Investigation of Metallic and Metallic Glass Hollow Spheres for Fusion Target Application

Abstract

ABSTRACTHigh quality metallic and metallic-glass microballoons (MMB and MGMB) are of considerable interest for fusion target applications on account of the intrinsic properties of these materials such as high density, high strength and high atomic number. We report the first successfully formed submillimeter and millimeter spherical shells of tin and of a gold-lead-antimony alloy by means of the hollow-jet instability technique developed by one of us (JMK). Examination of tin specimens by means of SEM has revealed that surface quality varied from poor to excellent. Whereas this metal has been employed only as a convenient and inexpensive material, the gold alloy is important because it is hard, has high atomic number, and may be solidified into the amorphous state through the provision of a modest cooling rate. We have produced AuPbSb spherules up to 1.5 mm in diameter using LN2 or chilled methanol as a coolant, and have found that these amorphous samples possess a superb surface smoothness compatible with fusion target requirements. Hollow spheres currently made of this alloy have an average O.D. of 2000 μm.