Abstract
In this technique, gas-atomization was used at the first stage to produce alloy powders with molten metal. subsequently the atomized alloy powders are flown down, and then crushed into a vapidly notating disk with a high speed of about 250 m/s. Non-solidified and half solidified alloy powders were broken to the smaller ones. According to this mechanism, the further subsequent crash is likely to occur for the remaining non-solidified and half solidified alloy powders.
This non-solidified and half solidified alloy powders can be broken to fine powders one by through the multistage crush mechanism.
In this method, the size of fine powders could be controlled by changing the temperature and flux of molten metal, flux of gas, tangential velocity of rotating disk, distance between disk and nozzle for molten metal, flux of cooling media, and so on. Furthermore, the powders are flown and rotated simultaneously by the rapidly circumrotating disk, The unique mechanism rsuets in the production of spherical powders. In the case of producing Cu powders. The first stage gas atomization, 40μm diameter powders are obtained by the first stage second crush on the rapidly circumrotating disk can produce 10μm powders. Similarly, We also confirmed the production of fine 7μm Al powders. These fine spherical powders, can have various nonequilibrium phases such as nano-crystalline and amorphous phases owing to high cooling rates.
