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

Table 7

Influence of pH on IE of caffeine (200 ppm)-Zn²⁺ (50 ppm)-malic acid (25 ppm).

System	pH	CR (mdd)		IE (%)
		Presence of inhibitor	Absence of inhibitor
Caffeine (200 ppm)-Zn^2+ (50 ppm)-malic acid (25 ppm).	3	71.73	88.56	19
	5	49.24	72.41	32
	7	24.55	52.23	53
	8	8.97	22.42	60
	11	1.30	10.81	88