Who Needs to Characterize Powders and Spray Systems

The list of industries using powders, or processes in which there is a substance used as spray or a mist, is long and increasing. My first exposure to the problems of powder technology began in 1955 when I studied the characterization of powders used to fabricate parts of nuclear weapons. One study involved the metal beryllium which was used in powder form. The production of dense beryllium required powders having a specific size and shape distribution. Beryllium powder is however a respirable health hazard and to characterize the powder in a safe atmosphere required the development of new methods of characterizing powders. 

After working with beryllium I moved on to study nuclear reactor fabrication. In this study I worked on determining the surface area, size and shape distributions of uranium dioxide and plutonium dioxide powders used to fabricate fuel rods. Looking back I see that my initiation into powder technology was a baptism of fire since all of these powders were extremely toxic and dangerous. The technology that I studied in those years is currently very applicable to the study of modern ceramic materials and powder metallurgical routes to finished products [1,2]. 

After my studies of the technology for creating nuclear weapons I soon became involved in studying the fallout from nuclear weapons tests and similar problems of occupational diseases, such as pneumoconiosis and silicosis caused by the inhalation of fineparticles. The study of respirable hazards in industry and from nuclear fallout requires detailed knowledge of the shape and size of fineparticles [3, 4]. 

Size characterization studies have often evolved in parallel in many of these industries and sometimes there is vocabulary confusion because of the different perspectives of scientists from the various industries. We will attempt to develop and use a consistent terminology as we study the muldmdes of powders used in various industries. 

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