1 kW imaging furnace with in situ measurement of surface temperature

This article describes the development and characterization of a 1 kW imaging furnace that allows to investigate materials such as sulfides at ultrahigh temperatures under controlled atmosphere. Peak flux densities up to (15.37±0.66)×106 W m−2 corresponding to a maximum stagnation temperature of 3090 K can be reached in the center of the heating zone of 3 mm diameter (full width at half height). Individual sample holders can be mounted on a generic sample stage that is aligned in three axes. Together they define an experiment. Experiments can thus be easily interchanged without requiring any realignment. The use of a specific sample holder is reported where the sample rests on a water-cooled tip to avoid contamination by crucible material and where a protective glass dome can be mounted to allow the study of samples releasing condensable or corrosive gases. With the dome in place the peak flux density decreases to a value of (13.59±0.45)×106 W m−2 (Tstag = 2980 K). The surface temperature of the sample and the average irradiance can be measured simultaneously by the pyrometric method flash assisted multiwavelength pyrometry. The irradiance on the sample and, thus, the temperature reached can be controlled by adjusting the position of the sample. This is effected by a computer controlled fork lift with a resolution of 0.05 mm.