摘要 |
A finishing agent, which can provide a chromium-free surface treatment layer for use in forming an overcoat on an oxidation-resistant layer on a substrate, comprises an aluminum-containing substance in the form of at least one of a cation, a salt of the cation, and a coordination compound containing the cation; a zinc-containing substance in the form of at least one of a cation, a salt of the cation, and a coordination compound containing the cation; a chelating agent which is able to form a coordination compound with an aluminum ion; and a film-forming substance containing a first element selected from the group consisting of P, Mo, W, Ce, Mn, Si, Ti, Zr, and V. The preferable chelating agent is citric acid. The finishing agent may further contain an organic binder. |