A new possibility to improve thermal properties and lifetime of electrical machines is adding some micro-or nano-particles to the epoxy resin and improve the heat dissipation of the machine. This will reduce the temperature in a stator winding. The paper reviews actual work in the field of epoxy materials enriched with aluminum nitride (AlN) or boron nitride (BN). Properties of the particles are described, same as preparation process and influence of usage of coupling agents that creates a bond between particles and epoxy. Brief introduction to the thermal aging of insulation is presented same as influence of the temperature reduction on lifetime of the winding insulation. Further suggestions for improvements and trends are established in discussion.