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  2. Passivation (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Passivation_(chemistry)

    Aluminium naturally forms a thin surface layer of aluminium oxide on contact with oxygen in the atmosphere through a process called oxidation, which creates a physical barrier to corrosion or further oxidation in many environments. Some aluminium alloys, however, do not form the oxide layer well, and thus are not protected against corrosion ...

  3. Hall–Héroult process - Wikipedia

    en.wikipedia.org/wiki/Hall–Héroult_process

    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 Hall–Héroult process ...

  4. Chemical coloring of metals - Wikipedia

    en.wikipedia.org/wiki/Chemical_coloring_of_metals

    Chemical coloring of metals is the process of changing the color of metal surfaces with different chemical solutions. The chemical coloring of metals can be split into three types: electroplating – coating the metal surface with another metal using electrolysis. patination – chemically reacting the metal surface to form a colored oxide or salt.

  5. Aluminium oxide - Wikipedia

    en.wikipedia.org/wiki/Aluminium_oxide

    Aluminium oxide in its powdered form. Al 2 O 3 is an electrical insulator but has a relatively high thermal conductivity ( 30 Wm−1K−1) [ 2] for a ceramic material. Aluminium oxide is insoluble in water. In its most commonly occurring crystalline form, called corundum or α-aluminium oxide, its hardness makes it suitable for use as an ...

  6. Electrophoretic deposition - Wikipedia

    en.wikipedia.org/wiki/Electrophoretic_deposition

    Electrophoretic deposition ( EPD ), is a term for a broad range of industrial processes which includes electrocoating, cathodic electrodeposition, anodic electrodeposition, and electrophoretic coating, or electrophoretic painting. A characteristic feature of this process is that colloidal particles suspended in a liquid medium migrate under the ...

  7. Halloysite - Wikipedia

    en.wikipedia.org/wiki/Halloysite

    Halloysite is an aluminosilicate clay mineral with the empirical formula Al 2 Si 2 O 5 (OH) 4. Its main constituents are oxygen (55.78%), silicon (21.76%), aluminium (20.90%), and hydrogen (1.56%). It is a member of the kaolinite group. Halloysite typically forms by hydrothermal alteration of alumino-silicate minerals. [ 4]

  8. Decoupage - Wikipedia

    en.wikipedia.org/wiki/Decoupage

    Decoupage or découpage ( / ˌdeɪkuːˈpɑːʒ /; [ 1] French: [dekupaʒ]) is the art of decorating an object by gluing colored paper cutouts onto it in combination with special paint effects, gold leaf, and other decorative elements. Commonly, an object like a small box or an item of furniture is covered by cutouts from magazines or from ...

  9. Conservation and restoration of frescos - Wikipedia

    en.wikipedia.org/wiki/Conservation_and...

    Water acts as a type of binding agent that allows the pigment to merge with the plaster, and once the plaster sets the painting becomes an integral part of the wall. Materials (chemical make-up) Lime cycle. Fresco chemicals consist of the following: Silicon dioxide (sand) Calcium oxide (quick lime) Dihydrogen oxide (water)