Colloidal Stability of Metal Nanoparticles in Engine Oil under Thermal and Mechanical Load

Jendrzej, Sandra; Gökce, Bilal; Barcikowski, Stephan

doi:10.1002/ceat.201600541

Cited by 21 publications

(11 citation statements)

References 61 publications

(81 reference statements)

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“…Jendrzej et al [89] dispersed in engine oil gold nanoparticles synthesized by pulsed laser ablation. After nine months, almost no agglomeration occurred.…”

Section: Additives To Greasesmentioning

confidence: 99%

The Effect of Addition of Nanoparticles, Especially ZrO2-Based, on Tribological Behavior of Lubricants

Rylski

Siczek

2020

Lubricants

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The aim of the paper was to discuss different effects, such as, among others, agglomeration of selected nanoparticles, particularly those from zirconia, on the tribological behavior of lubricants. The explanation of the difference between the concepts of ‘aggregation’ and ‘agglomeration’ for ZrO2 nanoparticles is included. The factors that influence such an agglomeration are considered. Classification and thickeners of grease, the role of additives therein, and characteristics of the lithium grease with and without ZrO2 additive are discussed in the paper. The role of nanoparticles, including those from ZrO2 utilized as additives to lubricants, particularly to the lithium grease, is also discussed. The methods of preparation of ZrO2 nanoparticles are described in the paper. The agglomeration of ZrO2 nanoparticles and methods to prevent it and the lubrication mechanism of the lithium nanogrease and its tribological evaluation are also discussed. Sample preparation and a ball-on disc tester for investigating of spinning friction are described. The effect of ZrO2 nanoparticles agglomeration on the frictional properties of the lithium grease is shown. The addition of 1 wt.% ZrO2 nanoparticles to pure lithium grease can decrease the friction coefficient to 50%. On the other hand, the agglomeration of ZrO2 nanoparticles in the lithium grease can increase twice the friction coefficient relative to that for the pure grease.

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“…Jendrzej et al [89] dispersed in engine oil gold nanoparticles synthesized by pulsed laser ablation. After nine months, almost no agglomeration occurred.…”

Section: Additives To Greasesmentioning

confidence: 99%

The Effect of Addition of Nanoparticles, Especially ZrO2-Based, on Tribological Behavior of Lubricants

Rylski

Siczek

2020

Lubricants

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“…The dynamics of the cavitation bubble and its influence on the nanoparticle formation has been investigated by many researchers 28,[37][38][39][42][43][44] . Surprisingly, there is a lack of literature investigating cavitation bubbles in highly viscous liquids, although viscous liquids are becoming more and more interesting for LAL applications in oils 45,46 or monomers 47 through offering the possibility for one-step synthesis of colloids. For example, nanoparticles as additives in engine oil are relevant for the automotive industry, where nanoparticles are often used to enhance the tribological properties of the lubricant 46,48 .…”

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confidence: 99%

Dynamics of laser-induced cavitation bubbles at a solid–liquid interface in high viscosity and high capillary number regimes

Hupfeld

Laurens

Mérabia

et al. 2020

Journal of Applied Physics

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No unified model is available yet to explain the dynamics of laser-induced cavitation bubbles during laser ablation of solid targets in liquids, when an extremely high capillary number is achieved (>100), i.e. when the viscous forces strongly contribute to the friction. By investigating laser-induced bubbles on gold and yttrium iron garnet targets as a function of the liquid viscosity, using a nanosecond laser and an ultrafast shadowgraph imaging setup, we give a deeper insight into what determines the bubble dynamics. We find that the competition between the viscous forces and the surface tension (capillary number Ca), on the one hand, and the competition between the viscous forces and inertia (Reynolds Number Re), on the other hand, are both key factors. Increasing the viscous forces and hereby Ca up to 100 has an impact on the bubble shape and result in a very pronounced rim, which separates the bubble in a spherical cap driven by inertia and an interlayer. The temporal evolution of the footprint radius of the interlayer can be addressed in the framework of the inertiocapillary regime. For an intermediate viscosity, the thickness of the interlayer is consistent with a boundary layer equation.Interestingly, our data cannot be interpreted with simplified hydrodynamic (Cox-Voinov) or molecularkinetic theory models, highlighting the originality of the dynamics reported when extremely high capillary numbers are achieved. Upon bubble collapse, spherical persistent microbubbles are created and partly dispersed in water, whereas the high-viscous polyalphaolefines lead to long-standing oblate persistent bubbles sticking to the target´s surface, independent of the ablated target. Overall, liquid´s viscosity determines laser ablation-induced cavitation.

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“…Cavitation effects further play an important role in the field of liquid‐assisted laser applications, e.g., medical laser applications, [9, 10] laser‐micromachining, [11–13] or laser ablation in liquids (LAL) [14] . In the latter case, laser pulses are focused onto a bulk target immersed in a liquid, enabling the cost‐effective [15] production of colloids on the gram‐scale [16, 17] from a wide range of different material classes such as metals, [18–20] oxides [21–23] or alloys [24–28] in different liquids [29–32] . These synthesized nanoparticles typically are of high purity [33] and are promising materials for application fields such as biomedicine, [24, 34] catalysis, [35–38] or 3D printing [39–43] …”

Section: Introductionmentioning

confidence: 99%

“…[14] In the latter case, laser pulses are focusedo nto ab ulk target immersed in a liquid, enabling the cost-effective [15] production of colloidso n the gram-scale [16,17] from aw ide range of different material classes such as metals, [18][19][20] oxides [21][22][23] or alloys [24][25][26][27][28] in different liquids. [29][30][31][32] These synthesized nanoparticles typically are of high purity [33] and are promising materials for application fields such as biomedicine, [24,34] catalysis, [35][36][37][38] or 3D printing. [39][40][41][42][43] Generally,L AL is characterized by differentc ompeting physical and chemical phenomena that are determined by the interaction between the laser,t he target,a nd the liquid.…”

Section: Introductionmentioning

confidence: 99%

How the Physicochemical Properties of the Bulk Material Affect the Ablation Crater Profile, Mass Balance, and Bubble Dynamics During Single‐Pulse, Nanosecond Laser Ablation in Water

Kalus

Barcikowski

Gökce

2021

Chemistry A European J

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Understanding the key steps that drive the laser‐based synthesis of colloids is a prerequisite for learning how to optimize the ablation process in terms of nanoparticle output and functional design of the nanomaterials. Even though many studies focus on cavitation bubble formation using single‐pulse ablation conditions, the ablation efficiency and nanoparticle properties are typically investigated under prolonged ablation conditions with repetition rate lasers. Linking single‐pulse and multiple‐pulse ablation is difficult due to limitations induced by gas formation cross‐effects, which occur on longer timescales and depend on the target materials’ oxidation‐sensitivity. Therefore, this study investigates the ablation and cavitation bubble dynamics under nanosecond, single laser pulse conditions for six different bulk materials (Au, Ag, Cu, Fe, Ti, and Al). Also, the effective threshold fluences, ablation volumes, and penetration depths are quantified for these materials. The thermal and chemical properties of the corresponding bulk materials not only favor the formation of larger spot sizes but also lead to the highest molar ablation efficiencies for low melting materials such as aluminum. Furthermore, the concept of the cavitation bubble growth linked with the oxidation sensitivity of the ablated material is discussed. With this, evidence is provided that intensive chemical reactions occurring during the very early timescale of ablation are significantly enhanced by the bubble collapse.

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Colloidal Stability of Metal Nanoparticles in Engine Oil under Thermal and Mechanical Load

Cited by 21 publications

References 61 publications

The Effect of Addition of Nanoparticles, Especially ZrO2-Based, on Tribological Behavior of Lubricants

The Effect of Addition of Nanoparticles, Especially ZrO2-Based, on Tribological Behavior of Lubricants

Dynamics of laser-induced cavitation bubbles at a solid–liquid interface in high viscosity and high capillary number regimes

How the Physicochemical Properties of the Bulk Material Affect the Ablation Crater Profile, Mass Balance, and Bubble Dynamics During Single‐Pulse, Nanosecond Laser Ablation in Water

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