A method including: employing pure magnesium or a magnesium alloy as a substrate material, and sanding and cleaning the substrate material; preparing an electrolyte including 0.8-8 mmol/L of Zn.sup.2+, 30-50 mmol/L of Ca.sup.+, 15-35 mmol/L of H.sub.2PO.sub.4.sup., 0-0.5 mol/L of NaNO.sub.3, and 0-0.05 mmol/L of a magnesium ion complexing agent; employing the substrate material as a cathode, a graphite flake as an anode, heating the electrolyte to a temperature of between 60 and 90 C., and synchronously immersing the cathode and the anode into the electrolyte; and implementing an electrochemical deposition method in the electrolyte for between 20 and 60 min.

A method including: employing pure magnesium or a magnesium alloy as a substrate material, and sanding and cleaning the substrate material; preparing an electrolyte including 0.8-8 mmol/L of Zn.sup.2+, 30-50 mmol/L of Ca.sup.+, 15-35 mmol/L of H.sub.2PO.sub.4.sup., 0-0.5 mol/L of NaNO.sub.3, and 0-0.05 mmol/L of a magnesium ion complexing agent; employing the substrate material as a cathode, a graphite flake as an anode, heating the electrolyte to a temperature of between 60 and 90 C., and synchronously immersing the cathode and the anode into the electrolyte; and implementing an electrochemical deposition method in the electrolyte for between 20 and 60 min.

Disclosed is a solution composition which may be used for a single-bath electrochemical passivation and a method using the same. The solution composition includes a metal cation, a metal-oxide anion; and an organic ligand, and optionally includes a non-metallic oxide anion or a polymer. The solution composition may prevent undesired precipitation of metal oxides before performing passivation. In addition, the method of passivation using the solution composition in a single-bath use is also provided.

Disclosed is a solution composition which may be used for a single-bath electrochemical passivation and a method using the same. The solution composition includes a metal cation, a metal-oxide anion; and an organic ligand, and optionally includes a non-metallic oxide anion or a polymer. The solution composition may prevent undesired precipitation of metal oxides before performing passivation. In addition, the method of passivation using the solution composition in a single-bath use is also provided.

Methods for treating a substrate are disclosed. The substrate is deoxidized and then immersed in an electrodepositable pretreatment composition comprising a lanthanide series element and/or a Group IIIB metal, an oxidizing agent, and a metal-complexing agent to deposit a coating from the electrodepositable pretreatment composition onto a surface of the substrate. Optionally, the electrodepositable pretreatment composition may comprise a surfactant. A coating from a spontaneously depositable pretreatment composition comprising a Group IIIB and/or Group IVB metal may be deposited on the substrate surface prior to electrodepositing a coating from the electrodepositable pretreatment composition. Following electrodeposition of the electrodepositable pretreatment composition, the substrate optionally may be contacted with a sealing composition comprising phosphate and a Group IIIB and/or IVB metal. Substrates treated according to the methods also are disclosed.

Methods for treating a substrate are disclosed. The substrate is deoxidized and then immersed in an electrodepositable pretreatment composition comprising a lanthanide series element and/or a Group IIIB metal, an oxidizing agent, and a metal-complexing agent to deposit a coating from the electrodepositable pretreatment composition onto a surface of the substrate. Optionally, the electrodepositable pretreatment composition may comprise a surfactant. A coating from a spontaneously depositable pretreatment composition comprising a Group IIIB and/or Group IVB metal may be deposited on the substrate surface prior to electrodepositing a coating from the electrodepositable pretreatment composition. Following electrodeposition of the electrodepositable pretreatment composition, the substrate optionally may be contacted with a sealing composition comprising phosphate and a Group IIIB and/or IVB metal. Substrates treated according to the methods also are disclosed.

A process of making a dense, cohesive and uniform aluminum oxide coating on a metallic substrate includes electrodepositing polynuclear aluminum oxide hydroxide clusters from a polynuclear aluminum oxide hydroxide cluster solution on a metallic substrate to form a precursor coating, and post-treating the precursor coating to form a final aluminum oxide coating on the metallic substrate.

A process of making a dense, cohesive and uniform aluminum oxide coating on a metallic substrate includes electrodepositing polynuclear aluminum oxide hydroxide clusters from a polynuclear aluminum oxide hydroxide cluster solution on a metallic substrate to form a precursor coating, and post-treating the precursor coating to form a final aluminum oxide coating on the metallic substrate.

There is provided a surface-treated steel sheet (1) comprising: a tin-plated steel sheet (10) obtained by tin-plating a steel sheet (11); a phosphate compound layer (20) containing tin phosphate formed on the tin-plated steel sheet (10); and an aluminum-oxygen compound layer (30) on the phosphate compound layer (20), a main constituent of the aluminum-oxygen compound layer (30) being an aluminum-oxygen compound; wherein, when the 3d.sub.5/2 spectrum of tin in the aluminum-oxygen compound layer (30) is determined using an X-ray photoelectron spectroscopy, the ratio of the integration value of the profile derived from tin oxide to the integration value of the profile derived from tin phosphate (tin oxide/tin phosphate) is 6.9 or more.

There is provided a surface-treated steel sheet (1) comprising: a tin-plated steel sheet (10) obtained by tin-plating a steel sheet (11); a phosphate compound layer (20) containing tin phosphate formed on the tin-plated steel sheet (10); and an aluminum-oxygen compound layer (30) on the phosphate compound layer (20), a main constituent of the aluminum-oxygen compound layer (30) being an aluminum-oxygen compound; wherein, when the 3d.sub.5/2 spectrum of tin in the aluminum-oxygen compound layer (30) is determined using an X-ray photoelectron spectroscopy, the ratio of the integration value of the profile derived from tin oxide to the integration value of the profile derived from tin phosphate (tin oxide/tin phosphate) is 6.9 or more.