During the combustion process of coal

biomass or other solid fuels

the phenomenon of ash deposition is a common but serious problem is that it can seriously affect the safe and stable operation and performance of the equipment. During the ash deposition process

the adhesive behavior between different ash particles plays an important role. Solid and liquid bridge forces are two important type of adhesive force. But the studies of solid- bridge force are not enough now. An experimental system for the measurement of solid-bridge force of ash at high temperatures was designed and developed. The maximum temperature of the system was 1600℃. By using this experimental system the solid-bridge force can be measured and the effect of different temperatures

contact pressure and duration can be researched. The result indicated that the temperature dependence of the neck tensile strength development showed a bimodal distribution. It was because that the phase conditions of ash were changed by increasing temperature

resulting in the change of the content of the glassy substance. The molecular diffusion rate at the interface of the ash column was accelerated with increasing temperature. And it also accelerated the improvement of the void and the lattice defect in the neck. By increasing the contact duration

the neck tensile strength increased because the process of the improvement of the void and the lattice defect in the neck became more fully. If the duration was enough

the neck tensile strength would reach a steady state. The neck tensile strength was increased with increasing contact pressure. The high pressure made the contact between the two interface of the ash column more closely and it was conducive to accelerate the molecular diffusion rate. High temperature and contact pressure could make the neck tensile strength reach a steady state in a shorter duration. The work provided a basis to establish the model of solid-bridge force of coal ash and predict the behavior of coal ash deposition in the specific conditions.