Quantification of surface orientation effect on the thermal stability of γ-Al2O3 with different morphologies

Feng, Hao; Wang, Hao; Ma, Zhejie; Wang, Shiyao; Li, Ping

doi:10.1016/j.apsusc.2022.153509

Cited by 8 publications

(3 citation statements)

References 37 publications

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“…The strong diffraction peaks appearing at 2θ = 31.4, 37.7, 39.3, 45.5, 60.3, and 66.8° corresponded to (220), (311), ( 222), (400), (511), and (440) crystal planes of the face-centered cubic (fcc) structure of γ-Al2O3, which are in good agreement with the common JCPDS (card NO. 10-0425) and no impurity peaks are observed [20,21]. The peak intensities of all samples exhibit remarkable similarity, thereby confirming their analogous crystalline nature.…”

Section: Preparation Of Al2o3 Nanoparticlesmentioning

confidence: 53%

Tribological Properties of Nano-Scale Al2O3 Particles with Different Shapes as Lubricating Oil Additives

Wang,

Wang

et al. 2024

JMSE

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Enhancing lubrication across various tribological systems in the maritime industry is essential for improving safety, efficiency, and environmental sustainability. Al2O3 nanoparticles, employed as additives in lubricating oils, demonstrate favorable tribological properties including anti-wear and anti-friction characteristics. In this work, nano-scale γ-Al2O3 particles with different shapes, i.e., nanosheet, nanorod, nanosphere, and irregular-shaped nanoparticles, were prepared and calcinated forming the same crystalline phase with nanoscale size, which dispersed well in lubricating oil. The tribological properties of Al2O3 nanoparticles as lubricating oil additives were examined using block-on-ring wear tests, and the effects of the particle shape and particle concentration were investigated. The results indicated that the frictional properties are largely influenced by the particle shape and the concentration of the Al2O3 additives, with the optimal concentration being around 0.1 wt% for each shape. The lubricating oil with nanosheet additives presented the best tribological performance, followed by those with nanorod, nanosphere, and irregular-shaped Al2O3 nanoparticle additives. Al2O3 nanosheets as the lubricating oil additives reduced the stress effect on the friction surface because of their larger bearing area and are inter-particle-sheared during sliding due to the movement of friction pairs, which can further improve the tribological properties compared to other shapes.

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Section: Preparation Of Al2o3 Nanoparticlesmentioning

confidence: 53%

Tribological Properties of Nano-Scale Al2O3 Particles with Different Shapes as Lubricating Oil Additives

Wang,

Wang

et al. 2024

JMSE

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“…Li et al analyzed the changes in phase compositions and specific surface areas of three types of γ-Al 2 O 3 materials (cluster, nanorod, and nanoplate) as a function of temperature (600–1200 °C). 81 The characterization results indicate that the proportions of exposed crystal planes differ significantly among the three γ-Al 2 O 3 materials with different morphologies. The simulated phase compositions of the samples, calcined at various temperatures, are presented in Fig.…”

Section: Morphology Control Of Alumina and Its Influence On Propertiesmentioning

confidence: 92%

Advances in morphology-controlled alumina and its supported Pd catalysts: synthesis and applications

Yang,

Miao,

Wang

et al. 2024

Chem. Soc. Rev.

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“…Intermediate aluminas are structurally based on a slightly distorted cubic closed-packed sublattice of oxygen ions [8] containing structurally ordered vacancies, stacking faults and antiphase boundaries [8][9][10]. Besides, structural defects and their thermodynamic consequences for the nucleation and growth of ordered domains in the γ matrix, phase transitions and surface properties are also affected by the morphology of the respective crystals [1,[11][12][13], leading to, e.g., a direct γ→θ transition [1]. Typically, the transition from one intermediate state to the next is not marked by a certain transition temperature but a transition range [14,15], which shows time dependence [16,17] and structural ordering [18,19].…”

Section: Introductionmentioning

confidence: 99%

Thermal Expansion and Phase Transformation up to 1200 °C of Metastable Aluminas Produced by Flame Spraying

Zienert

Aneziris

2023

Crystals

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The transition aluminas δ1 and the cubic, non-spinel-type η-Al2O3 were detected in addition to α-Al2O3 in flame-sprayed material. Their transitions from room temperature up to 1200 °C were investigated by high-temperature XRD measurements. Structural changes with time and temperature were observed for all transition aluminas (η-, δ1- and θ-Al2O3). The phases followed the expected transition sequence of η→δ1→θ→α and showed mainly linear, temperature-independent transition rates. Based on the determined thermal expansion of the phases, it is proposed that the metastable transitions are at least partly mechanically induced. In addition, a second-order phase transition from η→θ might be indicated around 1050–1075 °C by the determined trends of density.

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Quantification of surface orientation effect on the thermal stability of γ-Al2O3 with different morphologies

Cited by 8 publications

References 37 publications

Tribological Properties of Nano-Scale Al2O3 Particles with Different Shapes as Lubricating Oil Additives

Tribological Properties of Nano-Scale Al2O3 Particles with Different Shapes as Lubricating Oil Additives

Advances in morphology-controlled alumina and its supported Pd catalysts: synthesis and applications

Thermal Expansion and Phase Transformation up to 1200 °C of Metastable Aluminas Produced by Flame Spraying

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