Showing papers on "Tantalum capacitor published in 2023"

Electrolytic capacitor: Properties and operation

Abstract: Due to their high specific volumetric capacitance, electrolytic capacitors are used in many fields of power electronics, mainly for filtering and energy storage functions. Their characteristics change strongly with frequency, temperature and aging time. Electrolytic capacitors are among the components whose lifetime has the greatest influence on the reliability of electrical systems. Over the past three decades, many efforts in academic research have been devoted to improving reliability capacitor. Industrial applications require more reliable power electronic products. It is in this context that the different electrolytic capacitors and their characteristics are discussed. The aging process of aluminum electrolytic capacitors is explained. Finally, this paper reviews existing methods of failure prognosis of electrolytic capacitors.

An Ultra‐Thin, Ultra‐High Capacitance Density Tantalum Capacitor for 3D Packaging

Abstract: Although embedded capacitors have been applied and researched for many years, their large‐scale application still faces challenges such as low capacitance density, high thickness, high cost, and incompatibility with integrated processes. In this work, a breakthrough has been made in the fabrication of ultra‐thin tantalum (Ta) capacitors with ultra‐high capacitance density that can be used for 3D packaging. The key to these excellent performances is the application of Ta foil with nano‐porous structure to the anode of the capacitor. The Ta foil with high specific surface area (SSA) is successfully prepared by direct current pulse etching. At a current density of 15 mA cm−2, a pulse frequency of 50 Hz, and a duty cycle of 30%, the SSA of Ta foil is increased by 76 times after etching in an electrolyte with 0.01 v% TOA for 30 min. Based on this, Ta capacitors with a form factor of less than 40 µm, showing a capacitance density of 750 nF mm−2 and a leakage current of less than 2.1 × 10−7 A at 8 V is successfully fabricated. To the best of the authors’ knowledge, this is the highest capacitance density reported to date for the mentioned form factors.

Surface enlargement of tantalum capacitor foils by pulsed direct current etching and laser cladding

Abstract: Electrochemical etching for the surface enlargement of tantalum capacitor foils has always been a challenge, due to the ultra-high chemical stability of tantalum foils. Herein, pulsed direct current etching of tantalum capacitor foils assisted by laser cladding was investigated and high surface area enlargement was achieved. The effects of electrolyte composition, power supply parameters and external environment on the etching process of tantalum foil were systematically studied, to screen out the best experimental conditions. Furthermore, iron particles with diameters of 3–5 μm were successfully laser cladded on the surface of tantalum foils. These particles will be easily etched in the electrochemical process to form more previous pores, which can serve as etching sites for further tantalum foil etching. Under the best conditions, high-specific capacitance tantalum foils with a capacitance of 155.1 nF/mm2 were obtained at a high forming voltage of 100 V, which were 8 times larger than the unetched light foils. The surface enlargement of tantalum capacitor foils is expected to realize the development of novel tantalum capacitors with both high operating voltage and high capacitance.

Tantalum Recovery Technique for Recycling of Tantalum Coated Composite Materials

Abstract: In recent years, tantalumTantalum is being increasingly researched as a replacement for coatings for high-temperature applications. TantalumTantalum is a refractory metalMetal with low recyclingRecycling rate of less than 1% because most tantalumTantalum secondary recoverySecondary recovery techniques are primarily meant for recoveryRecovery of other elements. In this study, the objective is to review various potential methods for recyclingRecycling of tantalum coated steel composite, either at its end of life or for coating refurbishment purposes when coating is damaged. Tantalum can be recovered by both pyrometallurgical and hydrometallurgical methods, or a combination of the two, and it usually involves a whole process development with multiple steps for separationSeparation and purificationPurification from other elements. The main factor for selecting the best recoveryRecovery method is dependent on the materials which are mechanically or chemically bonded with tantalumTantalum. This review summarizes various methods to recover tantalum from different secondary sources like tantalumTantalum capacitors, tantalum mill products, and tantalum in chemical processing industry. Lastly, we comment on the best method to recover tantalum from tantalumTantalum coated scrap.

Electrochemical power sources: Capacitors

Abstract: This overview chapter compares electrostatic capacitors, electrolytic capacitors, and electrochemical capacitors. Conventional electrostatic capacitors contain a dielectric whereas electrochemical capacitors have a liquid electrolyte and do not operate simply in an “electrostatic” way. Principle, function and design of classical capacitors using polymer dielectrics, solid-state electrolytes, metal-films and ceramics, and so-called supercapacitors are outlined.