Wear Rate Of Friction Material Research Articles

Preparation and properties of resin-based wet friction materials reinforced by SiCp/basalt fiber cloth

A new type of wet friction material was prepared by solution impregnation with phenolic resin as binder, SiC particles and basalt fiber cloth as reinforcement.The hardness, density, porosity, microstructure, tribological properties and surface roughness were analyzed. The results show that the coefficient of friction (COF) and COF stability of the prepared material is more than 0.11 and 90%, respectively, while the wear rate is 0.26 × 10−7 cm3/J. The main wear pattern of this wet friction material is resin shedding. There is no large-sized “third body” abrasive debris on the friction surface, resulting in low wear rate of friction material.

Effect of pore structure on mechanical and tribological properties of paper-based friction materials

To explore the effect of the pore structure of paper-based friction materials on the friction and wear properties, the composites with different pore structures were obtained using physical foaming technology. Results displayed that the bulk density and average pore size of composites increased after the foaming treatment, while the total pore area and porosity showed a tendency to gradually decrease after hot pressing. The tensile and interlaminar shear strength of the composites were improved by 18% and 42% respectively after the optimization of the pore structure. Moreover, the application of foaming technology significantly increased dynamic friction coefficient and reduced wear rate of the friction materials. In particular, the wear rate of paper-based friction materials decreased by 44.6% from 1.57x10−8 cm3/J to 0.87x10−8 cm3/J with the increase of foaming agent content. Most importantly, the pore structure of paper-based friction materials can be effectively changed due to the introduction of physical foaming technology. This research lays a solid foundation for optimizing the pore structure of paper-based friction materials in the future.

Tribological Behavior of CF/PTFE Composite and Anodized Al-Rotor in Traveling Wave Ultrasonic Motors

The tribological behavior of stator friction material and rotor in the traveling wave ultrasonic motor (TWUSM) shows some particularities because of the applied way and the special contact between stator and rotor. In this investigation, the tribological behavior of carbon fiber-reinforced polytetrafluoroethylene composite, which is used as stator friction material, sliding against an anodized aluminum rotor in a TWUSM is reported. The performances of TWUSM were tested, and the surface topography was examined in different stages. The results shown that the speed of USM remained stable at 120 r/min after 60 h of operating and the holding torque and stall torque tended to stabilize after 100 h. Moreover, the fluctuation of roughness of friction material was small, while the surface roughness of rotor decreased 28.8% after 10 h of operating. Both the roughness of friction material and rotor tended to stabilize after 100 h of operating. The wear mechanisms of stator friction material in steady wear stage were found to be adhesive wear and plastic deformation, which was quite different from that of rotor friction material. The wear rate of friction material decreased with time, and wear 1 μm of height required approximately 68 h. The surface topography of rotor changed little, and the wear height after 200 h of operating was less than 2 μm.

철도차량용 금속계 소결마찰재의 조성에 따른 트라이볼로지 특성

Graduate School of Railroad, Seoul National University of Science and Technology(Received September 22, 2014; Revised November 10, 2014; Accepted November 17, 2014)Abstract − Sintered metallic brake pads and low alloy heat resistance steel disks are applied to mechanical brake sys-tems in high energy moving machines that are associated with recently developed 200km/h trains. This has ledto the speed-up of conventional urban rapid transit. In this study, we use a lab-scale dynamometer to investigatethe effects of the composition of friction materials on the tribological characteristics of sintered metallic brakepads and low alloy heat resistance steel under dry sliding conditions. We conduct test under a continuous pressureof 5.5 MPa at various speeds. To determine the optimal composition of friction materials for 200 km/h train, wetest and the evaluate frictional characteristics such as friction coefficients, friction stability, wear rate, and thetemperature of friction material, which depend on the relative composition of the Cu-Sn and Fe components. Theresults clearly demonstrate that the average friction coefficient is lower for all speed conditions, when a largequantity of iron power is added. The specimen of 25 wt% iron powder that was added decreased the wear ofthe friction materials and the roughness of the disc surface. However when 35 wt% iron powder was added, thedisc roughness and the wear rate of friction materials increased By increasing the amount of iron powder, thesurface roughness, and temperature of the friction materials increased, so the average friction coefficientsdecreased. An oxidation layer of Fe

디스크 질량 변화에 따른 철도차량용 제동디스크의 마찰 특성

Low alloy heat resistant brake disk and sintered brake pad are applied to mechanical brake system for the speed-up of urban rapid transit. In this research, we analyzed how the frictional characteristics between brake disk and pad are influenced by the disk mass. At a high disk mass, the friction stability was the lower value as a result of the lack of tribofilm formation at the disk surface. Wear rates of friction materials showed the higher value at a low disk mass and wear rates of 10 mm and 15 mm showed the similar level. Average friction coefficient was the lower value at the 10 mm disk thickness and range of variation of average friction coefficient was also the smaller value at the 10 mm disk thickness. However, there were no significant changes in the friction coefficients under any of test conditions. Surface roughness of a disk showed the highest value at the 5 mm disk and surface roughnesses of 10 mm and 15 mm showed the similar level. As a result, friction characteristics of disk mass influenced the friction stability, as well as the wear rate of friction pad and disk, but not the friction coefficient.

Research on the Performance Influence of Second Adhesive to Friction Materials

The friction materials have many species and they are being used widely, but people have higher requests to friction materials along with the development of technology. the friction material of this expermental optimization formula have the advantages of suitable and stable friction coefficient under high temperature, low wear rate, good restoration characteristics and so on. It can effcetively reduce heat fade of friction and wear under high temperature barking. fricton and wear performance of friction material with second adhesive is better than common preparation friction material , it has higher friction coefficient and lower wear rate, It was determined by physical chemical properities of tin and sulfer. while heating or wearing, the temperature of friction material reach melting temperature of tin, it will become molten state, and sulfer has strong oxidation, on the one hand, tin and sulfer occurred chemical reaction, generating sulfide, stannous (one sulfide tin),on the other hand, while the sulfer is being molten state, it will absorb some abrasive dust, at the same time of generating sulfide, abrasive dust will be adsorb and solidify to pits of friction surface, forming abrasive dust membrane, let the friction coefficient of sample become stable rapidly, reducing the wear rate of friction material.

Effect of pressure on tribological characteristics between sintered friction materials and steel disk

The effect pressure on tribological characteristics between sintered metallic material and low alloy heat resistance steel was investigated under dry sliding condition with lab-scale dynamometer. Tests were conducted under continuous speed at 8m/s with various pressures. The results were analyzed with SEM (scanning electronic microscopy) and X-ray diffraction. Wear rate of friction materials was change with morphology of friction surface. Stable tribolayers at friction surface affect wear rate of friction material. Tribolayer which formed both friction surfaces was Fe2O3. Contact temperature was as high as 385°C at 1.0MPa. Also, high brake pressure promotes an increase in height difference on friction materials’ contact surface thus trap wear debris which consider to increase friction coefficient.