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US4215088A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for fabricating boron carbide articles

Assignee: United States Department of Energy
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Filing: 1978-10-31
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Granted: 1980-07-29
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Expires: 1998-10-31
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Abstract

Abstract The present invention is directed to the fabrication of boron carbide articles having length-to-diameter or width ratios greater than 2 to 1. The process of the present invention is practiced by the steps comprising hot pressing boron carbide powder into article segments or portions in which the segments have a length-to-diameter or width ratio less than 1.5, aligning a plurality of the initially hot-pressed segments in a hot-pressing die with the end surfaces of the segments placed in intimate contact with one another, and then hot pressing the aligned segments into an article of the desired configuration. The resulting article exhibits essentially uniform density throughout the structure with the bonds between the segments being equivalent in hardness, strength, and density to the remainder of the article.

Inventors

  • 👤 Zane L. Ardary
  • 👤 Carl D. Reynolds

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 03:50
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/563; C04B35/622; C04B35/64; C04B35/645

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 207 words
A method for fabricating an essentially uniformly dense boron carbide article of a length-to-diameter or width ratio greater than 2 to 1 comprising the steps of providing a plurality of article segments to be joined together to form the article with each of said article segments having a length-to-diameter or width ratio less than 1.5 to 1 and each being fabricated by hot pressing a composition consisting of boron carbide powder at a pressure and temperature effective to provide the article segment with a density greater than about 85% of theoretical density, providing each article segment with parallel planar end surfaces, placing a plurality of said article segments in a hot-pressing die in a line with the planar surfaces of adjacent article segments being disposed in intimate contact, and hot pressing the aligned article segments at a temperature and pressure effective to provide said article with a density over the length thereof in the range of about 94 to 98 percent theoretical density and greater than the density provided in the discrete hot pressing of each of the article segments and to provide a bond between adjacent article segments with said bond being at least equivalent in hardness, strength and density to a remainder of said article.
Claim 2
Independent Claim 207 words
A method for fabricating an essentially uniformly dense boron carbide article of a length-to-diameter or width ratio greater than 2 to 1 comprising the steps of providing a plurality of article segments to be joined together to form the article with each of said article segments having a length-to-diameter or width ratio less than 1.5 to 1 and each being fabricated by hot pressing a composition consisting of boron carbide powder at a pressure and temperature effective to provide the article segment with a density greater than about 85% of theoretical density, providing each article segment with parallel planar end surfaces, placing a plurality of said article segments in a hot-pressing die in a line with the planar surfaces of adjacent article segments being disposed in intimate contact, and hot pressing the aligned article segments at a temperature and pressure effective to provide said article with a density over the length thereof in the range of about 94 to 98 percent theoretical density and greater than the density provided in the discrete hot pressing of each of the article segments and to provide a bond between adjacent article segments with said bond being at least equivalent in hardness, strength and density to a remainder of said article.
Claim 3
Dependent Claim 58 words
The method claimed in claim 1, wherein said composition of boron carbide powder is a nominal stoichiometric composition, wherein the pressure and temperature utilized in the hot pressing of each of the article segments and in the hot pressing of the aligned article segments is in the range of 2500 to 3000 psi and 2000 to 2150° C.
Claim 4
Dependent Claim 30 words
The method claimed in claim 2, wherein the hot-pressing steps of the individual article segments and the aligned article segments are provided in die means provided with axially displaceable pistons.

References Cited (Backward Citations)

US2207786A Cited
US3003885A Cited
US3632710A Cited
US4071372A Cited
US3859399A Cited
US3729372A Cited
US3730826A Cited
US3976735A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1983-07-29 1984-01-28 1984-07-29 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1987-07-29 1988-01-28 1988-07-29 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1991-07-29 1992-01-28 1992-07-29 $7700.00 Window Closed / Lapsed

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