5. Application examples and outlook

At present, the main use for ultra-refractory ceramics is in the space sector, and in particular in the production of thermal protection for vehicles, enabling them to survive the very high heat fluxes (10 MW.m ^–2 ) generated by the hypersonic speed of the vehicle (figure 18 ). But new applications for these ceramics are envisaged, such as new-generation fission reactors, high-temperature electrodes for metal purification or hydrogen production, or in power microelectronics. These ceramics are also being considered for the design of solar receivers for tower power plants, with the aim of increasing plant efficiency by raising the temperature of the heat transfer fluid heated directly in the solar receiver