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Title
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Wear and Friction in Liquid Nitrogen and Hydrogen of the Materials Combinations Carbon-Stainless Steel and Carbon-Carbon
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Description
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Wear and friction of conventional mechanical carbons for seals and bearings are excessive in liquid nitrogen and in liquid hydrogen. Better performance is needed for components of rocket engine turbopumps using liquid hydrogen. The problem was considered to result from the inability of the carbon to form an adherent lubricating graphitic film on the mating metal surface. The sliding of carbon on carbon rather than of carbon on metal was considered to offer a possible solution to this wear and friction problem.
Data were obtained with 3/16-inch-radius rider specimens sliding on the flat surface of a rotating disk submerged in liquid nitrogen (-320°F), liquid hydrogen (-423°F), or dry air (75°F). Surface speed was 2300 feet per minute and load was 1000 grams. The wear of a typical hard mechanical carbon sliding on itself in liquid nitrogen was less than 1 percent of that obtained with the same carbon in sliding contact with type 304 stainless steel. Friction coefficient was reduced from 0.18 to 0.04. In liquid hydrogen the wear reduction was not as great, while the difference in friction coefficient was greater (0.26 and 0.03). These data support the considerations on the importance of graphitic films on the mating surface.
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Creator
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Wisander, D. W.
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Johnson, R. L.
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Format
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1 online resource (9 pages) : ill.
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Type
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article
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Abstract
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Wear and friction of conventional mechanical carbons for seals and bearings are excessive in liquid nitrogen and in liquid hydrogen. Better performance is needed for components of rocket engine turbopumps using liquid hydrogen. The problem was considered to result from the inability of the carbon to form an adherent lubricating graphitic film on the mating metal surface. The sliding of carbon on carbon rather than of carbon on metal was considered to offer a possible solution to this wear and friction problem.
Data were obtained with 3/16-inch-radius rider specimens sliding on the flat surface of a rotating disk submerged in liquid nitrogen (-320°F), liquid hydrogen (-423°F), or dry air (75°F). Surface speed was 2300 feet per minute and load was 1000 grams. The wear of a typical hard mechanical carbon sliding on itself in liquid nitrogen was less than 1 percent of that obtained with the same carbon in sliding contact with type 304 stainless steel. Friction coefficient was reduced from 0.18 to 0.04. In liquid hydrogen the wear reduction was not as great, while the difference in friction coefficient was greater (0.26 and 0.03). These data support the considerations on the importance of graphitic films on the mating surface.
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Extent
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9
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Corporate Author
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Lewis Research Center, National Aeronautics and Space Administration
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Report Number
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ASD-TDR-62-465 p. 157-165
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Report Availability
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Full text available
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Date
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1962
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Date Issued
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1962-05
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Contract
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AF 33(616)-7223
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DoD Project
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3044
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DoD Task
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30169
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30340
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Distribution Classification
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1
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Distribution Conflict
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No
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Index Abstract
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Contrails only
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Relation
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This paper was published in the Proceedings Of The Air Force-Navy-Industry Propulsion Systems Lubricants Conference held in San Antonio, Texas on 15, 16, and 17 November 1960
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Identifier
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AD0278843
