Surface treatment chemicals and bath for aluminum or its alloy and surface treatment method
AssigneeNippon Paint Co., Ltd.
InventorsSatoshi Ikeda, Shigeyuki Meguro
Life of this patent
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Abstract
A surface treatment chemicals for aluminum or its alloy consisting essentially of 10-1000 parts by weight of niobium ion and/or tantalum ion, and 1-50 parts by weight of effective fluorine ion, and optionally 10-500 parts by weight of zirconium ion and/or titanium ion and 10-500 parts by weight of phosphate ion. A surface treatment bath is produced by diluting the surface treatment chemicals so as to have a pH of 1.5-4.0. Excellent resistance to blackening by boiling water and adhesion to an overlying polymer coating film can be obtained by a surface treatment using this bath.
Claims3
A method of surface-treating aluminum or its alloy comprising the steps of (a) applying to said aluminum or its alloy a surface treatment bath consisting essentially of 10-1000 ppm of niobium ion and/or tantalum ion, and 1-50 pm of isolated fluorine ion released from compounds selected from the group consisting of HF, NH.sub.4 F, NH.sub.4 HF.sub.2, NaF and NaHF.sub.2, and having a pH of 1.5-4.0, at a temperature between room temperature and 50.degree. C., and (b) washing the treated surface of said aluminum of its alloy with water.
Dependencies are inferred from the claim text.