润滑剂用磁流体的磁流变学性能研究

Study on the Magnetic Rheological Character of Magnetic Fluid as Lubricant

由道森-希金森最小油膜公式可知，润滑荆用磁流体的摩擦磨损与磁流体的粘度有关．设计了一种测量磁流体粘度的流变仪来研究其变化．从实验结果可知，磁流体粘度随外磁场增大而增大，变化范围为1～10倍，粘度增加与磁场施加之间大约有5S的滞后；同一磁场作用时，随着时间的改变，粘度也随之增加；磁场强度越大，变化率也越大；载液、磁性粒子和耦合剂也同样会引起磁流体粘度的改变．上述因素影响到油膜厚度，在实际工况中可以通过控制磁流体的粘度来控制油膜厚度，从而控制其摩擦性能．

The frictional wear of magnetic fluid is related to its viscosity,and this result can be obtained by the Dawson-Higginson formula for calculating the least thickness of lubricant film. We have designed a rheometer to study the change in the magnetic fluid viscosity. From the experimental results, it can be seen that the magnetic fluid viscosity increases with the stronger external magnetic field intensity, and its values range from onefold to ten- fold,but there is a five-second lab between the increase of viscosity and the infliction of the magnetic field. The vis- cosity increases with the time increasing when the same magnetic field operates. The larger the magnetic field inten- sity is,the larger the changing rate is. Carrier liquid,magnetic particles and dispersants may result in the changes of magnetic fluid viscosity. The above-mentioned factors affect the lubricant film, so we can control the film thickness by controlling the magnetic field intensity in actual practice,and thus control its frictional behavior.