Evaluation Of Friction Performance And Friction Mechanism Of Semi-Metallic Friction Materials

The semi-metallic friction materials are used widely in the car industry nowadays because they have excellent friction performance such as steady friction coefficient and small wear loss. In order to prepare semi-metallic brake linings with higher friction performance and lower cost, combinatorial friction materials research (CFMR) was conducted. Friction mechanisms and role of abrasives in semi-metallic friction materials were analyzed. The trajectories model of debris was created.Raw materials used were screened by four criteria: (a) selecting those raw materials with good wear resistance; (b) select those raw materials which have good wear resistance when they combine with group (a) raw materials; (c) selecting those raw materials that have special functions; and (d) selecting those raw materials which can cut the cost but don't degrade friction performance.Following research was carried out in this thesis:The raw materials used were selected according to the above-mentioned methods. Latin square coupled with Golden Section approach was utilized for experimental formulations design. Friction performance of semi-metallic friction material samples was tested. The friction layer was characterized by SEM and EDX.The friction performance of different friction formulations was compared with fuzzy comprehensive assessment method. Three novel parameters were introduced: steady friction, comprehensive wear rate, and overall friction performance. In addition, the software of fuzzy comprehensive evaluation procedure was developed.The trajectories model of debris was created with the knowledge of physics and mathmatics.Two best formulations were obtained. One is the semi-metallic friction material containing 3.4 vol.% of SiC and another is the semi-metallic friction material containing 5.6 vol.% of Al₂O₃. Therefore, the V mechanism was proved.