|
Owing to the excellent performance of boron nitride, scholars at home and abroad have carried out a large number of studies for its preparation, properties and applications. But its future development directions are how to prepare higher purity boron nitride under lower pressure and at lower temperature with cheaper, low toxic or nontoxic materials, and take full advantage of their good nature. Therefore a preliminary research was made mainly about boron nitride nano-particles for its preparation and application.1. Boron nitride nano-particles were prepared with boron oxide and methanol as raw materials, using vapor deposition methord at different temperature.And the products were characterized by scanning electron microscopy, X-ray diffraction and other means.2. The results showed that with the increase of the reaction temperature, all of oxygen, carbon, hydrogen and other miscellaneous elements had been removed, and the contents of BN increased correspondingly in the productd,namely, the purity increased.When the reaction temperature was 980℃, the products were boron nitride nanosperes, furthermore the average particle size was in a small distribution range.However, when the temperature was higher, there was a agglomeration phenomenon in the products, and the morphology of boron nitride nano-particle changed, the twinning particles could be seen. Therefore, the optimum reaction temperature was 980℃.3. The carbon fibers were coated with boron nitride films, aiming at making a surface treatment to carbon fibers to improve the interface effect. So that when they were used as the reinforcements for the composite materials, they could combine more firmly with the matrix. At the same time,the composites also had good thermal conductivity, lubrication property like boron nitride. Experiments also proved that, through the vapor deposition methord, boron nitride nano-particls can be well wrapped in the carbon fiber surface.4. The BN/Nylon 6 composites were prepared by melt blending of boron nitride nano-particles with Nylon 6, and the process was the same for BN/CF/Nylon6, CF/Nylon6 composites. Then the performance of the composites was tested, such as mechanical performance, themal conductivity, self-lubricating, ect.5. By detecting the analysis, it was shown that boron nitride nano-particles in the BN/Nylon 6 composites did exist and evenly distributed. What’s more, boron nitride nano-particles effectively changed the performance of Nylon 6 in varying degrees, for example:mechanical properties, thermal conductivity and self-lubricating properties. Besides, in the preparation process, the crystal morphology of Nylon 6 and the micro-morphology of boron nitride did not change.
|