Reduction of Shear Stresses in Friction Units with an Electrical Insulation Coating of the ITER Blanket Modules

During operation of the International Thermonuclear Experimental Reactor (ITER), its removable blanket modules undergo significant shock loads in the process of plasma disruption, which lead to the displacement of parts with a gas-thermal insulating coating on the mount points of the protective panels of the vacuum chamber. A high friction coefficient ≥ 0.28 at maximum shear resistance provokes peeling, fracturing, and chipping of insulating coatings. Methods of reducing the friction coefficient of supporting surfaces coated with an electrical insulation coating (Al 2 O 3 , MgAl 2 O 4 ) and mount points of the ITER blanket modules experiencing significant shear stresses are considered. The tribotechnical tests of electrical insulating coatings paired with the proposed modified zirconium alloy plates with an antifriction layer in the range of sliding speeds = 10 –5 −10 –2 m/s, loads = 100−600 N according to the pin-on-disk scheme at temperatures = 20°C, T = 250°C showed a change in the friction coefficient in the range = 0.08−0.23 and high wear resistance of ceramic coatings. The use of innovative intermediate plates with a modified layer (ZrO 2 −C) in blanket modules could be an alternative to low pressure plasma spraying of an antifriction MoS 2 finish layer on electrical insulation coatings.