1203 Tribology Properties of Ultra Thin Lubricant Film on Magnetic Disk by Pin-on-disk Test

2012 ◽  
Vol 2012.87 (0) ◽  
pp. _12-3_
Author(s):  
Toshiya MITSUTOME ◽  
Hiroshi TANI ◽  
Norio TAGAWA
Author(s):  
Sahar Ghatrehsamani ◽  
Saleh Akbarzadeh

Wear coefficient and friction coefficient are two of the key parameters in the performance of any tribo-system. The main purpose of the present research is to use continuum damage mechanics to predict wear coefficient. Thus, a contact model is utilized that can be used to obtain the friction coefficient between the contacting surfaces. By applying this model to the continuum damage mechanics model, the wear coefficient between dry surfaces is predicted. One of the advantages of using this model is that the wear coefficient can be numerically predicted unlike other methods which highly rely on experimental data. In order to verify the results predicted by this model, tests were performed using pin-on-disk test rig for several ST37 samples. The results indicated that the wear coefficient increases with increasing the friction coefficient.


2021 ◽  
Vol 63 (2) ◽  
pp. 143-150
Author(s):  
Torben Buttler ◽  
Jens Hamje ◽  
Rolf Reiter ◽  
Volker Wesling

Abstract During polymer extrusion there are a variety of situations in which the screwthread of the extrusion screw has an unlubricated metal-to-metal contact with the barrel wall. At the same time the screw coating is subjected to the highest loads. The combination of a secondary hardening cold work steel 1.2379 and a chromium nitride coating deposited by ARC-PVD, which is frequently used in polymer processing, is characterized and investigated. The characterization is done by metallographic examination, SEM and CLSM. The tests were performed on a pin-on-disk and a pin-roll test rig. Different roughness levels were tested on the pin-on-disk test, where massive differences in wear behavior were found. A hybrid surface structure is proposed to optimize the tribosystem. On the pin-on-disk test stand, rollers made of the same material pairing were tested. The test speed was varied to highlight differences and similarities between the tribological systems. A wear minimization of 50 % was achieved and the similarities between the tribological systems were highlighted. In addition, the investigations led to the development of a new model thesis which provides a reason for the development of stippling on the screw when processing polycarbonate.


2011 ◽  
Vol 672 ◽  
pp. 17-22 ◽  
Author(s):  
Mario Rosso ◽  
Eva Dudrová ◽  
Marco Actis Grande ◽  
Róbert Bidulský

The present paper is focused on the wear characteristic of vacuum sintered Cr-Mo-[Mn]-[Cu] steels. The effect of chemical composition and the processing conditions in a vacuum furnace were evaluated. In such furnaces the cooling rate is generally determined by the pressure of the gas (N2) introduced into the chamber, the average cooling rates were calculated in the range of 1240°C to 400°C. The wear characteristics were analyzed as function of the processing and microstructures of the tested alloys through pin on disk test. Sintering of specimens in vacuum together with rapid cooling resulted in the formation of dominant martensitic microstructures with some small bainitic areas. The effect of both surface hardness and microstructure on the wear behaviour of the investigated steels shows the relation between the hardness and the wear rate. The influence of processing condition on the amount of martensite is also presented.


Author(s):  
Kenji Yanagisawa ◽  
Youichi Kawakubo ◽  
Masato Yoshino

In Hard Disk Drives, lubricants are very important materials to reduce head and disk wear. Therefore, it is necessary to know the lubricant depletion under flying heads. Lubricant depletion due to flying heads has been studied experimentally. We developed simulation program to calculate numerically the change in lubricant thickness under a flying head on a thin-film magnetic disk from 10nm thick lubricant film. In recent HDDs, the lubricants thickness has become molecularly thin and polar lubricants have been used. In this paper, we took account of thickness-dependent lubricants diffusion and viscosity in our simulations to calculate a 1.2 nm thick polar lubricant film used in recent HDDs. The simulated results considering the thickness-dependent diffusion and viscosity showed that depletion was small in molecularly thin lubricant films. We considered it necessary to include thickness-dependent diffusion and viscosity in lubricant depletion simulation.


2012 ◽  
Vol 188 ◽  
pp. 422-427 ◽  
Author(s):  
Iosif Hulka ◽  
Viorel Aurel Şerban ◽  
Kari Niemi ◽  
Petri Vuoristo ◽  
Johannes Wolf

The aim of the work was to study the microstructure and wear properties of fine-structured HVOF and HVAF sprayed WC-10Co-4Cr coatings prepared from powder having submicron-sized tungsten carbides. The coatings were deposited by HVOF (High Velocity Oxygen Fuel) and HVAF (High Velocity Air Fuel) using propane as a fuel gas in both processes, and using oxygen or air as oxidizing gas for combustion, respectively. Nitrogen was used as carrier gas for the powder. Commercially available agglomerated and sintered cermet powder with main carbide sizes under 500 nm was used in this study. Scanning electron microscopy (SEM) and X-ray diffraction were performed in order to characterize the powder and the microstructures formed during the spraying processes. The microhardness HV0.3 of the coatings was investigated and the pin on disk test was used to determine the sliding wear behaviour. The rubber wheel abrasion test was performed in order to determine the abrasion wear resistance of the coatings.


2019 ◽  
pp. 1-12
Author(s):  
C. F. Onyeanusi ◽  
S. C. Nwigbo ◽  
N. B. Anosike ◽  
C. A. Nwajude

Friction and wear control of movable parts in machines remain a critical challenge in the industries. Determination of measurement to control this often involves both the material and the lubricant. A wear test experiment using pin-on-disk apparatus to determine the wear pattern on a sample of aluminium and copper materials, lubricated with vegetable oil of palm kernel origin was conducted. Wear parameters, which include frictional coefficient, wear rate, and heat generation (temperature) were evaluated alongside thermal stress-strains on the pin on disk. Results showed that under the same conditions, the coefficient of friction reduces with the application of lubricant up to 84% and 7% for aluminium and copper respectively. The wear pattern for both materials when lubricated were evaluated and compared with dry condition to establish the relationships.


Author(s):  
Mark Chong Wai Lup ◽  
Sujeet K. Sinha ◽  
Seh Chun Lim

This paper aims to model abrasive wear for polymers using intersecting scratching technique. Scratch test and pin-on-disc test were conducted on five different polymers. Wear debris generated by intersecting scratching test was compared and correlated with the specific wear rates of the same polymers in a pin-on-disk test using ground steel surface as the counterface. It is the purpose of this paper to establish that an intersecting scratching test can be used as a means to qualitatively and quantitatively characterize wear performance of polymers.


Sign in / Sign up

Export Citation Format

Share Document