Patents by Inventor Alexandr I. Dudyak

Alexandr I. Dudyak 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 for producing polycrystals of cubic boron nitride
    Patent number: 4361543
    Abstract: A process for producing polycrystals of cubic boron nitride which comprises exposure of hexagonal boron nitride to a pressure of from 40 to 70 kbar at a temperature of from 1,200.degree. to 1,800.degree. C. When the conversion of hexagonal boron nitride to cubic boron nitride reaches 20 to 65% by weight, the heating is switched off and pressure is increased to a value of from 80 to 120 kbar. Then the heating is resumed and temperature is elevated to 1,800.degree.-3,000.degree. C. Under these conditions the process is continued to full conversion of hexagonal boron nitride to cubic modification thereof.The process can be conducted in the presence of 0.5 to 10% by weight of a catalyst contributing to the conversion of hexagonal boron nitride into its cubic modification. The main portion of the catalyst is concentrated in the central portion of the volume of hexagonal boron nitride, the remainder - in the peripheral portion.
    Type: Grant
    Filed: April 27, 1982
    Date of Patent: November 30, 1982
    Inventors: Gennady M. Zhdanovich, Alexandr I. Dudyak, Mikhail I. Galkov, Vladimir P. Baraban, Jury V. Zherebtsov, Anatoly P. Zholob, Mikhail M. Zhuk, by Galina K. Zhuk, administrator