in alpha -Ti-rich and Ti(O,N)-rich regions having microstructures produced by equilibrium processes at the solidification front. Use of nitrogen during thermal spraying produced a coating with more uniform composition, less cracking and lower resistivity than using air atomization. Shrouding of the spray gun is recommended for further improvement of anode composition and structure when using nitrogen atomization.

• Research Organization: Albany Research Center (ARC), Albany, OR (United States)
• Sponsoring Organization: USDOE - Office of Fossil Energy (FE)
• OSTI ID: 900813
• Report Number(s): DOE/ARC-1998-011; TRN: US200711%%566
• Resource Relation: Conference: Role of Characterization in Understanding Environmental Degradation of Materials, Seattle, WA, July 20-23, July 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANODES
ATOMIZATION
CATALYSTS
CATHODIC PROTECTION
COATINGS
COBALT
CONCRETES
INTERSTITIALS
NITROGEN
SOLIDIFICATION
SPLAT COOLING
STEELS
TITANIUM
US DOT
bridges (structures)
corrosion
concrete construction
reinforcing steels
corrosion prevention
titanium
coatings
hot spraying
corrosion resistance
coating effects
cathodic protection