Spray conversion process for the production of nanophase composite powders
OwnerLarry E. McCandlish, Bernard H. Kear +1inventors
InventorsLarry E. McCandlish, Bernard H. Kear, Swarn J. Bhatia
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OwnerLarry E. McCandlish, Bernard H. Kear +1inventors
InventorsLarry E. McCandlish, Bernard H. Kear, Swarn J. Bhatia
Estimating the term…
A process is described for the production of composite powders with ultrafine microstructures. The process involves three coordinated steps: 1) preparation and mixing of an appropriate starting solution; 2) spray drying to form a chemically homogeneous precursor powder; and 3) fluid bed thermochemical conversion of the precursor into the desired nanophase composite powder. Both spray drying and fluid bed conversion are scaleable technologies, and together provide the means for producing bulk quantities of nanophase composite powders at low manufacturing cost. Processing parameters are controlled to ensure maintenance of chemical and microstructural uniformity at the nanoscale (less than 0.1 micron) level. Spray conversion processing is a versatile technology, which can be applied to a variety of metal--metal (e.g. W--Cu), ceramic-metal (e.g. WC--Co), and ceramic--ceramic (e.g. Al.sub.2 O.sub.3 --SiO.sub.2) nanophase composite powders ceramic-metal (e.g. WC--Co), and ceramic--ceramic (e.g. Al.sub.2 O.sub.3 --SiO.sub.2) nanophase composite powders.
A spray conversion process for the production of nanophase composition tungsten carbide cobalt powders comprising the steps of:
A spray conversion process for the production of nanophase tungsten carbide-cobalt (WC--Co) comprising the steps of:
The process according to claim 11 wherein during the thermochemical conversion step the carburization temperature is in the range 700.degree. C. to 1100.degree. C., the carbon activity is controlled in the range a.sub.c =0.3 to 1.0 and the Co/W atomic ratio is in the range 0.1 to 1.5.
Dependencies are inferred from the claim text.