一、前言关于制取超细金属粉的方法已有很多种,但是从惰性气体(如氢、氦、氙)中用蒸发金属制取细粉是较简单的方法。如果把金属在压力为1～30托的氦气中蒸发,则能看到在蒸发源的周围有烟状物质产生,在四周的壁上附有煤粉状的物质。将这些煤状物质放在电子显微镜下观察,将能看到有时平均粒度为数十埃、有时是数百埃甚至数千埃的 I. INTRODUCTION There are many ways to make ultrafine metal powders, but it is a simpler method to make fines from evaporated metals from inert gases such as hydrogen, helium and xenon. If the metal is evaporated in helium at a pressure of 1 to 30 Torr, it can be seen that a smoke-like substance is generated around the evaporation source and pulverized coal is attached to the surrounding walls. Observing these coal-like substances under an electron microscope will reveal that sometimes the average particle size is tens of angstroms, sometimes hundreds or even thousands of angstroms