Cerium oxide is an important rare earth oxide, mainly used in smelting metal cerium and additives for various materials. Since 1940, rare earth polishing powder with high content of cerium oxide began to replace iron oxide (i.e. iron-red) in glass polishing, and became one of the key materials in glass polishing process. Compared with the traditional polishing powder – iron oxide, rare earth polishing powder has the advantages of fast polishing speed, high finish and long service life, and can change the polishing quality and operating environment. For example, if you use Cerium Oxide polishing powder to polish a lens, the workload will be completed in one minute, while if you use Iron Oxide polishing powder, it will take 30~60 minutes.
The excellent performance of cerium oxide in glass polishing lies in the polyvalent state of cerium element and its easy transformation property. The redox reaction of Ce(+3)/Ce(+5) will destroy the silicate crystal lattice, and through chemical adsorption, the substances on the surface of the glass that are in contact with the polishing agent (including glass and hydrolyzed compounds) will be oxidized or formed into the complexes and be removed. In addition, Cerium Oxide has the same polishing properties on silica glass, crystals, calcium fluoride and other crystals.
一、 Classification of Cerium Oxide Polishing Powder
Due to the excellent performance of Cerium Oxide on silica glass and crystals, the classification of Cerium Oxide Grinding Solution is mainly based on the content of Cerium Oxide and the particle size of micropowder.
1. Low Cerium polishing powder
Low cerium polishing powder generally contains about 50% CeO2, the other 50% is La2O3, Nd2O3, Pr6O11, etc. or LaOF, NdOF, PrOF and other alkali fluoride. Due to the presence of the element Pr, the appearance is red or brownish-red, and the higher the content of Pr, the darker the color. With the advancement of science and technology and the development and utilization of perylene, low-celium polishing powder perylene has been refined, so there are also white low-celium polishing powder products. The price of this kind of polishing powder is low, but the initial polishing ability is almost no difference with the high cerium polishing powder, so it is widely used in the polishing of flat glass, picture tube glass, eyeglass lenses and other low-end products, but the service life is lower than that of the high cerium polishing powder.
