填料粒度对汽车制动摩擦材料性能的影响

Effect of Filler Size on Performance of Automotive Brake Friction Materials

目的研究填料粒度对树脂基汽车制动摩擦材料性能的影响。方法选取硅酸锆、氧化铝、石墨和蛭石作为填料,树脂基摩擦材料采用热压成型法制成,在X-DM摩擦试验机上进行摩擦磨损试验。采用正交试验法,对填料粒度不同的树脂基摩擦材料的摩擦因数标准差和高温磨损率进行极差分析,以获得填料粒度组合最佳的摩擦材料配方。采用扫描电子显微镜对该材料和未经过粒度优化材料在不同温度下的磨损表面形貌进行对比分析。结果随着硅酸锆和氧化铝颗粒尺寸的增大,摩擦因数和高温磨损率均增大,但硅酸锆和氧化铝颗粒尺寸过大或过小都会造成摩擦因数的稳定性变差;石墨粒度变化对摩擦因数的稳定性影响不大,随着石墨颗粒尺寸的增大,高温磨损率减小;随着蛭石颗粒尺寸的增大,摩擦因数的稳定性变差,且高温磨损率增大。结论硅酸锆和氧化铝粒度在320~400目之间,石墨粒度在100~200目之间,蛭石颗粒尺寸小于80目为最佳的粒度组合,制成的摩擦材料的摩擦磨损性能最佳,试样的摩擦因数稳定,高温磨损率较低,抗热衰退性能好。

Objective To study the effect of filler size on friction and wear properties of phenolic resin matrix friction materials.Methods Zirconium silicate,alumina,graphite and vermiculite were selected as fillers of friction materials. The friction materials were prepared by hot pressing method,tribological properties were tested on X-DM friction testing machine. The design method used in this paper was orthogonal test,and range analysis method was used to analyze the standard deviation of friction coefficient（ COF） and the wear rate at high temperatures to find a best formula of the friction material. The morphologies of this material and normal friction material at different temperatures were studied by SEM. Results The results showed that with the increases of zirconium silicate and alumina particle sizes,both the COF and the wear rate at high temperatures were increased,but too large or too small zirconium silicate and alumina particles would result in instable COF; the size of graphite had little effect on friction stability.With the increase of graphite size,the wear rate at high temperatures decreased; with vermiculite size increased,the friction stability deteriorated and the wear rate at high temperatures increased. Conclusion When zirconium silicate and alumina particle sizes were between 320 ~ 400 mesh,graphite particle size was between 100 ~ 200 mesh,vermiculite particle size was smaller than 80 mesh,the friction material had the best friction and wear properties,with high and stable COF and relatively low wear rate,and the performance of thermal fading resistance at elevated temperature was excellent.