A multi-step reaction route was developed to synthesize boron nitride(BN) nanoparticles via the reaction between NaN3 and BCl3 in a benzene-thermal solution.By means of this route,the crystallinity of BN nanoparticles was improved via increasing the reaction steps.Meanwhile,a phase transformation from hexagonal BN(hBN) or turbostratic BN(tBN) to cubic BN(cBN) occurred,resulting in the increase of cBN content.Moreover,the content of cBN also slightly increased when the temperature was elevated from 265°Cto280 °C.
TAN MiaoLIAN GangZHANG XiaoZHANG Shun-jieCUI De-liangWANG Qi-long
Al2O3 porous nanosolid was prepared via solvothermal hot-press(SHP) method.The dielectric constant of Al2O3 porous nanosolid is as low as 2.34,while its compressive strength is very poor.In order to improve the compressive strength and maitain low dielectric constant,polyimide was introduced to prepare Al2O3 /polyimide composite porous nanosolid.Compared to Al2O3 porous nanosolid,Al2O3 /polyimide composite porous nanosolid possesses much higher compressive strength,which reaches its saturation value when the mass loading of polyimide is 7.75%.In addition,the in situ Fourier transformation infrared(FTIR) monitoring result reveals that Al2O3 /polyimide composite porous nanosolid is stable up to 400 °C.
