• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.225-232
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• 1999

The effect of manufacturing parameters such as molding and curing conditions on friction characteristics of friction materials was studied using a pad-on-disk type friction tester. Friction materials containing 15 ingredients were investigated for an optimal manufacturing condition for the best friction characteristics employing Taguchi robust experimental design. The main effects were different for mechanical properties and friction characteristics and were strongly influenced by manufacturing conditions. An optimum manufacturing condition was obtained to achieve the best friction characteristics concerning mechanical properties(hardness, porosity, wear resistance), friction stability, and change of rotor temperature.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.310-317
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• 2000

Tribological properties of friction materials containing different volume ratios of solid lubricants (graphite and MoS$_2$) were studied using a pad-on-disk type friction tester. Morphology and thickness of the friction film were carefully examined to correlate the friction performance with the property of the friction film. Results showed that the friction materials containing 16vo1. % of graphite and 5 vol. % of MoS$_2$exhibited best friction stability among others. In particular, the thickness of the friction film decreased as the amount of MoS$_2$increased and severe friction oscillation was observed when the friction material contained MoS$_2$only (21 vol. %). Microscopic observations and friction tests suggested that the coherent thick transfer film improved the friction stability.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.535-541
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• 2023

Friction material, an integral constituent of bearing supports, facilitates frictional interactions between two components. Polytetrafluoroethylene (PTFE), a commonly employed friction material in bearing supports, has assessed resultant friction equilibrium. Nonetheless, protracted utilization diminishes frictional performance as the lubricating agent is progressively depleted. Friction materials can affect the entire structural system. Hence, this study applied ceramic material as a friction material due to its high strength, low friction, and low deformation. The frictional behavior was investigated using a cyclic friction test, considering various friction materials as the primary design variables and examining their covariance in cyclic frictional movements. The results substantiated that the ceramic friction material yielded a low variance and friction coefficients in cyclic frictional movements.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.213-218
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• 1999

Friction and wear characteristics of novolac resin-based friction materials reinforced with aramid pulp and potassium titanate were investigated by using a pad-on-disk type friction tester. Friction properties such as friction stability, surface morphology, and wear rate varied according to the relative amount of aramid pulp and potassium titanate. The friction materials reinforced with both aramid pulp and potassium titanate showed superior friction stability and wear resistance due to the formation of durable transfer layer.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.255-264
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• 1999

Friction characteristics of automotive friction materials containing different metallic fibers rubbing against Al-MMC and cast iron disk specimens have been studied. Friction materials containing aluminum, copper or low steel carbon fiber were tested. Friction tests were composed of three different phases to investigate the effect of temperature, pressure, speed, and drag time. The results showed that the friction material containing Al fibers has lower friction force and wear amount than the others with Cu or Steel fiber. On the other hand, the wear of friction material was severe in the case of using Al-MMC rotors. These results showed that the thermal decomposition of solid lubricants (and organic components), formation of transfer layer, and SiC particles in the AI-MMC rotor play crucial roles in determining the friction characteristics.

• Tribology and Lubricants
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• v.22 no.1
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• pp.1-7
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• 2006

The sliding friction and wear properties of mineral fiber reinforced composite(MF) and glass fiber reinforced composites(GF) are investigated to clarify their field of use and the role of each fiber in friction material. Friction and wear test reveals that GF composite has better wear resistance even though with low friction coefficient, comparing with MF composite. Glass fiber strengthen effectively the matrix and may absorb friction energy to convert it into the fracture energy of them, as well as its lubricative role. However, mineral fiber in MF composite is too small to strengthen the matrix. Then MF composite are easily plowed and worn out by asperity on counter material. Friction coefficient of MF composite is higher friction coefficient than that of GF composite and varied widely with test.

• Tribology and Lubricants
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• v.16 no.5
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• pp.365-372
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• 2000

Tribological behavior of novolac resin-based friction materials with three different relative amounts of graphite and zirconium silicate was investigated by using a pad-on-disk type friction tester. The goal of this paper is to examine the effects of the relative amount of a lubricant and an abrasive in the automotive friction material on friction and wear characteristics at elevated temperature. Friction and wear of friction materials were affected by the existence of transfer film(3$\^$rd/ body layer) at friction interface and the composition of friction material, especially lubricant amount. The friction material with higher content of graphite indicated homogenized and durable transfer film, and resulted in stable friction coefficient regardless of the increase in friction heat. The experimental result also showed that the higher concentration of ZrSiO$_4$ in friction material aggravated friction stability and wear resistance due to the higher friction heat generated at fiction interface during high temperature friction test.

• Tribology and Lubricants
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• v.13 no.1
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• pp.34-41
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• 1997

Frictional behavior of three automotive friction materials (brake pads) containing different amounts of antimony trisulfide ($Sb_2S_3$) and zirconium silicate ($ZRSiO_4$) were investigated using a front brake system. The friction materials were tested on a brake dynamometer (dyno) with gray cast iron rotors. The dynamometer(dyno) test simulated the dragging of a ehicle maintaining 70 km/h and vehicle stops from 100 km/h using 20 different combinations of initial brake temperature (IBT) and input pressure (IP). The results showed a strong influence of the relative amount of $Sb_2S_3$ and $ZrSiO_4$ in friction materials on friction characteristics. Friction stability was improved with the higher concentration of $Sb_2S_3$ in the friction material. Torque variation during drag cycle was increased with an increase of the $ZrSiO_4$ concentration in the friction material. Average friction coefficient and the wear rate of the friction material increased by using more aggressive friction materials containing more $ZrSiO_4$ and less $Sb_2S_3$. Generation of the disk thickness variation (DTV) increased when friction materials with higher concentration of $ZrSiO_4$ were used Careful examination of DTV change showed that aggressiveness of the friction material played an important role in determining torque variation.

• Tribology and Lubricants
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• v.33 no.1
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• pp.15-22
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• 2017

Because the running speed of vehicles is increasing and a shorter braking distance is required, high heat-resistant brake pads are needed to satisfy the requirements of customers and car makers. In the near future, hazardous materials such as Cu, Cr, Zn, and Sb will be restricted from use in friction materials. Ceramic composites reinforced by carbon fibers are good candidates for eco-friendly friction materials. In this study, we develop ceramic composite friction materials. The friction materials are composed of carbon fibers, Si, SiC, graphite, and phenol resin and are prepared by hot forming and heat treatment at high temperatures. The density, void ratio, and compressive strength are $1.59-1.66g/cm^3$, 16.6-20, and 70-90 MPa, respectively. Friction and wear tests are performed using a pin-on-plate-type reciprocating friction tester at 25, 100, and $200^{\circ}C$. The counterpart material is a CrMoV steel extracted from a KTX brake disc. Friction coefficient, wear amount, and wear mechanism are measured and examined. We determine that the friction coefficients depend on the temperature and the fluctuation of the friction coefficients is larger at higher temperatures. The amount of wear increases with the surface temperatures of the specimens. The tribological properties of the developed composites are similar to those of a Cu-based sintered friction material. Through this study, it is confirmed that ceramic composite materials can be used as friction materials.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.247-254
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• 1999

The effect of manufacturing parameters such as molding and curing conditions on friction characteristics of friction materials were studied using a pad-on-disk type friction tester. The optimal manufacturing rendition for the best friction characteristics were investigated using friction materials containing 15 ingredients employing Taguchi robust design experiment. The friction characteristics were strongly affected by pressing time, pressing temperature, pressing pressure, curing time, curing temperature.