Color is another optical property that gives ceramic parts a variety of applications. When certain ions in the machining materials of precision ceramic parts contain easily excited electrons, light in the visible range may be absorbed. At this point, the ceramic part takes on a color. This occurs mainly in d layers with a single fill (e.g. V.cr., Mn.Fe.Ni.Cu. Or F-layer (rare earth elements) of the transition elements, they are relatively unstable. They have higher energy, require more energy, and can be excited with less energy, so they can selectively absorb visible light, such as C+ ions, and slightly collect orange, yellow and some green light, showing purple-blue; Ni2+ absorbs other light through violet and red light to form purplish gray; Cu+ ions absorb red, orange, yellow and violet light, allowing blue and green to pass through: rare earth elements such as Ce have pinnate absorption in blue-purple, yellow; Nd3+ (neodymium) absorbs orange and yellow and appears reddish purple.

Coloring of alumina ceramic parts processing

Al2O3 often needs coloring in practical applications, and industrial ceramic parts processing manufacturers can present different colors by introducing colored ion compounds. For example, in semiconductor integrated circuits, aluminum oxide used as a package housing should be light-resistant. Therefore, the Al2O3 on the backplane of the nixie tube is also required to be black to ensure a clear digital display. For this purpose, Fe2O3, CoO.Cr2O3, TiO2, MnO and other colored oxides can be introduced into Al2O3. The black of Al2O3 ceramic parts is due to the partial reduction of Ti+ in ceramic parts to Ti4+ under the action of reducing atmosphere (H2) and high temperature. Ti3+ can actually be seen as T1+ bound to electrons, that is, Ti4+e-. This bound electron is a weakly bound electron, which can be seen as the "color center" in titanium dioxide, so such ceramic parts appear black. Another commonly used red purple Al2O3 is the introduction of Cr2O3 and MnO in Al2O3 ceramic parts. Containing about 1% Cr2O3, Al2O3, ceramic parts are often red, because the Cr3+ ion in the solid solution α-Al2O3 lattice has a strong selective absorption of the blue-green of visible light, so that the body shows a blue-green complementary color, that is, pink.