Grinding and Polishing

The aforementioned methods of specimen preparation, except microtomy, are regarded as an important part of metallography. These methods are also used for non-metallic materials 

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Corundum. Comndum [1302-75-5] (see Aluminum compounds) is a naturally occurring massive crystalline mineral composed of aluminum oxide. It is an impure form of the gems mby and sapphke. Prior to 1900 comndum was an important abrasive for the production of grinding wheels. Today it is mainly employed as a loose abrasive for grinding and polishing optical lenses. Almost all the world s supply of comndum now comes from Africa, primarily from Zimbabwe. 

Wearable coated abrasive wheels of the radial-fiap type can grind and polish contours that are almost impossible for bonded abrasive wheels. 

In the float-glass process, adopted by all leading plate-glass manufacturers, the molten glass is allowed to float and soHdify on the surface of a pool of molten tin which provides an ideally flat surface. The endless glass ribbon has a surface so smooth that cosdy grinding and polishing are unnecessary. 

Artifacts introduced through sample preparation are common materials these may be bits of facial tissue, wax, epithelial cells, hair, or dried stain, all inadvertently introduced by the microscopist. Detergent residues on so-called precleaned microscope slides and broken glass are common artifacts, as are knife marks and chatter marks from sectioning with a faulty blade, or scratch marks from grinding and polishing. 

The corrosion process is modified by the physical state of the surface. Grinding and polishing processes, in particular, leave the structure in a more open state and with a degree of roughness and residual stress all can contribute to accelerated corrosion. 

HANDBOOKOF CERAMIC GRINDING AND POLISHING edited by loan D. Mavinescu, Hans K. Tonshoff, and Ichiro Inasaki... 

Diamond Precious-stone grinding and polishing Pure carbon High refractive index hardest material on earth... 

Deviations of the collecting surface from an ideal parabola must not exceed a tiny fraction of the shortest wavelength to be analysed. Grinding and polishing are the bread and butter of optical astronomy. 

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