图3. 4种钢腐蚀72和360 h后的锈层截面SEM像
Fig.3. Cross sections of rust layers formed on Q420 (a, b), 2Cr (c, d), 5Cr (e, f) and 9Cr (g, h) steels after corrosion for 72 h (a, c, e, g) and 360 h (b, d, f, h)