Content ratio of oxygen to aluminum before and after corrosion (viz., R_[O]/[Al],bc and R_[O]/[Al],ac) and the increasing ratio (IR) calculated by the eqn (7).

Sample	R [O]/[Al],bc	Static corrosion, 18 d		Dynamic corrosion, 2.0 m s−1, 50 h
		R [O]/[Al],ac	IR	R [O]/[Al],ac	IR
Al–HCl–SA	0.05	1.49	2880.0%	0.49	880.0%
Al–HCl–BT–SA	0.07	0.94	1242.9%	0.42	500.0%
Al–HCl–H2O–SA	0.73	1.15	57.5%	1.01	38.4%
Al–HCl–H2O–BT–SA	0.84	0.98	16.7%	0.91	8.3%