Investigation on Surface/Interfaces of Steel Using Synchrotron Radiation

摘要

Synchrotron-radiation has been applied to investigation of corrosion at surface/interfaces of steel. Three topics are shown: (1) In situ observation of reactions at the interface has been carried out for localized corrosion of stain-less steel. It is shown that change in states of Cr~(3+) and Br~- ions near the interface is deeply related with a breakout of the passivation film. (2) Phase transformation of Zn-coated steel at high temperature was investigated by a new system of in situ observation. It has been found that an addition of small amount of phosphorus changes an incubation time before the alloying reaction starts. (3) Nano structures of rusts formed on steel after atmospheric corrosion. Evolution of "Fe (O,OH)_6 network" is the key to understand how the durable rusts of weathering steel prevent from formation of more rusts.