Oxidation mechanism of aluminum nitride revisited

Yeh, Chih-Ting; Tuan, Wei‐Hsing

doi:10.1007/s40145-016-0213-1

Cited by 39 publications

(25 citation statements)

References 19 publications

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“…This result is in agreement with literature data compiled by Smialek et al [46]. The diffusion of Al 3+ cations and O 2anions through the lattice and grain boundaries in aluminum oxide is very low, 10 -19 and 10 -22 m²•s -1 respectively at 1373 K [11]. It suggests that the diffusion length should be of some tens of nanometers and the oxide layer reaches a value of some µm after 94 h oxidation at 1373 K. For AlN coated samples, many small pores are found within the oxidized layer.…”

Section: High Temperature Oxidation Oxidation Kinetics and Scale Micrsupporting

confidence: 93%

“…Figure 5 (b) shows a typical microstructure of the porous layer (here for N/Al=5). The reaction of AlN with air involves the release of nitrogen [11,[47][48]. In the first hours, the driving force for the oxidation of AlN is the formation of small pores which generate large fresh surface area leading to further reaction to take place.…”

Section: High Temperature Oxidation Oxidation Kinetics and Scale Micrmentioning

confidence: 99%

“…Aluminum nitride coating, deposited by chemical vapor deposition at 1373 K was selected for its high thermal conductivity, low thermal expansion coefficient, high temperature stability and its ability to develop stable alumina scales at high temperature [11]. Al2O3 layer which is formed during high temperature air exposure can modify underlying substrate properties [12][13][14][15] [11,[16][17]. Along with low fabrication costs, these coatings also present self-healing effects if the protective surface oxide layer fails [18].…”

Section: Introductionmentioning

confidence: 99%

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High temperature properties of AlN coatings deposited by chemical vapor deposition for solar central receivers

Chen

Colas

Mercier

et al. 2019

Surface and Coatings Technology

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There is an increasing interest for tower concentrated solar power (CSP) systems which can work at temperatures higher than 1073 K to optimize the efficiency. One of the challenges is to design the receiver that will be heated at high temperatures. On the contrary to coatings in gas turbine engine, the coating/substrate system must have a high thermal conductivity to ensure a good heat transfer to the fluid. Aluminum nitride (AlN) coating, deposited by chemical vapor deposition at 1373 K at a growth rate of 10-50 µm h-1 , was selected for its high thermal conductivity, low thermal expansion coefficient, high temperature stability and its ability to develop stable alumina scales above 1273 K. Cast and ODS (Oxide Dispersion Strengthened) FeCrAl alloys, also alumina-formers, were chosen as model substrates to reduce the influencing parameters in real-life receivers and to study the potential of these coatings. Accelerated cyclic oxidation tests and emissivity measurements allowed the evaluation of AlN coatings as materials for high temperature CSP receivers. The multilayered systems showed low degradation after hundreds of thermal cycles at 1073 K in air and can support higher temperatures (1373 K) for 100 to 500 h depending on the coating thickness. Nevertheless the fast cyclic oxidations in solar furnace generated cracks through the coatings. The measurement of the optical properties also revealed a decrease of the absorptivity after oxidation.

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Section: High Temperature Oxidation Oxidation Kinetics and Scale Micrsupporting

confidence: 93%

Section: High Temperature Oxidation Oxidation Kinetics and Scale Micrmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High temperature properties of AlN coatings deposited by chemical vapor deposition for solar central receivers

Chen

Colas

Mercier

et al. 2019

Surface and Coatings Technology

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“…Niu et al introduced carbon nanotubes as templates into their alumina sol [50]. Consequently, they also followed a similar procedure as in described in the above-mentioned patents, i.e., the alleged transformation from γ-Al 2 O 3 into α-Al 2 O 3 was performed under N 2 flow at 1150-1300 • C, followed by pyrolytic carbon removal by oxidation at 500-750 • C. Products obtained via this method are certainly porous, and likely alumina, despite the possibility of aluminum nitride formation above 900 • C [51][52][53][54]. However, the authors of this review contest the formation of 100% pure corundum under the conditions described.…”

Section: Pore Protection By Carbon Fillingmentioning

confidence: 99%

Towards Macroporous α-Al2O3—Routes, Possibilities and Limitations

2020

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This article combines a systematic literature review on the fabrication of macroporous α-Al2O3 with increased specific surface area with recent results from our group. Publications claiming the fabrication of α-Al2O3 with high specific surface areas (HSSA) are comprehensively assessed and critically reviewed. An account of all major routes towards HSSA α-Al2O3 is given, including hydrothermal methods, pore protection approaches, dopants, anodically oxidized alumina membranes, and sol-gel syntheses. Furthermore, limitations of these routes are disclosed, as thermodynamic calculations suggest that γ-Al2O3 may be the more stable alumina modification for ABET > 175 m2/g. In fact, the highest specific surface area unobjectionably reported to date for α-Al2O3 amounts to 16–24 m2/g and was attained via a sol-gel process. In a second part, we report on some of our own results, including a novel sol-gel synthesis, designated as mutual cross-hydrolysis. Besides, the Mn-assisted α-transition appears to be a promising approach for some alumina materials, whereas pore protection by carbon filling kinetically inhibits the formation of α-Al2O3 seeds. These experimental results are substantiated by attempts to theoretically calculate and predict the specific surface areas of both porous materials and nanopowders.

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“…For instance, the activation energies for the oxidation of AlN obeying the parabolic rate law have been reported as 160 kJ/mol for the CaC 2 -doped AlN bulk at temperatures above 1523 K 50 and 255 kJ/mol for the AlN bulk in the temperature range of 1173–1373 K 51 . The activation energies associated with the linear oxidation rate law of AlN have been reported as 175 kJ/mol for the AlN bulk in the temperature range of 1423–1623 K 52 and 187 kJ/mol for the Y 2 O 3 -doped AlN bulk in the temperature range of 1323–1623 K 53 .…”

Section: Discussionmentioning

confidence: 99%

AlN formation by an Al/GaN substitution reaction

Noorprajuda

Ohtsuka

Adachi

et al. 2020

Sci Rep

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Aluminium nitride (Aln) is a promising semiconductor material for use as a substrate in high-power, high-frequency electronic and deep-ultraviolet optoelectronic devices. We study the feasibility of a novel Aln fabrication technique by using the Al/Gan substitution reaction method. the substitution method we propose here consists of an Al deposition process on a Gan substrate by a sputtering technique and heat treatment process. the substitution reaction (Al + Gan = Aln + Ga) is proceeded by heat treatment of the Al/Gan sample, which provides a low temperature, simple and easy process. C-axis-oriented Aln layers are formed at the Al/Gan interface after heat treatment of the Al/Gan samples at some conditions of 1473-1573 K for 0-3 h. A longer holding time leads to an increase in the thickness of the AlN layer. The growth rate of the AlN layer is controlled by the interdiffusion in the Aln layer. Aluminium nitride (AlN) is a promising semiconductor material for use as a substrate in high-power, highfrequency electronic and optoelectronic devices. It can be used as a substrate in AlGaN-based ultraviolet C (UV-C) optoelectronic devices owing to its wide bandgap (above 6 eV) 1 , UV transparency 2 , and close lattice constant with that of AlGaN 3. AlN can be grown in two forms: film and bulk. AlN films have been fabricated by various methods, such as metal-organic vapour-phase epitaxy (MOVPE) 4,5 , hydride vapour phase epitaxy (HVPE) 6,7 , pulsed laser deposition (PLD) 8,9 , molecular beam epitaxy (MBE) 10,11 , or sputtering 12,13 , to improve its crystalline quality, surface area, growth rate, or lower its processing temperature. Annealing techniques have been demonstrated to improve the crystalline quality of AlN films 14-16. To facilitate the further development of AlN crystal growth, several researchers have developed original and unconventional techniques. For example, the pyrolytic transportation method 17 , the liquid phase epitaxy (LPE) method using a Ga-Al binary solution 18 , Al-Sn flux growth 19 , AlN fabrication by using Al and Li 3 N solid sources 20 , and elementary-source vapour-phase epitaxy (EVPE) 21 have been demonstrated. In the pyrolytic transportation method 17 , α-Al 2 O 3 is used as an Al-source material, and it is heated at 2223 K to form Al 2 O gas in the nitrogen gas flow. The Al 2 O gas is transported to the growth zone to react with nitrogen gas at 2023 K on a sintered AlN plate for 30 h, which yields a rod-like AlN crystal (48-mm long). The advantages of this method are an economically friendly α-Al 2 O 3 source and good crystalline quality of AlN. Wu et al. 21 used metallic Al and nitrogen gas as source materials to grow an AlN crystal, which they called elementary-source vapour-phase epitaxy (EVPE). They grew the AlN with a growth rate of 18 μm/h under an optimum growth zone temperature of 1823 K. The advantages of this method are that it is conducted at a temperature lower than that of the sublimation method using no hazardous gas. Regarding the LPE methods, Adachi et al. 18 grew a 1-µm-...

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Oxidation mechanism of aluminum nitride revisited

Cited by 39 publications

References 19 publications

High temperature properties of AlN coatings deposited by chemical vapor deposition for solar central receivers

High temperature properties of AlN coatings deposited by chemical vapor deposition for solar central receivers

Towards Macroporous α-Al2O3—Routes, Possibilities and Limitations

AlN formation by an Al/GaN substitution reaction

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