Surface Chemistry of Submicron cBN Powders

New grades of submicron and nanosized powders of cubic boron nitride

“…The thermal desorption spectra of the powders were obtained using a MI-1201 mass spectrometer at a heating rate of 30 deg/min, under a vacuum of 1 ⋅ 10 -6 , between 20 and 600°C [10]. Electrochemical studies that involved plotting cathodic potentiodynamic curves in hydrochloric acid [5] were conducted using a P-5848 potentiostat and starting and modified submicron and nanosized cBN powders with grain sizes of 1/0.5, 0.5/0.25, 0.25/0.1, and 0.1/0.…”

“…Mass spectrometry previously [6,7] identified water vapors, hydroxyl groups, molecular and atomic oxygen, molecular nitrogen, ammonia, nitrogen and boron oxides and hydroxides, magnesia, and boron hydrate B 6 H 10 on the surface of submicron and nanosized cBN powders. The compounds and functional groups desorbed from the surface of cBN powders are conventionally divided into those that are absorbed physically and chemically, depending on the type of bonding.…”

“…Thus, to make polycrystalline samples and tools, powders that contain the minimum amount of surface impurities and have no oxygen-bearing groups (hydrophobic surface) are needed. Hydrophilic cBN powders are required to produce suspensions and pastes [5][6][7][8].…”

Combined Vibrational Spectroscopic and Theoretical Study on Nature ofc-BN Powders Surface

“…properties of H-terminated − and amino-functionalized c -BN. It is also established that a thin film of boron oxide is formed on the surface of the c -BN upon heating to 1473 K . It should be emphasized that spectral features of the boron oxide were previously detected, in the case when nanosized c -BN fractions were analyzed instead of films or bulk samples.…”