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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Tribologists and Lubrication Engineers
Journal Basic Information
Journal DOI :
The Korean Society of Tribologists and Lubrication Engineers
Editor in Chief :
Volume & Issues
Volume 15, Issue 4 - Dec 1999
Volume 15, Issue 3 - Sep 1999
Volume 15, Issue 2 - Jun 1999
Volume 15, Issue 1 - Mar 1999
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Electrorheological Properties of Phosphoric Ester Cellulose ER Fluids on the Elevated Temperature
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 8~16
The electrorheological (ER) behavior of suspensions in silicone oil of phosphoric ester cellulose powder (average particle size : 18
) was investigated on the elevated temperature up to 10
. For development of anhydrous ER fluids using at wide temperature range, it should be researched to how the effect of temperature on the ER activities. As a first step, the anhydrous ER suspensions mixing with the phosphoric ester cellulose particles which were made from the phosphoric ester reaction of cellulose were measured. As increasing the temperature, not only the analysis of electrical properties such as dielectric constant current density and electrical conductivity but also the rheological properties of ER fluids were studied. From the experimental results, the temperature had a large influence to the ER properties of anhydrous ER fluids. The current density, conductivity and elecoorheological effect (
) of phosphoric ester cellulose ER fluids were proportional to the temperature with power law. And the shear stress of them was closely related with the square of dielectric constant mismatch parameter (
) under constant shear rate and electric field.d.
On the Design Parameters of Gerotor Hydraulic Motors
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 17~23
A Gerotor hydraulic motor is a planar mechanism consisting of a pair of rotors one of which encloses another rotor. The motion of the inner-rotor relative to the outer-rotor is produced by the pressure difference between the adjacent chambers. A design method of inner-rotor tooth profile using unit tangential vectors is presented in this work. Based on the relationships derived, the influence of the eccentricity of inner-rotor and the radius of circular arc tooth on the flow rate, torque and curvatures were investigated. It was shown that the flow rate and mean torque is proportional to eccentricity, but inversely proportional to the radius of circular arc teeth. Also, the maximum value of the equivalent curvature is increased as the eccentricity and the radius of circular arc teeth increased.
A Study on the Parallel Line Pivoted Pad Thrust Bearing
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 24~28
This paper describes a new pivoting technique to improve bearing performance in pivoted pad thrust bearings. This new technique adjusts the pivot line in a line pivoted pad thrust bearing to be parallel to the trailing edge of a sector shaped pad. Bearing performance factors such as load carrying capacity, frictional torque and flow rate are numerically investigated for conventional point-pivoted and line-pivoted pads and for the new parallel-line pivoting technique. It is shown that the load carving capacity can be maximized with the new technique.
Investigation of Micro-tribological Properties of Coated Silicon Wafer under Light Load
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 29~38
In recent years, the tribological behavior of coated ceramic material has been the issue of much interest. Particularly, the understanding of the tribological performance of thin film under light load is important for its potential in applications of MEMS. The friction and wear behavior of ceramic material that occur at light load depends on several factors such as surface roughness, contact area and material properties. In this work, the tribological behavior of coated silicon under light load and low speed was investigated. Particularly, the effects of coated materials, humidity and undulated surface were also studied. The results show that the effect of humidity on fiction was influenced by the apparent area of contact between the two surfaces. Also both adhesive and abrasive wear occurred depending on the sliding condition. Finally, undulations on the silicon wafer were found to be effective in trapping wear particles and resulted in the reduction of friction.
Evaluation of Wear Chracteristics for
Sprayed on Casted Aluminum Alloy
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 39~45
The wear behavior of
deposited on casted aluminum alloy (ASTM A356) by APS (Air Plasma Spray) against SiC ball has been investigated in this work. Wear tests were carried out at room temperature. The friction coefficient of
coating is lower than that of pure
coating indicated the existence of the optimal coating thickness. It is found that voids and pores of coating surface resulted in the generation of cracks, and the cohesive of splats and the porosity of surface play a role in wear characteristics. It is suggested that the mismatch of thermal expansion of substrate and coating play an important role in wear performance. Tension and compression under thermo-mechanical stress may be occurred by the mismatch between thermal expansion of substrate and coating. The crack propagation above interface is observed in SEM.
Lateral Crack in Abrasive Wear of Brittle Solids
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 46~51
An analytical model about lateral crack occurring in abrasive wear of brittle solids is developed. Stress field around the lateral crack and stress intensity factor at the crack tip are analytically modeled. Abrasive wear by abrasive particle is experimentally studied. In soda-lime glass, it is observed that chipping by lateral crack occurs and produces the greatest material removal when normal load applied by the abrasive particle is about 1.5∼3.0 N. The prediction of lateral crack length from the model is compared with the experimentally measured length in soda-lime glass.
A Study on the Microscopically Characteristics of Properties of the Magnetic Recording Disk
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 52~58
Nano-indentation and nano-scratch tests were peformed to assess the mechanical and tribological properties of the coating on a commercially available thin-film magnetic recording disk. Surface topography and roughness of the disk was studied using atomic force microscopy. The hardness and elastic modulus data show a peak at an indentation depth equivalent to the thickness of carbon overcoat, indicating strong influence of the coatin
strate interaction and the coating surface roughness on the measurements. The variations of surface roughness data were analysed statistically based on the normal probability distribution theories and Weibull cumulative probability theories.es.
Preparation and Erosion Properties of Reaction-Bonded SiC Reinforced by Carbon Fiber
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 59~67
Three kinds of reation-bonded SiC that reaction-bonded SiC(RBSC), RBSC reinforced by carbon fiber and RBSC reinforced by activated carbon fiber were prepared for investigating the change of erosion properties. The characteristics of microstructures and the phases have been investigated by using scanning electron microscope and XRD analysis. The hardness test toughness test and erosion test was carried out. In the cases with no carbon fiber, those kind of specimens had the highest value of hardness and the lowest value of toughness. With the increase of carbon fiber content the hardness and the weight loss were decreased, but the toughness was increased in the cases with carbon fiber. In the cases with activated carbon fiber specimens had the highest value of toughness and the lowest value of hardness with 30% contents of activated carbon fiber.
Nonlinear frequency Response Analysis of Hydrodynamic Journal Bearing Under External Disturbance
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 68~76
This paper presents the nonlinear characteristics of the oil lubricated hydrodynamic journal bearing. The traditional approach is to characterize the behavior and performance of fluid film hydrodynamic journal bearings by means of linearized bearing analysis. The objective of this paper is to examine the nonlinear characteristics of the journal bearing when an external sinusoidal shock is given to the system. The oil film force is obtained by solving the finite width Reynolds equation at each time step by the solution of the column method. Frequency response function and journal orbit obtained from both linear and nonlinear bearing simulations are compared with each other.
Solid Lubricant and Its Application to Ball Bearing
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 77~82
The processing conditions fur the synthesis of platelet W
lubricant powder through a solid-gas reaction were optimized. The mixture of tungsten and sulfur powders were sealed in a vacuum of 10
torr, prior to heat-treating at 85
fur 8 days. The reaction product showed a well-developed platelet W
powder with an average size of 3.8
. The TGA/DTA analysis of the synthesized W
powder was performed up to 120
at a rate of 1
/min in flowing air (100
/min) atmosphere. The weight loss was about 6% up to 120
compared to the original weight. A rapid weight loss of about 5% occurred in the temperature range of 44
and an exothermic peak observed due to the transition of W
. The synthesized W
powder was coated on the commercial deep grooved ball bearing (No. 6203) to examine the effect of W
, coating layer on the noise and endurance of the ball bearing. The level of noise obtained from W
, coated-ball bearing (56 ㏈) was higher. than the value (32 ㏈) occurred in the case of greece lubrication. The endurance of the ball-bearing assembled after the coating of W
powder onto each part increased 50 times compared to the non-coated ball-bearing..
Comparison of Fretting Wear Characteristics of Zircaloy-4 Tube in Light Water and in Air
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 83~89
The fretting wear behaviour of Zircaloy-4 tube used as the fuel rod cladding in PWR nuclear power plants has been investigated at the different test environment, in light water and in air as a function of slip amplitude, normal load, test duration and frequency. Zircaloy-4 tubes were used for both of oscillating and stationary specimens. A fretting wear tester was designed to be suitable for this fretting test. The wear volume and specific wear rate of Zircaloy-4 tube in water was greater than those in air under various slip amplitude. Delaminates and surface cracks were observed at low slip amplitude and high load of fretting test in water, but the traces of adhesion and plowing were observed at and above 200 Um. The water accelerates the wear of Zircaloy-4 tube at lower slip amplitude in fretting.
Analysis of the Lubricational Characteristics for Chemical-Mechanical Polishing Process
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 90~97
Chemical-Mechanical Polishing (CMP) refers to a material removal process done by rubbing a work piece against a polishing pad under load in the presence of chemically active, abrasive containing slurry. CU process is a combination of chemical dissolution and mechanical action. The mechanical action of CMP involves tribology. The liquid slurry is trapped between the wafer (work piece) and pad (tooling) forming a lubricating film. For the first step to understand material removal rate of the CMP process, the lubricational analyses were done with commercial 100mm diameter silicon wafers to get nominal clearance of the slurry film, roll and pitch angle at the steady state. For this purpose, we calculate slurry pressure, resultant forces and moments at the steady state in the range of typical industrial polishing conditions.
Effects of Oil Supply into Inner Film on Performance of Floating-Ring Journal Bearing
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 98~107
In this work the effect of pressure drop at inner film due to centrifugal forces acting on the lubricating fluid is investigated for static and dynamic characteristics of floating ring journal bearing. The momentum effect of oil supply into a inner film through oil feeding holes of floating ring on the bearing performance is also studied. It is compared the pressure drop effects and the momentum effect of oil supply into a inner film fur all bearing performance parameters. It is shown that some performance of floating ring bearings can be controled by the momentum of oil supply into a inner film.
Oil-impregnated Sintered-metal Bearing and Herringbone-grooved Fluid Bearing for High-speed Scanner Motors
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 15, issue 1, 1999, Pages 108~115
The electrical and frictional properties of oil-impregnated sintered-metal bearing (OSB) and herringbone-grooved fluid bearing (HFB) with varying loads and speeds were measured. OSB shows very good performance up to 20,000 rpm and 0.05 N, and HFB successfully works up to 35,000 rpm and 0.05 N. From the endurance tests on start-stop and continuous operation, it was confirmed that those bearings could be mass-produced fur use on scanner motor in a laser scanner unit.