铁磁材料摩擦过程中磁化效应机制研究

为探究摩擦过程中磁记忆效应产生机制,采用Bitter粉纹法对摩擦过程中摩擦接触区域的磁畴组织进行原位观测,测量不同摩擦次数及不同摩擦载荷下磨痕表面的磁场变化以及摩擦影响区域内磁畴组织的时效变化。实验结果表明:摩擦过程中磨痕表面的磁场经历剧烈增加、缓慢增加到稳定变化3个阶段;摩擦接触区域内的畴壁在摩擦过程中转向垂直于往复摩擦方向,畴壁厚度和间距增加,畴壁的形态呈现弯曲状,且摩擦载荷为40 N时畴壁的这些变化比载荷为20 N时更加明显;摩擦后的磁畴组织发生时效变化,在静置60天后接触区域内畴壁变化后的状态开始消散,摩擦载荷为40 N时消散程度较20 N时小。

Research on Magnetization Mechanism of Ferromagnetic Materials in the Process of Rubbing

In order to investigate the mechanism of magnetic memory effect in the process of friction,magnetic domains in the rubbing contacting area were in situ observed by Bitter powder pattern.The surface magnetic field of wear scar under the different sliding cycles and different friction load was measured,and the changes of magnetic domain in the rubbing contacting area were observed over time.Experiments show the surface magnetic field of wear scar experiences a three-stage process:intense variation,slow increase,steady stage.The domain wall in the friction contact area turns perpendicular to the direction of reciprocating friction during the friction process,the thickness and spacing of the domain wall is increased,and the shape of the domain wall presents a curved shape,and these changes of the domain wall are more obvious when the friction load is 40 N than when it is 20 N.After the friction,the magnetic domain structure experiences aging changes,and the state of domain wall within the contact area begin to dissipate after 60 days under the earth's magnetic field,and the dissipation degree is smaller when the friction load is 40 N than when it is 20 N.