Abstract
Because the diamond-like carbon (DLC) thin film overcoat on either a hard disk surface or an air bearing surface plays an important role in maintaining the reliability and durability of the head-disk interface, nanoscale DLC wear and degradation is a critical issue in heat-assisted magnetic recording (HAMR). The use of helium in hard disk drives (HDDs) has been developed and put into practical use to decrease air-induced structural vibrations, and temperature rise. In this study, fundamental experiments were conducted to understand the wear and related degradation characteristics of an ultra-thin DLC overcoat subjected to laser heating in both air and inert gas environments, using a pin-on-disk tester. An inert gas environment was simulated using helium gas. The experiments were conducted using DLC-coated glass pins and actual magnetic disks without a lubricant film. The differences in the wear and degradation characteristics of a DLC overcoat on the pin and disk surfaces between inert gas and air environments were investigated after wear tests were performed, primarily through Raman spectroscopy. We found that wear and graphitization of DLC films became greater with laser heating, while the friction coefficients between the pin and magnetic disk became markedly smaller. However, our tests also revealed that wear and graphitization of the DLC film were significantly less in an inert gas environment than in an air environment. This is because the wear observed in this experiment was predominantly due to a wear mechanism that is based on tribo-chemical oxidation.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
References
Mate, C.M., Dai, Q., Payne, R.N., Knigge, B.E., Baumgart, P.: Will the numbers add up for sub-7-nm magnetic spacings? Future metrology issues for disk drive lubricants, overcoats, and topographies. IEEE Trans. Magn. 41(2), 626–631 (2005)
Marchon, B., Olsen, T.: Magnetic spacing trends: from LMR to PMR and beyond. IEEE Trans. Magn. 45(10), 3608–3611 (2009)
Challener, W.A., Peng, C., Itagi, A.V., Karns, D., Peng, W., Peng, Y., Yang, X.M., Zhu, X., Gokemeijer, N.J., Hsia, Y.T., Ju, G., Rottmayer, R.E., Seigler, M.A., Gage, E.C.: Heat-assisted magnetic recording by a near-field transducer with efficient optical energy transfer. Nat. Photon. 3(4), 220–224 (2009)
Tagawa, N., Andoh, H., Tani, H.: Study on lubricant depletion induced by laser heating in thermally assisted magnetic recording systems: effect of lubricant thickness and bonding ratio. Tribol. Lett. 37(2), 411–418 (2009)
Wang, Y., Wei, X., Tsui, K.L., Chow, T.W.S.: Tribological degradation of head–disk interface in hard disk drives under accelerated wear condition. IEEE Trans. Magn. 50(3), 3301007 (2014)
Waltman, R.J., Deng, H., Wang, G.J., Zhu, H., Tyndall, G.W.: The effect of PFPE film thickness and molecular polarity on the pick-up of disk lubricant by a low-flying slider. Trib. Lett. 39, 211–219 (2 010)
Yang, Y., Li, X., Stirniman, M., Yan, X., Huang, F., Zavaliche, F., Wang, H., Huang, J., Tang, H., Jones, P.M., Kiely, J.D., Brand, J.I.: Head-disk lubricant transfer and deposition during heat-assisted magnetic recording write operations. IEEE Trans. Magn. 51(11), 3300604 (2015)
Kasai, P.H., Tang, W.T., Wheeler, P.: Degradation of perfluoropolyethers catalyzed by aluminum oxide. Appl. Surf. Sci. 51, 201–211 (1991)
Liu, J., Stirniman, M.J., Gui, J.: Catalytic decomposition of perfluoropolyether lubricants. IEEE Trans. Magn. 39, 749–753 (2003)
Tagawa, N., Tani, H., Asada, H., Lu, R., Koganezawa, S.: Decomposition of perfluoropolyether lubricant on air bearing surfaces during heat-assisted magnetic recording. IEEE Trans. Magn. 53(3), 1–5 (2017)
Tani, H., Koganezawa, S., Tagawa, N.: Thermal behavior of frictional properties on ultra-thin perfluoropolyether lubricant film. Tribol. Online 11(1), 1–12 (2016)
Marchon, B., Heiman, N., Khan, M.R.: Evidence for tribochemical wear on amorphous carbon thin film. IEEE Trans. Magn. 26(1), 168–170 (1990)
Tagawa, N., Tani, H., Koganezawa, S.: Degradation of carbon overcoat subjected to laser heating in an inert gas environment in thermally assisted magnetic recording. IEEE Trans. Magn. 50(11), 3302404 (2014)
Acknowledgment
This work was supported in part by Kansai University Grant-in-Aid for the Promotion and Upgrading of Education and Research 2016, and MEXT KAKENHI Grant Number 15H02216.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2019 Springer Nature Singapore Pte Ltd.
About this paper
Cite this paper
Tagawa, N., Tani, H., Koganezawa, S., Lu, R. (2019). Nanoscale Wear of Carbon Overcoat Subjected to Laser Heating in an Inert Gas Environment. In: Abdel Wahab, M. (eds) Proceedings of the 7th International Conference on Fracture Fatigue and Wear. FFW 2018. Lecture Notes in Mechanical Engineering. Springer, Singapore. https://doi.org/10.1007/978-981-13-0411-8_62
Download citation
DOI: https://doi.org/10.1007/978-981-13-0411-8_62
Published:
Publisher Name: Springer, Singapore
Print ISBN: 978-981-13-0410-1
Online ISBN: 978-981-13-0411-8
eBook Packages: EngineeringEngineering (R0)