Dr. Neomy Zaquen, Lapinus, NETHERLANDS

Mr. Arno Kerssemakers, Lapinus, NETHERLANDS

Mr. Fernao Persoon, Lapinus, NETHERLANDS

Global emission – due to pollution and the use of fossil fuels – has risen drastically since the start of the industrial revolution and is at the core of the problems within the current society. Within the automotive industry, not only the exhaust of vehicles is seen as a large contributor to pollution, also wear of the tires and the brake pads of vehicles contribute to pollution in the form of emission. In 2015 it was concluded that PM2.5 as a direct result of disc brakes, contributes to high percentages of the total amount of non-exhaust emission from road transport within the EU. Due to the severe adverse health effects of PM, the EU has defined general emission guidelines for both fine (PM2.5) as well as coarse (PM10) particle matter. We expect these values to be translated to the automotive industry in the (near) future.

Within Lapinus, we actively investigate the reduction of emission as a direct result of wear of disk brake pads. By using our engineered mineral fibre, friction levels are stabilized and both pad as well as disc wear are reduced, due to the formation of a stable third body layer. Previous studies on mineral fibres have shown the friction performance when using different grades and morphologies of fibres in the friction matrix. While shorter fibres act as anchoring point, engineered fibres spheres can collect wear debris during braking, leading to overall reduced wear.

In this study, a closer look into the formation of the tribolayer was taken when using a NAO/non-steel formulation. Mineral fibres of different length as well as engineered fibre spheres were added to the friction matrix to correlate the impact of performance with the tribolayer formation. Dynamometer full scale tests were executed to compare the friction performance, stability of the friction level and wear of the different (non)-spherical materials. The tribolayer formed on the brake pad surface – and related to that disc surface – was studied by means of SEM-EDX and optical microscopy.

This work shows the importance of mineral fibres not only from a performance, but also tribolayer point of view. Especially the use of engineered fibre spheres leads to new insights with respect to the tribolayer. Combined with the excellent friction performance and decreased wear, this work can be considered an important solution towards the reduction of non-exhaust emissions.