| 摘要 |
<p>A surface treated steel plate for fuel tanks, comprising a Zn-x alloy plating metal plus chromate, wherein a chromate film is formed which has a x content of the plating metal as a whole of Ni: 9-18 wt. %, Co: 0.02-3 wt.%, Mn: 25-45 wt.% or Cr: 8-20 wt.%, an amount of deposition of the plating metal of 5-40 g/m2 and a metal Cr-converted amount of deposition of the plating metal of 10-200 mg/m2, the Zn-Ni film of the plating metal corresponding to at least an inner surface of a tank (1) having cracks in the outer surface, the density of the cracks being 1000-150000 in terms of the number of plated regions surrounded by cracks in a visual field of 1mm x 1mm, a maximum width of the cracks being not more than 0.5 νm, or (2) having a x/(x+Zn) atomic percentage (x¿2?) determined by a surface analysis based on ESCA of x1¸x2 (wherein x1: average value of the plating metal as a whole), Ni: 5-25 at%, Co: 0.009-10 at%, Mn: 15-65 at% or Cr: 5-25 at%.</p> |
