Electron probe microanalysis of ball-bearing steel powder obtained using the method of electroerosion dispersion in kerosene
The results of electron probe microanalysis of powder obtained using the method of electroerosion dispersion of ball-bearing steel scrap have been provided. It has been determined that the main elements of powder obtained using the method of electroerosion dispersion of ball-bearing steel scrap in water are ferrum, oxygen, carbon, silicon, molybdenum, and chrome.
Deuterium penetration into the bulk of a steel ball of a ball bearing due to its rotation in vacuum
Abstract The experiments were performed to study a phenomenon of mechanically stimulated solution of adatoms into the bulk under friction. A ball bearing with carbon chromium steel balls of 3.97 mm diameter was used for testing. An axial load of L =34 N was applied per ball. After degassing the ball bearing performed a total of 23.8×10 3 revolutions at n =196 rpm at deuterium pressure p =5×10 −2 Torr. The same ball bearing was kept in the chamber without motion as a reference. The SIMS depth profiling of the contact surface areas of the ball shows that deuterium concentration has the highest value of C 0 =1.3×10 18 atoms cm −3 at a depth of 0.1 μm from the surface. Then, it decreases to a background value of C 1 =6.5×10 16 atoms cm −3 at a depth less than 0.55 μm. For the reference ball, a considerable deuterium concentration was observed only on the surface. These results are in a good agreement with recent computer simulation of the phenomenon.
Tribological performance and tribochemistry of nanocrystalline WC/amorphous diamond-like carbon composites
Abstract The tribological performance and tribochemistry of vacuum deposited nanocrystalline WC/amorphous diamond-like carbon (DLC) composite coatings were investigated. Coating chemistry was varied by regulation of carbon content between 30 and 90 at.%. Deposition temperature was used to adjust the degree of β-WC crystallinity from near amorphous with 1–3 nm sized grains to nanocrystalline with 5–10 nm sized grains, which were embedded in unhydrogenated DLC matrix. The microstructure critically influenced both the hardness and tribological properties of WC/DLC composites. Coatings with poorly crystallized WC were softer (15 GPa) and exhibited lower friction and higher wear rates in comparison to harder (26 GPa) composites with larger WC nanocrystals. The hardness of WC/DLC composites was at least twice as high as the hardness of metal doped DLC coatings reported in the literature. Micro Raman and X-ray photoelectron analysis was performed on transfer films formed on the surface of steel balls in sliding against WC/DLC composites in humid air and dry nitrogen, which found both oxides and graphite carbon, providing self-lubrication. The high hardness and self-lubricating properties of WC composites resulted in low wear rates and friction coefficients of about 0.2. Relationships among coating chemistry, structure, hardness, friction, wear rates, as well as, tribofilm composition and structure are discussed.