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Antiwear

The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform

Xiaobo Wang – 1st expert on this subject based on the ideXlab platform

  • effect of a new phosphate compound bafdp addition on the lubricating performance of engine oils at elevated temperatures
    Tribology International, 2016
    Co-Authors: Xinhu Wu, Gaiqing Zhao, Xiaobo Wang

    Abstract:

    Abstract A new phosphate compound bisphenol AF bis(diphenyl phosphate) (BAFDP) has been synthesized, characterized, and its tribological behaviours as a potential additives in aircraft engine oil were investigated at elevated temperature. BAFDP has high solubility in synthetic polyol esters and it is noteworthy that BAFDP exhibited effective friction reduction and Antiwear characteristics when blended with trimethylolpropyl trioleate (TMPTO) and pentaerythritol oleate (PETO). The tribological properties of BAFDP were generally superior to the traditionally used tricresyl phosphate (TCP) in TMPTO and PETO. The Antiwear mechanism is tentatively proposed on the basis of the morphology features and the chemical composition of the worn surfaces by SEM and XPS.

  • tribological properties of alkylphenyl diphosphates as high performance Antiwear additive in lithium complex grease and polyurea grease for steel steel contacts at elevated temperature
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Xinhu Wu, Gaiqing Zhao, Qin Zhao, Xiaobo Wang

    Abstract:

    The alkylphenyl diphosphates pentaerythritol tetrakis(diphenyl phosphate) (PDP) and trimethylolpropane tris(diphenyl phosphate) (TDP) were evaluated as the Antiwear additives in lithium complex grease and polyurea grease at 200 °C. The results indicated that both additives may effectively reduce the sliding friction and wear as compared to the base greases. The tribological performances were generally better than the normally used molybdenum disulfide (MoS2)-based additive package in lithium complex grease and also in polyurea grease. Boundary lubrication films composed of Fe(OH)O, Fe3O4, FePO4, and compounds containing the P–O bonds were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance.

  • tribological properties of naphthyl phenyl diphosphates as Antiwear additive in polyalkylene glycol and polyurea grease for steel steel contacts at elevated temperature
    RSC Advances, 2014
    Co-Authors: Xinhu Wu, Xiaobo Wang

    Abstract:

    Naphthyl phenyl diphosphates: 1-naphthyl diphenyl phosphate (NDP) and 1,5-dihydroxynaphthalene bis(diphenyl phosphate) (DDP) were evaluated as the Antiwear additives in polyalkylene glycol and polyurea grease at 200 °C. Results showed that they could effectively reduce the friction and wear of sliding pairs compared with the cases without these additives. Furthermore, the tribological properties of NDP and DDP were generally better than the normally used tricresyl phosphate (TCP) in PAG and molybdenum disulfide (MoS2) in polyurea grease. Boundary lubrication films composed of Fe(OH)O, Fe3O4, FePO4 were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance.

Xinhu Wu – 2nd expert on this subject based on the ideXlab platform

  • effect of a new phosphate compound bafdp addition on the lubricating performance of engine oils at elevated temperatures
    Tribology International, 2016
    Co-Authors: Xinhu Wu, Gaiqing Zhao, Xiaobo Wang

    Abstract:

    Abstract A new phosphate compound bisphenol AF bis(diphenyl phosphate) (BAFDP) has been synthesized, characterized, and its tribological behaviours as a potential additives in aircraft engine oil were investigated at elevated temperature. BAFDP has high solubility in synthetic polyol esters and it is noteworthy that BAFDP exhibited effective friction reduction and Antiwear characteristics when blended with trimethylolpropyl trioleate (TMPTO) and pentaerythritol oleate (PETO). The tribological properties of BAFDP were generally superior to the traditionally used tricresyl phosphate (TCP) in TMPTO and PETO. The Antiwear mechanism is tentatively proposed on the basis of the morphology features and the chemical composition of the worn surfaces by SEM and XPS.

  • tribological properties of alkylphenyl diphosphates as high performance Antiwear additive in lithium complex grease and polyurea grease for steel steel contacts at elevated temperature
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Xinhu Wu, Gaiqing Zhao, Qin Zhao, Xiaobo Wang

    Abstract:

    The alkylphenyl diphosphates pentaerythritol tetrakis(diphenyl phosphate) (PDP) and trimethylolpropane tris(diphenyl phosphate) (TDP) were evaluated as the Antiwear additives in lithium complex grease and polyurea grease at 200 °C. The results indicated that both additives may effectively reduce the sliding friction and wear as compared to the base greases. The tribological performances were generally better than the normally used molybdenum disulfide (MoS2)-based additive package in lithium complex grease and also in polyurea grease. Boundary lubrication films composed of Fe(OH)O, Fe3O4, FePO4, and compounds containing the P–O bonds were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance.

  • tribological properties of naphthyl phenyl diphosphates as Antiwear additive in polyalkylene glycol and polyurea grease for steel steel contacts at elevated temperature
    RSC Advances, 2014
    Co-Authors: Xinhu Wu, Xiaobo Wang

    Abstract:

    Naphthyl phenyl diphosphates: 1-naphthyl diphenyl phosphate (NDP) and 1,5-dihydroxynaphthalene bis(diphenyl phosphate) (DDP) were evaluated as the Antiwear additives in polyalkylene glycol and polyurea grease at 200 °C. Results showed that they could effectively reduce the friction and wear of sliding pairs compared with the cases without these additives. Furthermore, the tribological properties of NDP and DDP were generally better than the normally used tricresyl phosphate (TCP) in PAG and molybdenum disulfide (MoS2) in polyurea grease. Boundary lubrication films composed of Fe(OH)O, Fe3O4, FePO4 were formed on the worn surface, which resulted in excellent friction reduction and Antiwear performance.

M Kasrai – 3rd expert on this subject based on the ideXlab platform

  • a variable temperature mechanical analysis of zddp derived Antiwear films formed on 52100 steel
    Wear, 2007
    Co-Authors: Gavin Pereira, P R Norton, M Kasrai, Andreas Lachenwitzer, David Munozpaniagua, Weston T Capehart, Thomas A Perry, Yangtse Cheng

    Abstract:

    Abstract The nanomechanical properties of Antiwear films formed from zinc dialkyl-dithiophosphates (ZDDPs) on steel have been studied by nanoindentation techniques as a function of temperature. X-ray absorption P K- and L- near edge structure (XANES) spectroscopy has shown that films prepared from oils containing ZDDPs on 52100 steel (pin on flat coupons) consist primarily of medium chain polyphosphates with sulphur (S K-edge) predominantly present as sulphide. Using various scanning probe techniques, high-resolution topographic images and mechanical properties can be extracted at the same length scale. Using focused ion beam (FIB) milling we have compared real cross-sectional film thickness with a value estimated from the P K-edge XANES. We report the first measurements of the elastic modulus of the Antiwear films at elevated temperatures relevant to the automobile operating conditions (T ≤ 200 °C). The Antiwear films demonstrated a relatively constant indentation modulus over a wide range of temperatures consistent with their efficacy in reducing wear by preventing asperity contact.

  • nanometer scale chemomechanical characterization of Antiwear films
    Tribology Letters, 2004
    Co-Authors: Mark A Nicholls, P R Norton, G M Bancroft, M Kasrai, Than Do, B H Frazer, G De Stasio

    Abstract:

    We report the first nanometer scale chemical and mechanical (chemomechanical) characterization of selected features of a tribologically derived zinc dialkyl-dithiophosphate (ZDDP) Antiwear film. AFM permits identification of the features responsible for preventing wear. These features are identified by nearby microscale fiducial marks, and their mechanical properties are determined by imaging nanoindentation. The same features are then studied by X-ray photoelectron emission microscopy (X-PEEM), which provides both elemental and chemical information at ∼200 nm spatial resolution. The mechanical properties are then determined for the same features, which are formed of a polyphosphate glass. This information provides new insights into the mechanisms by which ZDDP Antiwears films are effective at inhibiting asperity contact between two metal surfaces

  • chemomechanical properties of Antiwear films using x ray absorption microscopy and nanoindentation techniques
    Tribology Letters, 2004
    Co-Authors: Mark A Nicholls, P R Norton, M Kasrai, B H Frazer, Michael G Bancroft, Gelsomina De Stasio, Lisa M Wiese

    Abstract:

    The first chemomechanical comparison between an Antiwear film formed from a solution containing zinc dialkyl-dithiophophates (ZDDPs) to a solution containing ZDDP plus a detergent (ZDDPdet) has been performed. X-ray absorption near-edge structure (XANES) analysis has shown a difference in the type of polyphosphate between each film. The ZDDPdet film has been found to contain short-chain polyphosphates throughout. X-ray photoelectron emission microscopy (X-PEEM) has provided detailed spatially resolved microchemistry of the films. The large pads in the ZDDP Antiwear film have long-chain polyphosphates at the surface and shorter-chain polyphosphates are found in the lower lying regions. The spatially resolved chemistry of the ZDDPdet film was found to be short-chain calcium phosphate throughout. Fiducial marks allowed for the re-location of the same areas with an imaging nanoindenter. This allowed the nanoscale mechanical properties, of selected Antiwear pads, to be measured on the same length scale. The indentation modulus of the ZDDP Antiwear pads were found to be heterogeneous, ~120 GPa at the center and ~90 GPa at the edges. The ZDDPdet Antiwear pads were found to be more uniform and have a similar indentation modulus of ~90 GPa. A theory explaining this measured difference, which is based on the probing depths of all techniques used, sheds new insight into the structure and mechanical response of ZDDP Antiwear films.