A method for preparing niobium powder and other metal powder. The method involves grinding metal powder at high temperatures and in the presence of at least one liquid solvent. The method of the present invention can reduce DC leakage of metal powders and/or increase capacitance when made into capacitor anodes. The invention can also significantly shorten the grinding time required to form a high surface area metal powder, thereby reducing the content of dirt in the metal powder. It also relates to metal powders such as niobium powder that reduce dirt content and/or DC leakage or capacitance. The invention further relates to a method for preparing sheet metal by wet grinding metal powder into sheet metal in which at least one fluorinated liquid is present during the wet grinding process. This method is especially suitable for the preparation of high purity metal flakes, such as niobium or tantalum.
For this reason, despite initial hopes that niobium might be a suitable substitute for tantalum, evidence suggests that niobium is not a substitute for tantalum in the electrolytic electrical vessel market. Besides tantalum electrolytic capacitors, there is also a market demand for aluminum electrolytic capacitors. However, there are remarkable differences in performance between aluminum electrolytic capacitors and tantalum electrolytic capacitors. The driving force in electronic circuit systems today is the incremental move to lower equivalent series resistance (ESR) and equivalent series inductance (ESL). As IC performance increases with submicron geometry, it is necessary to reduce the supply voltage and noise limit. At the same time, increasing IC speed requires higher power. Such conflicting requirements require better power management. This is achieved by a distributed electrical source that requires a larger current to decouple the noise. Increasing IC speed also means less switching time and higher transient current. Because of this, the circuit must also be designed to reduce transient load response. If the circuit has a large enough capacitance and low ESR and ESL, it can meet a wide range of requirements.
The feature is to provide wet - ground metal sheets. Another feature of the invention is to provide a wet - grinding valve metal sheet, e.g., sheet niobium and sheet tantalum. Another feature of the invention is to provide a wet grinding method using an inert wet grinding fluid or solvent which results in a metal sheet formed with little or no impurities. Other features and advantages of the invention are described in detail below and are clearly visible from the specification or from the practice of the invention.
