BN-アルミニウム間反応を利用したAlN基複合材料の合成におけるプロセス条件の影響

抄録

  The reactive infiltration of molten aluminum into a powder preform was investigated as a processing route for aluminum nitride (AlN) matrix composites. As the powder preform, titanium and boron nitride (BN) powders were blended and compacted, the infiltration occurred spontaneously at temperatures ranging from 1073 K to 1673 K. The conversion ratio of BN to TiB₂ and AlN turned out to be insufficient (<0.8) at temperatures below 1273 K. The conversion ratio increased by increasing the processing temperatures, and it exceeded 0.95 at 1673 K. The conversion ratio at 1473 K was almost saturated with a 3.6 ks holding and the effect of extending the holding time was not confirmed. Decreasing the BN powder size was effective to promote the reaction between aluminum, titanium and BN. The effectiveness was particularly prominent at 1473 K in comparison with the specimen fabricated at 1673 K. The titanium powder size did not show a significant effect on the formation of AlN and TiB₂. The volume fraction of AlN increased by changing the atmospheric gas from argon to nitrogen.