The Role of Graphitic Carbon Nitride in the Formulation of Copper-Free Friction Composites Designed for Automotive Brake Pads

In this study, graphitic carbon nitride (g-C3N4, labelled as gCN) was tested in the formulation of copper-free (Cu-free) friction mixtures, which are potentially interesting for brake pad manufacturing. Three formulations of friction composites were prepared starting from a common Cu-free master batch: (i) without graphite, (ii) with graphite and (iii) with gCN. The mixtures were pressed in the form of pins by hot-press moulding. The friction-wear performance of the prepared pins was investigated using a pin-on-disc (PoD) test at room temperature (RT), high temperature (HT) (400 °C) and, again, at room temperature (H-RT). The values of the friction coefficient (µ) for the composites with gCN (or graphite) were as follows: (i) RT test, µRT = 0.52 (0.47); (ii) HT test, µHT = 0.37 (0.37); (iii) RT after the HT tests, µH-RT = 0.49 (0.39). With respect to wear resistance, the samples with graphite performed better than the samples without this solid lubricant. To the best of our knowledge, this is the first report regarding the evaluation of the role of gCN in friction composites designed for automotive brake lining applications. The results indicate the main role of gCN as a soft abrasive.

REVIEW: CORN COB POTENTIAL FOR APPLICATIONS IN COMMERCIAL PRODUCTS

Post-harvest activities of agricultural products often generate wastes. One of the agricultural wastes that increase every year is corn cobs, which have a high cellulose content and can potentially be used as raw materials for making natural fibers. Therefore, this study aims to examine several potential commercial products from corn cobs. The method used is a literature study by tracing the sources of previous writings. Furthermore, how to process corn cobs waste for the manufacture of natural fibers and commercial products will be discussed. From the previously traced sources in the utilization of corn cobs waste, 4 products were obtained. The results are nano hydrogels based on gamma radiation, activated carbon with a carbonation process, bioethanol using the SSF process, and the use of corn cob cellulose as good-quality brake lining.

Review of automotive brake lining materials and their tribological properties

Brake lining material properties are considered an essential aspect of the safe operation of vehicles. The presented paper aims to present a comprehensive review of brake lining materials and their tribological properties including the proposed materials, their advantages and disadvantages, analysis of results, and test rig experiments. The first section of the paper includes brief information on brake lining materials, friction modifier additives, and recent developments in friction additives. The second section discusses the tribological performance of brake lining materials. Furthermore, the key mechanisms of the friction layer produced on the worn brake lining surface have been explained microscopically (HRTEM). Part of this review is devoted to demonstrating current research gaps and challenges related to brake performance in automotive for further research. In brief, this review study is highly significant, as it provides more detailed information regarding the performance of brake lining materials.

Characterization of mechanical properties of composite materials with filler coconut shell powder and sawdust with coconut fiber reinforcement as an alternative to low loaded brake friction materials

The purpose of the study is to determine the best composition variation of the fifth variation of the composition of the composite material against the wear test, hardness test, tensile test comparing values ​​ with the safety standards of the brake lining composite SAEJ 661. Making the specimens was performed by mixing the ingredients with a mixer for 15 minutes and then do the process of compaction, with a load of 4 tons and detained achieve holding time is desired, then dies (mould) are placed in the oven and do the sintering process at a temperature of 1500 C for 180 minutes and specimens removed from the mould, the process of finishing and testing. These test results show that the composition of the material that is on variation V best price obtained 96.575 HBN hardness, wear rates of 1,29x10-6 gr / (mm2.detik), and a tensile strength of 0.842 MPa, but the brake friction material not meet safety standards SAEJ brake 661.

Effect of In-situ Tribo-oxide-layer on the Non-lubricated Tribological Behaviors of LM27/ SiCp Composites

In this study, an investigation on the influence of In-situ tribo-oxide-layer on non-lubricated tribological behaviours of LM27/SiCp composites was carried out at different applied loads. The variations in wear performance and microstructure of brake lining friction material (LM27) with the addition of different amounts and sizes of SiCp are explored. For this purpose, LM27/SiCp composite materials were manufactured by stir casting route varying the amount of particle reinforced from 3wt.% to 12wt.% with a different size range (fine: 1-20µm and coarse: 106-125µm). Non-lubricated dry wear tests of LM27/SiCp composites samples were trialled at different loads from 9.8N to 49N by using a pin-on-disc machine system. At a contact pressure of 0.2-1 MPa, LM27/SiCp composites with 12wt.% reinforcement showed a lower coefficient of friction than other composites. In-situ formation of oxide layers on the contact region of the specimen supports the self-lubrication during the wear test, which is responsible for better wear performance of LM27/SiCp composites. However, these study portraits that composite with 12wt. % fine size SiCp exhibits better wear performance in comparison to the other developed composites.

Development of prototype machine brake and car safety gear testers for traction lift systems

Machine brakes and safety gears of traction lifts are two critical components of the biggest safety concerns, as the main braking system and redundant fail-safe mechanism respectively stop and hold lift cars from unintended car movement, overspeed or under a free-fall condition during emergency. There are challenges of routine maintenance on how to continually verify the effectiveness of them to mitigate risk potentials of equipment failure. This pilot study intends to design, implement and test low-cost, non-intrusive and on-line prototype testers with the aid of sensors for real-time monitoring of critical parameters of these safety devices. Critical parameters that are measurable include real-time variations of brake lining temperature, brake solenoid current, vibrational patterns of brake arms and lift car, position of lift car, and the actuating status of safety gears. Critical parameters after processing include a newly defined energy of brake arm operation and estimated deceleration rate of a fully loaded car by safety gears operation on an unloaded car. Early signs of abnormalities of these two safety devices can be detected before they fail. Additionally, the prototype testers can facilitate more frequent unloaded full-speed testing of safety gears to verify the effectiveness. The proof-of-concept prototype could be a quick monitoring alternative to existing and new traction lift systems.

Brake Noise Reduction Method Based on Monte Carlo Sampling and Particle Swarm Optimization

Brake noise is one of the principal components of vehicle noise and is also one of the most critical measures of vehicle quality. During the braking process, the occurrence of brake noise has a significant relationship with the working conditions of the brake system. In the present study, dynamometer test data and the finite element method (FEM) were used to analyze the direct and indirect effects of variations in the working parameters on the brake noise, and a brake noise reduction method was developed. With this method, Monte Carlo sampling was used to consider variations in the parameters of the brake lining during the braking procedure, and the particle swarm optimization method was used to calculate the optimal parameter combination for the brake lining. A dynamometer test was carried out to validate the effect of optimization on brake noise mitigation.