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Babbitt alloy is a widely used bearing material. In order to improve its thermal and anti-fatigue performance, the combined effect of additive La and heat treatment of tin-Babbitt were studied. The microhardness, wettability, and tribological performances of the Babbitt were first considered. The Babbitt alloy modified with La element (0.1 wt%) was prepared and then heat treatment was carried out (marked by the modified Babbitt). The friction and wear performances of the bare Babbitt, heated Babbitt, and modified Babbitt were conducted by a ball-on-disc tester under oil lubricated condition. The results showed that the microstructure of the modified Babbitt alloy was homogeneous. The cubic phase of SnSb intermetallic was refined and the SnSb cubes were also passivated. The microhardness of the modified Babbitt increased from 24.67 Hv to 37.84 Hv and wettability was improved with the addition La and heat treatment. Therefore, the anti-wear performance of the Babbitt was improved. The modified Babbitt alloy is observed to resist the instant scratching from the journal.

In this paper, an unbalanced Jeffcott rotor supported by the roller bearings is modelled, and the dynamic differential equations are obtained by the Lagrange’s equations. The fourth order Runge–Kutta method is employed to simulate this system in two cases. Simulation results show the combined effect of the coupled lateral and torsional vibrations and the variable compliance vibration of the rotor. In the case of that only a large and constant radial force is applied, the sum and difference between variable compliance and rotational frequency components of the torsional vibrations of the disk are induced because of the roller bearings’ rotation. And when they are near to the natural frequency of the torsional vibration, the resonance peaks appear. In the case of that a large and constant radial force and a harmonic torque are simultaneously applied, the two components, the sum and difference between rotational frequency and the frequency of the external torque, of the lateral vibrations of the disk are induced. When the frequency of the external harmonic torque approximatively equal to a special value, the two frequency band lines, variable compliance and the sum of rotational frequency and the frequency of external torque, intersect near the natural frequency of the lateral vibration, and the vibration may aggravate.

This paper aims to improve wear resistance of bare Babbitt modified by CuLa and evaluates the effect of different sliding modes on tribological properties of bare Babbitt, Babbitt modified by 0.5 wt% CuLa (marked by mbabbitt-1), and Babbitt modified by 1 wt% CuLa (marked by mbabbitt-2). First, bare Babbitt was modified with different contents of CuLa. The microstructure, microhardness, and wettability of Babbitt were tested and studied. Then, the tribological properties of bare Babbitt, mBabbitt-1, and mBabbitt-2 were conducted by the reciprocating mode and unidirectional mode under the lubricated condition. The results showed that the SnSb grain of the modified Babbitt was refined and uniformly distributed. The microhardness of mBabbitt-1 was higher than that of bare Babbitt and mBabbitt-2. Compared with bare Babbitt, the wettability of mBabbitt-1 and mBabbitt-2 was improved. Anti-friction and wear resistance of specimens under the reciprocating mode were better than that of specimens under the unidirectional mode, which was attributed to low strain and equivalent stress of bare Babbitt under the reciprocating mode. Moreover, anti-wear of bare Babbitt was improved by adding CuLa due to refined grain and high microhardness.

In this study, composite coatings of polyvinylidene fluoride (PVDF) and epoxy resin deposited with La2O3 and MoS2 nanoparticles on the surface of a Babbitt alloy have been studied in order to improve its tribological performance. A pin-on-disc tribometer was used to evaluate the tribological properties of the Babbitt alloys with and without the composite coatings. The results showed that compared with the polymer-La2O3 composite coating, the polymer-MoS2 composite coating was more effective in reducing the friction coefficient and the wear rate of the Babbitt substrate under both dry and boundary lubrication conditions compared with the polymer-La2O3 composite coating. However, the wear rate of the Babbitt alloy with the polymer-La2O3 composite coating was lower than that of the alloy with the polymer-MoS2 composite coating. The wear scratches were analyzed using a scanning electron microscope (SEM). The worn surface of the polymer-La2O3 coating was much smoother and more continuous than that of the polymer-MoS2 coating, meanwhile transfer films were respectively detected on the pin surfaces. The addition of nanoparticles can reduce the wear rate and friction coefficient of polymer composite coating by forming a transfer film. Hence, the polymer composite coating can protect the Babbitt substrate.

After total joint replacement surgery, frequent injection of lubricating substances is required due to lubrication failure caused by the absorption of lubricants by the human body, which will cause serious physiological and psychological burdens on patients. In this study, with the help of surface texture aggregation of particles, gelatin microgel particles with a diameter of about 4 μm were used as lubricating substances to achieve aggregation in the texture, thus improving the friction environment under low-concentration lubricants. The study found that the rectangular cross-sectional texture demonstrated the most effective anti-friction properties, resulting in a 26% reduction in friction coefficient compared to non-textured surfaces. Additionally, utilizing comsol for particle flow simulation, researchers observed the motion behavior of particles within the texture and clarified the mechanism of particle aggregation and the improvement of lubrication on the surface. This article confirms the beneficial effects of combining surface texture and particles on lubrication, thus providing valuable insight for improving lubrication in dilute particle solutions.