Patents by Inventor Cathleen H. Chang

Cathleen H. Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Process of maintaining hybrid etch
    Patent number: 7138342
    Abstract: Process for combined chemical cleaning and etching of parts made of aluminum and/or aluminum alloys including: (a) providing a cleaning and etching solution including 5–30 grams/liter of phosphoric acid; 5–30 grams/liter of hydrogen fluoride; 120–220 grams/liter of sulfamic acid; 55–85.0 grams/liter of glycol ether; and balance water; (b) contacting the parts with the solution for a time sufficient to achieve the desired amount of cleaning and etching; (c) periodically measuring the etching rate of the solution; (d) when the etching rate is below the required minimum rate, adding sufficient hydrogen fluoride to restore the etching rate above the required minimum rate; and (e) periodically adding sufficient sulfamic acid to prevent the formation of scale made of hydrated aluminum fluoride.
    Type: Grant
    Filed: October 31, 2003
    Date of Patent: November 21, 2006
    Assignee: The Boeing Company
    Inventors: Cathleen H. Chang, Terry C. Tomt
  • Boelube R dissolving alkaline cleaning solution
    Patent number: 6240935
    Abstract: A process for descaling, derusting, dissolving, and removing machining lubricants coated on steel and other iron alloy objects, the process comprising the steps of: (a) providing an alkaline cleaning solution consisting of: water; about 2.5% to 25% by weight of a water-soluble alkali; about 2% to 8% by weight of sodium gluconate; about 5% to 20% by weight of sodium xylene sulfonate; and about 2% to 20% by weight of a water-soluble surfactant consisting of C9-C11 alcohol ethoxylates and 6 ppm of ethylene oxides; and (b) contacting the soiled object with the alkaline cleaning solution at a temperature of about 60° F. to 200° F. for about 3 to 30 minutes, wherein the object is descaled, derusted, and the machining lubricant is dissolved and removed.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: June 5, 2001
    Assignee: The Boeing Company
    Inventor: Cathleen H. Chang
  • Alkaline cleaning solution
    Patent number: 6197736
    Abstract: An improved alkaline cleaning solution that has the ability to descale, derust, and completely dissolve machining lubricants coated on steel and other iron alloy objects, the alkaline cleaning solution consisting essentially of: (a) water; (b) about 10% to 95% by volume of a water-soluble descaling and derusting agent; and (c) about 2% to 8% by weight of a water-soluble sequestering agent selected from the group consisting of sodium gluconate and its functional equivalents.
    Type: Grant
    Filed: December 16, 1999
    Date of Patent: March 6, 2001
    Assignee: The Boeing Company
    Inventor: Cathleen H. Chang