Table 2: Inhibition efficiency, corrosion rate, and surface coverage for aluminium in 1 N and 2 N hydrochloric acid solution with given inhibitor addition for 24 h at 298 ± 1 K.

Conc. Inh (%)Inhibition efficiencyCorrosion rateSurface coverageInhibition efficiencyCorrosion rateSurface coverage
(1 N)(1 N)(1 N)(2 N)(2 N)(2 N)

Pet. Ether extract
0.1229.4450.470.294488.6130.430.8861
0.2444.9639.370.449688.7729.990.8877
0.3646.5738.210.465789.7427.400.8974
0.4855.6135.330.556191.6822.210.9168
0.6054.0332.880.540392.6619.610.9266
Acetone extract
0.1225.8153.060.258161.72102.240.6172
0.2428.6351.050.286364.3695.170.6436
0.3639.1143.550.391191.6322.350.9163
0.4857.8630.140.578693.3017.880.9330
0.6073.3919.030.733998.274.610.9827
Methanol extract
0.1211.9063.010.119049.30135.400.4930
0.2420.2857.100.202854.27122.140.5427
0.3634.6846.720.346858.80110.020.5880
0.4838.5150.470.385162.09101.230.6209
0.6049.6036.050.496067.1287.820.6712