摘要 |
A composition for surface treatment of aluminium, aluminum alloys, magnesium or magnesium alloys and the treating solutions being diluted to the desired concentration are defined. The composition contains (1) compound A containing at least one metal element selected from the group consisting of Hf(IV), Ti(IV) and Zr(IV), (2) a fluorine-containing compound of sufficient amount to make fluorine exist in the composition in an amount of at least 5 times the molarity of the total molarity of the metal contained in the above-mentioned compound A, (3) at least one metal ion B selected from the group of alkaline earth metals, (4) at least one metal ion C selected from the group consisting of Al, Zn, Mg, Mn and Cu, and (5) nitric ion and the mol concentration of compound A is 0.1-50 mmol/L as the metal element of Hf(IV), Ti(IV) and Zr(IV). A metal treated with the treating method of the present invention solution has an excellent resistance to various corrosive environments.
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