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Tantalum ores often contain significant amounts of niobium, which is itself a valuable metal.As such, both metals are extracted so that they may be sold. The overall process is one of hydrometallurgy and begins with a leaching step; in which the ore is treated with hydrofluoric acid and sulfuric acid to produce water-soluble hydrogen fluorides, such as the heptafluorotantalate.
Chemical vapour deposition allows control of the thickness of the film on a nanometre scale, which is essential for some applications. Direct pyrolysis is convenient for optical applications, [ 10 ] where transparent materials with low light loss due to absorption is important, [ 16 ] and has also been used to prepare nitride read-only memory ...
The rutile crystal structure of TiO 2. The majority of transition metal dioxides (MO 2) have the rutile structure, seen to the right.Materials of this stoichiometry exist for Ti, Cr, V and Mn in the first row transition metal and for Zr to Pd in the second.
Atomic layer deposition (ALD) is a thin-film deposition technique based on the sequential use of a gas-phase chemical process; it is a subclass of chemical vapour deposition. The majority of ALD reactions use two chemicals called precursors (also called "reactants"). These precursors react with the surface of a material one at a time in a ...
In chemistry, deposition occurs when molecules settle out of a solution. Deposition can be defined as the process of direct transition of a substance from its gaseous form, on cooling, into a solid state without passing through the intermediate liquid state. [1] Deposition can be viewed as a reverse process to dissolution or particle re ...
The beta phase is metastable and converts to the alpha phase upon heating to 750–775 °C. Bulk tantalum is almost entirely alpha phase, and the beta phase usually exists as thin films [30] obtained by magnetron sputtering, chemical vapor deposition or electrochemical deposition from a eutectic molten salt solution. [31]
Underpotential deposition (UPD), in electrochemistry, is a phenomenon of electrodeposition of a species (typically reduction of a metal cation to a solid metal) at a potential less negative than the equilibrium potential for the reduction of this metal. The equilibrium potential for the reduction of a metal in this context is the potential at ...
Electron-beam-induced deposition (EBID) is a process of decomposing gaseous molecules by an electron beam leading to deposition of non-volatile fragments onto a nearby substrate. The electron beam is usually provided by a scanning electron microscope , which results in high spatial accuracy (potentially below one nanometer) and the possibility ...