Ultrahigh temperature processing by concentrated solar energy with accurate temperature measurement

Highlights: • A platform for concentrated-solar-energy-based ultrahigh-temperature processing is presented. • Tantalum (melting point 3017 °C) foil is melted by simulated concentrated solar radiation . • Ultrahigh temperatures (>2500 °C) are achieved and measured accurately (relative error < ±2%). • Proves the feasibility of using concentrated solar energy as a high-temperature heat source. • A direct, simple and cost-effective way of heat flux gauge calibration at high temperatures. -- Abstract: An ultrahigh temperature solar processing platform consisting of a High-Flux Solar Simulator (HFSS) and auxiliary equipments is developed to research high-temperature materials and processes. Refractory metals of zirconium (melting point of 1855 °C), niobium (2477 °C) and tantalum (3017 °C) were successfully melted by concentrated light from xenon lamps of the HFSS. The melting experiment was monitored by a charge-coupled device camera, and the temperature was recorded by a near-infrared multi-wavelength pyrometer. Then the processed metals were examined by SEM and EDS to compare the difference before and after the ultrahigh-temperature experiments. In addition, a numerical model combining Monte-Carlo ray-tracing method and finite-element method was established to simulate the melting process, the results of which agreed well with experimental results. Furthermore, melting temperatures measured by the well-calibrated near-infrared multi-wavelength pyrometer were close to the melting points of the refractory metals (i.e., ±2% relative error). The experimental platform also demonstrates the capability of providing high radiative flux and ultrahigh temperatures (>2000 °C) for the calibration of heat flux gauges and the testing of high-temperature properties of materials. The concentrated solar energy based ultrahigh temperature technology provides an innovative approach for processing refractory materials in general.