Effect of heat treatment on the lubricating properties of lithium lubricating grease

Pan, Jiabao; Cheng, Yanhai; Yang, Jinyong

doi:10.1039/c5ra08917d

Cited by 21 publications

(5 citation statements)

References 25 publications

(54 reference statements)

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“…5, indicating that there was change of chemical property in the same functional group. This results similarly reported by Jiabao et al [9] where physical property of their tested greases changed without considerable change in the chemical property, was analyzed using FTIR. Lubricant and FAME derived from thickeners and additive were analyzed in the GC-MS. Colloidal aqueous layer was present during extraction using heptane in the sample preparation of NOEM2, NOEM3 and Prop1, which was probably attributed to emulsion of short-chain methyl esters that dissolved in water.…”

Section: Corrosive and Safetysupporting

confidence: 84%

Grease Quality Issues on Middle Voltage Switchgear: Corrosivity, Resistivity, Safety and Ageing

Mahmud¹,

Sanuri²,

Razali³

et al. 2019

IIUMEJ

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Grease products recommended by OEM for conventional 11kV switchgears are generally trusted. Some disadvantages might however exist among them or their supply could be insufficient and lead to use of non-OEM-recommended grease. This paper reports analysis methods to evaluate both types of grease that were recently used in the switchgears at local electrical distribution stations owned by Tenaga Nasional Berhad. Hardened, greenish and severely irritating greases probably caused by incompatible compounding, electrochemical reaction, and hazardous components, respectively, were among common problems faced by workers. Eight physical tests and four chemical tests were conducted on 10 grease samples using thermogravimetry, switchgear rig, gas chromatography and infrared spectroscopy besides other equipment and standard methods. Grease stability, oil bleeding, flammability of grease droplet and dropping point were among the characteristics determined in the analyses. The results reveal copper corrosion, chemical change, instable and inconsistent grease, and toxics in grease, which surprisingly included the OEM-recommended one. ABSTRAK: Produk gris yang disyorkan oleh Pengeluar Peralatan Asal (OEM) bagi gear-suis konvensional 11 kV secara umumnya dipercayai ramai. Kemungkinan terdapat kekurangan pada produk-produk tersebut ataupun bekalan gris mereka yang tidak mencukupi telah mendorong kepada penggunaan gris yang tidak disyorkan oleh OEM. Kaedah analisis kajian ini melaporkan tentang kedua-dua jenis gris yang kebelakangan ini digunakan oleh Tenaga Nasional Berhad pada gear-suis di stesen pencawang elektrik. Gris mengeras, berlumut dan menjengkelkan mungkin disebabkan oleh sebatian bahan yang tidak sesuai, tindak balas elektrokimia dan komponen yang tidak selamat, masing-masing adalah antara masalah yang dihadapi oleh para pekerja. Lapan ujian fizikal dan empat ujian kimia telah dijalankan pada 10 sampel gris menggunakan termogravimetri, pemakai gear-suis, kromatografi gas dan spektroskopi inframerah selain alatan lain dan kaedah-kaedah piawai. Antara ciri-ciri yang dikaji dalam analisis ini adalah kestabilan gris, sifat lelehan minyak, sifat mudah terbakar titisan gris dan takat rendah gris. Hasil kajian mendapati gris ini menyebabkan tembaga terhakis, sifat kimia berubah, sifat gris yang tidak stabil dan mudah berubah, dan juga beracun memberi kejutan kerana pihak OEM tetap mengesyorkan gris jenis ini.

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Section: Corrosive and Safetysupporting

confidence: 84%

Grease Quality Issues on Middle Voltage Switchgear: Corrosivity, Resistivity, Safety and Ageing

Mahmud¹,

Sanuri²,

Razali³

et al. 2019

IIUMEJ

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“…The speci c peak at 1560 cm − 1 and 1579 cm − 1 indicated the presence of lithium soap for the greases. [33] And the absorption band at 1746 cm − 1 indicated the ester group [34] in the MOAT. And there were -CH 2 asymmetric and symmetric stretching bands at 2959, 2923 and 2849 cm − 1 .…”

Section: Dropping Point Oil Separation and Ir Characterizationmentioning

confidence: 99%

Methyl Oleate-Alkylated Tetralin with Dual-Functional Groups as Base Oil with PAO to Improve the Performance of Lithium-Based Grease

Tang,

Zhao,

et al. 2023

Tribol Lett

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A novel dual-functional group base oil was synthesized by alkylation of methyl oleate from biomass and tetralin from coal chemical industry. Interestingly, the monoalkylated product (MOAT) exhibited low pour point, high ash point and viscosity index compared with the traditional alkyl aromatic lubricating oil (AN5), owing to the combination of the naphthenic aromatic (tetralin) and the methyl oleate framework.MOAT as co-base oil with PAO8 was studied to prepare lithium-based greases for the rst time, their rheological and tribological properties were evaluated in detail. The microstructure of the MOAT based grease displayed high entanglement of lithium ber. The 20% MOAT based grease markedly reduced friction and wear compared with PAO8 based grease and 20% AN5 based grease. The excellent tribological performances were attributed to the strong interaction between the ester group and the soap ber that provides more relative elasticity of grease and improves tribological behavior. Our nding clearly demonstrated that MOAT had the potential as a new class of base oil for obtaining high-performance lithium grease.

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“…The high temperature in the running process of roller bearings will lead to the thermal aging of grease, which is one of the most important reasons for severe local wear of roller bearings [23]. Pan et al [24] simulated the static thermal degradation of grease in a drying oven; the results show that lithium grease has better anti-friction and anti-wear properties after heat treatment at 120 • C. The temperature will affect the rheological properties and microstructure of grease [15]; it is, therefore, important to explore the rheological properties of grease at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

Rheological and Tribological Properties of Lithium Grease and Polyurea Grease with Different Consistencies

et al. 2022

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The rheological properties of lithium grease and polyurea grease at different temperatures and consistencies were determined with a rotary rheometer. The plateau moduli of the greases were calculated, and the mechanism of influence of consistency and temperature on the rheological properties of the greases was explained. The tribological and wear properties of the two greases were measured by high-temperature friction and wear tester. The friction and wear mechanisms are probed by the rheological properties of lubricating grease. The results show that the plateau modulus GN can be used to assess the structural strength of different greases, but it can only assess the degree of entanglement of the same grease. The higher the consistency of the grease, the larger the apparent viscosity, structural strength, and yield stress. The rheological properties of PAO-polyurea grease are greatly affected by temperature, but its structural strength is better than that of mineral oil-lithium grease. The consistency of mineral oil-lithium grease is expected to affect the friction coefficient and wear through its influence on the grease’s structural strength and film-forming ability. For PAO-polyurea, the consistency in a certain range has little effect on the friction coefficient and wear resistance.

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Effect of heat treatment on the lubricating properties of lithium lubricating grease

Cited by 21 publications

References 25 publications

Grease Quality Issues on Middle Voltage Switchgear: Corrosivity, Resistivity, Safety and Ageing

Grease Quality Issues on Middle Voltage Switchgear: Corrosivity, Resistivity, Safety and Ageing

Methyl Oleate-Alkylated Tetralin with Dual-Functional Groups as Base Oil with PAO to Improve the Performance of Lithium-Based Grease

Rheological and Tribological Properties of Lithium Grease and Polyurea Grease with Different Consistencies

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