Boron oxide glass, hardness

Pure boric oxide is perhaps the best glass former (even better than silica). Crystals of BjOj are hard to obtain from a melt at the slowest cooling rates. (All of the commercially sold anhydrous boric oxide is actually boric oxide glass.) The structure is composed of fiiUy connected BOj triangles with the boron atoms slightly out of the plane formed by the oxygens. 

Glass is produced by fusing the oxides of silicon, boron, or phosphorous with a basic oxide or sodium, calcium, magnesium, or potassium, and cooling the product rapidly to prevent crystallization. It is a transparent, hard, brittle and amorphous material resistant to all acids except hydrofluoric acid. 

Extensive ranging of abrasive wheel geometries, abrasive materials (aluminum oxide, emery, corundum, diamond. Cubic Boron Nitride (CBN)), grain size, hardness grading and bond types (resin, vitrified glass, rubber, metal) are available. 

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