Steel sheet with enhanced corrosion resistance having a silane treated silicate coating

A method of coating steel with a nontoxic, inorganic, corrosion resistant coating, comprising the steps of:

• providing an alkaline solution maintained at an elevated temperature,
• said alkaline solution being aqueous and including a silicate and a metal salt,
• said alkaline solution having a pH of at least about 10 and the concentration of each of said silicate and said salt being at least about 0.005M,
• rinsing a steel sheet with said alkaline solution,
• drying said sheet thereby forming a relatively insoluble silicate coating,
• rinsing said silicate coated sheet in another solution,
• the other solution being aqueous and including a concentration of 0.5-5.0 vol.-% silane.

A method of coating steel with a nontoxic, inorganic, corrosion resistant coating, comprising the steps of:

• providing an alkaline solution maintained at an elevated temperature of about 25.degree.-60.degree. C.,
• said alkaline solution being aqueous and including a silicate and a metal salt,
• said alkaline solution having a pH of about 10-12 and the concentration of each of said silicate and said salt being at least about 0.005M,
• rinsing a steel sheet with said alkaline solution,
• drying said sheet thereby forming a relatively insoluble silicate coating having a thickness of at least 2 nm,
• rinsing said silicate coated sheet in another aqueous solution,
• the other solution being aqueous and including a concentration of 0.5-5.0 vol.-% silane, and
• painting said silane treated sheet.

A method of coating steel with a nontoxic, inorganic, corrosion resistant coating, comprising the steps of:

• providing a steel sheet and an acidic solution,
• said sheet including one or more layers of hot-dipped or electroplated metallic coating of lead, lead alloy, nickel and nickel alloy,
• rinsing said sheet with said acidic solution,
• providing an alkaline aqueous solution maintained at an elevated temperature,
• said alkaline solution including a silicate and a metal salt,
• rinsing said sheet with said alkaline solution,
• drying said sheet thereby forming a relatively insoluble silicate coating,
• rinsing said silicate coated sheet in another aqueous solution,
• the other solution including a silane wherein said silicate coating minimizes rusting of said metallic coated sheet.

A method of coating steel with a nontoxic, inorganic, corrosion resistant coating, comprising the steps of:

• providing a steel sheet and an acidic solution,
• said sheet including one or more layers of hot-dipped or electroplated metallic coating of lead, lead alloy, nickel and nickel alloy,
• rinsing said sheet with said acidic solution,
• providing an alkaline aqueous solution maintained at an elevated temperature,
• said alkaline solution having a pH of at least about 10 and including about 0.005M of a silicate and about 0.005M of a metal salt,
• rinsing said sheet with said alkaline solution,
• drying said sheet thereby forming a relatively insoluble silicate coating,
• rinsing said silicate coated sheet in another solution,
• the other solution being aqueous and including a concentration of 0.5-5.0 vol.-% silane wherein said silicate coating minimizes rusting of said metallic coated sheet.

A method of coating steel with a nontoxic, inorganic, corrosion resistant coating, comprising the steps of:

• providing a steel sheet and an acidic solution,
• said sheet including one or more layers of hot-dipped or electroplated metallic coating of lead, lead alloy, nickel and nickel alloy,
• rinsing said sheet with said acidic solution,
• providing an alkaline aqueous solution maintained at an elevated temperature of about 25.degree.-60.degree. C.,
• said alkaline solution having a pH of 10-12 and including about 0.005M of a silicate and about 0.005M of a metal salt,
• rinsing said sheet with said alkaline solution,
• drying said sheet thereby forming a relatively insoluble silicate coating having a thickness of at least 2 nm,
• rinsing said silicate coated sheet in another solution,
• the other solution being aqueous and including a concentration of 0.5-5.0 vol.-% silane wherein said silicate coating minimizes rusting of said metallic coated sheet.