生物质燃油碳烟的组成和结构以及摩擦学特性研究

Composition and Structure as well as Tribological Performance of Bio- fuel Soot

用自制碳烟捕集装置收集了生物质燃油碳烟(Bio-fuel soot,简称BS),采用四球摩擦磨损试验机考察了BS对液体石蜡(Liquid paraffin,简称LP)摩擦学特性的影响,借助扫描电镜/能谱仪、X射线光电子能谱仪、高分辨透射电镜、X射线衍射仪等分析了BS的组成、结构及摩擦学作用机理.结果表明:BS由平均粒径约40 nm的球形颗粒组成链状团聚体,主要成分为无定型碳和氧,并含少量石墨烯微晶,且其氧含量高于柴油碳烟.随着BS在LP中添加质量百分数的增大,最大无卡咬负荷先增大后减小,钢球平均磨斑直径呈线性增大,而平均摩擦系数先稍有减小后趋于增大.就摩擦学作用机理而言,一方面,BS中的含氧官能团使BS在摩擦过程中易于吸附到摩擦表面,影响边界润滑膜的作用;另一方面,BS引起磨粒磨损和腐蚀磨损,使得摩擦表面的金属氧化膜在摩擦过程中易脱落成磨粒,从而加剧磨损.

Bio- fuel soot( BS) was collected with a homemade soot trapping equipment. A four- ball friction and wear tester was used to investigate the effect of BS on the tribological performance of liquid paraffin( LP). The composition,structure and tribological mechanism of BS were investigated by means of scanning electron microscopy /energy- dispersive spectrometry,X- ray photoelectron spectroscopy,high resolution transmission electron microscopy,and X- ray diffraction.Results show that chain- like agglomeration of BS was composed of spherical nanoparticles with an average size of about40 nm. The main ingredients of BS included amorphous carbon and oxygen,as well as a small amount of graphene microcrystal,and the oxygen content of BS was higher than that of diesel soot. With increasing content of BS in LP,the maximum non- seizure load firstly increased and then decreased. In addtion,the average wear scar diameters rose linearly,and the average friction coefficient firstly decreased slightly and then increased. In terms of the tribological mechanism,on the one hand,owing to the action of O- containing functional groups,BS can be easily adsorbed on rubbing surface therebyinfluencing the effect of boundary lubrication film. On the other hand,BS caused abrasive wear and corrosive wear and promoted detachment of metal oxide film on rubbing surface as abrasive particles,and thereby enhanced wear of the steel-steel sliding pair.