| Rolling bearings are the core components for mechanical transmission systems and are important to the reliability and service life of high-end equipment.In the water environment,due to the low viscosity of water,the thickness of the formed water film is small,which leads to the low loading capacity of water film and results non-fluid friction working conditions,and accelerated the friction and wear of rolling bearings,it will lead to the premature failure of rolling bearing materials.In order to improve the friction and wear resistance for rolling bearing materials under water environment,a water environment friction and wear test machine was designed and built in this paper.The ta-C,Cr-DLC,CrN and CrAIN films were prepared in this study and compared by the test machine.The CrN films showed the best performance in the experiments,and the process parameters were optimized at low temperature,process parameters for CrN films which showed the best tribological properties were obtained.The basic conclusions were as follows:Firstly,based on rolling bearing operating parameters,the design requirements for water environment friction and wear tester are determined.Secondly,according to these design requirements,the test machine model was built by using SolidWorks 3D design software,and the key components of the tester model were simulated and optimized by Ansys finite element analysis software,which completed the tester design.Finally,the tester was built according to the design drawings.After the construction of the tester,it was calibrated and followed by a series of verification experiments.It was proven that the tester worked in a good condition and was accurate,and it met the design requirements and accuracy.The friction and wear tests for various friction pairs under water environment.The ta-C,Cr-DLC,CrN and CrAIN films were prepared on the surface of GH05 alloy by multi-functional ion plating deposition system.The friction and wear tests of GH05 alloy and four films were carried out under water environment,and the CrN film showed the best performance on tribological properties,it was well preserved and its friction coefficient was stable which its average value was around 0.256;it had a minimum wear depth of 0.507 ?m;and its wear rate was the 3.359×10-10mm3/Nm which was the lowest.Comparing with the GH05 substrate and three other film systems,its wear rate was one to three orders of magnitude lower.To further improve the friction and wear properties of CrN films under water environment,six kinds of CrN films with different process parameters were prepared by low temperature deposition technology,and comparing experiments were carried out.The results showed that CrN film,which was deposited by bias of-60V and current of 80A,was partially exfoliated,and the CrN film prepared by bias of-40V and current of 120A was completely exfoliated,on the contrary,four other films were well preserved,which had no crack or flake.Among all six kinds of-CrN films,CrN film which prepared with the bias of-80V and current of 100A had the lowest average friction coefficient of 0.164 and the lowest wear rate of 2.087×10-10mm3/Nm,which has the best friction and wear resistance.In conclusion,the best process parameters were bias of-80V and current of 100A.According to the above experimental results,the film which was selected by the self-developed water environment friction and wear tester can improve the friction and wear resistance of the rolling bearing materials in water environment.It provides strong support for the development and application of vacuum coating technology in the field of rolling bearings in water environment.It is significant to improve the reliability and service life for equipment under water environment. |
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