Corrosion process of carbon steel in aqueous solution under the atmospheric environment and the oxygen depleted environment has been reviewed by focusing the corrosion film formed on carbon steel in neutral pH. In the neutral solution under the atmospheric condition which contains oxygen, the critical pH to form the corrosion film and the precipitation ratio of dissolved iron ions depending on pH and the parabolic growth rate law were discussed. Under oxygen depleted environment, H2O works as oxidizing agent to oxidize Fe to produce Fe3O4 film with production of H2 gas. At high temperatures, the dissolution process of the Fe3O4 film controls the corrosion rate, whereas, at lower temperatures, the film growth process controls the corrosion rate and a steady dissolution rate of Fe3O4 film determines the corrosion rate after long exposure time.
Atmospheric corrosion commonly initiates and develops under thin water films formed by dew or rain drops. A composition of water film depends on the air pollutant deposition rate, and changes with the humidity and temperature conditions of the atmosphere. Many sensors and the measurement techniques have been developed to evaluated corrosivities in atmospheric environments and corrosion behaviors in those environments. In this paper, the present state and visions of atmospheric corrosion researches are discussed based on the roles of water and deposits and environmental factors which are evaluated by those sensors and measurement techniques.
The recent investigation on passivation and passive oxide film of metals was reviewed. The development of analytical techniques and apparatuses are introduced. In the recent two decades, Raman spectroscopy, SPM, and radiation X-ray spectroscopy are widely applied. For the passive oxide films on iron, the composition of γ-Fe2O3- Fe3O4 has been detected. The following themes were discussed; mechanism of the oxide film growth and dehydration of the passive oxide film. Future prospects on the investigation on passivation and passive oxide film were described in which development of the in-situ techniques in sub nm levels with a quite high response was stressed.
Recent research progress of high temperature corrosion and protection in Japan was summarized in groups of Al2O3 scale, synchrotron radiation method, water vapor effect, metal dusting, hot corrosion, halogen vapor effect, simulation method and analyses, breakaway phenomena, interaction between stress and oxidation behavior, refractory metals, TiAl, and coatings （Pt addition, DBC system, coating on TiAl, Electrolytic deposition from fused salts.
Recent studies on localized corrosion of corrosion-resistant metals and alloys are reviewed from the viewpoint of the development of new techniques that enable in situ and real-time observation of changes in morphology and solution chemistry during the initiation process of localized corrosion. Some examples of application of the new techniques are shown, focusing on the initiation of pitting, crevice corrosion and stress corrosion cracking on stainless steels.
Based on the current tendency in early 21th century regarding the plenty of the occurrence of failures in the field of social and industrial infrastructures, the importance of RBM and its expected future are mentioned. From the view points of the necessarily of environmental conservation and natural resources preservation, change of the maintenance technology, concept of RBM, current situation of risk based corrosion technology and its systemization, activities of JSPS #180 committee (Risk based asset management committee) and the technologies which should be improved in the near future for better maintenance are introduced.