Mechanically stimulated outgassing from ball bearings in vacuum

This study investigates the outgassing of bare stainless steel and MoS2 coated ball bearings, both of which are widely used in modern high vacuum technological equipment. Three well-distinguished stages of outgassing are observed as a function of time, which correspond to different phases of a ball bearing's lifetime. For both type of bearings, hydrogen, carbon oxide and methane were the main outgassing species. Two main processes govern the outgassing from a ball bearing: (i) local heating of the contact surfaces and (ii) plastic deformation and fracture of counterfaces. Outgassing from a ball bearing is very sensitive to damage of the contacting surfaces and demonstrates a good correlation with dissipative parameters, such as self-resistant torque and vibration. The mean outgassing rate is highly sensitive to the average dissipation energy, whereas the oscillation of the outgassing signal around the mean value is dependent upon the formation of new defects on counterfaces.Peer reviewe

Outgassing of stainless steel during sliding friction in ultra-high vacuum

Outgassing of SS surfaces under sliding friction in ultra-high vacuum has been studied by ad-desorption mass-spectrometry and Auger electron spectroscopy. Experiments have been performed at normal loads of the indent in the range from 0.02 up to 0.87N, sweeping frequencies from 48 to 124 min-1 and linear sliding speed 7.5 mm/s. The P–t outgassing curve presents an oscillating current over a continuous one and three well different parts: (i) an initial desorption peak of high intensity, (ii) a region of nearly stable pressure and (iii) a decreasing of the pressure when friction is stopped. The outgassing rate slowly decreases with the number of sweeps. The AES analysis shows that the chemical composition and rugosity of the rubbed area of surface depends on the friction conditions. For loads from 0 to 72 mN, no chemical changes in the surface composition are observed, while for loads up to 870 mN, the concentration of Fe increases and concentration of Cr decreases depending on the friction duration. The outgassing process is a combination of gas diffusing process from the outermost layers and desorption from the surface.R. Nevshupa acknowledges the grant of the President of the Russian Federation.Peer reviewe

A new type of wide-range vacuum sensor

This work is focused on simplification of a residual pressure measurement. The presented simple and reliable tribology based vacuum sensor allows measuring of the residual pressure in the range of 10 Pa to 10 Pa. It can substitute all other high and ultrahigh vacuum gauges with itself