磁流体是大量的强磁微粒稳定地分布在水或油等介质中的一种固液混合物,强磁微粒表面附有表面活性剂,在重力场和磁场中不会出现凝聚、沉淀等现象。用超声波探伤时,往往在探头、试料表面涂沫水、油、冷却剂等液体,以防止试料表面反射 Magnetic fluid is a kind of solid-liquid mixture in which a large number of ferromagnetic particles are stably distributed in mediums such as water or oil. The surface of the ferromagnetic particles is provided with a surfactant, and condensation and precipitation do not occur in the gravitational and magnetic fields. Ultrasonic testing, often in the probe, the sample surface coated with water, oil, coolant and other liquids to prevent the sample surface reflection