The Corrosion and Environmental Effects Laboratory (CEEL) is part of the Department of Materials Science and Engineering of the University of Southern California, Los Angeles, CA, USA. Dr. Florian B. Mansfeld is the Director of CEEL.

Dr. Mansfeld received his BS in Physics (1960), MS (1964) and Ph.D. (1967) degrees in Physical Chemistry, all from the University of Munich, Germany. From 1969 to 1985 he was employed at the Rockwell International Science Center, where he was Manager of the Interface Phenomena Group. Dr. Mansfeld received the Alexander von Humboldt Award in 1979, the Sam Tour Award of ASTM in 1984, the Whitney Award of NACE in 1988 and the W. W. Horner Award of ASCE in 1993. He became Fellow of NACE in 1994 and Fellow of The Electrochemical Society in 1995. He is Past­Chairman of the Corrosion Division of The Electrochemical Society. Dr. Mansfeld is Director of the Corrosion and Environmental Effects Laboratory (CEEL) at the University of Southern California and a Registered Professional Corrosion Engineer in California.

OBJECTIVES: Research is conducted at CEEL to determine the electrochemical kinetics and mechanisms of corrosion phenomena for a wide range of materials and environments. Based on the knowledge of corrosion mechanisms, improved approaches to corrosion monitoring and control are investigated. Emphasis is placed on the evaluation of various methods of corrosion protection such as the use of inhibitors and coatings of non-toxic nature ("green technology"). The major areas of current interest are:

1. Corrosion Protection by Surface Modification - In search for replacements of toxic materials such as hexavalent chromium used in corrosion protection the concept of corrosion protection by surface modification has been developed. The natural oxides on various aluminum alloys have been modified by immersion in solutions of rare earth metal salts and anodic polarization in a molybdate solution. Surfaces with excellent resistance to localized corrosion were obtained ("stainless aluminum"). A similar approach has been used for sealing of anodized aluminum alloys. Two patents covering these processes have been awarded. The passive film of stainless steel type 304 has been modified by an electrochemical process to produce marked improvements of the corrosion resistance in acid media. The surface modified stainless steel is competitive with higher alloyed, more expensive materials. New methods of cleaning and passivation of stainless steels have been evaluated in order to solve problems with waste disposal of presently used nitric acid.

2. Microbiologically Influenced Corrosion (MIC) - The electrochemical and microbiological reactions occurring on stainless steels, titanium and various commercial copper-nickel alloys have been evaluated during exposure to natural seawater using electrochemical and surface analytical techniques. The impact of microorganisms on corrosion protection of steel by polymer coatings is being studied by exposure to natural seawater. Coating performance is being evaluated using sophisticated electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and electrochemical noise analysis (ENA). An experimental approach has been developed which allows data collection from remote test sites. These investigations are supported by laboratory investigations. Time laws for coating degradation have been established.

3. Corrosion Protection by Inhibitors and Coatings - Surface modification by inhibitors, passive films and coatings is an important approach for corrosion protection. Theoretical and experimental work is being carried out to develop a better understanding of the corrosion behavior of "real" surfaces and the changes of these properties due to surface modification. The present effort focuses on corrosion inhibition in neutral, aerated media and the description of the electrochemical properties of inhomogeneous surfaces which has important applications in localized corrosion processes. The use of EIS and ENA as tools for monitoring the corrosion behavior of polymer coated metals at remote locations and determining the remaining lifetime of coatings is being further evaluated. Pit growth laws have been determined for Al alloys exposed to chloride solutions.

4. Corrosion Protection of Composite Materials - Composite materials such as Al/SiC, Al/graphite or Mg/graphite have very desirable mechanical properties, but very poor corrosion resistance. For metal matrix composites, corrosion protection by chemical conversion coatings, anodizing and/or application of polymer coatings is being evaluated using sophisticated electrochemical techniques such as EIS, which allows detection of changes of coating properties and metal surfaces properties due to exposure to corrosive environments. The concept of surface modification is applied to these materials in order to improve their corrosion resistance using "green technology".

5. Materials Damage Due to Acid Rain and Fog - Laboratory studies have been conducted to determine the effects of acid deposition on structural materials of economic significance in Southern California. The role of pollutants such as S02, N02 and 03 and the chemistry of acid fog which may contain sulfuric and/or nitric acid has been studied under carefully controlled conditions in atmospheric test chambers for materials such as zinc, nickel, aluminum, house paints and polymers. Atmospheric corrosion rate monitors which provide a continuous record of the corrosivity have been exposed at various test sites and in the test chambers. These data are collected with a computerized data logging system and are used in statistical analyses of the correlation between corrosion damage and atmospheric chemistry.

6. Corrosion Behavior in Low Conductivity Media - Electrochemical techniques are being evaluated which will allow the determination of corrosion kinetics in media of low conductivity such as very dilute aqueous solutions and organic solutions. The corrosion behavior of stainless steels, Al and Ti alloys has been studied in distilled water, hydrazine and nitrogen tetroxide.

7. Evaluation of the Long-Term Corrosion Behavior of Implant Materials - The corrosion behavior of implant materials such as stainless steels, titanium alloys and Cr-Co-Mo alloys has been evaluated using electrochemical impedance and noise measurements. Emphasis is placed on the resistance to localized corrosion, i. e. pitting and crevice corrosion.

8. Testing of New Battery Materials - New battery materials proposed for use in electric cars have been evaluated by performing cyclic voltammetry and determining the charge/discharge characteristics as a function of the properties of these new materials.

FACILITIES: Research in corrosion and applied electrochemistry is carried out in the Corrosion and Environmental Effects Laboratory (CEEL) which is equipped with modern electrochemical equipment such as potentiostats, transfer function analyzers and noise analyzers. Most of this equipment is computerized for collection and analysis of the experimental data. Software has been developed for the collection of electrochemical impedance and noise data from equipment placed at remote test sites and analysis of these data based on appropriate models. Test chambers for corrosion studies under controlled atmospheric conditions are available.

TEACHING ACTIVITIES: The following classes related to corrosion and applied electrochemistry are being taught by Prof. Mansfeld:

MASC 521 - Corrosion Science

MASC 522- Corrosion Technology

MASC 523 - Principles of Electrochemical Engineering

MASC 440 - Materials and the Environment

MASC 599 - Techniques and Mechanisms of Electrochemistry and Corrosion