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Title: New production routes for manufacture of flake powders
Author: James, J. D.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1988
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A study has been made of the characteristics of flake brass powders, and a route has been developed to produce such powders by small scale vibratory batch milling. Brass flakes are used as pigments for producing a 'gold leaf' appearance in ink and paints, and there are a variety of other applications. The commercial production route involves the slow process of rotary ball milling a coarse feed powder on a continuous basis. Initially a range of industrially produced powders were examined by a variety of techniques to determine the relationship between powder characteristics and commercial quality. Numerical calculations were carried out for the elastic deformation of balls on impact and the resulting plastic deformation of powder to flakes during ball milling. Vibratory ball milling of brass powder to flakes was then undertaken in the laboratory. The principal variables investigated were: milling time, ball size, initial particle size, total weight of powder and quantity of additive employed. The effect of these variables on flake production is described in terms of the processes of microforging, fracture and agglomeration. It was found that, providing one starts with a fine powder, vibratory milling could produce flakes similar to the industrial product much more rapidly than rotary ball milling. Vibratory milling is thus an excellent method for rapid production of small quantities of brass flakes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available