February 19th, 2021
Cubic boron nitride is a unique crystalline form of boron nitride with exceptional thermomechanical properties. It has outstanding hardness approaching that of diamond, plus fantastic thermal stability with an oxidation threshold of approximately 1,000°C—with oxidization completing at approximately 1,500°C. Cubic boron nitride is a comparatively recent material innovation and has been referred to as one of the best technological developments for abrasives of all time.
Cubic boron nitride has a boron oxide layer which protects against oxidation, this means it can withstand ultra-high speeds in abrasive grinding. Abrasives are employed in many different manufacturing applications; mainly comprising hard metallic or mineralogical grains bound to a substrate like a grinding wheel or a band. Intensive grinding processes cause abrasive grains to gradually break down due to mechanical wearing which is determined by a complex interplay of chemical, physical, and thermal phenomena.
Cubic boron nitride has four times the abrasion resistance and twice the hardness of conventional abrasives, making it extremely wear-resistant. Its unique chemical properties also make it uniquely suited to grinding ferrous substrates.
There is an extensive range of chemistries and forms of cubic boron nitride. When choosing cubic boron nitride abrasives there are a number of parameters which should be considered. These include particle size distribution, morphology, toughness index, aspect ratio, percentage coating by weight, and morphology.
Cubic boron nitride can be used in grinding wheels. A mesh of electroless, nickel-coated particles are sintered directly on the wheel which creates an extremely robust and sturdy tool. Resin bond wheels compose semi-blocky cubic boron nitride abrasive grains with specific friability for non-ferrous grinding applications. Vitrified grinding wheels include synthetic bonding systems and either micron or mesh carbon boron nitride grains, subject to the specified use.
Saint-Gobain Surface Conditioning are at the forefront of abrasive grain engineering and offer a range of cubic boron nitride abrasive materials. Saint-Gobain’s cubic boron nitride mesh is usually 40µm or higher in particle size and is available in an electroless nickel (Ni) coating of 60% by weight. Saint-Gobain’s electroless coated particles offer improved grinding wheel performance with increased longevity as heat removal from the grinding zone is improved and abrasive adhesion in the bond system is enhanced.