Iron-tungsten coating formulations and processes

A method of forming an iron-tungsten alloy coating layer comprising:

• preparing an electrolyte solution consisting of an aqueous medium;
• a divalent iron salt comprising iron (II) sulfate, iron (II) halide, iron (II) nitrate, iron (II) acetate, or iron (II) perchlorate;
• an alkali metal citrate comprising sodium citrate or potassium citrate;
• a tungstate salt comprising an alkali metal tungstate;
• a citric acid;
• and sodium hydroxide, potassium hydroxide, sulfuric acid, or a combination thereof by:
• dissolving in the aqueous medium, the divalent iron salt in an amount ranging from about 0.05 to about 0.5 mol per liter of the electrolyte solution and the alkali metal citrate in an amount ranging from about 0.05 to about 2 mol per liter of the electrolyte solution to form a first solution;
• dissolving in the first solution the tungstate salt in an amount ranging from about 0.1 to about 1.5 mol per liter of the electrolyte solution to form a second solution;
• and
• dissolving in the second solution the citric acid in an amount ranging from about 0.01 to about 1 mol per liter of the electrolyte solution to form the electrolyte solution;
• and
• passing a current between a cathode and an anode through the electrolyte solution to form the iron-tungsten alloy coating layer when the pH of the electrolyte solution is maintained at about 3 to about 12.