Poly(Alkylene) Carbonates As Binders In The Manufacture Of Valve Metal Anodes For Electrolytic Capacitors

An anode for an electrolytic capacitor is described. The anode is of a valve metal in powdered form, for example tantalum powder, that has been pressed into a pellet and sintered under a vacuum at high temperatures. Preferably, a poly(alkylene)carbonate binder is used to promote cohesion with the pressed powder body. The binder adds green strength to the pressed body and helps with powder flow before pressing. The poly(alkylene)carbonate binders are superior in that they leave virtually no residual carbon behind when burnt out during the sintering process. The pressed valve metal powder structure is then anodized to a desired voltage in a formation electrolyte to form a continuous dielectric oxide film on the sintered body as well as a terminal lead/anode lead weld extending therefrom.