Abstract: A method of producing an abrasion resistant anodized coating on a magnesium containing article. The method including mixing a chemical slurry including a quantity of an aqueous soluble hydroxide, a fluoride composition, at least one of silicate or vanadate, and between about 5 g/L and about 150 g/L of at least one physical property modifying agent, immersing a magnesium containing article in the chemical slurry, and applying at least one of an electrical current or electrical potential to the magnesium containing article to promote a chemical reaction on a surface of the magnesium containing article resulting in the growth of an abrasion resistant porous magnesium oxide layer on a surface of the magnesium containing article.
Abstract: A two-step process for the coating of magnesium and its alloys is disclosed. The first step comprises immersing the magnesium workpiece in a first electrochemical solution comprising about 3 to 10 wt-% of a hydroxide and about 5 to 30 wt-% of a fluoride having a pH of at least about 12. By controlling a current density to about 10 to 200 mA/cm.sup.2, an increasing voltage differential is established between an anode comprising the pretreated article and a cathode also in contact with the electrolytic solution. Next, the article is immersed in an aqueous electrolytic solution having a pH of at least about 11 and which solution is prepared from components comprising a water soluble hydroxide, a fluoride source and a water soluble silicate in amounts to result in an addition of about 2 to 15 g of a hydroxide per liter of solution, about 2 to 14 g of a fluoride per liter of solution and about 5 to 40 g of a silicate per liter of solution. Again, by controlling the current density to about 5 to 100 mA/cm.sup.
Type:
Grant
Filed:
September 10, 1992
Date of Patent:
November 30, 1993
Assignee:
Technology Applications Group, Inc.
Inventors:
Duane E. Bartak, Brian E. Lemieux, Earl R. Woolsey
Abstract: A two-step process for the coating of magnesium and its alloys is disclosed. The first step comprises immersing the magnesium workpiece in a first electrochemical solution comprising about 3 to 10 wt-% of a hydroxide and about 5 to 30 wt-% of a fluoride having a pH of at least about 12. By controlling a current density to about 10 to 200 mA/cm.sup.2, an increasing voltage differential is established between an anode comprising the pretreated article and a cathode also in contact with the electrolytic solution. Next, the article is immersed in an aqueous electrolytic solution having a pH of at least about 11 and which solution is prepared from components comprising a water soluble hydroxide, a water soluble fluoride source and a water soluble silicate in amounts to result in an addition of about 2 to 15 g of a hydroxide per liter of solution, about 2 to 14 g of a fluoride per liter of solution and about 5 to 40 g of a silicate per liter of solution.
Type:
Grant
Filed:
July 15, 1991
Date of Patent:
November 23, 1993
Assignee:
Technology Applications Group, Inc.
Inventors:
Duane E. Bartak, Brian E. Lemieux, Earl R. Woolsey
Abstract: A two-step process for the coating of magnesium and its alloys is disclosed. The first step comprises immersing the magnesium workpiece in an aqueous solution comprising about 0.2 to 5 molar ammonium fluoride having a pH of about 5 to 8 and a temperature of about 40.degree. to 100.degree. C. The second step is an electrochemical treatment of the pretreated article in an aqueous electrolytic solution having a pH of at least about 12.5 and which solution comprises about 2 to 12 g/L of a aqueous soluble hydroxide, about 2 to 15 g/L of a fluoride-containing composition selected from the group consisting of fluorides and fluorosilicates, and about 5 to 30 g/L of a silicate. This process results in a superior coating which has increased abrasion and corrosion resistance.
Type:
Grant
Filed:
July 22, 1992
Date of Patent:
August 31, 1993
Assignee:
Technology Applications Group, Inc.
Inventors:
Duane E. Bartak, Brian E. Lemieux, Earl R. Woolsey