Microstructure investigation of textured CVD alumina coatings

Shoja, Siamak; Mortazavi, N.; Lindahl, Erik; Norgren, Susanne; Bäcke, Olof; Halvarsson, Mats

doi:10.1016/j.ijrmhm.2019.105125

Cited by 29 publications

(9 citation statements)

References 24 publications

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“…However, the MTCVD Ti(C,N) layer has an important function as a diffusion barrier for W and Co from the cemented carbide substrate to the α-Al 2 O 3 -Ti(C,N) interface. These elements may disturb the initial growth of α-Al 2 O 3 [1,30]. The problem is well-known in cutting tool industry and confirmed in a recent TEM study [30].…”

Section: Manipulation Of α-Al 2 O 3 Microstructuresmentioning

confidence: 73%

“…These elements may disturb the initial growth of α-Al 2 O 3 [1,30]. The problem is well-known in cutting tool industry and confirmed in a recent TEM study [30]. Further, the texture of the MTCVD Ti(C,N) layer, which is more profound in thicker layers, may also affect nucleation and growth of the alumina layer.…”

Section: Manipulation Of α-Al 2 O 3 Microstructuresmentioning

confidence: 85%

“…In the experiments discussed above a thin (~3µm) layer of MTCVD Ti(C,N) without optimized texture was applied, which could have affected the alumina growth. In addition, the thin Ti(C,N) layer may have allowed diffusion of the substrate elements (Co, W) to the Ti(C,N)-Al 2 O 3 interface disturbing the process [1,30]. However, the suggested process windows presented in Figure 4 are assumed to hold reasonably well for CO 2 values higher than~3 vol %.…”

Section: Texture Developmentmentioning

confidence: 99%

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Influence of Process Conditions on the Growth and Texture of CVD Alpha-Alumina

Ruppi¹

2020

Coatings

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In the present study, the influence of experimental variables on the growth characteristics and texture development in chemically vapour deposited α-Al2O3 coatings was investigated. The emphasis was on the effects of H2S. The α-Al2O3 layers were deposited from the AlCl3-H2-CO2-HCl-H2S precursor system onto intermediate Ti(C,N) layers. The substrate was cemented carbide. The coatings were characterized with respect to microstructure and texture using X-ray diffraction, scanning electron microscopy and electron back-scattering diffraction. The observations were unpredictable, suggesting that in addition to the growth rate, H2S strongly affected the texture of the α-Al2O3 coatings. The uncatalyzed α-Al2O3 coatings (H2S = 0) developed (11 2 ¯ 0) texture. With the increment of H2S concentration the texture changed from (11 2 ¯ 0) texture through (10 1 ¯ 0), (10 1 ¯ 2) and (10 1 ¯ 4) textures to (0001) texture. Growth regimes for (11 2 ¯ 0), (10 1 ¯ 0), (10 1 ¯ 2), (10 1 ¯ 4) and (0001) textures were depicted as a function of the H2S/CO2 ratio. Examples of grain-boundary and microstructural manipulation of CVD α-Al2O3 layers by applying texture control were presented.

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Section: Manipulation Of α-Al 2 O 3 Microstructuresmentioning

confidence: 73%

Section: Manipulation Of α-Al 2 O 3 Microstructuresmentioning

confidence: 85%

Section: Texture Developmentmentioning

confidence: 99%

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Influence of Process Conditions on the Growth and Texture of CVD Alpha-Alumina

Ruppi¹

2020

Coatings

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“…As can be seen in the IPF-Y EBSD maps, both coatings exhibit columnar grain growth in the [001] direction. However, as indicated by the differently tilted hexagonal cells of α-Al2O3 in Figure 4a, grains with orientations other than the (0001) also exist in the lower area of the micro-cantilevers, i.e., closer to the TiCN/α-Al2O3 interface, suggesting competitive growth, which is commonly observed for CVD α-Al2O3 coatings [1,26]. It should be mentioned that the micro-cantilever was prepared approximately 1 µm above the TiCN/α-Al2O3 interface; thus, the nucleation zone of the α-Al2O3 is not visible in the EBSD scan.…”

Section: Mechanical Propertiesmentioning

confidence: 85%

“…As reported in literature and confirmed by our calculations in Figure 3b, αand κ-Al 2 O 3 exhibit highly anisotropic mechanical properties. Thus, different stress fields caused by nanoindentation and micro-cantilever bending tests may explain the deviation of the Young's modulus values [22,26,27]. The resulting fracture stress and fracture toughness from the micro-cantilever bending tests are illustrated in Figure 5b.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Fracture Properties of α– and ĸ–Al2O3 Hard Coatings Deposited by Chemical Vapor Deposition

Konstantiniuk

Tkadletz

Czettl³

et al. 2021

Coatings

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Although α– and κ–Al2O3 hard coatings deposited by chemical vapor deposition are well established in the metal-cutting industry for their ability to increase the performance and lifetime of cutting tools, the literature on their fracture properties is scarce. Thus, within this study, the microstructure and mechanical properties of α– and κ–Al2O3 coatings were investigated and compared to each other. X-ray diffraction and scanning electron microscopy combined with electron backscatter diffraction showed that both coatings exhibited a fiber texture, where the α-Al2O3 coating displayed a (0001) texture and the κ–Al2O3 coating a (001) texture with a certain (013) contribution. Higher hardness and Young’s modulus values of 31.0 ± 0.9 GPa and 474.6 ± 12.5 GPa, respectively, were obtained for the α–Al2O3 coating, compared to 24.2 ± 0.8 GPa and 356.8 ± 7.9 GPa for κ–Al2O3. While the α–Al2O3 coating exhibited a higher fracture stress of 8.1 ± 0.3 GPa (compared to 6.4 ± 0.6 GPa for κ–Al2O3), the κ–Al2O3 coating showed a higher fracture toughness of 4.4 ± 0.3 MPa*m1/2 (compared to 3.2 ± 0.3 MPa*m1/2 for alpha).

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Research progress of surface modification and solid–liquid lubrication synergistic friction reduction and wear resistance

Chen

Yang

et al. 2022

Int J Adv Manuf Technol

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Microstructure investigation of textured CVD alumina coatings

Cited by 29 publications

References 24 publications

Influence of Process Conditions on the Growth and Texture of CVD Alpha-Alumina

Influence of Process Conditions on the Growth and Texture of CVD Alpha-Alumina

Fracture Properties of α– and ĸ–Al2O3 Hard Coatings Deposited by Chemical Vapor Deposition

Research progress of surface modification and solid–liquid lubrication synergistic friction reduction and wear resistance

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