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US 4,231,980 AGranted
Large boron nitride abrasive particles
AssigneeGeneral Electric Company
InventorFrancis R. Corrigan
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Abstract
Hard boron nitride particles of wurtzite and zincblende crystal structure of larger than 50 microns particle size are formed by subjecting recrystallized pyrolytic boron nitride to dynamic shock treatment to create pressures and temperatures in which the stable form of boron nitride has a wurtzite or zincblende crystal structure.
Claims6
A method for producing large-sized, high density particles comprising the steps of:
- (a) placing in a reaction holder a reaction charge consisting essentially of low-density-recrystallized pyrolytic boron nitride and
- (b) subjecting said reaction holder and reaction charge to a shock wave to create pressure and temperature conditions in the high density boron nitride direct conversion region of the boron nitride phase diagram where the stable form of boron nitride is high-density boron nitride to produce in said holder high-density boron nitride particles of at least 50 microns in size.
Dependencies are inferred from the claim text.