The deposition of coal ash particles on to a superheater tube under pulverised coal combustion conditions was simulated using Soda Lime Silica Glass (SLSG) particles. For this purpose a small-scale furnace and an air-cooled probe representing a superheater tube was located in the duct section in the path of the flue gases. The deposition rate of particles was determined for various parameters. Deposition was found to start when the particle viscosity was less than 6.7 x 10(9) Pa.s. The deposition rate increased with probe surface temperature, gas temperature and velocity; it also showed a complex dependence on particle size. For large particles (16, 29 and 35 mu m) deposition was controlled by stickiness of the probe surface (probe surface temperature) up to 700 degrees C; however, small particles did not show any dependence on stickiness. Addition of 1% NaCl to SLSG raised the rate of deposition to 100%. The formation of crystalline phases (Plagioclase and Melilite) reduced the deposition rate of SLSG particles when NaCl and CaCO3 were added to them.