Patents by Inventor Sai V. Raj

Sai V. Raj 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).

  • Formulations for engineered ceramic matrix composites for high temperature applications
    Patent number: 10654756
    Abstract: An engineered ceramic matrix is provided to blunt and self-heal matrix cracks to reduce oxygen ingress into a fiber reinforced composite.
    Type: Grant
    Filed: January 19, 2018
    Date of Patent: May 19, 2020
    Assignee: United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Sai V. Raj
  • Engineered matrix self-healing composites
    Patent number: 10590044
    Abstract: An engineered matrix is provided to blunt and self-heal matrix cracks to reduce oxygen ingress into a fiber reinforced composite.
    Type: Grant
    Filed: January 20, 2017
    Date of Patent: March 17, 2020
    Assignee: United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Sai V. Raj
  • Advanced protective coatings for gr-based nuclear propulsion fuel elements
    Patent number: 10068675
    Abstract: A protective coating for a graphite (Gr) containing fuel element used in a nuclear thermal propulsion system includes a first layer that is configured to resist hot hydrogen attacks. The first layer has a coefficient of thermal expansion that is higher than a coefficient of thermal expansion of the Gr containing substrate. The coating also includes a plurality of second layers located between the first layer and the substrate. The second layers are configured to mitigate the differences in coefficients of thermal expansion between the first layer and the substrate to minimize debonding and exposure of the substrate to hydrogen attack. Preferably, the protective coating can comprise an outermost first layer including zirconium carbide (ZrC), a second layer including niobium (Nb), a third layer including molybdenum (Mo), and a fourth layer including molybdenum carbide (Mo2C) located adjacent to the substrate.
    Type: Grant
    Filed: October 20, 2014
    Date of Patent: September 4, 2018
    Assignee: The United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventors: Sai V. Raj, Mark Stewart, James A. Nesbitt
  • Blanch resistant and thermal barrier NiAl coating systems for advanced copper alloys
    Patent number: 6838191
    Abstract: A method of forming an environmental resistant thermal barrier coating on a copper alloy is disclosed. The steps include cleansing a surface of a copper alloy, depositing a bond coat on the cleansed surface of the copper alloy, depositing a NiAl top coat on the bond coat and consolidating the bond coat and the NiAl top coat to form the thermal barrier coating. The bond coat may be a nickel layer or a layer composed of at least one of copper and chromium-copper alloy and either the bond coat or the NiAl top coat or both may be deposited using a low pressure or vacuum plasma spray.
    Type: Grant
    Filed: May 20, 2003
    Date of Patent: January 4, 2005
    Assignee: The United States of America as represented by the Admistrator of the National Aeronautics and Space Administration
    Inventor: Sai V. Raj
  • High temperature creep and oxidation resistant chromium silicide matrix alloy containing molybdenum
    Patent number: 5330590
    Abstract: Cr.sub.3 Si is alloyed with molybdenum which produces a two-phase microstructure of (Cr,Mo).sub.3 Si and (Cr,Mo).sub.5 Si.sub.3. About 50 weight percent of molybdenum is present in the alloy. The alloy forms two protective oxides over a wide range of temperatures. Chromium and molybdenum oxide volatize under flowing air at high temperatures above 1200.degree. C. which facilitates the formation of SiO.sub.2 on the surface. Below 1200.degree. C. Cr.sub.2 O.sub.3 is formed. The new alloy has excellent high temperature strength and creep properties.
    Type: Grant
    Filed: May 26, 1993
    Date of Patent: July 19, 1994
    Assignee: The United States of America, as represented by the Administrator of the National Aeronautics & Space Administration
    Inventor: Sai V. Raj