scholarly journals Regularities of the influence of submicron ceramic powders TiO2, AlN, Cr2O3 on the tribological properties of a friction material

2021 ◽  
Vol 99 (1) ◽  
pp. 20-27
Author(s):  
A. Leshok ◽  
◽  
A. Dykha ◽  
Keyword(s):  
Friction Coefficient ◽  
Friction Material ◽  
Metallic Phase ◽  
Boundary Friction ◽  
Powder Materials ◽  
Frictional Material ◽  
Friction Materials ◽  
Composition Materials ◽  
Friction Assemblies ◽  
Experimental And Theoretical Studies

Friction units for automotive and special vehicles are designed to operate under boundary friction conditions. Modern vehicles contain friction assemblies that use friction materials. Currently, friction materials are actively used: based on thermosetting resins; pulp and paper-based materials; sintered powder materials; materials of carbon or carbon composition; materials with a ceramic matrix. The development of a unified understanding of the effect of the size and chemical nature of ceramic additives on the processes occurring in a friction material during friction is very important and can be obtained both on the basis of experimental and theoretical studies. The paper presents the results of a study of the effect of submicron TiO2, Cr2O3, AlN powders with a size of 0.2-0.5 microns on the tribotechnical properties of a frictional material based on copper intended for operation under boundary friction conditions. It was found that when using the addition of Cr2O3 powder, the greatest increase in the value of the friction coefficient is noted - from 0.042 to 0.082, a slightly smaller increase in the friction coefficient is shown by the use of AlN and TiO2 defects - 0.042-0.074 and 0.042-0.060, respectively. The least wear of the friction material was obtained when using 3.0 vol. % aluminum nitride additive - 2.1 microns / km. Increasing the addition of any of the submicron powders by more than 7 vol. % leads to a significant decrease in wear resistance. This is due to the formation on the surface of the friction material of a modified layer containing ceramic particles and the metallic phase of the friction material. For the friction material, an unstable value of the friction coefficient and increased wear were recorded

scholarly journals A new kind of resin-based wet friction material: Non-woven fabrics with isotropic fiber networks as preforms

Friction ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 92-103 ◽  
Author(s):  
Yewei Fu ◽  
Le Zhou ◽  
Tao Yin ◽  
Zhongyao Luo ◽  
Hejin Li ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Low Cost ◽  
Static Friction ◽  
Friction Material ◽  
Woven Fabrics ◽  
Mechanical And Thermal Properties ◽  
Friction Materials ◽  
Dynamic Friction Coefficient ◽  
Wet Friction ◽  
Long Fibers

AbstractAs an alternative to short fibers, non-woven fabrics (NWFs) were made using different types of long fibers to optimize the performance of paper-based friction materials and their technology. In this investigation, the fillers and resin were impregnated into these NWFs to prepare three kinds of wet friction material. The tribological, mechanical, and thermal properties of the new wet friction material were studied. The results indicate that the dynamic friction coefficient of the new friction material is approximately 0.12 and the static friction coefficient is approximately 0.15; the better wear rate is 0.81334 × 10-14 m3·(N·m)-1. In addition, the temperature for 10% mass loss yielded 100 °C enhancement and the tensile strength was improved by 200%, compared to previously reported values. Most importantly, the advantages include a simple preparation flow, low cost, and resource conservation. This is a promising approach for the future development of paper-based friction materials.

Influence of carbon nanotubes on the properties of friction composite materials

2019 ◽  
Vol 54 (16) ◽  
pp. 2101-2111
Author(s):  
Emad F EL-kashif ◽  
Shaimaa A Esmail ◽  
Omayma AM Elkady ◽  
BS Azzam ◽  
Ali A Khattab
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Friction Coefficient ◽  
Tribological Properties ◽  
Smart Materials ◽  
Arc Discharge ◽  
Weight Ratio ◽  
Friction Material ◽  
Operating Conditions ◽  
Friction Materials

Carbon nanotubes have a lot of applications in mechanical fields. This is because nanomaterials have many superior mechanical properties such as very high strength-to-weight ratio, high modulus-to-weight ratio, high corrosion resistance, and super intelligence properties, which make them as smart materials. One of these attractive applications is the use of carbon nanotubes in vehicle brake friction material. Therefore, the fabrication and testing processes of these nanomaterials should be performed carefully to evaluate their mechanical, tribological, and noise properties. In this paper, friction material mixed with carbon nanotubes have been fabricated with different carbon nanotube contents and the same fabrication parameters. The carbon nanotubes have been produced using the conventional submerged arc discharge technique. The produced friction materials have been cut into pieces with standard sizes and then tested mechanically and tribologically. The results of tests have illustrated that the addition of carbon nanotubes into the friction materials could improve their mechanical properties (hardness, strength, and modulus) and also could enhance their tribological properties (wear rate and friction coefficient). Moreover, the tests showed that the presence of carbon nanotubes in friction materials could reduce the noise, vibration of the friction materials, and reduce the temperature rise due to the effect of friction, which means that the carbon nanotubes could raise the thermal conductivity of friction material, while the friction coefficient has stayed within the allowable standard limits (0.35–0.45). Surface morphology shows that the presence of carbon nanotubes in the friction materials could help to avoid surface friction cracks or fins within the normal operating conditions. The good combination of mechanical and tribological properties was obtained at 0.5% carbon nanotubes.

Research on the Performance Influence of Second Adhesive to Friction Materials

2013 ◽  
Vol 461 ◽  
pp. 415-420
Author(s):  
Jie Peng ◽  
Yu Cheng Liu ◽  
Zhi Feng Yan ◽  
Bao Gang Wang ◽  
Fu Dong Lin ◽  
...  
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Friction Material ◽  
Molten State ◽  
Wear Performance ◽  
Friction Materials ◽  
Low Wear ◽  
The One ◽  
Better Than

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.

Burnishing Effect on Disc Brake Corrosion and Frictional Performance of Corroded Disk

2014 ◽  
Vol 66 (3) ◽  
Author(s):  
M. K. Abdul Hamid ◽  
A. M. Kaulan ◽  
A. R. Abu Bakar ◽  
W. B. Wan Nik
Keyword(s):  
Friction Coefficient ◽  
Oxide Layer ◽  
Frictional Force ◽  
Friction Material ◽  
Disc Brake ◽  
Friction Materials ◽  
Brake Torque ◽  
Disc Brakes ◽  
Frictional Performance ◽  
Brake Dynamometer

This work examined the frictional force induced by the disc brake when the disc brake gets corroded. The corrosion process was carried out on two types of disc brake labelled disc A and disc B where both disc brakes were made from gray cast iron but having different design. Both discs were burnished with two types of friction materials labelled P-1 and P-2 before they were exposed to the open air environment to simulate the disc corrosion for a parked vehicle. The change in brake torque and friction coefficient was analyzed using a single-end brake dynamometer. The results showed that the burnishing effect of the friction material has significant effect on the formation of oxide layer. Oxide layer formed on disc burnished with friction material P-2 was more concentrated and thicker compared to the disc burnished with friction material P-1. Also, the results showed that brake torque and friction coefficient were closely dependent on the removal of the oxide layer and by the friction film on the burnished disc surface while applying the brake. Thus the composition of friction materials is critical to affect the formation of the oxide layer on the disc and consequently, the performance of the frictional force of disc brake system.

Effect of Composition on the Tribological Behaviors of Ceramic-Matrix Friction Materials

2014 ◽  
Vol 1061-1062 ◽  
pp. 645-648 ◽  
Author(s):  
Fa Hui Wang ◽  
Ying Liu
Keyword(s):  
Friction Coefficient ◽  
Clay Content ◽  
Ceramic Matrix ◽  
Friction Material ◽  
Potash Feldspar ◽  
Friction Materials ◽  
Temperature Changes ◽  
Pull Out ◽  
Adhesion Wear ◽  
Different Content

The steel fiber reinforced ceramic matrix friction material is prepared by nitrogen protection sintering method. The specimens of the three different friction materials containing different content of alumina, clay and potash feldspar are formulated. The friction and wear characteristics are determined by using the XD-MSM constant speed friction tester. The testing results show that the increase of potash feldspar and the decrease of clay content make friction coefficient become more stable and diminish the sensitivity of friction coefficient to the temperature changes. This study also identify that among the three friction materials investigated, the main wear mechanism converts from grain pull-out and fracture wear to adhesion wear and abrasive wear.

Effects of Hair Fibers on Braking Friction Materials

2011 ◽  
Vol 399-401 ◽  
pp. 1725-1728
Author(s):  
Yun Hai Ma ◽  
Bao Gang Wang ◽  
Sheng Long Shen ◽  
Xue Ying Geng ◽  
Hong Lei Jia ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Friction Material ◽  
Wear Property ◽  
Rockwell Hardness ◽  
Friction Materials ◽  
Wear Rates ◽  
Hair Fiber ◽  
The Stability ◽  
The Impact

In this experiment, the effects of hair fibers on friction and wear property, Rockwell hardness and impact strength of friction materials were examined. The results showed that friction coefficient increases and stabilizes and specific wear rates were decrease as the hair fibers were filled and, particularly, 1% of the hair fiber content had a significant effect in the friction material. As temperature was changed, the stability of the friction coefficient of friction materials can be improved, the Rockwell hardness decrease and the impact strengths increase by way of increasing the content of hair fibers. The worn surfaces of friction materials were examined by scanning electron microscopy and wear mechanisms were analyzed. So it’s a kind of quite good non-asbestos friction material.

Studies on Dynamic Tribology Properties of Friction Materials by Using an Approximate In Situ Observation for Worn Surfaces

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Weitao Sun ◽  
Wenlong Zhou ◽  
Jianfa Liu ◽  
Xuesong Fu ◽  
Guoqing Chen ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Friction Material ◽  
In Situ Observation ◽  
Friction Materials ◽  
In Situ Method ◽  
Friction Tester ◽  
Tribology Performance ◽  
Worn Surfaces

This paper primarily focused on the dynamic tribology properties of one certain nonasbestos organic (NAO) friction material by using an approximate in situ method. This study was performed through a pad-on-disk type friction tester under different temperature conditions. Results showed that temperature has a significant effect on the dynamic tribology performance. At 100 °C, friction coefficient and wear rate after the running-in stage varied little with time. At 250 °C, friction coefficient after the running-in stage increased gradually and then tended to be stable, while wear rate decreased gradually. From 100 to 350 °C, friction coefficient increased first as a function of temperature, but decreased sharply when the temperature was over 250 °C. Simultaneously, wear rate also increased sharply over 250 °C. Additionally, three dynamic evolution models of worn surfaces corresponding to different cases were established.

scholarly journals EXPERIMENTAL STUDIES ON MECHANICAL, FRICTION AND WEAR OF NON ASBESTOS ORGANIC BRAKE LININGS FOR LIGHT MOTOR VEHICLE

2013 ◽  
pp. 272-280
Author(s):  
M.P. NATARAJAN ◽  
B. RAJMOHAN ◽  
S. DEVARAJULU
Keyword(s):  
Fly Ash ◽  
Friction Coefficient ◽  
Glass Fiber ◽  
Coefficient Of Friction ◽  
Motor Vehicle ◽  
Experimental Studies ◽  
Friction Material ◽  
Wear Loss ◽  
Friction Materials ◽  
Brake Lining

In this study, flyash based non asbestos organic brake lining composition of more than 14 ingredients was investigated to study the effect of ingredients on various behavior of friction properties. Two types of friction materials with different combinations were developed: i) fly ash range (10 %to 60%) and ii) without fly ash based friction materials were investigated to study the effect of ingredients on the friction characteristics and wear. The main focus on the average normal coefficient of friction, hot coefficient of friction (Fade and recovery), wear loss, mechanical, as the function of the relative amount of the ingredient. The results also showed that the friction coefficient of fly ash based friction material was better in the range of 0.35 to 0.48 when compared barites based brake linings in the range of 0.46 to 0.58. The materials such as potassium titanate(terraces), wollastonite, friction dust powder have strongly influence on friction coefficient. The wear résistance of the brake linings was strongly affected by the presence of rock wool calcium hydroxide and zircon silicate. The presence of glass fiber, twaron fiber, glass fiber has increased the strength of the friction material. All these samples were tested on chase type friction tester at automobile ancillary unit.

Hybrid Biological Fiber-Reinforced Resin-Based Friction Materials Friction and Wear Performance Test

2013 ◽  
Vol 461 ◽  
pp. 388-396 ◽  
Author(s):  
Yun Hai Ma ◽  
Sheng Sheng Ma ◽  
Sheng Long Shen ◽  
Jin Tong ◽  
Li Guo
Keyword(s):  
Friction Coefficient ◽  
Experimental Design ◽  
Mass Fraction ◽  
Friction And Wear ◽  
Friction Material ◽  
Orthogonal Experimental Design ◽  
Fiber Reinforced ◽  
Wear Performance ◽  
Friction Materials ◽  
Reinforced Fiber

Friction material is essential for automotive braking system. Based on previous study of existing friction material problems, hybrid biological fiber-reinforced resin-based friction materials (HBRMs, from the reinforced fiber component of resin-based friction materials) were explored in this study. Bamboo fiber, jute fiber and wool fiber (all have length of 3-5 mm) were processed to make three types of HBRMs and considered as three factors of biological reinforced fiber in test using orthogonal experimental design. Each factor had three levels of 1%, 2% and 3% fiber mass fraction while the ratio of other raw materials remains unchanged. According to the orthogonal experimental design table, nine formulations (denoted as M1-M9) were determined to test the HBRMs. For comparison, non-bio-fiber reinforced friction material (NBM) was added in the test. The properties of the HBRMs tested included Rockwell hardness, impact strength and density. The friction and wear performance of the braking materials was examined by a speed friction tester. The results show that the friction coefficient of the HBRMs was slightly higher than that of the NBM, indicating biological fibers affected the friction coefficient. The friction coefficient of the HBRMs decreased firstly with the increase of temperature and had the lowest value when the temperature reached 300°C, and it increased then as temperature increased. During recovery process, the friction coefficient of the HBRMs firstly increased with the decrease of temperature and then decreased greatly when the temperature dropped to 100°C. The wear rates of the HBRMs increased with the increase of temperature and reached maximum value when temperature reached 200°C, then it decreased with the increase of temperature. The results of fuzzy comprehensive evaluation analysis on the friction coefficient and wear rate show that the best comprehensive properties were presented when the mass fraction of bamboo, jute and wool fiber were 3%, 3% and 1%，respectively.

scholarly journals Boundary Friction of ZDDP Tribofilms

2020 ◽  
Vol 69 (1) ◽  
Author(s):  
Jie Zhang ◽  
Mao Ueda ◽  
Sophie Campen ◽  
Hugh Spikes
Keyword(s):  
Friction Coefficient ◽  
Group Structure ◽  
Boundary Friction ◽  
Considerable Proportion ◽  
Base Oil ◽  
Characteristic Boundary ◽  
Long Duration ◽  
Structure Boundary ◽  
Alkoxy Groups ◽  
20 Nm

AbstractThe frictional properties of ZDDP tribofilms at low entrainment speeds in boundary lubrication conditions have been studied in both rolling/sliding and pure sliding contacts. It has been found that the boundary friction coefficients of these tribofilms depend on the alkyl structure of the ZDDPs. For primary ZDDPs, those with linear alkyl chains give lower friction those with branched alkyl chain ZDDPs, and a cyclohexylmethyl-based ZDDP gives markedly higher friction than non-cyclic ones. Depending on alkyl structure, boundary friction coefficient in rolling-sliding conditions can range from 0.09 to 0.14. These differences persist over long duration tests lasting up to 120 h. For secondary ZDDPs, boundary friction appears to depend less strongly on alkyl structure and in rolling-sliding conditions stabilises at ca 0.115 for the three ZDDPs studied. Experiments in which the ZDDP-containing lubricant is changed after tribofilm formation by a different ZDDP solution or a base oil indicate that the characteristic friction of the initial ZDDP tribofilm is lost almost as soon as rubbing commences in the new lubricant. The boundary friction rapidly stabilises at the characteristic boundary friction of the replacement ZDDP, or in the case of base oil, a value of ca 0.115 which is believed to represent the shear strength of the bare polyphosphate surface. The single exception is when a solution containing a cyclohexylethyl-based ZDDP is replaced by base oil, where the boundary friction coefficient remains at the high value characteristic of this ZDDP despite the fact that rubbing in base oil removes about 20 nm of the tribofilm. XPS analysis of the residual tribofilm reveals that this originates from presence of a considerable proportion of C-O bonds at the exposed tribofilm surface, indicating that not all of the alkoxy groups are lost from the polyphosphate during tribofilm formation. Very slow speed rubbing tests at low temperature show that the ZDDP solutions give boundary friction values that vary with alkyl group structure in a similar fashion to rolling-sliding MTM tests. These variations in friction occur immediately on rubbing, before any measurable tribofilm can develop. This study suggest that ZDDPs control boundary friction by adsorbing on rubbing steel or tribofilm surfaces in a fashion similar to organic friction modifiers. However it is believed that, for primary ZDDPs, residual alkoxy groups still chemically bonded to the phosphorus atoms of newly-formed polyphosphate/phosphate tribofilm may also contribute to boundary friction. This understanding will contribute to the design of low friction, fuel efficient crankcase engine oils. Graphical Abstract

Sign in / Sign up

Export Citation Format

Share Document