The Effects of Environmental Water and Oxygen on the Temperature-Dependent Friction of Sputtered Molybdenum Disulfide.
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| Title: | The Effects of Environmental Water and Oxygen on the Temperature-Dependent Friction of Sputtered Molybdenum Disulfide. |
|---|---|
| Authors: | Khare, H. S.1, Burris, D. L.1 dlburris@udel.edu |
| Source: | Tribology Letters. Dec2013, Vol. 52 Issue 3, p485-493. 9p. |
| Subjects: | Molybdenum disulfide, Friction, Oxidation of water, Transition temperature, Temperature effect, Surfaces (Physics), Tribology |
| Abstract: | Molybdenum disulfide (MoS 2) is well known for exceptional friction and wear properties in inert and high vacuum environments. However, these tribological properties degrade in humid and high temperature environments for reasons that are not fully understood. A prevailing hypothesis suggests that moisture and thermal energy facilitate oxidation, which increases the shear strength of the sliding interface. The purpose of this study is to elucidate the contributions of water, oxygen, and temperature to the tribological degradation of MoS 2. Generally speaking, we found a minimum friction coefficient that occurred at a temperature we defined as the transition temperature. This transition temperature ranged from 100 to 250 °C and was a strong function of the MoS 2 preparation and thermal sliding history. Below the transition temperature, friction increased with increased water, but was insensitive to oxygen. Above the transition, friction increased with increased oxygen, but decreased to a limited extent with increased water. These results are generally consistent with prior results, but clarify some inconsistencies in the literature discussions. Contrary to the prevailing hypothesis, the results suggest that water does not promote oxidation near room temperature, but directly interferes with lamellar shear through physical bonding. Increased temperatures drive off water and thereby reduce friction up to the transition temperature. The results suggest that oxidation causes increased friction with increased temperature above the transition temperature. The data also suggest that water helps mitigate high temperature oxidation by displacing the environmental oxygen or by preferentially adsorbing to the surface. [ABSTRACT FROM AUTHOR] |
| Copyright of Tribology Letters is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 91857426 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The Effects of Environmental Water and Oxygen on the Temperature-Dependent Friction of Sputtered Molybdenum Disulfide. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Khare%2C+H%2E+S%2E%22">Khare, H. S.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Burris%2C+D%2E+L%2E%22">Burris, D. L.</searchLink><relatesTo>1</relatesTo><i> dlburris@udel.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Tribology+Letters%22">Tribology Letters</searchLink>. Dec2013, Vol. 52 Issue 3, p485-493. 9p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Molybdenum+disulfide%22">Molybdenum disulfide</searchLink><br /><searchLink fieldCode="DE" term="%22Friction%22">Friction</searchLink><br /><searchLink fieldCode="DE" term="%22Oxidation+of+water%22">Oxidation of water</searchLink><br /><searchLink fieldCode="DE" term="%22Transition+temperature%22">Transition temperature</searchLink><br /><searchLink fieldCode="DE" term="%22Temperature+effect%22">Temperature effect</searchLink><br /><searchLink fieldCode="DE" term="%22Surfaces+%28Physics%29%22">Surfaces (Physics)</searchLink><br /><searchLink fieldCode="DE" term="%22Tribology%22">Tribology</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Molybdenum disulfide (MoS 2) is well known for exceptional friction and wear properties in inert and high vacuum environments. However, these tribological properties degrade in humid and high temperature environments for reasons that are not fully understood. A prevailing hypothesis suggests that moisture and thermal energy facilitate oxidation, which increases the shear strength of the sliding interface. The purpose of this study is to elucidate the contributions of water, oxygen, and temperature to the tribological degradation of MoS 2. Generally speaking, we found a minimum friction coefficient that occurred at a temperature we defined as the transition temperature. This transition temperature ranged from 100 to 250 °C and was a strong function of the MoS 2 preparation and thermal sliding history. Below the transition temperature, friction increased with increased water, but was insensitive to oxygen. Above the transition, friction increased with increased oxygen, but decreased to a limited extent with increased water. These results are generally consistent with prior results, but clarify some inconsistencies in the literature discussions. Contrary to the prevailing hypothesis, the results suggest that water does not promote oxidation near room temperature, but directly interferes with lamellar shear through physical bonding. Increased temperatures drive off water and thereby reduce friction up to the transition temperature. The results suggest that oxidation causes increased friction with increased temperature above the transition temperature. The data also suggest that water helps mitigate high temperature oxidation by displacing the environmental oxygen or by preferentially adsorbing to the surface. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Tribology Letters is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s11249-013-0233-8 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 9 StartPage: 485 Subjects: – SubjectFull: Molybdenum disulfide Type: general – SubjectFull: Friction Type: general – SubjectFull: Oxidation of water Type: general – SubjectFull: Transition temperature Type: general – SubjectFull: Temperature effect Type: general – SubjectFull: Surfaces (Physics) Type: general – SubjectFull: Tribology Type: general Titles: – TitleFull: The Effects of Environmental Water and Oxygen on the Temperature-Dependent Friction of Sputtered Molybdenum Disulfide. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Khare, H. S. – PersonEntity: Name: NameFull: Burris, D. L. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 12 Text: Dec2013 Type: published Y: 2013 Identifiers: – Type: issn-print Value: 10238883 Numbering: – Type: volume Value: 52 – Type: issue Value: 3 Titles: – TitleFull: Tribology Letters Type: main |
| ResultId | 1 |
