Novel Ionic-Liquid-Type Lubricant for Heat-Assisted Magnetic Recording System

Hatsuda, Kouki; Tano, Nobuo; Tani, Hiroshi

doi:10.1109/tmag.2019.2918473

Cited by 4 publications

(5 citation statements)

References 14 publications

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“…Indeed, some ILs have recently been evaluated as candidates of media lubricants in HDDs. [14][15][16][17] However, a high surface tension and a low bonded ratio (i.e., weak interaction between the lubricant and the substrate) have been shown to be the major challenges. To date, the advantages of IL lubricants over PFPEs are yet to be demonstrated.…”

Section: Introductionmentioning

confidence: 99%

“…Notably, ILs, on the other hand, are promising as next‐generation media lubricants due to their high thermal stability, nonvolatility, and small size of ion pairs. Indeed, some ILs have recently been evaluated as candidates of media lubricants in HDDs 14–17 . However, a high surface tension and a low bonded ratio (i.e., weak interaction between the lubricant and the substrate) have been shown to be the major challenges.…”

Section: Introductionmentioning

confidence: 99%

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A functionalized ionic liquid as the next‐generation nano‐lubricant

Wang

Tirado

Yang

et al. 2022

Droplet

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Ionic liquids (ILs) have attracted intensive research interest due to their outstanding physiochemical properties. However, comprehensive design is necessary for targeted applications and has rarely been conducted. As a result, the industry‐scale application of ILs is still very limited. In this academia–industry collaborative research among the University of Pittsburgh, Virginia Tech. University, and Seagate Technology LLC, we report the design, synthesis, molecular dynamics (MD) simulation, and characterization of a nanometer‐thick IL, which contains abundant fluorinated segments and a hydroxyl endgroup, as the next‐generation nano‐lubricant for hard disk drives (HDDs). The lab‐ and industry‐level testing results indicate that the IL lubricant performs significantly better than the state‐of‐the‐art lubricant, that is, perfluoropolyether (PFPE) that has been utilized for three decades in the HDD industry in two key functions: thermal stability and fly clearance. Meanwhile, the IL lubricant also shows excellent lubricity and durability. The outstanding performance of the IL has been attributed to its unique molecular structure on the solid substrate, which is supported by MD simulation results. Our work establishes the IL as a promising candidate among the next‐generation media lubricants in HDD industry. Meanwhile, the finding obtained here has important implications in many other applications involving nano‐lubricants.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A functionalized ionic liquid as the next‐generation nano‐lubricant

Wang

Tirado

Yang

et al. 2022

Droplet

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“…Palacio et al studied [Bmim][PF 6 ] and [Bmim][OctSO 4 ] as ultrathin lubricants for potential applications in NEMS/MEMS, HDDs, and digital micromirror devices because of the excellent electrical and thermal conductivity of the ILs. ,− Zhu et al studied nanometer-thick ILs with 3-butyl-1-methylimidazolium ([Bmim]) cations and concluded that high hydrophobicity of ILs leads to lower friction . Hatsuda et al investigated the lubrication of magnetic media using thin DBU- and TBD-based protic ILs. , Gong et al demonstrated the potential of nanometer-thick ILs with fluorinated tris(pentafluoroethyl)trifluorophosphate ([FAP]) anions for lubrication in heat-assisted magnetic recording (HAMR) . Lertola et al reported that ILs with lower surface tension have better tribological properties when confined to charged solid surfaces .…”

Section: Introductionmentioning

confidence: 99%

“…19 Hatsuda et al investigated the lubrication of magnetic media using thin DBU-and TBDbased protic ILs. 20,21 Gong et al demonstrated the potential of nanometer-thick ILs with fluorinated tris(pentafluoroethyl)trifluorophosphate ([FAP]) anions for lubrication in heatassisted magnetic recording (HAMR). 5 Lertola et al reported that ILs with lower surface tension have better tribological properties when confined to charged solid surfaces.…”

Section: Introductionmentioning

confidence: 99%

Highly Fluorinated Ionic Liquid Films as Nanometer-Thick Media Lubricants for Hard Disk Drives

Wang

Moran

Tang

et al. 2020

ACS Appl. Nano Mater.

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Ionic liquids (ILs) are promising candidates for the nextgeneration nanometer-thick lubricants in hard disc drives (HDDs) because of their excellent physiochemical properties and low monolayer (ML) thicknesses. However, the commercially available ILs have higher surface tension and higher friction than the state-of-the-art perfluoropolyether (PFPE) lubricant. In the current study, a fluorinated IL (FIL) lubricant, which contains cations with highly fluorinated alkyl chains, has been successfully synthesized. The surface tension of FIL is comparable to that of PFPE, which is ideal for enhancing the tribological performance of the FIL lubricant. The thermogravimetric analysis results showed that FIL has higher thermal stability than PFPE Ztetraol. Atomic force microscopy revealed that because of the intrinsically smaller molecular size of FIL, the ML thickness is only ∼50% of that of Ztetraol, which is expected to induce a lower lubricant thickness and higher areal density. Compared to the commercially available ILs, reduced friction of the nanometerthick FIL lubricant on carbon overcoat was also achieved because of its intrinsically lower surface tension. Our results demonstrate that FIL has great potential for application as the next-generation media lubricant in HDDs.

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“…When chemical structure of the IL is optimized, the monolayer thickness of the IL compare with that of multidentate PFPE is of great interest. There are several other reports on the use of ILs as lubricants for magnetic disk [16][17][18][19][20][21], the motivation of those studies is applying the ILs in the next generation of recording systems: heat assisted recording system (HAMR) because the thermal stability of ILs are high. Several attractive data seems to be obtained, however basic ultrathin film properties are necessary to use IL in this practrical application, since there are many specification on the current hard disk drive to ensure a relaiable head-disk interface.…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid Lubricant for Ultra-Low Head-Media Spacing in Hard Disk Drives

2020

Self Cite

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In order to attain high recording density in a hard disk drive, reduction of the head-media spacing (HMS) is crucial. The contribution of lubricant thickness to the HMS is a significant factor in performance. Because the lubricant thickness is on the order of angstroms, molecules of long-chain lubricants, such as perfluoroether, must lay parallel to the magnetic disk surface to reduce lubricant thickness. In this study, new lubricants were designed using ionic liquids (ILs). The ILs had smaller molecular weight than that of current perfluoropolyether (PFPE) lubricants but with lower evaporation loss. The molecular conformation of the ILs was controlled by two hydroxyl groups, which were placed in a cation moiety at both terminal ends (IL-1) or placed on one side of the cation (IL-2). The monolayer thickness of IL-1 and IL-2 was seen to be 0.6 nm and 1.2 nm, respectively. The adhesion force at a lubricant thickness of 1.0 nm decreased in the order: PFPE (Z-Dol 2000) > IL-2 > IL-1. The small adhesion force, which is one of the essential parameters for low flight of a magnetic head, was achieved by changing the molecular conformation of the IL.

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Novel Ionic-Liquid-Type Lubricant for Heat-Assisted Magnetic Recording System

Cited by 4 publications

References 14 publications

A functionalized ionic liquid as the next‐generation nano‐lubricant

A functionalized ionic liquid as the next‐generation nano‐lubricant

Highly Fluorinated Ionic Liquid Films as Nanometer-Thick Media Lubricants for Hard Disk Drives

Ionic Liquid Lubricant for Ultra-Low Head-Media Spacing in Hard Disk Drives

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