Thermomechanical characterization of brazed SiC assemblies for receivers of CSP plants

Abstract

In order to increase the performance of solar tower power plants, it is necessary to improve the receivers in order to reach higher temperatures or a longer life span. Silicon carbide is a promising material for this purpose, but large parts cannot be made in one piece: a joining process is required. BraSiC® brazing alloys have been developed to produce silicon carbide assemblies that can withstand temperatures of about 1000°C, but their thermomechanical behavior is poorly understood. The understanding of the failure mechanisms as well as the knowledge of the limits of use of these materials is essential to be able to produce reliable receivers. In this article, two types of BraSiC® braze have been studied: CEA 0 and CEA 1, using the IMPACT test bench, specifically developed to characterize materials under concentrated solar flux. The results show that the CEA 1 braze is more resistant to thermomechanical stresses. Two damage mechanisms of the brazed joints were also identified using acoustic emission.