Corrosion induces damages that can result in enormous costs and safety issues. Steels are the most commonly used metallic structural materials but they can corrode rapidly when exposed to corrosive environments and need to be protected. The thesis research focuses on two aspects of steel protection. The first aspect is using barrier protection mechanism to protect steel pipeline structures in the presence of Super-Critical CO2. The second aspect is improving cathodic protection of steels by metal rich coatings in ground vehicles, bridges, water tanks, and other structures. In part one, coatings for protection of steel pipeline used for carbon transportation in the form of supercritical carbon dioxide were examined. Pipeline coatings serve to protect pipelines by maintaining their integrity and to increase their service time. Different pipeline coatings with the exposure to SCCO2 have been examined, and these results will be presented here. Different parameters, such as the thickness of coatings, the exposure temperature and pressure, and the exposure time as they affect pipeline coating were investigated and will be described. In the second part of this thesis research, the addition of magnesium particles to the standard zinc particles as metal rich primer was examined for the improvement of current zinc rich coatings to serve as protection for metal substrates in Army ground vehicles. Optimization of primer formulation, such as ratio of Mg and Zn, was investigated. The test primers were exposed in accelerated weathering tests, including ASTM B117 salt spray method and ProhesionTM cycle test as part of this research. The results have been compared with the behavior of the current commercial zinc rich primers to identify the improvements in the protection of the steel with mixed metal systems. For both investigations, electrochemical impedance spectroscopy was mainly used to examine coating performance. Other tests, including color measurement, thickness measurement, X-ray diffraction measurements, and pH measurements, were used to examine the corrosion behavior of steel structures under different corrosive environments. Results showed that coating systems can protect ferrous structures in ways of barrier protection and cathodic protection and can be improved by the application of modern methods and equipment.