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Tantalum pentoxide, also known as tantalum(V) oxide, is the inorganic compound with the formula Ta 2 O 5. It is a white solid that is insoluble in all solvents but is attacked by strong bases and hydrofluoric acid. Ta 2 O 5 is an inert material with a high refractive index and low absorption (i.e. colourless), which makes it useful for coatings ...
A typical tantalum capacitor is a chip capacitor and consists of tantalum powder pressed and sintered into a pellet as the anode of the capacitor, with the oxide layer of tantalum pentoxide as a dielectric, and a solid manganese dioxide electrolyte as the cathode.
The main difference between the polymer capacitors is the anode material and its oxide used as the dielectric: Polymer tantalum electrolytic capacitors use high purity sintered tantalum powder as an anode with tantalum pentoxide (Ta 2 O 5) as a dielectric and
Tantalum electrolytic capacitors use a sintered pellet (“slug”) of high-purity tantalum powder with tantalum pentoxide as dielectric; Niobium electrolytic capacitors use a sintered "slug" of high-purity niobium or niobium oxide powder with niobium pentoxide as dielectric.
The permittivity of tantalum pentoxide is approximately three times higher than aluminium oxide, producing significantly smaller components. However, permittivity determines only the dimensions. Electrical parameters, especially conductivity , are established by the electrolyte's material and composition.
Because the thickness of the effective dielectric is proportional to the forming voltage, the dielectric thickness can be tailored to the rated voltage of the capacitor. For example, for low voltage types a 10 V electrolytic capacitor has a dielectric thickness of only about 0.014 μm, a 100 V electrolytic capacitor of only about 0.14 μm.
Tantalum capacitors are, under some conditions, prone to self-destruction by thermal runaway. The capacitor typically consists of a sintered tantalum sponge acting as the anode , a manganese dioxide cathode , and a dielectric layer of tantalum pentoxide created on the tantalum sponge surface by anodizing .
Dielectric absorption is the name given to the effect by which a capacitor, that has been charged for a long time, discharges only incompletely when briefly discharged. Although an ideal capacitor would remain at zero volts after being discharged, real capacitors will develop a small voltage from time-delayed dipole discharging, [ 1 ] a ...