Table 4.

Surface roughness and initial contact angle of water droplet on surface of machined Zr and main group samples.

	Etching Time, s	Ra, μm	Rz, μm	Sa, μm	Average Contact Angle, °
Machined Zr	—	0.43	3.94	0.95	93.8
M-NaF	45	0.33	2.80	0,91	112.9
	75	0.46	3.29	1.49	116.1
M-NH4F	45	0.42	3.34	1.27	107.1
	75	0.34	2.75	0.87	106.2
M-KNO3	45	0.42	3.37	1.16	103.3
M-HF	10	0.83	5.94	3.05	59.0
	60	3.28	18.32	3.21	55.4