Tribological behavior of NiCr-base blended and nanostructured composite APS coatings by rig test

Cho, Jinhwan; Xiong, Yao; Kim, Juneseob; Lee, Changhee; Hwang, S.Y.

doi:10.1016/j.wear.2008.03.008

Cited by 10 publications

(3 citation statements)

References 14 publications

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“…The larger contact area results in dissipation of higher frictional force at longer sliding distance. Under the friction force, the localized shear stress induced by friction heat would result in fracture and spallation of coating at the weak regions, such as microcracks, pores and hard-Cr 2 O 3 /softmatrix-splat boundary [16]. Cyclic stress causes weakening of tribofilm with the material.…”

Section: Discussionmentioning

confidence: 99%

“…If these junctions are formed at lower loads, then the oxide film generated at the junctions is not totally torn by the deformation of the underlying metal. Then, the wear debris will contain metallic particles, with oxide layers produced by shearing at the interface between the oxide and bulk of the metal [4,16]. These mechanisms can influence the change in wear rate with progressive sliding, which can significantly change the rate of frictional force.…”

Section: Morphology Of Oxide Scalesmentioning

confidence: 99%

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Evolution of Tribological Properties of Reactor-Grade NiCr-B Coating

et al. 2011

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The tribological properties of reactor-grade NiCr-B hardfaced coating were studied at a constant load and sliding velocity. The objective of the present article is to investigate the changes in coefficient of friction that accompanies morphological and phase changes occurring in wear scars. Such changes result from the sliding with a spherical steel ball. The transition from the low to high coefficient of friction at higher sliding distance is attributed to severe cracking as well as fretting wear-induced deformation of surface oxide scales. Increased value of coefficient of friction arises from protracted sliding over longer distances continued to deform and detachment of weakly adhered oxides like Fe 2 O 3 and Cr 2 O 3 . Such scales are tribochemically formed on the wear scars and contribute to alteration in the coefficient of friction. The evolution of oxide phases in wear scars is found to be one of the main mechanisms for dissipation of frictional force.

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Section: Discussionmentioning

confidence: 99%

Section: Morphology Of Oxide Scalesmentioning

confidence: 99%

Evolution of Tribological Properties of Reactor-Grade NiCr-B Coating

et al. 2011

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“…The morphology of APS coatings is characteristically a porous lamellar microstructure with micro-pores and micro-cracks in the coatings, as shown in Figure 3-23 [121]. The basic structure of APS coating is built up with pancake-shape splats due to the impact of molten powder particles [122] (Figure 3-24).…”

Section: Microstructure Of Aps Coatingsmentioning

confidence: 99%

Cyclic and Isothermal Oxidation Resistance of ASPS Thermal Barrier Coating Systems

Li¹

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To systematically study the oxidation performances of thermal barrier coatings (TBCs) deposited by axial suspension plasma spraying (ASPS) method, isothermal and cyclic oxidation tests were conducted at a peak temperature of 1080C. The TBC systems are based on two different nickel-base superalloy substrates (CMSX-4 or IN738LC), platinum aluminide bond coat and yttria stabilized zirconia (8YSZ) top coat with either vertical cracks (VC) or columnar structure. After the oxidation tests, the samples were analyzed using a scanning electron microscope (SEM) and an X-Ray diffractometer. Samples with IN738LC substrate demonstrated longer isothermal oxidation lives whereas samples with CMSX-4 substrate showed greater cyclic oxidation lives. Outward elemental diffusion (of W and Ta) in TBC system containing CMSX-4 contributed to reduced isothermal oxidation life while the mismatch of coefficients of thermal expansion (CTE) between TGO, bond coat and substrate was believed to be responsible for early failure of TBC system with IN738LC substrate. TBC systems with columnar YSZ overall had longer isothermal oxidation life while vertically cracked YSZ seemed to result in longer cyclic life. Cr2O3 and spinels (CS), in addition to thermally grown aluminum oxide (TGO), were detected on tested TBC samples. The growth of spinels highly depended upon a coating's accessibility to oxygen and test duration and was found to contribute the spallation of the coating layer.iv

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