Development of a Tabletop Model for the Generation of Amorphous/ Microcrystalline Metal Powders
Interin technical rept. 1 May 1978-30 Apr 1980
PHRASOR SCIENTIFIC INC DUARTE CA
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Electrohydrodynamics EHD has been explored for the generation and control of charged liquid droplets in order to produce micro-size particles and splat coatings. The aim of this work is the development of a Tabletop Powder Generator capable of controlled production of powder sizes that are both smaller and more narrowly distributed than those produced by conventional atomizers. This tool is being designed for use in fundamental studies of the effect of solidification variables on microstructures and the development of new alloy compositions attainable through rapid solidification processing. The EHD technique requires the use of intense electric fields to generate liquid droplets directly from the liquid state. This is achieved by delivering a molten alloy to the tip of a fine capillary nozzle to which high voltage is applied. A variety of droplet source configurations and materials were explored on this program. Resistance heater technology was improved resulting in greater reliability and temperatures of 1800K were achieved while experiencing minimal erosion. Several modes of source operation were encountered depending upon the interaction of the molten metals with source materials. Rapid solidification and cooling rates of beam droplets in a vacuum environment have been analyzed from novel points of view. Powders smaller than 0.01 micron have been produced with calculated cooling rates of approximately 10,000,000 Ks from radiation cooling alone.
- Ceramics, Refractories and Glass
- Metallurgy and Metallography
- Fabrication Metallurgy