Patents by Inventor Carlo Ligotti

Carlo Ligotti 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).

  • Patent number: 4886637
    Abstract: A presinter treatment is provided to reduce oxygen contamination prior to sintering a predominantly iron powder compact comprising carbon powder and a liquating diffusible boron source, such as nickel boride powder optionally in combination with iron boride powder. A preferred treatment is carried out at a temperature effective to dissociate iron oxide within the compact but not to initiate a liquid phase by said boron source and further is carried out in a vacuum to evacuate oxygen released thereby from compact pores prior to sintering. The presinter treatment enhances carbon and boron diffusion into the iron during sintering. In a preferred embodiment, the fraction of borocementite particles formed by diffused carbon and boron in the sintered iron structure is increased by the presinter treatment of this invention.
    Type: Grant
    Filed: April 17, 1989
    Date of Patent: December 12, 1989
    Assignee: General Motors Corporation
    Inventors: William F. Jandeska, Jr., Vadim Rezhets, Carlo Ligotti
  • Patent number: 4849164
    Abstract: A sintering aid is disclosed for use in a powder metallurgical method for manufacturing an iron alloy article by compacting and sintering a predominantly iron powder mixture comprising carbon powder and a boron-containing additive, such as nickel boride. The sintering aid comprises an oxygen getter to inhibit boron oxidation that, if formed, is believed to retard carbon diffusion. The sintering aid also preferably includes a second constituent to produce, in combination with the getter, a melting point suitable for forming a transient liquid phase during the early stages of sintering. Preferred sintering aids include intermetallic iron titanium compounds, intermetallic ferro-vanadium compound and intermetallic nickel magnesium compound.
    Type: Grant
    Filed: February 29, 1988
    Date of Patent: July 18, 1989
    Assignee: General Motors Corporation
    Inventors: William F. Jandeska, Vadim Rezhets, Carlo Ligotti