Tantalum-polymer capacitors are widely used in various electronic devices due to their high capacitance, low ESR, and stable performance. The production process of tantalum-polymer capacitors involves several steps, including tantalum powder preparation, tantalum capacitor fabrication, and polymer electrolyte formation. In this article, we will discuss the mainstream tantalum-polymer capacitor production process in detail.

Tantalum Powder Preparation

The first step in the production of tantalum-polymer capacitors is the preparation of tantalum powder. Tantalum is a rare metal that is extracted from tantalite ores. The tantalite ore is first crushed and ground into a fine powder. The powder is then roasted in a furnace to remove impurities and convert the tantalum oxide into tantalum metal. The tantalum metal is then crushed and ground into a fine powder.

The tantalum powder is then mixed with a binder, such as polyvinyl alcohol (PVA), to form a slurry. The slurry is then poured into a mold and pressed into a compact shape. The compact is then sintered in a furnace at high temperatures to form a solid tantalum capacitor.

Tantalum Capacitor Fabrication

The next step in the production of tantalum-polymer capacitors is the fabrication of the tantalum capacitor. The tantalum capacitor is made up of a tantalum anode, a dielectric layer, and a cathode. The tantalum anode is made from the tantalum powder compact that was sintered in the previous step.

The tantalum anode is then etched in an acid solution to remove the surface oxide layer and expose the fresh tantalum metal. The etched tantalum anode is then anodized in an electrolyte solution to form a dielectric layer on the surface of the tantalum metal. The dielectric layer is formed by applying a voltage to the tantalum anode while it is immersed in the electrolyte solution. The voltage causes the tantalum metal to react with the electrolyte solution and form a thin layer of tantalum oxide on the surface of the anode.

The thickness of the dielectric layer is controlled by the anodizing voltage and time. The dielectric layer thickness determines the capacitance of the tantalum capacitor. After anodizing, the tantalum anode is rinsed in water to remove any residual electrolyte solution.

Polymer Electrolyte Formation

The final step in the production of tantalum-polymer capacitors is the formation of the polymer electrolyte. The polymer electrolyte is formed by immersing the anodized tantalum anode in a solution of a conductive polymer, such as polypyrrole or polyaniline. The conductive polymer solution is absorbed into the pores of the anodized tantalum oxide layer and forms a thin layer of polymer electrolyte on the surface of the dielectric layer.

The polymer electrolyte provides a low ESR (Equivalent Series Resistance) and stable performance to the tantalum capacitor. The polymer electrolyte also prevents the formation of dendrites, which are tiny metal spikes that can grow from the anode and short-circuit the capacitor.

After the polymer electrolyte is formed, the tantalum capacitor is rinsed in water to remove any residual polymer solution. The capacitor is then dried and tested for capacitance, ESR, and leakage current.

Conclusion

In conclusion, the production process of tantalum-polymer capacitors involves several steps, including tantalum powder preparation, tantalum capacitor fabrication, and polymer electrolyte formation. The process requires careful control of the parameters, such as anodizing voltage and time, to ensure consistent performance and reliability of the capacitors. Tantalum-polymer capacitors are widely used in various electronic devices, such as smartphones, laptops, and power supplies, due to their high capacitance, low ESR, and stable performance.