Hexagonal boron nitride powder synthesis and sintering behaviours

Hexagonal boron nitride which is synthetic materials is used many areahas unique properties. Boron nitride can be produced by different productionmethods. In this study, raw boron nitride was nitrided with boron oxide which isproduced from boric acid at 700, 800 and 900 oC. Raw boron nitride includesimpurities as boron oxide and calcium borate phosphate which were purified byleaching process. Produced raw boron nitride has turbostatic structure. Occurrenceof hexagonal boron nitride were examined by heating process at 1400, 1500, 1600and 1700 oC. Unit weights, densities, XRD patterns, La and Lc indexes, FTIRspectrums, particle sizes and microstructures of produced boron nitride powderswere examined. Boron nitride pellets which is produced from boron oxidepowders nitrided at 900 oC and calcinated powders at 1400 oC were sintered at1800 and 1900 oC. Pellets with no additives, (2, 4 and 6)% B2O3 and (2, 4 and6)% Y2O3 additives were produced. Densities, Vickers hardness, XRD patterns, Lcindexes and microstructures of sintered samples were examined. High purityhexagonal boron nitride were synthesized by nitriding boron oxide with ammoniaand calcinated of this produced boron nitride. It was observed that boron nitridepowders has laminate and agglomerate structure. It was found that B2O3 and Y2O3additives affects sintering process positively and theoretical density is about 70%.Keywords: Hexagonal boron nitride, Nitridation, Thermal process, Sintering,Characterization