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Sodium silicate solutions can also be used as a spin-on adhesive layer to bond glass to glass [21] or a silicon dioxide–covered silicon wafer to one another. [22] Sodium silicate glass-to-glass bonding has the advantage that it is a low-temperature bonding technique, as opposed to fusion bonding. [21]
Silicate mineral paints or mineral colors are paint coats with mineral binding agents. Two relevant mineral binders play a role in the field of colors: Lime and silicate. Under influence of carbon dioxide, lime-based binders carbonate and water silicate-based binders solidify. Together they form calcium silicate hydrates. [1]
Water glass ( sodium silicate [Na 2 SiO 3 or (Na 2 O)(SiO 2)] ) is a high strength binder used with silica molding sand both for cores and molds. [22]: 69–70 To cure a mixture of finely ground sand (e.g. by using a sand muller) and 3 to 4% of sodium silicate the binder, carbon dioxide (CO 2) gas is used.
The subunits of colloidal silica particles are typically in the range of 1 to 5 nm. Whether or not these subunits are joined depends on the conditions of polymerization. Initial acidification of a water-glass (sodium silicate) solution yields Si(OH) 4. If the pH is reduced below 7 or if salt is added, then the units tend to fuse together in chains.
The most typical geopolymer is generally described as resulting from the reaction between metakaolin (calcined kaolinitic clay) and a solution of sodium or potassium silicate . Geopolymerization tends to result in a highly connected, disordered network of negatively charged tetrahedral oxide units balanced by the sodium or potassium ions.
An aqueous solution of sodium silicate is acidified to produce a gelatinous precipitate that is washed, then dehydrated to produce colorless silica gel. [6] When a visible indication of the moisture content of the silica gel is required, ammonium tetrachlorocobaltate(II) (NH 4) 2 [CoCl 4] or cobalt(II) chloride CoCl 2 is added. [6]
For example, the commercially available sodium silicate pentahydrate Na 2 SiO 3 ·5H 2 O is formulated as Na 2 SiO 2 (OH) 2 ·4H 2 O, and the nonahydrate Na 2 SiO 3 ·9H 2 O is formulated as Na 2 SiO 2 (OH) 2 ·8H 2 O. [5] The pentahydrate and nonahydrate forms have their own CAS Numbers, 10213-79-3 and 13517-24-3 respectively.
Sodium silicate is produced by fusing sodium carbonate with sand or heating both ingredients under pressure. It has been in use since the 19th century. It has been in use since the 19th century. It can be a deterrent against insect attack and possesses minor flame-resistant properties; however, it is easily washed out of wood by moisture ...