Boron nitride （BN） powders were synthesized by pyrolysis at various temperatures to investigate the hydrolysis mechanism of borazine-derived BN pyrolysized below 1200 ℃. The BN was hydrolysized near room tem-peratu...Boron nitride （BN） powders were synthesized by pyrolysis at various temperatures to investigate the hydrolysis mechanism of borazine-derived BN pyrolysized below 1200 ℃. The BN was hydrolysized near room tem-perature at 65% or 90% relative humidity （RH） over 45 days. The long-term hydrolysis mechanism and structure evolution were investigated by a measurement of mass growth and by X-ray diffraction （XRD）, Fourier-transform infrared （FT-IR） spectroscopy, and scanning electron microscopy （SEM） analyses. The sam-ples pyrolysized below 1200 ℃ were very sensitive to moisture, and their mass growth was closely related to the pyrolysis temperature. At 25 ℃ and 65% RH, the sample pyrolysized at 400 ℃ exhibited almost 100 wt% mass growth within 8 days, while the sample pyrolysized at 1200 ℃ exhibited about 20 wt% mass growth. The XRD analysis suggested a hydrolysis mechanism that corresponded to the interlayer spacing in the BN, which was consistent with the results reported. should be directly due to the residual N-H bonds On the other hand, the instability of borazine-derived BN in the compound, as suggested by FT-IR analysis.展开更多
基金supported by the National Natural Science Foundation of China (No. 90916019)
文摘Boron nitride （BN） powders were synthesized by pyrolysis at various temperatures to investigate the hydrolysis mechanism of borazine-derived BN pyrolysized below 1200 ℃. The BN was hydrolysized near room tem-perature at 65% or 90% relative humidity （RH） over 45 days. The long-term hydrolysis mechanism and structure evolution were investigated by a measurement of mass growth and by X-ray diffraction （XRD）, Fourier-transform infrared （FT-IR） spectroscopy, and scanning electron microscopy （SEM） analyses. The sam-ples pyrolysized below 1200 ℃ were very sensitive to moisture, and their mass growth was closely related to the pyrolysis temperature. At 25 ℃ and 65% RH, the sample pyrolysized at 400 ℃ exhibited almost 100 wt% mass growth within 8 days, while the sample pyrolysized at 1200 ℃ exhibited about 20 wt% mass growth. The XRD analysis suggested a hydrolysis mechanism that corresponded to the interlayer spacing in the BN, which was consistent with the results reported. should be directly due to the residual N-H bonds On the other hand, the instability of borazine-derived BN in the compound, as suggested by FT-IR analysis.
