Sintered valve metal powders for implantable capacitors
View Patent ↗A sintering method for valve metal powders, such as tantalum, niobium, aluminum, titanium, and their alloys, is described. The valve metal powders are pressed into a pellet and sintered at a relatively high temperature, but for a relatively short time. The anodized valve metal structure is then useful as an anode in an electrolytic capacitor.
1. An anode for a capacitor, the anode comprising:
a) a tantalum powder provided in the form of a pressed body;
b) wherein the tantalum body is characterized as having been heated to a sintering temperature of about 1,550° C. to about 1,650° C. for up to about 8 minutes.
2. The anode of claim 1 wherein the tantalum is characterized as having been heated to the sintering temperature of about 1,590° C. to about 1,640° C. for up to about 6 minutes.
3. The anode of claim 1 wherein the tantalum is characterized as having been heating to the sintering temperature in a vacuum ranging from about 10 −4 to about 10 −6 Torr.
4. A capacitor, which comprises:
a) an anode of tantalum powder provided in the form of a pressed body, wherein the tantalum body is characterized as having been heated to a sintering temperature of about 1,550° C. to about 1,650° C. for up to about 8 minutes;
b) a cathode;
c) a separator segregating the anode from the cathode; and
d) a working electrolyte.
5. The capacitor of claim 4 wherein the tantalum is characterized as having been heated to the sintering temperature of about 1,590° C. to about 1,640° C. for up to about 6 minutes.
6. The capacitor of claim 4 wherein the tantalum is of either a beam melt or a sodium reduced type.
7. The capacitor of claim 4 of either an electrolytic or an electrochemical/electrolytic hybrid type.
8. A method for providing an anode for a capacitor, the method comprising the steps of:
a) pressing a tantalum powder into the form of a pressed body; and
b) heating the pressed tantalum powder at a sintering temperature of about 1,550° C. to about 1,650° C. for up to about 8 minutes to thereby provide a sintered valve metal body.
9. The method of claim 8 including heating the tantalum to the sintering temperature of about 1,590° C. to about 1,640° C. for up to about 6 minutes.
10. The method of claim 8 including heating the tantalum to the sintering temperature in a vacuum ranging from about 10 −4 to about 10 −6 Torr.
11. The method of claim 8 including providing the tantalum being of either a beam melt or a sodium reduced type.
12. The method of claim 8 including providing the capacitor as either an electrolytic or an electrochemical/electrolytic type.
13. A capacitor, which comprises:
a) an anode of either a beam melt or a sodium reduced type of tantalum powder provided in the form of a pressed body, wherein the tantalum body is characterized as having been heated to a sintering temperature for about 10 minutes, or less;
b) a cathode;
c) a separator segregating the anode from the cathode; and
d) a working electrolyte.