| 摘要 |
Methods of forming tantalum powders and other valve metal powders are described. The method involves high impact milling a starting powder in a fluid medium and optionally a milling media using a high energy mill. The methods of the present invention have the ability to reduce DC leakage and/or increase capacitance capabilities of valve metal powders when formed into capacitor anodes. The methods of present invention further reduce the milling time necessary to form high surface area valve metal powders and leads to reducing contaminant levels in the valve metal powders. The process is particularly well-suited for forming metal flakes, such as tantalum or niobium flakes, of high purity. The obtained tantalum powder has a BET surface area of at least 1.5 m2/g. When said powder is formed into an electrolytic capacitor anode, the capacitance will be at least 190000 CV/g, when formed at a Vf of 20V and sintered at 1400°C for 10 minutes. |
