A study of the formation and self-lubrication mechanisms of boric acid films on boric oxide coatings

Conference · Mon Jan 01 04:00:00 EST 1990

DOI:https://doi.org/10.1016/B978-1-85166-813-7.50063-2· OSTI ID:6963459

Erdemir, A; Fenske, G R; Erck, R A

An investigation was made of the formation and self-lubrication mechanisms of boric acid films on boric oxide coatings prepared by vacuum evaporation. Measured friction coefficients of a steel ball sliding on a boric-oxide-coated-steel disk and a sapphire ball sliding on a boric-oxide-coated-alumina disk were 0.025 to 0.05 at steady state, depending on load and substrate material. This low friction was correlated with the formation of a lubricious boric acid film on boric oxide coatings exposed to open air. For the mechanism of self-lubrication, the layered-triclinic-crystal structure of boric acid was proposed. The atoms constituting each boric acid molecule are arrayed in closely packed and strongly bonded layers that are 0.318 nm apart and held together by weak forces, such as van der Waals. It is hypothesized that during sliding, these layers can align themselves parallel to the direction of relative motion, and once so aligned,, can slide over one another with relative ease to provide low friction. Structural and chemical findings were included to substantiate the proposed solid lubrication mechanism. 15 refs., 5 figs.

• Research Organization: Argonne National Lab., IL (USA)
• Sponsoring Organization: DOE/CE
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6963459
• Report Number(s): CONF-900419-4; ON: DE90010115
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
360603* -- Materials-- Properties
ALLOYS
BORIC ACID
BORON COMPOUNDS
BORON OXIDES
CERAMICS
CHALCOGENIDES
CHEMICAL ANALYSIS
COATINGS
DEPOSITION
FRICTION
HYDROGEN COMPOUNDS
INORGANIC ACIDS
IRON ALLOYS
IRON BASE ALLOYS
LUBRICATION
OXIDES
OXYGEN COMPOUNDS
SLIDING FRICTION
STEELS
SUBSTRATES
TRIBOLOGY