A powder-fluidizing apparatus is presented which is applicable to feeding ultra-fine and nano-size powders, and powders with a broad particle size distribution, in a uniform manner over a long period of time. Generally, this is accomplished by using a rotating brush to sweep the powder through holes in a removable sieve plate, which breaks up agglomerated particles in the powder and controls the powder feed rate. The powder then drops from the holes into a funnel, where it is fluidized by being entrained into a carrier gas, and then flows through the funnel out of the apparatus to an applicator. The funnel surface is vibrated to avoid powder build-up on the surface that can break loose and cause pulses of increased material in the powder flow. Ultrasonic waves are introduced into the funnel to break up any agglomerated particles remaining in the powder before it reaches the applicator.