Table 1.

Inhibition efficiencies (%IE) and corrosion rates (CR) of the studied thiosemicarbazides for the corrosion of mild steel in H₂SO₄ solutions using both the weight loss (at 303 and 333 K) and hydrogen evolution techniques at 303 K only.

Systems	%IE (CR)
	303 K	333 K
1 M H2SO4 (Blank)	(34.69)	(96.23)
4 × 10−4 M AP4PT + 1 M H2SO4	94.0 a(2.08) [92.2]b	78.92 (20.29)
8 × 10−4 M AP4PT + 1 M H2SO4	96.0 (1.37) [94.6]	90.80 (8.85)
12 × 10−4 M AP4PT + 1 M H2SO4	97.0(1.04) [95.9]	91.90 (7.79)
16 × 10−4 M AP4PT + 1 M H2SO4	97.6 (0.82) [96.1]	92.80 (6.93)
20 × 10−4 M AP4PT + 1 M H2SO4	98.7 (0.44) [97.2]	93.40 (6.35)
4 × 10−4 M HP4PT + 1 M H2SO4	90.7 (3.23) [88.6]	52.80 (45.42)
8 × 10−4 M HP4PT + 1 M H2SO4	93.1 (2.38) [91.8]	75.90 (23.19)
12 × 10−4 M HP4PT + 1 M H2SO4	94.4 (1.93) [92.9]	79.00 (20.21)
16 × 10−4 M HP4PT + 1 M H2SO4	95.1 (1.70) [94.2]	89.84 (9.78)
20 × 10−4 M HP4PT + 1 M H2SO4	96.2 (1.30) [95.0]	91.21 (8.46)
4 × 10−4 M D44PT + 1 M H2SO4	91.2 (3.05) [90.1]	54.42 (43.86)
8 × 10−4 M D4PT + 1 M H2SO4	91.9 (2.79) [88.4]	66.40 (32.33)
12 × 10−4 M D4PT + 1 M H2SO4	93.8 (2.15) [91.5]	70.50 (28.39)
16 × 10−4 M D4PT + 1 M H2SO4	94.4 (1.93) [93.2]	79.20 (20.02)
20 × 10−4 M D4PT + 1 M H2SO4	95.1 (1.70) [93.9]	89.98 (9.64)

^a%IE obtained from the weight loss technique.

^b%IE obtained from the hydrogen evolution technique.