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Schematic illustration of one reaction cycle of the ALD process, using the trimethylaluminium (TMA) -water process to make thin aluminium oxide films as (simplified) example. There, the starting surface contains hydroxyls (OH groups) as reactive sites; Step 1 is the reaction of TMA; Step 2 is a purge or evacuation step, Step 3 is the reaction ...
Also known as hafnium dioxide or hafnia, this colourless solid is one of the most common and stable compounds of hafnium. It is an electrical insulator with a band gap of 5.3~5.7 eV. [2] Hafnium dioxide is an intermediate in some processes that give hafnium metal. Hafnium(IV) oxide is quite inert.
The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite , aluminium 's chief ore, through the Bayer process ) in molten cryolite and electrolyzing the molten salt bath, typically in a purpose-built cell.
The white hafnium(IV) oxide (HfO 2), also known as hafnium dioxide or hafnia, with a melting point of 2,812 °C and a boiling point of roughly 5,100 °C, is very similar to zirconia, but slightly more basic. [13] It is an electrical insulator with a band gap of 5.3~5.7 eV. [15] Hafnium(IV) oxide typically adopts the same structure as zirconia ...
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer. Bauxite, the most important ore of aluminium , contains only 30–60% aluminium oxide (Al 2 O 3 ), the rest being a mixture of silica , various iron oxides , and titanium dioxide . [ 1 ]
A process flow diagram (PFD) is a diagram commonly used in chemical and process engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between major equipment of a plant facility and does not show minor details such as piping details and designations.
The process produces a quantity of fluoride waste: perfluorocarbons and hydrogen fluoride as gases, and sodium and aluminium fluorides and unused cryolite as particulates. This can be as small as 0.5 kg per tonne of aluminium in the best plants in 2007, up to 4 kg per tonne of aluminium in older designs in 1974.
Sequential infiltration synthesis (SIS) is a technique derived from atomic layer deposition (ALD) in which a polymer is infused with inorganic material using sequential, self-limiting exposures to gaseous precursors, enabling precise manipulation over the composition, structure, and properties. The technique has applications in fields such as ...