Surface modification of nodular cast iron: A comparative study on graphite elimination

Karamış, Mehmet; Yıldızlı, Kemal

doi:10.1016/j.msea.2010.04.067

Cited by 32 publications

(21 citation statements)

References 9 publications

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“…Compared with the graphite of Figure 3 d, the graphite phase was broken and there were gaps between the matrix and the graphite in Figure 4 a,b. Grum [ 20 ] and Karamış [ 21 ] thought that both hydrodynamic forces and buoyancy forces of the laser molten pool, and the larger size and gradual dissolving speed of graphite particles were the main causes for the graphite particles appearing in the laser cladding coating of the cast iron. In addition, because the thermal expansivity was not matched, the gap appeared between the matrix and the graphite during the fast cooling of the laser molten pool.…”

Section: Resultsmentioning

confidence: 99%

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

Liu

2016

Materials

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In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS) confirmed that the coating was composed of TiC particles and two kinds of α-Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991) and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage.

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Section: Resultsmentioning

confidence: 99%

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

Liu

2016

Materials

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“…In this type of cast iron, the iron-based phase which forms the main material, is more electrochemically active and dissolves into an ion by oxidation reaction by acting anodically in the event of corrosion. Graphite in the structure is steadier than iron, hence, it acts cathodically during the event of corrosion [4,29,30]. When Tafel polarization curves given in Fig.…”

Section: Corrosion Behaviormentioning

confidence: 99%

Effects of Vermiculariser, Inoculant and Copper Addition on Microstructure and Corrosion Properties of Vermicular Graphite Cast Iron

2022

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“…As evidenced, graphite regions near the surface in both substrates play a key role in thin-film applications, especially considering these graphite sites represent mechanical voids regardless of their morphology and, thus, spalling of coatings such as DLC may appear in these regions during tribological contact (Salvaro et al, 2017). Due to the cruciality of this aspect, surface treatments were developed by different research groups to remove all near-surface graphite before the nitriding of similar materials (Karamiş and Yildizli, 2010;Zenker et al, 2013). Another critical issue is the relatively low hardness of cast iron metallic matrixes, which induced the necessity of the development of suitable mechanical support layers, being the nitriding of ferrous substrates a commonly used solution (Agarwal et al, 2013;Ebrahimi et al, 2015;Shioga et al, 2016;Giacomelli et al, 2017).…”

Section: Substrate Naturementioning

confidence: 99%

In situ Tribo-Fluorination for Oil-Less Hermetic Compressor Applications

et al. 2021

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In the present work, we overview the multidisciplinary development of a regular, lubricated, hermetic compressor which works in an on-off cycle, circular motion, single-speed, many tribological contacts, into an innovative, linear motion, variable displacement, single tribological contact, oil-less hermetic compressor presenting high versatility in terms of refrigerator design, sustainability and improved efficiency. The original approach encompassed the development of new surface engineering procedures applying purpose-oriented phases to soft substrates. Particular emphasis is given to the in situ fluorination of the tribolayer formed in the piston-cylinder tribopair. Although chlorinated halocarbons (CFC) are efficient refrigerants from a thermodynamic point of view, they do have serious environmental implications that have forced the refrigeration industry to switch to more environmentally friendly hydrofluorocarbon (HFC) based refrigerants. The first and most successful alternative to the CFCs was tetrafluorocarbon, particularly tetrafluoroethane (CF3CH2F), aka R134a refrigerant. The current trend to downsizing mechanical systems, smaller clearances, and increased speeds leading to greater energy efficiencies associated with miscibility issues imposing the use of costly, fully synthetic lubricants with the R134a refrigerant gas led to the introduction of a new hermetic compressor design, the Wisemotion®, the first, and until now, unique, oil-free hermetic compressor on the world market. In this context different types of multi-layers, their thickness, substrate material, processing routes, etc., have been studied and optimized. Si-rich hydrogenated DLC (a:C-H) presented enhanced tribological properties when tested under fluorine-rich atmospheres, and semi-industrial scale tests have been carried out to understand this point further. A homemade tribological emulator was developed allowing close-to-real tribopair, atmosphere, and imposed mechanical conditions used in an oil-free commercial hermetic compressor. The tests were carried under different stroke frequencies (5, 20, and 40 Hz) and atmospheres (R134a, ambient air, and argon). Results showed a strong influence of both atmosphere and stroke frequencies. The friction coefficients were significantly lower (~3.8X) for the refrigerant gas atmosphere, attributed to the fluorine and highly disordered graphitic structures rich tribolayers. Under the high frequency (40 Hz), the energy input seems to be a deterrent to the formation of stable tribolayers, and the DLC coating shatters on the first few sliding meters.

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Surface modification of nodular cast iron: A comparative study on graphite elimination

Cited by 32 publications

References 9 publications

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

Effects of Vermiculariser, Inoculant and Copper Addition on Microstructure and Corrosion Properties of Vermicular Graphite Cast Iron

In situ Tribo-Fluorination for Oil-Less Hermetic Compressor Applications

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