The temperature of the feedstock affects the viscosity and the transfer of heat from the drying air in the chamber to the droplets. Both the temperature of the feedstock and the temperature of the chamber air need to be considered when selecting nozzle seal materials.
Some feedstock is solid at room temperature and must be melted in order to atomize them. Prilling or spray cooling involves forming pellets or crystals by spraying melted feedstock into a chamber through which cooling air is flowing.
The abrasiveness of the feedstock must be considered when selecting the material for the internal nozzle components. For most applications, tungsten carbide is the material of choice for the swirls and orifice discs. Tungsten carbide has excellent resistance to abrasion and good corrosion resistance for most feedstock.
For some feedstock, corrosive attack on the nozzle components is a greater problem than abrasion. For these cases, 316 stainless steel or Nitronic may be good choices.