Abstract: The present invention provides a surface treatment method for magnesium alloys that can form a uniform, fine, and dense conversion coating on a magnesium alloy surface on which mold release agent, an oxide layer, and an alloying component (e.g., aluminum and zinc) segregation layer are potentially present, and also provides magnesium alloy member whose surface has been treated by the aforesaid surface treatment method. The surface treatment method of the present invention comprises a degreasing process to degrease the surface of the magnesium alloy, a chemically etching process to chemically etch the alloy, and a conversion treatment process to form a conversion coating. The chemical etching forms a magnesium phosphate coating having a coating weight of 10 to 2,000 mg/m2, measured as phosphorus, by bringing the surface of the magnesium alloy into contact with an aqueous solution containing a phosphoric acid-type compound.

Abstract: Here are provided a composition for hydrophilic treatment of aluminum or aluminum alloy which can form film having persistent corrosion resistance and hydrophilicity and not generating odor, and a method for hydrophilic treatment.

Abstract: A surface of aluminiferous metal is brought into contact at 25 to 65.degree. C. for 2 to 100 seconds with a surface treatment bath with a pH of 1.0 to 6.0 that contains phosphate ions, dissolved titanium and/or zirconium compounds, dissolved fluorine-containing anions, and a water soluble polymer in the following weight proportions: 1-100:1-50:1-200:1-200. This is followed by a water rinse and drying. The water soluble polymer has a chemical structure conforming to formula (I), in which each of X.sup.1 and X.sub.2 represents a hydrogen atom, a C.sub.1 to C.sub.5 alkyl group, or a C.sub.1 to C.sub.5 hydroxyalkyl group; each of Y.sup.1 and Y.sup.2 represents a hydrogen atom or a moiety "Z" that to formula (II) or (III), wherein each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 represents a C.sub.1 to C.sub.10 alkyl group or a C.sub.1 to C.sub.10 hydroxyalkyl group; the average value for the number of Z moieties substituted on each aromatic ring in the polymer molecules is from 0.2 to 1.

Abstract: Treatment of aluminiferous metal surfaces with an aqueous liquid composition which has a pH value in the range from 1.8 to 4.0 and comprises (A) from 0.01 to 1.0 g/L of phosphate ions, (B) from 0.01 to 0.5 g/L, measured as its total stoichiometric equivalent as metal, of water-soluble zirconium and titanium compounds, (C) from 0.01 to 2-0 g/L, measured as fluorine, of simple and/or complex fluoride anions; and (D) from 0.01 to 2.0 g/L of water-soluble polyamides that contain at least one tertiary amino or polyoxyalkylene moiety forms a highly corrosion-resistant, strongly paint-adherent, and low friction conversion coating on the metal surface.

Abstract: This invention relates to particular aqueous coating compositions comprising particular organic acids and processes of using these compositions to treat plastic moldings.