液体磁性磨具固相颗粒表面改性及稳定性研究

Study on Surface Modification and Stability of Solid Particles in Fluid Magnetic Abrasive

针对液体磁性磨具的沉降稳定性差,提出了采用羧基化多壁碳纳米管和聚二甲基二烯丙基氯化铵水溶液以及水溶性聚合物对磨具中的固相颗粒进行表面改性,提升液体磁性磨具的沉降稳定性。对改性前后的固相颗粒的结构、形貌、电位以及磁性粒子的磁饱和强度的表征和分析表明:改性后的羰基铁粉颗粒外表面吸附有碳纳米管,颗粒密度由4.3g/cm^3降低到1.55g/cm^3且改性后的羰基铁粉不易氧化,电位绝对值提升到15.3mV,饱和磁强度提升了26%;改性后的碳化硅表面吸附一层有机物,电位绝对值提升到68.7mV;磨具的稳定性有了很大的改善,静置20h到40h达到稳定,沉降率低于1%。改性剂的添加会增大磨具的黏度,但对其流变性能的影响较小。经过表面改性固相颗粒,液体磁性磨具的沉降稳定性有了较大的提升。

In view of the poor settlement stability of the fluid magnetic abrasive, the surface modification of solid particles in the abrasive was carried out with the carboxylated multi-wall carbon nanotubes, polydimethyldiallyl ammonium chloride aqueous solution and water-soluble polymer. The structure, morphology and potential of the modified solid particles were characterized. At the same time, FMA with carbonyl iron powder and silicon carbide as suspension phase and deionized water as dispersed phase was prepared. Carbon nanotubes were adsorbed on the surface of the modified carbonyl iron powder particles, which reduced the density of the particles from 4.3 g/cm ^3 to 1.55 g/cm^ 3 and the modified carbonyl iron powder was not easy to rust. The absolute value of the silicon carbide particle potential was improved to 15.3 mV and 68.7mV respectively and the stability of the abrasives had been greatly improved. Static 20 h to 40 h is stable, and the settlement rate is less than 1%. The viscosity of the FMA could be increased by the addition of the modifier, but the effect on the rheological properties of the FMA was less influence. After the surface modification of solid particles, the settlement stability of fluid magnetic abrasive has been improved.