NASA missions for planetary exploration require high power, long-life Hall thrusters. However, thruster power and lifetime are limited by the erosion of plasma channel walls. Current plasma channel insulators, BN or Borosil, have the required low secondary electron emission (SEE) but are susceptible to xenon plasma erosion. AlN has exceptionally high plasma erosion resistance but suffers from high SEE yield. AlN can be a "revolutionary" replacement for BN channel insulator since it provides high plasma erosion resistance with structural robustness and high thermal conductivity if it's SEE yield can be reduced. In Phase I program we demonstrated the SEE yield of AlN can be reduced to the levels of state-of-the-art BN-based materials by microstructural engineering without sacrificing its thermal and mechanical properties for long-life plasma channel insulators in high power Hall thrusters.