Coating composition and methods of coating
View Patent ↗Various coatings and methods of coating fasteners are disclosed. In one embodiment, a method of coating includes applying a chromate coating to a fastener. In other embodiments, the method may include deoxidizing an aluminum fastener, etching the fastener, deoxidizing the fastener a second time, applying a chromate coating to the fastener, and dying the fastener.
1. A method comprising:
preparing a rivet of 2117 Aluminum alloy by subjecting the rivet to deoxidizing and etching operations, wherein a deoxidizing operation precedes and follows an etching operation;
applying a composition including chromic acid, potassium ferricyanide, sodium nitrate, and sodium silicofluoride as a chromate coating to the prepared rivet; and
after applying the chromate coating, dying the rivet by placing the rivet in an environment comprising 3 grams of dye per liter at a pH between 4 and 4.2 at a temperature between 90° F. and 100° F. for a period between 1.5 and two minutes.
2. The method of claim 1 , wherein applying comprises:
placing the rivet in a bath containing between approximately 1.5 and 1.75 ounces of chromate per gallon at a temperature between 70° F. and 80° F. for a period between 80 and 100 seconds.
3. A method comprising:
deoxidizing and etching a rivet of 2117 Aluminum alloy wherein deoxidizing precedes and follows etching;
applying a composition including chromic acid, potassium ferricyanide, sodium nitrate, and sodium silicofluoride as a chromate film to the rivet in compliance with an aircraft manufacturing industry standard; and
after applying the chromate film, dying the rivet by placing the rivet in an environment comprising 3 grams of dye per liter at a pH between 4 and 4.2 at a temperature between 90° F. and 100° F. for a period between 1.5 and two minutes.
4. The method of claim 3 , wherein dying comprises dying the rivet an orange color.