The paper concerns some questions connected with the interaction of high-temperature plasma-ion fluxes with solid materials inside experimental chambers used for fusion-oriented research, and particularly inside the Torsatron-type facilities. Mechanisms of the boron carbide erosion are described and discussed. Also described is the behaviour of TiN-coated stainless-steel surfaces under the irradiation with hydrogen plasma-ion fluxes. In summary, there are described damages in the boron carbide layers and changes in the composition of the TiN-coatings.