The corrosion resistance of mild steel (used to make hull plates in ship technology) in seawater before paint coating (Nippon paint, weatherbond advance) and after paint coating has been measured by electrochemical studies such as Polarisation study and AC impedance spectra. It is observed that after paint coating, the corrosion resistance of mild steel hull plates increases. Polarization study reveals that after paint coating, the linear polarization resistance increases and corrosion current decreases. AC impedance spectra reveal that in the presence of paint coating charge transfer resistance value increases, impedance value increases, phase angle increases and double layer capacitance value decreases.

Corrosion resistance of Gold 21K alloy immersed in artificial sweat in the absence and presence of 100 ppm of urea and also 100 ppm of D-Glucose has been investigated by polarization study and AC impedance spectra. It is observed that Corrosion resistance of Gold 21K alloy immersed in artificial sweat in the presence of 100 ppm of urea / D-Glucose increases. Hence it is concluded that people wearing ornaments made of Gold 21K alloy need not worry about the excess of urea / D-Glucose in their sweat. When Gold 21K alloy is immersed in artificial sweat in the presence of 100 ppm of urea, Linear Polarisation Resistance value increases from 103389Ohmcm2 to 123437Ohmcm2 ; corrosion current decreases from 4.036 x10-7A/cm2 to 3.308 x10-7A/cm2 ; charge transfer resistance value increases from 10490 Ohmcm2 to 14070 Ohmcm2 ; impedance value increases from 4.253 to 4.324; double layer capacitance decreases from 4.862x10-10 F/cm2 to 3.625x10-10 F/cm2 , and phase angle increases from 38.91 to 70.14. When Gold 21K alloy is immersed in artificial sweat in the presence of 100 ppm of D-Glucose, Linear Polarisation Resistance value increases from 103389Ohmcm2 to 4817257Ohmcm2 ; corrosion current decreases from 4.036 x10-7A/cm2 to 0.161x10-7A/cm2 ; charge transfer resistance increases from 10490Ohmcm2 to 33300Ohmcm2 ; impedance value increases from 4.253 to 4.977; double layer capacitance decreases from 4.862x10-10 F/cm2 to 1.5315x10-10 F/cm2 , and phase angle increases from 38.91° to 79.74°.

Mild steel is relatively less expensive. So in reinforced concrete, mild steel can be used. Mild steel in concrete structures may experience corrosion. To avert corrosion of mild steel, a number of inhibitors are used along with concrete admixtures. In this category of research, saturated calcium hydroxide solution is considered as simulated concrete pore solution (SCPS). Numerous corrosion inhibitors have been utilized in this field along with organic coatings. In the present investigation show case polish coated mild steel has been used in concrete. The corrosion resistance has been calculated by electrochemical studies such as polarization study and AC impedance spectra. When show case polish coated mild steel is immersed in SCPS, the corrosion resistance of mild steel increases. This is long-established by the facts that in presence of show case polish coating , the linear polarization resistance value increases, corrosion current value decreases, charge transfer resistance increases, double layer capacitance decreases, impedance increases, and phase angle increases. The protecting layer functions as anodic inhibitor and controls the anodic reaction primarily. The protective coating offers 99.99% inhibition efficiency. It implies that the show case polish coated mild steel can be used in concrete technology. This will increase the lifetime of the rebars.

The corrosion resistance of mild steel in simulated concrete pore solution (SCPS) in the absence and presence of thiourea has been investigated by polarization study and AC impedance spectra. Polarisation study reveals that thiourea system functions as anodic inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. When mild steel is used as rebar, thiourea may be mixed with concrete. Thus the mild steel will be protected from corrosion. The protective film consists of iron-thiourea complex formed on metal surface. In the presence of thiourea the linear polarisation resistance increases, corrosion current decreases, charge transfer resistance (Rt) increases, impedance increases, phase angle increases and double layer capacitance (Cdl) value decreases. This formulation may find application in concrete technology.

Simulated oil well water (SOWW) is conceded out by pipelines made of several alloys, for instance mild steel L80. These alloys may simulated oil well water undergo corrosion owing to presence of various aggressive ions present in SOWW. To prevent this several inhibitors have been used. Inhibition of corrosion of L80 alloy pipeline carrying simulated oil well water by succinic acid has been evaluated by electrochemical studies such as polarization study and AC impedance spectra (EIS). Polarisation study reveals that in the presence of inhibitor linear polarization resistance increases and corrosion current decreases. AC impedance spectra reveal that in presence of succinic acid, RT value increases, impedance value increases, phase angle increases and Cdl value decreases. The present study reveals that when succinic acid is added to simulated oil well water, the corrosion resistance of L80 alloy increases. It implies that succinic acid may be added to simulated oil well water flowing through pipe line made of L80 alloy.