Technology Available for Licensing

Case 12358

Hard Coating for High Temperature Applications

Keywords:

Electrodeposited chromium coating, Trivalent chemical baths, Cr-C alloy, Cr-C-P coating, Annealing

Applications:

Chromium coating in elevated-temperature environments

Problem:

• Temperature limit of conventional hard chromium coating
• Detrimental effects on the environment of chemical baths based on hexavalent chromium

Technology:

The invention introduces a strategy to improve upon Cr-C plating derived from a trivalent bath through the addition of Phosphorous to the coating. Phosphorous is incorporated into the coating when hypophosphite-based baths are employed, but may also be introduced by addition of hypophosphite in organic baths, or by electroless deposition. The improved coating has hardness greater than 900 kgf/mm² in advantageous conditions, and may similarly have hardness greater than 1000 kgf/mm² at a temperature greater than 650⁰C. The coating can be deposited electrolytically or in the form of vapor. The coating should be exposed to a sufficient temperature to produce body centered cubic chromium, and annealed for at least five minutes. Upon thermal treatments, chromium nanocrystallization as well as precipitation of carbides and phosphides occurs, and the mechanical properties of the coating are improved. Detail composition of electrolytic baths can also be provided.

Advantages:

• The Cr-C coating hardens considerably upon heating.
• Less health and environmental concerns

Inventors:

• Professor Christopher A. Schuh(Department of Materials Science and Engineering, MIT)
• Dr. Marcelo Gines (Center for Industrial Research, Argentina)

Intellectual Property:

US Patent Number 7,910,231, issued on March 22, 2011

Publications:

N/A>

Please contact: Christopher R. Noble MIT Technology Licensing Officer 1 Cambridge Center, Kendall Square, NE18-501 Cambridge, Massachusetts 02142-1601

Email: crn@mit.edu Tel: 617-253-6966 Fax: 617–258-6790 Website: http://tlo.mit.edu