Cryogenic vacuum tests of scaled down narrow support elements for the W7-X coil system

Estimation of MoS2 Coating Performance on Bronze and Steel in Vacuum at High Temperatures

We compared two modes of magnetron sputter deposition of MoS2 on substrates made of steel AISI 316L and bronze CuAl9NiFe4Mn1 with different initial roughness Ra 0.05–2.32 µm. The deposition was carried out at a bias voltage of −20 and +100 V, and the deposition rate of these modes differed by 30%. Measurements of the friction coefficient and lifetime tests were made in accordance with ASTM G133. Measurements of the friction coefficient and lifetime tests in vacuum at load 7H, temperature of samples 250 °C, and pressure in the chamber <10−6 Pa were carried out according to ASTM G133. The adhesive strength, the chemical composition of the coatings before and after tribological tests, the degree of crystallinity of the coatings, and the distance between the planes were evaluated. Mechanical and structural properties of coatings are discussed concerning the deposition mode parameters. The average coefficient of friction of the MoS2 coatings in steady-state friction did not exceed 0.051 for all samples. The influence of the sample pretreatment method on the growth of molybdenum disulfide crystals was revealed.