A Model for Shear Degradation of Lithium Soap Grease at Ambient Temperature

Yuxin Zhou (Corresponding Author), Rob Bosman, Piet M. Lugt

    Research output: Contribution to journalArticleAcademicpeer-review

    14 Citations (Scopus)
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    Abstract

    In this article, the shear degradation of lithium 12-hydroxy stearate grease will be measured using an in-house-developed Couette aging machine. In this device the shear rate is well defined. The aging is related to the generated entropy density as described in Rezasoltani and Khonsari's work (Tribology Letters, Vol. 56, No. 2, pp. 197–204, 2014). The rheological properties of the aged samples were evaluated using a parallel-plate rheometer. The results showed that there are two aging phases with different degradation rates: a progressive degradation phase at the early stage, followed by a rather slow deterioration afterwards. Based on this observation, an aging equation was formulated to describe the aging behavior of lithium-thickened grease. Atomic force microscopy results of the fresh and aged greases showed that the variation in thickener microstructure provides a good explanation for the lithium grease degradation mechanism: under shear, the original fibrous network is progressively destroyed and becomes fragmented, leading to the loss of consistency and a change in the rheological properties.
    Original languageEnglish
    Pages (from-to)61-70
    Number of pages10
    JournalTribology transactions
    Volume61
    Issue number1
    Early online date13 Feb 2017
    DOIs
    Publication statusPublished - 2018

    Fingerprint

    greases
    soaps
    Soaps (detergents)
    Lubricating greases
    Lithium
    ambient temperature
    lithium
    Aging of materials
    degradation
    shear
    Degradation
    Temperature
    Stearates
    stearates
    tribology
    rheometers
    Tribology
    Rheometers
    parallel plates
    deterioration

    Keywords

    • UT-Hybrid-D

    Cite this

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    title = "A Model for Shear Degradation of Lithium Soap Grease at Ambient Temperature",
    abstract = "In this article, the shear degradation of lithium 12-hydroxy stearate grease will be measured using an in-house-developed Couette aging machine. In this device the shear rate is well defined. The aging is related to the generated entropy density as described in Rezasoltani and Khonsari's work (Tribology Letters, Vol. 56, No. 2, pp. 197–204, 2014). The rheological properties of the aged samples were evaluated using a parallel-plate rheometer. The results showed that there are two aging phases with different degradation rates: a progressive degradation phase at the early stage, followed by a rather slow deterioration afterwards. Based on this observation, an aging equation was formulated to describe the aging behavior of lithium-thickened grease. Atomic force microscopy results of the fresh and aged greases showed that the variation in thickener microstructure provides a good explanation for the lithium grease degradation mechanism: under shear, the original fibrous network is progressively destroyed and becomes fragmented, leading to the loss of consistency and a change in the rheological properties.",
    keywords = "UT-Hybrid-D",
    author = "Yuxin Zhou and Rob Bosman and Lugt, {Piet M.}",
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    A Model for Shear Degradation of Lithium Soap Grease at Ambient Temperature. / Zhou, Yuxin (Corresponding Author); Bosman, Rob; Lugt, Piet M.

    In: Tribology transactions, Vol. 61, No. 1, 2018, p. 61-70.

    Research output: Contribution to journalArticleAcademicpeer-review

    TY - JOUR

    T1 - A Model for Shear Degradation of Lithium Soap Grease at Ambient Temperature

    AU - Zhou, Yuxin

    AU - Bosman, Rob

    AU - Lugt, Piet M.

    N1 - Taylor & Francis deal

    PY - 2018

    Y1 - 2018

    N2 - In this article, the shear degradation of lithium 12-hydroxy stearate grease will be measured using an in-house-developed Couette aging machine. In this device the shear rate is well defined. The aging is related to the generated entropy density as described in Rezasoltani and Khonsari's work (Tribology Letters, Vol. 56, No. 2, pp. 197–204, 2014). The rheological properties of the aged samples were evaluated using a parallel-plate rheometer. The results showed that there are two aging phases with different degradation rates: a progressive degradation phase at the early stage, followed by a rather slow deterioration afterwards. Based on this observation, an aging equation was formulated to describe the aging behavior of lithium-thickened grease. Atomic force microscopy results of the fresh and aged greases showed that the variation in thickener microstructure provides a good explanation for the lithium grease degradation mechanism: under shear, the original fibrous network is progressively destroyed and becomes fragmented, leading to the loss of consistency and a change in the rheological properties.

    AB - In this article, the shear degradation of lithium 12-hydroxy stearate grease will be measured using an in-house-developed Couette aging machine. In this device the shear rate is well defined. The aging is related to the generated entropy density as described in Rezasoltani and Khonsari's work (Tribology Letters, Vol. 56, No. 2, pp. 197–204, 2014). The rheological properties of the aged samples were evaluated using a parallel-plate rheometer. The results showed that there are two aging phases with different degradation rates: a progressive degradation phase at the early stage, followed by a rather slow deterioration afterwards. Based on this observation, an aging equation was formulated to describe the aging behavior of lithium-thickened grease. Atomic force microscopy results of the fresh and aged greases showed that the variation in thickener microstructure provides a good explanation for the lithium grease degradation mechanism: under shear, the original fibrous network is progressively destroyed and becomes fragmented, leading to the loss of consistency and a change in the rheological properties.

    KW - UT-Hybrid-D

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