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  • 1
    Electronic Resource
    Electronic Resource
    Lubricating durability of two GF category engine oils (2005)
    Bradford : Emerald
    Industrial lubrication & tribology 57 (2005), S. 161-167 
    Details
    ISSN: 0036-8792
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Purpose - Improved fuel economy, lower emission and longer durability are the major developing trends of engine oils. Aims to describe further research on the friction coefficient of engine oils. Design/methodology/approach - The lubricating durability D was defined based on definition of three characteristic points Pd, PS, Pi and three key time lengths Td, Ts, Ti. Two kinds of engine oils, respectively, belonging to GF-2 and GF-3 categories, were selected as samples to compare their lubricating durability. Findings - Test results indicate the GF-3 oil has much better lubricating durability than GF-2 oil. With investigation of the topography and chemical composition changes of wear tracks along with the tribotests' time extending, the meanings of three characteristic points were discussed. Analysis indicates much better tribofilm, formed by the synergistic effect of Ca-containing detergent with MoDTC/ZDTP in GF-3 oil, is the major factor resulting in GF-3 oil's longer lubricating durability. Originality/value - Provides further research on lubricating durability, which is important for engine oil change and maintenance, as well as decreased cost and pollution to the environment, and improved energy conservation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00368790510601725
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  • 2
    Electronic Resource
    Electronic Resource
    Tribological behaviors and molecular spectroscopic characterization of a lubricated piston ring/cylinder bore sliding contact under stepwise heating conditions (2002)
    Bradford : Emerald
    Industrial lubrication & tribology 54 (2002), S. 69-73 
    Details
    ISSN: 0036-8792
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The frictional behavior of a Mo alloy-coated piston ring sliding against cast iron cylinder bore was recorded as a function of temperature using a reciprocating tribotester and a fully formulated synthetic engine oil, with and without a friction modifier. It was observed that, as temperature increased in a stepwise mode, friction coefficients in the presence of MoDTC exhibited two local minimal values. Only one minimal friction coefficient value at 340–355?°C (µ = 0.065) was observed in the absence of MoDTC. Chemical characterization of worn tracks of the cylinder bore using reflected FTIR spectroscopy, Raman spectroscopy and ESCA, indicated that both the base stock and the tribological additives, ZDTP and MoDTC, experienced tribochemical reactions yielding MoO3, MoS2 and carbonaceous species as temperature ramped up stepwise. MoO3 and MoS2 reaction film formation are partially responsible for the local minimal friction coefficient found at the lower temperature and the ratio of the ordered carbon species accounts partially for the other local minimal friction coefficient found at the higher temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00368790210424158
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Precipitation of Magnesium Aluminum Spinel from Alumina-Matrix Solid Solution: I, Fundamental Concept and Precipitation Behavior (2000)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 83 (2000), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Al2O3 ceramics with magnesium aluminum spinel dispersion particulates were produced by a precipitation treatment of Al2O3-matrix solid solution, (Al1—2x,Tix,Mgx)2O3. We successfully constructed the precipitation process for synthesizing the nanocomposite, using the solubility dependence of titanium and magnesium in Al2O3 on the valence of titanium. Changing of the valence of titanium from 4+ to 3+ was accomplished by controlling the heating atmosphere, and, thereby, magnesium precipitation was promoted. The precipitation behavior was characterized using X-ray diffractometry, and the microstructure was observed using transmission electron microscopy. We confirmed that magnesium aluminum spinel nanosized particulate were precipitated in the Al2O3 grain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2000.tb01297.x
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  • 4
    Electronic Resource
    Electronic Resource
    Thermal properties of chemical vapour-deposition SiC-C nanocomposites (1991)
    Springer
    Journal of materials science 26 (1991), S. 5495-5501 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The relationship between the thermal properties and the microstructure of chemical vapour-deposition (CVD) SiC-C nanocomposites, covering the entire composition range from SiC to C, was investigated after measuring thermal conductivity and thermal expansion. The samples were prepared under deposition temperatures (T dep) of 1673 and 1773 K and total gas pressure (Ptot) of 40 kPa. The thermal conductivity of CVD SiC-C nanocomposites decreased as C content increased. For the deposits containing 24.3 to 71 mol % C prepared atT dep = 1773 K, some parts of the C phase formed a layered structure having its plane parallel to the deposition surface. This arrangement reduced the thermal conductivity in the direction perpendicular to the deposition surface to a much lower value. The CVD C and CVD C-SiC containing 〈 1.5 mol % SiC showed strong anisotropic thermal expansion. However, the thermal expansion of CVD SiC-C nanocomposites having a C content up to about 70 mol % was isotropic and nearly equal to that of CVD SiC. The low preferred orientation and the low modulus of elasticity of the C phase may be reasons for these results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02403948
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Thermal properties of chemical vapour-deposition SiC-C nanocomposites (1991)
    Springer
    Journal of materials science 26 (1991), S. 5495-5501 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The relationship between the thermal properties and the microstructure of chemical vapour-deposition (CVD) SiC-C nanocomposites, covering the entire composition range from SiC to C, was investigated after measuring thermal conductivity and thermal expansion. The samples were prepared under deposition temperatures (T dep) of 1673 and 1773 K and total gas pressure (Ptot) of 40 kPa. The thermal conductivity of CVD SiC-C nanocomposites decreased as C content increased. For the deposits containing 24.3 to 71 mol % C prepared atT dep = 1773 K, some parts of the C phase formed a layered structure having its plane parallel to the deposition surface. This arrangement reduced the thermal conductivity in the direction perpendicular to the deposition surface to a much lower value. The CVD C and CVD C-SiC containing 〈 1.5 mol % SiC showed strong anisotropic thermal expansion. However, the thermal expansion of CVD SiC-C nanocomposites having a C content up to about 70 mol % was isotropic and nearly equal to that of CVD SiC. The low preferred orientation and the low modulus of elasticity of the C phase may be reasons for these results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553649
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    Paper (German National Licenses)
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