Neutron diffraction residual strain measurements in post-treated thermal spray cermet coatings

Ahmed, Rehan; Yu, Hwan‐Chul; Stoica, V.; Edwards, L.; Santisteban, J.R.

doi:10.1016/j.msea.2008.08.023

Cited by 42 publications

(72 citation statements)

References 31 publications

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“…Neutron diffraction strain measurements were implemented at the UK's Science and Technology Facilities Council's (STFC) laboratory, by means of the ENGIN-X strain diffractometer at ISIS facility [32][33][34]. These tests were completed at room temperature on three anode coatings (Mo-Mo 2 C/Al 2 O 3 , MoMo 2 C/ZrO 2 , Mo-Mo 2 C/TiO 2 ) put down by air plasma spray (APS).…”

Section: Assessing Neutron Diffraction Residual Strainmentioning

confidence: 99%

“…To achieve a through-thickness residual strain profile with high resolution, a partially-submerged beam was used for measurements near the coating surface, as well as a beam submerged in the coating and substrate materials near the coatingsubstrate interface. A gauge volume of 0.2 × 8 × 4 mm was employed [34]. Strain checks were executed at the geometric centre of the specimen.…”

Section: Assessing Neutron Diffraction Residual Strainmentioning

confidence: 99%

“…Likewise, neutron diffraction has been argued to be superior for characterisation purposes as the high flux and deep penetration of neutrons facilitate the study of bulk materials at elevated temperatures, enabling it to derive the structural evolution during heating, annealing and cooling [31]. Although neutron diffraction has been used to investigate strain in the past in thermally sprayed coating-substrate systems [32][33][34], through thickness evaluation of strains in the thermally sprayed SOFC anode/interconnect system has not yet been realized.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Neutron Diffraction Residual Strain Measurements of Molybdenum Carbide-Based Solid Oxide Fuel Cell Anode Layers with Metal Oxides on Hastelloy X

et al. 2017

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Thermal spray deposition processes impart residual stress in layered Solid Oxide Fuel Cells (SOFC) materials and hence influence the durability and efficiency of the cell. The current study which is the first of its kind in published literature, reports results on using a neutron diffraction technique, to non-destructively evaluate the through thickness strain measurement in plasma sprayed (as-sprayed) anode layer coatings on a Hastelloy®X substrate. Through thickness neutron diffraction residual strain measurements were done on three different anode coatings (Mo-Mo 2 C/Al 2 O 3 , Mo-Mo 2 C/ ZrO 2 and Mo-Mo 2 C/TiO 2 ) using the vertical scan mode. The three anode coatings (developed through optimised process parameters) investigated had porosities as high as 20%, with thicknesses between 200 μm to 300 μm deposited on 4.76 mm thick Hastelloy®X substrate discs of 20 mm diameter. The results showed that while the through thickness residual strain in all three anodes was dissimilar for the investigated crystallographic planes, on average it was tensile. Other measurements include X-ray diffraction, nanoindentation and SEM microscopy. As the anode layer microstructures are complex (includes bi-layer alternate phases), nondestructive characterisation of residual strain, e.g. using neutron diffraction, provides a useful measure of through thickness strain profile without altering the stress field in the SOFC electrode assembly.

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Section: Assessing Neutron Diffraction Residual Strainmentioning

confidence: 99%

Section: Assessing Neutron Diffraction Residual Strainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neutron Diffraction Residual Strain Measurements of Molybdenum Carbide-Based Solid Oxide Fuel Cell Anode Layers with Metal Oxides on Hastelloy X

et al. 2017

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“…The role of carbide matrix in terms of ductility and its bond strength with the carbides therefore requires further research. The role of residual stress profile on the fracture response of the coating [51] and its dependence on the structure of the nanosized particles observed in suspension spraying also requires further investigations. However, this investigation shows that the size and nature of carbides in the wear debris dominated the wear mechanism in three-body abrasion, and was the main contributing factor for the differences in the wear rate observed for the steel ball counterface (Figure 10).…”

Section: Comparison Between S-hvof Hvof-jk and Hvof-jp Coatings Agaimentioning

confidence: 99%

Sliding wear investigation of suspension sprayed WC–Co nanocomposite coatings

Ahmed

Ali

Faisal

et al. 2015

Wear

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Sliding wear evaluation of nanostructured coatings deposited by Suspension High Velocity OxyFuel (S-HVOF) and conventional HVOF (Jet Kote (HVOF-JK) and JP5000 (HVOF-JP)) spraying were evaluated. S-HVOF coatings were nanostructured and deposited via an aqueous based suspension of the WC-Co powder, using modified HVOF (TopGun) spraying. Microstructural evaluations of these hardmetal coatings included X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDX). Sliding wear tests on coatings were conducted using a ball-on-flat test rig against steel, silicon nitride (Si 3 N 4 ) ceramic and WC-6Co balls. Results indicated that nanosized particles inherited from the starting powder in S-HVOF spraying were retained in the resulting coatings. Significant changes in the chemical and phase composition were observed in the S-HVOF coatings. Despite decarburization, the hardness and sliding wear resistance of the S-HVOF coatings was comparable to the HVOF-JK and HVOF-JP coatings. The sliding wear performance was dependent on the ball-coating test couple. In general a higher ball wear rate was observed with lower coating wear rate. Comparison of the total (ball and coating) wear rate indicated that for steel and ceramic balls, HVOF-JP coatings performed the best followed by the S-HVOF and HVOF-JK coatings. For the WC-Co ball tests, average performance of S-HVOF was better than that of HVOF-JK and HVOF-JP coatings. Changes in sliding wear 1 Corresponding author R.Ahmed@hw.ac.uk 2 behavior were attributed to the support of metal matrix due to relatively higher tungsten, and uniform distribution of nanoparticles in the S-HVOF coating microstructure. The presence of tribofilm was also observed for all test couples.

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“…The EDS spot analysis of the blocky phases revealed a high W and Fe content, suggesting that they are complex carbides (M 6 C) Fe 3 W 3 C. XRD analysis of the WRL confirmed the presence of Fe 3 W 3 C phase. Additionally, Xray diffraction data revealed the αFe (martensite), WC, W 2 C and also a significant fraction of a complex carbide (M 12 C) Fe 6 W 6 C. The presence of (M 12 C) Fe 6 W 6 C carbide is considered to be the result of decomposition of (M 6 C) Fe 3 W 3 C. Published data involving the Fe-W-C alloy system indicates that the Fe 6 W 6 C carbide is usually observed as a secondary carbide after the dissolution or decomposition of primary Fe 3 W 3 C carbide [16]. It is also supported by thermodynamic calculations, that do not show the presence of M 12 C phase, under both non-equilibrium and equilibrium conditions, Fig.…”

Section: Resultsmentioning

confidence: 99%

Diode Laser Surface Alloying of Armor Steel with Tungsten Carbide

Janicki¹,

Górka²,

Kwaśny³

et al. 2017

Archives of Metallurgy and Materials

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Metal matrix composite (MMC) surface layers reinforced by WC were fabricated on armor steel ARMOX 500T plates via a laser surface alloying process. The microstructure of the layers was assessed by scanning electron microscopy and X-ray diffraction.The surface layers having the WC fraction up to 71 vol% and an average hardness of 1300 HV were produced. The thickness of these layers was up to 650 μm. The addition of a titanium powder in the molten pool increased the wettability of WC particles by the liquid metal in the molten pool increasing the WC fraction. Additionally, the presence of titanium resulted in the precipitation of the (Ti,W)C phase, which significantly reduced the fraction of W-rich complex carbides and improved a structural integrity of the layers.

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Neutron diffraction residual strain measurements in post-treated thermal spray cermet coatings

Cited by 42 publications

References 31 publications

Neutron Diffraction Residual Strain Measurements of Molybdenum Carbide-Based Solid Oxide Fuel Cell Anode Layers with Metal Oxides on Hastelloy X

Neutron Diffraction Residual Strain Measurements of Molybdenum Carbide-Based Solid Oxide Fuel Cell Anode Layers with Metal Oxides on Hastelloy X

Sliding wear investigation of suspension sprayed WC–Co nanocomposite coatings

Diode Laser Surface Alloying of Armor Steel with Tungsten Carbide

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