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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.
Tantalum(V) oxide films have a variety of applications including as optical films with refractive indices as high as 2.039 [16] and as a thin-film dielectric material in dynamic random access memory and semiconductor field-effect transistors. [12] The approach chosen for preparation of these materials is determined by the desired properties.
By applying a positive voltage to the above-mentioned anode material in an electrolytic bath an oxide barrier layer with a thickness corresponding to the applied voltage will be formed (formation). This oxide layer acts as the dielectric in an electrolytic capacitor. The properties of these oxide layers are given in the following table:
Tantalum electrolytic capacitors exploit the tendency of tantalum to form a protective oxide surface layer, using tantalum powder, pressed into a pellet shape, as one "plate" of the capacitor, the oxide as the dielectric, and an electrolytic solution or conductive solid as the other "plate".
As quoted from this source in an online version of: J.A. Dean (ed), Lange's Handbook of Chemistry (15th Edition), McGraw-Hill, 1999; Section 4; Table 4.1, Electronic Configuration and Properties of the Elements Touloukian, Y. S., Thermophysical Properties of Matter, Vol. 12, Thermal Expansion, Plenum, New York, 1975.
Its relative dielectric constant is ~22 and it has a thermal expansion coefficient of 8~10×10 −6 /K. The thermal conductivity of LSAT is 5.1 Wm −1 K −1. [2] [3] LSAT's (cubic) lattice parameter of 3.868 Å makes it compatible for the growth of a wide range of perovskite oxides with a relatively low strain. [citation needed]
In this model the conduction is supposed to be carried by a free electron system moving in a self-consistent periodic potential. On the contrary, Frenkel derived his formula describing the dielectric (or the semiconductor) as simply composed by neutral atoms acting as positively charged trap states (when empty, i.e. when the atoms are ionized).