Strong Machinable Ceramic Nano-Composites with In Situ Synthesized BN

Abstract

A series of ceramic composites containing Si 3 N 4 , SiC, ZrO 2 , Al 2 O 3 and nano-sized h-BN was prepared. Boric acid and urea were ball-milled with these ceramic powders and then in-situ reduced into nano-sized BN coated on the surface of ceramic particles. The reaction processes and the microstructure characteristics of BN nanocomposite powders were analyzed by SEM, TEM, XRD and IR methods. t-BN first appeared as semifinished product during reduction and then turned into h-BN after reheated at higher temperature. Finally hot-pressing was applied to prepare ceramic composites. A drill test was also undertaken to evaluate the machinability. The results showed that all these materials containing more than 20wt% BN exhibit a combination of high strength and excellent machinability, which can be attributed to nano-sized h-BN particles dispersed in ceramic grain boundaries uniformly.

Study on Bamboo Particleboard Bambooceramics - PF Resin Content Influence on Properties of Bambooceramics

“…Woodceramics was a kind of environment material, and it had porous, conductive, self-lubrication properties, etc. So, it will has a broad application prospect in friction, electromagnetic shielding, house warm, and so on [3]. The wood resources was very shortage, and the contradiction between supply and demand is very prominent in China.…”

Study on Bamboo Particleboard Bambooceramics - Bamboo Particle Types and Resin Content Influence on Properties of Bamboo Particleboard

“…Woodceramics as a kind of new biomass ceramics material, it had porous, conductive, self-lubrication properties, etc. So, it will has a broad application prospect in friction, electromagnetic shielding, house warm, and so on [2]. Woodceramics was prepared mostly by using wood as raw material, but the wood resources was very shortage in China.…”

Fabrication and Characterization of Aluminum Nitride/Boron Nitride Nanocomposites by Carbothermal Reduction and Nitridation of Aluminum Borate Powders

“…To overcome these problems and improve properties, various processes involving precursors have been developed for nanocomposites. [23][24][25][26][27][28][29] To obtain a microstructure with a homogeneous dispersion of nanosized h-BN in a ceramic matrix such as Si 3 N 4 , a simple chemical process was used to synthesize Si 3 N 4 -BN nanocomposite powders by reducing Si 3 N 4 particles coated with a mixture of boric acid and urea as an h-BN source. However, this process did not yield an AlN/BN composite with inherently high thermal conductivity because the thermal conductivity of the resultant composite decreased considerably due to the oxygen dissolved in the lattice of the AlN grains during sintering at high temperatures.…”