Papers by Keyword: Tribological

Abstract: The self-lubricating coating which is dense in microstructure with low porosity and degradation is sprayed by HVOF and the spray powder is Nickel coated MoS2 with 22%wt of MoS2. The mean bonding strength and hardness of Ni-MoS2 coating is respectively about 13.68 MPa and HRB94.5. Tribological performance is evaluated by the test of dry friction coefficient, which fluctuates from 0.25 to 0.32, while the wear granule is symmetry with a uniform distribution in size, moreover, the experiment results indicate the main wear failure mode of coating is abrasive wear.

Abstract: We have done experimental researches of study of impact of different fillers on physical, mechanical and tribological properties and found the optimal substance of fillers, which provides with best properties of polypropylene composite materials. We suggested the principle of construction of antifriction and antifriction-wear resistant polypropylene composite materials, which have high strength and tribological properties and used in cotton machines and mechanisms.

Abstract: The interfacial interaction of carbon fiber reinforced polyimide(PI) composites is a very important issue because it is one of the key factors to influence the mechanical properties of materials. In this article, the interfacial interaction among the components in the composites has been studied by three point bending tests. The fracture surface analysis showed the fiber matrix interface dominates the mechanical and tribological properties.

Abstract: PA6 composites filled with nano-SiO₂ were synthesized. The aim of the research article is to study the mechanical and friction and wear behaviour of nano-SiO₂ reinforced PA6 composites. The worn surface of the composite was examined by scanning electron microscopy. The results showed that the addition of nano-SiO₂ can effectively improve the mechancial and tribological properties of the PA6 composites.

Abstract: The mechanical and tribological behaviors of the carbon/carbon (C/C) composites were evaluated by three-point bending and sliding wear tests. The effect of carbon fiber content on their mechanical behavior was also investigated. To produce the C/C composites, the precursor was introduced to the preforms by impregnating with phenolic solution. The C/C preforms were densified by thermal gradient chemical vapor infiltration. Results indicated that, the C/C composites show excellent mechanical and tribological properties. A kind of high performance brake materials was obtained.

Abstract: Kevlar pulps were employed as reinforcement for polyetherimide(PEI)composite. All filled and unfilled polyetherimide composites were tested against CGr15 ball and representative testing was performed. The effects of Kevlar content on tribological properties of the PEI composites were investigated. The worn surface morphologies of pure PEI and its composites were examined by scanning electron microscopy (SEM) and the wear mechanisms were discussed. Results show that all filled polyetherimides have superior tribological characteristics to unfilled ones.

Abstract: Cu nanoparticles as N32 base oil additives were studied in the paper. The structure of Cu nanoparticlcs was characterized by Transmission Electron Microscopy (TEM) and X-ray powder diffraction spectroscope (XRD). The widely used steel-steel friction system was chosen to test the feasibility and practicality of Cu nanoparticles as bearing lubricant additives. The results show that N32 base oil with 0.5% Cu nanoparticle can improve the test sample contact fatigue life than pure N32 base oil.

Abstract: A bismuth diamyl-dithiocarbamate additive was synthesized. A four-ball tester was used to evaluate the tribological performance of the additive in mineral oil, and compared with same types of metal additives. The results show that it exhibits better load-carrying capacities than said organic metal additives. The surface analytical tools such as X-ray photoelectron spectrometer (XPS) and Scanning electron microscopy (SEM) were used to investigate the topography, the compositions contents and the depth profile of some typical elements on the rubbing surface of worn scar. Smooth topography of worn scar further confirms that the additive showed good antiwear capacities, the results of X-ray photoelectron spectrometer and X-Ray Energy Dispersive Spectroscopy analyses indicated that tribochemical mixed protective films consists of bismuth compounds, sulfides, sulphates were formed on the rubbing surface, which contribute to improve the tribological properties of lubricants. Particularly, a large amounts of bismuth atoms play an important role in improving antiwear properties of oils.

Abstract: Surface roughening, with certain roughness topography, is thought to be as an effective tribological method of decreasing friction coefficient of kinematic pairs. Friction and wear of AISI1045 steel surface roughened by convenient and economical way of sandblasting was investigated under lubrication conditions. Roughened and polished samples run against Φ4mm GCr15 pin lubricated by engine oil were tested in reciprocating mode with different load and speed on UMT- testing machine. It is found that there exists the optima surface roughness (Ra is about 3.92μm) roughened by sandblasting in which the least wettability contact angle between engine oil and textured steel surface is obtained, hence the lowest friction coefficient and wear rate is due to the optima hydrodynamic sliding property, although the sliding surface was not in hydrodynamic lubrication state.

Abstract: A considerable test was made to figure out the effects of temperature and sliding conditions on the wear properties of the translucent Dy--Sialon. The friction coefficient was 0.54 at RT, 0.26 at 100 oC, and 0.81 at 600 oC respectively under an applied load of 5N. The wear rate was 6.91×10-15 at RT and 1.0×10-15 at 100 oC for the same Dy--Sialon sample. Obviously Dy-Sialon shows an excellent wear resistance under a suitable sliding condition, a load of 5N and at 100 oC. This appears attractive and important for Dy-Sialon ceramics to be used as a type of special wear resistant materials, with an optical translucence.