Fitting results using model IV for impedance spectra recorded after 48 h exposure in deaerated 0.05 mol dm⁻³ NaCl solution of titanium samples after anodization at 10 and 30 V at 60 °C for 10 min in DES bath composed of choline dihydrogencitrate salt and oxalic acid.

Sample	R s (Ω cm2)	CPEout-T (Ω−1 cm−2 s−P)	CPEout-P	R out (Ω cm2)	CPEin-T (Ω−1 cm−2 s−P)	CPEin-P	R in (Ω cm2)	Goodness of fit (χ2)
Anodized at 10 V	105	2.51 × 10−4	0.690	1.29 × 103	1.23 × 10−5	0.929	2.77 × 107	2.4 × 10−5
Anodized at 30 V	111	1.88 × 10−5	0.729	1.16 × 103	7.72 × 10−6	0.927	8.91 × 1013a	7.9 × 10−5

^a2 × 10⁷% error for this element.