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

Table 2

Corrosion rate (CR) of carbon steel immersed in well water, in the absence and presence of inhibitors, and the inhibition efficiency (IE) obtained by mass loss method.

Caffeine (ppm)	Zn^2+
	0 (ppm)		25 (ppm)		50 (ppm)
	CR (mdd)	IE (%)	CR (mdd)	IE (%)	CR (mdd)	IE (%)
0	22.42	—	20.18	10	19.73	12
50	21.97	02	12.33	45	11.66	48
100	20.85	07	11.66	48	9.87	56
150	20.18	10	9.87	56	7.85	65
200	19.73	12	8.97	60	4.04	82
250	19.51	13	4.71	79	4.04	82