图书来源:二元合金相图及中间相晶体结构 二元合金相图及中间相晶体结构
作 者:唐仁政 田荣璋
出版时间:2009-05
定 价:320元
图书ISBN:978-7-81105-831-4
出版单位:中南大学出版社
Feng Cao ,Kun Liu,Zhenyu Fang and Siqing Wang National Key Laboratory of Advanced Ceramic Fibers and Composites,College of Aerospace and Materials Engineering,National University of Defense Technology,Changsha 410073,China
摘 要:Boron nitride(BN) powders were synthesized by pyrolysis at various temperatures to investigate the hydrolysis mechanism of borazine-derived BN pyrolysized below 1200 C.The BN was hydrolysized near room temperature 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 samples pyrolysized below 1200 C were very sensitive to moisture,and their mass growth was closely related to the pyrolysis temperature.At 25 C and 65% RH,the sample pyrolysized at 400 C exhibited almost 100 wt% mass growth within 8 days,while the sample pyrolysized at 1200 C 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.On the other hand,the instability of borazine-derived BN should be directly due to the residual N-H bonds in the compound,as suggested by FT-IR analysis.
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