Thermal sprayed titanium anode for cathodic protection of reinforced concrete bridges

Stable operation of cobalt catalyzed thermal sprayed titanium anodes for ca thodic protection (CP) of bridge reinforcing steel was maintained in accele rated tests for period equivalent to 23 years service at Oregon Department of Transportation (Oregon DOT) bridge CP conditions with no evidence that o peration would degrade with further aging. The cobalt catalyst dispersed in to the concrete near the anode-concrete interface with electrochemical agin g to produce a more diffuse anode reaction zone. The titanium anode had a p orous heterogeneous structure composed of alpha-titanium containing interst itial oxygen and nitrogen, and a fee phase thought to be Ti(O,N), Splat coo ling rates were 10 to 150 K/s, and microstructures were produced by equilib rium processes at the splat solidification front. Nitrogen gas atomization during thermal spraying produced a coating with more uniform composition, l ess cracking, and lower resistivity than using air atomization.