Residual stress measurement in alumina coatings

Kraus, Ivo; Ganev, Nikolaj; Gosmanová, Galina; Tietz, Horst-Dieter; Pfeiffer, Lothar; Böhm, Sivasambu

doi:10.1016/0921-5093(95)09816-x

Cited by 14 publications

(4 citation statements)

References 1 publication

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“…The measurements were carried out for anatase and rutile at angles (from -36° to + 36°) and 7 angles (from -18° to + 18°) respectively with 0.01° (2 ) step size and 90 s exposure time. The gravity peak location method [16,20] with 10% threshold value was employed to calculate (215) anatase ( Fig. 3a) and…”

Section: Nanoindentationmentioning

confidence: 99%

Structural characteristics and residual stresses in oxide films produced on Ti by pulsed unipolar plasma electrolytic oxidation

Khan

Yerokhin

Matthews

2008

Philosophical Magazine

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International audienceOxide films, 7 to 10 μm thick, were produced on commercially pure titanium by plasma electrolytic oxidation in a sodium orthophosphate electrolyte using a pulsed unipolar current with frequency (ƒ) and duty cycle (δ) varied within f = 0.1 to 10 kHz and δ = 0.8 to 0.2 respectively. The coatings comprised a mixture of an amorphous phase with nanocrystalline anatase and rutile phases wherein the relative content of rutile varied from 17 to 25 wt%. Incorporation of phosphorus from the electrolyte into the coating in the form of PO2-, PO32- and PO43-, as demonstrated by EDX and FT-IR analyses, seems to contributed the formation of the amorphous phase. Residual stresses associated with the crystalline coating phase constituents were evaluated using the X-ray diffraction Sin2ψ method. It was found that, depending on the treatment parameters, internal direct and shear stresses in anatase ranged from -205 (±17) MPa to -431 (±27) MPa and from -98 (±6) MPa to -145 (±10) MPa respectively, whereas the rutile structure is comparatively stress free

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Section: Nanoindentationmentioning

confidence: 99%

Structural characteristics and residual stresses in oxide films produced on Ti by pulsed unipolar plasma electrolytic oxidation

Khan

Yerokhin

Matthews

2008

Philosophical Magazine

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“…Measurement of residual strains in these thermal spray coatings is critical for modeling and designing improved components. The influence of coating powder characteristics, spraying process, and spraying process parameters on the residual stress field of Al 2 O 3 coatings has also been the topic of recent investigations (Ref [10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Residual Strain and Fracture Response of Al2O3 Coatings Deposited via APS and HVOF Techniques

et al. 2011

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The aim of this investigation was to nondestructively evaluate the residual stress profile in two commercially available alumina/substrate coating systems and relate residual stress changes with the fracture response. Neutron diffraction, due to its high penetration depth, was used to measure residual strain in conventional air plasma-sprayed (APS) and finer powder high velocity oxy-fuel (HVOF (h-gun))-sprayed Al 2 O 3 coating/substrate systems. The purpose of this comparison was to ascertain if finer powder Al 2 O 3 coatings deposited via h-gun can provide improved residual stress and fracture response in comparison to conventional APS coatings. To obtain a through thickness residual strain profile with high resolution, a partially submerged beam was used for measurements near the coating surface, and a beam submerged in the coating and substrate materials near the coating-substrate interface. By using the fast vertical scanning method, with careful leveling of the specimen using theodolites, the coating surface and the coating/substrate interface were located with an accuracy of about 50 lm. The results show that the through thickness residual strain in the APS coating was mainly tensile, whereas the HVOF coating had both compressive and tensile residual strains. Further analysis interlinking Vickers indentation fracture behavior using acoustic emission (AE) was conducted. The microstructural differences along with the nature and magnitude of the residual strain fields had a direct effect on the fracture response of the two coatings during the indentation process.

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“…Simultaneously, the peaks of Fe α phase and cementite Fe 3 C were visible in the diffraction diagram because of the presence of these phases in the carburized zone below the iron borides. The penetration depth of Cu Kα radiation, used for phase analysis, usually does not exceed 20 µm for metallic materials [42][43][44]. Therefore, the Fe α and Fe 3 C phases were also detected, although they were located below the iron borides.…”

Section: Microstructure Characterizationmentioning

confidence: 99%

Gas Technique of Simultaneous Borocarburizing of Armco Iron Using Trimethyl Borate

2020

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The gas boriding process is an appropriate technique used for increasing the hardness and wear resistance of iron and steels. However, the boron halides (e.g., BCl3, BF3) are rarely used as a boron source during gas boriding in industry due to the toxic character of these reagents. The possibility of the use of organic compounds as a boron source in plasma assisted processes was the instigation to determine the possibility of applying these agents for gas boriding. In the present work trimethyl borate was used as an organic boron source. The use of a N2–H2–B(CH3O)3 atmosphere ensured the appropriate conditions for the simultaneous gas borocarburizing of Armco iron. The process was carried out at 1223 K (950 °C) for 2 h. The produced layer consisted of two zones: an outer zone containing a diffusion of boron atoms and an inner zone containing a diffusion of carbon atoms, under the outer zone. Due to the reduction of trimethyl borate with hydrogen, free atoms of carbon were released for the gas atmosphere. Therefore, there existed favorable conditions for carburizing. Unfortunately, the formation of a carburized layer was the reason for the difficult diffusion of boron atoms. As a consequence, the boron diffusion front was hindered, and the outer boride layer was relatively thin (ca. 7.8 µm). The boride layer contained only Fe2B phase, which was characterized by high hardness in the range from 1103 HV0.01 to 1546 HV0.01. The presence of iron borides in the outer layer was also the reason for increased wear resistance in comparison with untreated Armco iron.

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Residual stress measurement in alumina coatings

Cited by 14 publications

References 1 publication

Structural characteristics and residual stresses in oxide films produced on Ti by pulsed unipolar plasma electrolytic oxidation

Structural characteristics and residual stresses in oxide films produced on Ti by pulsed unipolar plasma electrolytic oxidation

Residual Strain and Fracture Response of Al2O3 Coatings Deposited via APS and HVOF Techniques

Gas Technique of Simultaneous Borocarburizing of Armco Iron Using Trimethyl Borate

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