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.

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.

Corrosion resistance of an orthodontic wire made of Ni-Ti alloy immersed in artificial saliva in the absence and presence of 500 ppm of Kopiko candy has been investigated by polarization study and AC impedance spectra. It is observed that corrosion resistance of Ni-Ti alloy immersed in artificial saliva in the presence of 500 ppm of Kopiko candy increases. Hence it is concluded that people clipped with orthodontic wire made of Ni-Ti alloy need not worry about taking Kopiko candy orally. When Ni-Ti alloy is immersed in artificial saliva in the presence of 500 ppm of Kopiko candy, Linear Polarization Resistance value increases from 347978 Ohmcm2 to 415003 Ohmcm2 ; corrosion current decreases from 1.346 x10-7A/cm2 to 1.105 x10-7A/cm2 ; charge transfer resistance value increases from 31945 Ohmcm2 to 44357 Ohmcm2 ; impedance value increases from 4.649to 4.819; double layer capacitance decreases from 1.596x10-10F/cm2 to 1.150 x10-10F/cm2 , and phase angle increases from 39.63° to 50°.

Corrosion resistance of SS 18/8 alloy and Gold 22 K alloy immersed in artificial sweat in the absence and presence of 100 ppm of D-Glucose has been investigated by polarization study and AC impedance spectra. It is observed that corrosion resistance of SS 18/8 alloy and also Gold 22 K alloy immersed in artificial sweat in the presence of 100 ppm of D-Glucose decreases. Hence it is concluded that people wearing ornaments made of these two alloys need to worry about the excess of D-Glucose in their sweat. When SS 18/8 alloy is immersed in artificial sweat in the presence of 100 ppm of D-Glucose, Linear Polarisation Resistance value decreases from 589308032 Ohmcm2 to 87905 Ohmcm2 ; corrosion current increases from 8.923x10-11A/cm2 to 4.008x10-9 A/cm2 ; charge transfer resistance value increases from 4884 Ohmcm2 to 3.168 x10-7 12210 Ohmcm2 ; impedance value decreases from 8.023 to 4.008; double layer capacitance increases from 8.9099x10-14F/cm2 to 1.4868 x10-9 F/cm2 , and phase angle decreases from 94° to 54°. When Gold 22 K alloy is immersed in artificial sweat in the presence of 100 ppm of DGlucose, Linear Polarisation Resistance value decreases from 4248438 Ohmcm2 to 236576 Ohmcm2 ; corrosion current increases from 8.038 x10-9A/cm2 to 1.546 x10-7A/cm2 ; charge transfer resistance decreases from 23680 Ohmcm2 to 6336 Ohmcm2 ; impedance value decreases from 4.647to 4.567; double layer capacitance increases from 2.154 x10-10 F/cm2 to 8.049x10-10 F/cm2 , and phase angle increases from 66° to 64°.