Effect of Caffeine-Zn²⁺ System in Preventing Corrosion of Carbon Steel in Well Water

Table 8

Corrosion parameters of carbon steel immersed in well water in the absence and presence of inhibitors.

System	Nyquist plot		Bode plot
	𝑅𝑡 Ohm cm^2	𝐶dl F/cm^2	Impedance value Log (𝑍/ohm)
Well water	1377	3.7005×10^−9	3.28
Caffeine (200 ppm)-Zn^2+ (50 ppm)	4435	2.6617×10^−9	3.34
Caffeine (200 ppm)-Zn^2+ (50 ppm)-malic acid (25 ppm)	2499	2.0390×10^−9	3.47