Borosilicate glass formulations give enhanced physical and chemical durability compared to soda-lime glasses commonly encountered as commercial container glasses. Borosilicate glasses are also frequently encountered in everyday life in the form of...
Glassflake’s Nanoflake range is the result of a number innovations in both process engineering, glass technology and chemical design. In a previous LinkedIn post, we described some of the raw materials used in our Glassflake. We also described how our first-melt approach to production helps us delivers a product that is not only consistent in performance but is sourced to be safe for use is consumer products.
In a new series of posts, starting this week we would like to further familiarise you with glass technology and chemistry, including the design considerations of glass formulation. Let’s start with a brief overview of the common subtypes of glass within the biggest family of glasses, silicate (SiO2) glasses.
Technically speaking glass could refer to any number of amorphous materials, but common usage means when someone refers to glass, they likely mean a silicate glass. This is because not only is it historically the oldest form of manufactured glass, it is also still the most commonly encountered in our everyday lives. It is also common knowledge that silicate glasses are manufactured from sand. However, very few of these glasses will be in fact be made purely from sand. Having an extremely high melting point, > 1700 °C this would be extremely energy intensive and therefore costly.
Glass manufacturers bypass this by not relying on melting the silica directly but instead through formation of a eutectic mixture with a flux material that produces a material with a drastically reduced melting point. A common example is sodium carbonate (“soda ash”) and the resultant glasses are referred to as a soda silicate glass. These glasses are however highly water soluble and as such have very limited practical applications. This problem can be resolved in turn by substitution of some of the soda for lime (calcium carbonate) and the resulting soda-lime [silicate] glasses are the basis of most commercial window panes and glass container bottles.
A very dramatic and potentially dangerous weakness of these glasses is their brittleness and hence their tendency to shatter -especially when exposed to sudden changes in temperature. Borosilicate glasses used in cookware and laboratory glassware remedy this and we will discuss these next time around.