The sol-gel process is used for making ceramic and glass materials. It is mainly the transition of a system from a solid to a liquid phase. By using this process, it is possible to make ceramic and glass materials in the following variety of forms: ultra-fine or spherical shaped powders, thin film coatings, ceramic fibers, micro porous inorganic membranes, monolithic ceramics and glasses, or extremely porous aero gel materials. By subjecting inorganic metal salts or metal organic compounds to hydrolysis and, the “sol” is formed.
By further processing the “sol,” a wide variety of ceramic or glass materials are able to be formed. For instance, thin films are capable of being formed by spin-coating a piece of substrate. This is how anti-reflective coatings can be formed. This coating also has potential in being used as a corrosion resistant layer. If the “sol” is poured into a mold, and subjected to drying and heat-treatments, it will form a dense ceramic or glass material. If it is removed from the mold in a “gel” form at super critical condition, an “aero gel” material is formed.
Fine ceramic powders can be made by precipitation, spray pyrolysis, or emulsion of the “gel” at certain. A “cryogen” can also be formed by a process of freeze-drying. This “cryogen” can be brought back to it’s identical original form by adding water to it. The importance of sol-gel comes from the wide variety of physical and chemical properties that can be obtained by using different processes. It can be used in everything from sun tan oils to high quality optics. The possibilities of this process have yet to reach their full potential, but the uses seem endless..
The Essay on Foreign Materials In Processed Food
Foreign Materials in Food Products Abstract This practical was carried out to learn the uniform evaluation of foreign materials in processed fruit and vegetable commodities. The main focus is on light filth analysis and the method used is Wildman method. It is also called Light filth flotation method since the food will remain in the aqueous layer and settle at the bottom while light filths are ...
