The element content variation of DW-ATNTAs during formation process.

Element/wt%	TC4	Before anodizing	After anodizing	Δ anodizing	After calcining	Δ calcining
Ti	87–90	89.43	53.85	−35.58	67.98	14.13
Al	5.5–6.8	6.01	3.53	−2.48	3.75	0.22
V	3.5–4.5	2.64	2.43	−0.21	2.40	−0.03
O	≤0.2	0	22.15	22.15	23.31	1.16
C	≤0.1	1.92	10.91	8.99	2.56	−8.35
F	0	0	7.13	7.13	0	−7.13