tailieunhanh - New Tribological Ways Part 14

Tham khảo tài liệu 'new tribological ways part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | A Novel Tool for Mechanistic Investigation of Boundary Lubrication Stable Isotopic Tracers X Rubbed area 439 Total positive ions m z 2 D m z 28 Si higher INTENSITY lower m z 318 OA-D35 Fig. 16. Chemical mapping of the C18OH OA-D35 binary film after the tribo-test By contrast the binary-component monomolecular film from C18OH OA-D35 provided a longer lifetime with low friction. Almost no changes in chemical mapping after the tribo-test for 200 s were observed Figure 16 . The results indicate that the C18OH OA-D35 binary film remained on the surface even after the tribo-test. In consequence the tribological properties of the binary-component monomolecular film are in good agreement with the results of SIMS analysis. An interaction between C18NH2 and OA-D35 through the ionic interactions is possible. This makes the adsorption force of OA-D35 on the Si surface which retards the durability of the film. On the other hand an interaction of C18OH with OA-D35 is possible through hydrogen bonding between the polar functional groups alcohol and carboxyl group. It should be noted that the hydrogen bond is much weaker than the ionic bond. Therefore the adsorption force of OA-D35 was not weakened by the presence of C18OH which advantageously seems to form certain mobile phases on the surface. Lubrication mechanism of diamond-like carbon coatings with water 17-18 Diamond-like carbon DLC coatings on metallic materials possess many advantages to tribo-materials such as corrosion resistance wear resistance and friction reduction 19 . One of the features of using a DLC coating as a tribo-material is its applicability in humid environments or in water 20 . Furthermore it has been reported that water improves the tribological properties of DLC. Although the formation of a boundary film by the tribochemical reaction of water with DLC has been suggested a mechanistic investigation based 440 New Tribological Ways on surface chemistry is difficult. The tribo-chemical reaction of water