Comparative Studies on the Dry Sliding Behavior of a Low-Metallic Friction Material with the Addition of Graphite and Exfoliated g-C3N4

Abstract

This study compares the effect of the addition of two types of lubricants on the dry sliding behavior of a simplified Cu-free phenolic resin-based composite material. The lubricants were commercial graphite and exfoliated graphitic carbon nitride (codenamed: TEX6). The graphite particles were rounded and of ‘flaky’ character. The TEX6 particles were not only flaky, but also irregular in shape, and ‘fluffy’. Both lubricants were added individually in the basic formulation and subjected to dry sliding tests on pin-on-disc testing equipment in mild conditions and against a grey cast-iron counterface. The tests with TEX6 observed a stable steady state in the friction coefficient (CoF) with lower scatter and lower average friction coefficient and pin wear magnitude when compared to samples containing graphite. Additionally, the worn surfaces of the TEX6-containing samples had extremely smooth, compact, and continuous secondary plateau coverage when compared to the graphite-containing samples. The counterface paired with the TEX6-containing samples observed much lower abrasive action compared to the graphite-containing samples. Through the wear testing and further evaluation of the secondary plateaus, the possible addition of TEX6 as a lubricant in friction material composition was explained, making it a promising component for automotive braking applications.

A novel path towards limiting non-exhaust particulate matter emissions of a commercial friction material through the addition of metallurgical slag

“…The pin wear in Fig. 4b is observed to increase with the addition of slag content when compared to virgin CFM, tending to an average value around 3.3 × 10 -14 m 2 /N, which is higher than the wear of the CFM composition but www.nature.com/scientificreports/ well within the mild wear regime 4,18,31 . Lastly, the average particle concentration of all compositions is depicted in Fig.…”

“…Lastly, the green body specimens were subjected to curing at 200 °C for 4 h in a muffle urnace. After the completion of the production process, the average height and www.nature.com/scientificreports/ diameter of the pins were 10 mm 4,18,31 . The pins were paired with a counterface in the form of discs.…”

“…The testing conditions employed were a contact pressure of 1 MPa (79 N) and a constant sliding velocity of 1.51 m/s (600 rpm for a wear track of 48 mm). The testing parameters selected here replicate mild braking condition and was selected as this scenario would not only assist in evaluating the friction and wear behavior, but also provide information on the secondary contact plateau characteristics (extension, compaction, smoothness) 4,18 . The trials with each composition were repeated three times to obtain repeatability in the results.…”

“…Friction materials for automotive braking systems must satisfy a vast array of requirements which includes stable and desirable friction coefficient (CoF), low system wear rate, and low noise and vibrations [1][2][3] . Therefore, friction material formulations include a range of constituents, sometimes more than 30 ingredients, which are divided into the binder, reinforcement, fillers, and friction modifiers (further divided into abrasive and lubricants) 4 . Recently, several efforts have been initiated to produce eco-friendly friction materials.…”

A novel study on the reduction of non-exhaust particulate matter emissions through system vibration control

“…The two formulations (BC and MC) were tested in the form of pins. The pins were obtained through a pre-defined production procedure 24 , 25 . All the constituents in Table 1 were carefully weighed, and except for the steel wool, were mixed continuously in a TURBULA ® mixer for 20 min.…”