Effect of nitriding atmosphere on the morphology of AlN nanofibers from solution blow spinning

High purity AlN fiber is a promising thermal conductive material. In this work, AlN fibers were prepared using solution blow spinning followed by nitridation under N-2 or NH3 atmosphere. Soluble polymer, such as poly-aluminoxane, and allyl-functional novolac resin were adopted as raw materials to form homogeneous distribution of Al2O3 and C nanoparticles within the fibers, which could inhibit the growth of alumina crystal and promote their nitridation process. The effect of nitriding atmosphere on the fiber morphology was investigated. XRD results showed that complete nitridation was achieved at 1300 degrees C in the NH3 or at 1500 degrees C in the N-2 atmosphere. Hollowed fiber structure was observed when fiber was nitrided in N-2 at high temperature, which was caused by gaseous Al gas diffusion, and this phenomenon was eliminated in NH3 atmosphere. The nitridation mechanisms in different atmosphere were analyzed in detail. It was demonstrated that the nitridation of Al2O3 fibers in the NH3 atmosphere offered the favored AlN morphology and chemical quality. Flexible AlN fiber with O content of 0.7 wt% was achieved after nitriding in NH3 at 1400 degrees C. The high quality AlN can be used in thermal conductive composite materials.

Automated summary

High purity AlN fibers were prepared using solution blow spinning and nitridation methods, with soluble polymer and novolac resin as raw materials. The study demonstrated that nitridation in NH3 atmosphere can offer favored AlN morphology and chemical quality. The high-quality AlN fiber can be used in thermal conductive composite materials.