材料期刊网

目的 为了提高铜基制动材料的力学性能和摩擦学性能,选用石墨烯作为增强填料添加到铜基制动材料中,研究石墨烯对铜基制动材料性能的影响.方法 采用粉末冶金的方法制备了石墨烯含量(质量分数,后同)分别为0%、0.2%、0.4%、0.6%、0.8%的铜基复合材料,并对不同试样的力学性能和摩擦磨损性能进行比较.结果 含有石墨烯的试样硬度为46.4~54.2HB,高于未添加石墨烯试样的硬度(44.5HB).含有石墨烯的试样抗弯强度为250~418 MPa,均高于未添加石墨烯试样的抗弯强度(218 MPa),其中石墨烯含量为0.4%的试样的硬度和抗弯强度最大,分别为54.2HB和418 MPa.随着石墨烯含量的增加,材料的密度逐渐下降.当石墨烯含量为0.2%~0.4%时,材料摩擦系数的稳定性提高且磨损率降低;当石墨烯含量为0.6%~0.8%时,材料摩擦系数的稳定性下降且磨损率变大.当石墨烯含量为0.4%时,材料的摩擦系数最稳定,摩擦系数的方差为0.3×10-3(未添加石墨烯的试样为1.4×10-3),磨损率最低,位于0.136×10-6~0.185×10-6 mm3/(N·m)之间(未添加石墨烯的试样位于0.42×10-6~0.82×10-6mm3/(N·m)之间).结论 少量的石墨烯(0.2%~0.4%)可以显著提高铜基制动材料的硬度和弯曲强度,其中石墨烯含量为0.4%时,制成的制动材料的机械性能最佳,同时试样的摩擦系数稳定,磨损率较低.

The work aims to improve mechanical properties and tribological properties of copper-based brake materials. Graphene was added to the copper-based brake materials as reinforcing filler. The copper-based brake materials containing 0.2%, 0.4%, 0.6% and 0.8% of graphene were prepared in powder metallurgy method, and mechanical properties as well as fric-tion and wear properties of different samples were prepared. Graphene could significantly improve hardness and tensile strength of the materials. Both hardness and bending strength of samples containing graphene was higher than (46.4~54.2HB, 250~418 MPa) that of those without graphene (44.5HB, 218 MPa). The sample containing 0.4% of graphene had the highest hardness (54.2HB) and best bending strength (418 MPa). Density of the materials decreased as graphene content increased. Stability of friction coefficient increased and wear rate decreased at the graphene content of 0.2%~0.4%. The stability of the friction coeffi-cient decreased and wear rate increased at the graphene content of 0.6%~0.8%. Compared with the sample without graphene (friction coefficientσ2=1.4×10-3, wear rate (0.42~0.82)×10-6 cm3/(N·m)), sample had the most stable friction coefficientσ2=0.3×10-3 and lowest wear rate (0.136~0.185)×10-6 cm3/(N·m) at the graphene content of 0.4% (mass fraction). Little gra-phene in the composite can significantly improve hardness and tensile strength of the materials at the content of 0.2%~0.4%. At the graphene content of 0.4%, the material has the best mechanical performance, the most stable coefficient of friction and low-est wear rate.