电爆炸法制备纳米颗粒收集方法

Using electrical explosion of wires to produce nanopowders has attracted wide interest because of the considerable overheat of the metal and the non-equilibrium process and it is considered to be an effective method to prepare expensive or difficult materials and powders with new properties. An experimental study on exploding Ti wire in atmosphere under a microsecond time-scale pulsed current was conducted. The influences of different collection methods on preparing Ti nanoparticles via electrical explosion were investigated. The reasons for different products characteristics were studied combined with the methods of electrical, radiant, self-emission images and the morphology characterization. Experimental results indicate that Ti explosion belongs to periodical discharge mode, the products channel expands to 1.7 cm before the end of discharge (about 40 μs), and then there develops cuspate protrusions with a speed of 55 m/s. To investigate the formation characteristics of nanoparticles under different states of exploded products, three methods were used for collecting products, namely: ① Placing a silicon wafer at 1.5 cm in radial direction; ② Placing a silicon wafer on the exit of the cavity; ③ Collecting by directional spraying on one electrode of the wire. The characterization results of products morphology show that products have prominent discrepancies under different collection methods. Products of the former two methods mix with ambient medium and then sedimentate to the silicon, producing dispersive and catenulate nanoparticles and dense and stacked clusters respectively. For the last method, the exploded products possess relatively greater density and directed velocity (toward silicon wafer), presenting two forms as powders and sintered chunks (near the wire axis).