Media Lubricant Research Articles

SiC‐bonded diamond ceramics for extreme conditions in subsea applications

AbstractExtremely reliable and wear‐resistant components are required for subsea pump applications. For this purpose, materials and components were developed and qualified within the framework of a joint project1, which under media lubrication with water containing particles, exhibit the highest possible wear resistance and can thus achieve the longest possible service life. The developed SiC‐bonded diamond ceramics have diamond contents of up to 60 % by volume and can be manufactured in the form of a solid material or as graded components containing diamonds only in the tribologically stressed areas. The results show that the investigated diamond‐containing ceramics are very suitable for media‐lubricated sliding bearings and mechanical seals in subsea applications. The friction values under media lubrication are very stable and independent of tribological loads. In mechanical seal application, SiC‐bonded diamond shows significantly better friction performance than the reference material SiC. An outlook is given on demonstrator tests that are currently in preparation.

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

AbstractIonic 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.

The challenges of developing ionic liquids as tribological lubricants for thin film media

Ionic liquids (ILs) could be promising candidates for heat-assisted magnetic recording media due to their extraordinary properties such as considerably thinner monolayer (ML) thickness and extremely good thermal stability. In this paper, the physical properties and mechanism clearance of some novel fluorinated ILs were investigated through several analytical technologies including contact angle, FTIR, XPS, AFM, TGA and Candela OSA. Although the ML thickness of the ionic lubricants was confirmed only 50 – 60 % of that of conventional PFPEs, their evaporation performance as two-dimension lubricant nanofilm is significantly inferior to conventional PFPEs. In addition, the greater surface energy of ILs vs conventional PFPE lubricants, resulting in their poor mechanical clearance. The findings here reveal critical challenges in the developing of ionic lubricants for thin film magnetic media and may serve as guidance for the future design of ILs as media lubricants.

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

Ionic liquids (ILs) are promising candidates for the next-generation nanometer-thick lubricants in hard disc drives (HDDs) because of their excellent physiochemical properties and low monolayer (ML...

Students’ preconceptions of the context of magnetic media lubricants and the related chemical contents

This study aims to analyze students’ preconceptions regarding the context of magnetic media lubricants and chemical content related to the context, as the basis for didactic design development that can teach technological aspects in high school chemistry learning. Descriptive research methods are used in explaining the results of the research obtained. This study involved 40 students from one of the high schools in the city of Bandung. The preconception test questions are based on a magnetic media lubrication enrichment book that was previously developed by researchers, which contains the context of magnetic media lubricants with chemistry contents are transition metals, chemical bonds, and intermolecular forces. Student answers are analyzed using a frequency distribution to categorize the criteria of conceptual understanding of each question and the answers are analyzed for errors to show learning obstacles that might arise in learning. In general, the results show that students still have a limited understanding. Therefore, it is necessary for educators to develop a didactic design based on the findings of student learning obstacles so as to be able to integrate technology in science learning comprehensively and optimally.

Nanometer-Thick Fluorinated Ionic Liquid Films as Lubricants in Data-Storage Devices

Media lubricants are critical to the reliability of hard disc drives (HDDs). Ideally, the lubricant should have high thermal stability and low monolayer (ML) thickness. Unfortunately, the state-of-...

Study on Nanometer-Thick Room-Temperature Ionic Liquids (RTILs) for Application as the Media Lubricant in Heat-Assisted Magnetic Recording (HAMR)

Nanometer-thick room-temperature ionic liquids (RTILs) have been studied for potential application as media lubricants for heat-assisted magnetic recording (HAMR) in the hard disk drive (HDD) industry. The RTILs containing fluorinated anions are readily solvable in Vertrel XF solvent and can be applied on the media by dip-coating, which is compatible to the current industry process. The thermal stability, topography and tribological performance of the RTILs nanofilms have been characterized by thermogravametric analysis (TGA), ellipsometry, atomic force microscopy (AFM) and nanotribometry. The experimental results showed that RTILs are thermally more stable than the state-of-the-art media lubricants in HDDs, i.e., perfluoropolyethers (PFPEs) such as diolic perfluoropoly(oxyethylene-ran-oxymethylene) commercially known as Zdol. The lubricant uniformity of most studied RTILs is better than that of Zdol, and no dewetting is observed even when the RTIL nanofilm is as thick as 10 nm. The friction coefficient o...

Total reflection X-ray photoelectron spectroscopy as a semiconductor lubricant elemental analysis method

Photoelectron spectra from a typical hard disk storage media device (HDD) were measured at total reflection and non-total reflection at unburnished, acetone-cleaned, and argon-sputtered conditions. F, O, N, and C usually making the upper layer of a typical hard disk medium were detected. Enhancement of the photoelectron emission of the fluorocarbon lubricant was observed at total reflection. Pt and Co were only found by non-total X-ray photoelectron spectroscopy (XPS) because they are constituents of a deeper region than the top and interface regions. Argon-sputtered, ultrasonic acetone-cleaned, and unburnished top layers were compared at total and non-total reflection conditions. Total reflection X-ray photoelectron spectroscopy (TRXPS) is demonstrated to be a powerful tool for storage media lubrication layer chemical state analysis, reliable for industrial quality control application , and reproducible.

Study on the Interaction between Talc and Perfluoropolyethers under Tribological Contact

Particle contamination at the head–disk interface (HDI) is a major concern for the long-term reliability of hard disk drives. In the current study, it is shown that, surprisingly, soft and lubricious talc particles have a significant damaging effect on the friction performance of media lubricants, nanometer-thick perfluoropolyethers. Thermogravimetric analysis (TGA) and the adsorption studies indicate that two mechanisms, Lewis acid–catalyzed decomposition and surface adsorption, are responsible for the observed tribological degradation. The potential impacts of the findings here on the design of next-generation media lubricant have been discussed.

Effect of π-π+ stacking on the layering of ionic liquids confined to an amorphous carbon surface.

In the current paper, AFM studies were conducted on nanometer-thick ionic liquids (ILs) confined to an amorphous carbon (AC) surface, which is critical to the design of the next-generation media lubricant for hard disk drives (HDDs). The results indicated that the existence of the delocalized ring in the cation is critical to layering of ILs. Extended layering was observed only when there is imidazolium ring in the cation. When the imidazolium ring is replaced by an aliphatic moiety, "drop-on-layer" (dewetting) structure was observed. On the basis of the experimental results, we proposed that π-π+ stacking between sp(2) carbon in the AC and the imidazolium cation in the ILs is the key to the extended layering of ILs at the ILs/AC interface.

TOF‐SIMS analysis of media lubricant under laser irradiation for HAMR application

AbstractHeat‐assistant magnetic recording (HAMR) is a promising approach for enabling large increases in storage density of a hard disk drive. Under HAMR conditions, all hard disk components including lubricant thin film used for hard disk media should have the property of high thermal stability. This paper studies the property of a potential and current commercial lubricant under HAMR laser irradiation conditions. Through the study of the relationship between the lubricant molecular structure and the properties, guidance for new lubricant design and development has been explored. Copyright © 2010 John Wiley & Sons, Ltd.