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The first type of lapping (traditionally often called grinding), involves rubbing a brittle material such as glass against a surface such as iron or glass itself (also known as the "lap" or grinding tool) with an abrasive such as aluminum oxide, jeweller's rouge, optician's rouge, emery, silicon carbide, diamond, etc., between them.
Glass disease, also referred to as sick glass or glass illness, is a degradation process of glass that can result in weeping, crizzling, spalling, cracking and fragmentation. [ 1 ] [ 2 ] Glass disease is caused by an inherent instability in the chemical composition of the original glass formula. [ 3 ]
The glass composition influences moulding tool life; Chalcogenide materials require certain preform shapes; Glass expansion/contraction is highly temperature and rate dependent phenomenon. The coefficient of thermal expansion (CTE) of mould and glass should match. High CTE difference means high deviation between the moulded glass and the mould.
In physical chemistry and engineering, passivation is coating a material so that it becomes "passive", that is, less readily affected or corroded by the environment. . Passivation involves creation of an outer layer of shield material that is applied as a microcoating, created by chemical reaction with the base material, or allowed to build by spontaneous oxidation
Unless stated otherwise, the properties of fused silica (quartz glass) and germania glass are derived from the SciGlass glass database by forming the arithmetic mean of all the experimental values from different authors (in general more than 10 independent sources for quartz glass and T g of germanium oxide glass). The list is not exhaustive.
Amorphous materials will have some degree of short-range order at the atomic-length scale due to the nature of intermolecular chemical bonding. [ a ] Furthermore, in very small crystals , short-range order encompasses a large fraction of the atoms ; nevertheless, relaxation at the surface, along with interfacial effects, distorts the atomic ...
The most common applications are in the making of pottery, glass, and some types of food, but there are many others, such as the vitrification of an antifreeze-like liquid in cryopreservation. In a different sense of the word, the embedding of material inside a glassy matrix is also called vitrification. An important application is the ...
It involves the use of small particles of grit to grind away small chips of material from the surface of an optical workpiece. The grit particles are known as free abrasives. The particles are added to a liquid slurry, which goes between a grinding plate and the material. Sliding motions between the grinding plate and the material are used. [4]