Journal articles: 'Al/AlN'

1

Makino, Yukio, Kesami Saito, Yoshihiro Murakami, and Katsuhiko Asami. "Phase Change of Zr-Al-N and Nb-Al-N Films Prepared by Magnetron Sputtering Method." Solid State Phenomena 127 (September 2007): 195–200. http://dx.doi.org/10.4028/www.scientific.net/ssp.127.195.

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In order to examine the critical content of AlN for phase change from B1 type to B4 type, Zr-Al-N and Nb-Al-N pseudobinary films were synthesized with an inductively combined rf-plasma assisted magnetron sputtering method. From phase identification of these films by XRD and Raman scattering methods, it is found that phase change from B1 structure to B4 one occurs in the range from 30mol%AlN to 35mol%AlN for Zr-Al-N pseudobinary films and from 62mol%AlN to 70mol%AlN for Nb-Al-N pseudobinary films. The critical AlN content for Zr-Al-N pseudobinary films shows excellent agreement with the value (33mol%AlN) predicted by band parameters. The critical content for Nb-Al-N pseudobinary films is larger than the predicted value (53mol%AlN). It is suggested that the disagreement is attributed to a highly defective structure in Nb-Al-N pseudobinary films.

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2

Goujon, C., P. Goeuriot, M. Chedru, J. Vicens, J. L. Chermant, F. Bernard, J. C. Niepce, P. Verdier, and Y. Laurent. "Cryomilling of Al/AlN powders." Powder Technology 105, no. 1-3 (November 1999): 328–36. http://dx.doi.org/10.1016/s0032-5910(99)00155-2.

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3

Amosov, Aleksandr P., Y. V. Titova, I. Y. Timoshkin, and Antonina A. Kuzina. "Fabrication of Al-AlN Nanocomposites." Key Engineering Materials 684 (February 2016): 302–9. http://dx.doi.org/10.4028/www.scientific.net/kem.684.302.

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A review of the methods of obtaining and properties of aluminum matrix composites, discretely reinforced with ceramic particles and nanoparticles of aluminum nitride AlN, is given. The survey shows that at low weight, nanocomposites Al-AlN possess improved physical and mechanical properties, including at high temperatures up to 400-550°C, which makes them very attractive for applications in automotive, aerospace and semiconductor technology. However, due to the long duration and energy consumption, expensive and complicated equipment, low productivity of existing solid-phase methods of powder metallurgy and liquid-phase metallurgical processes of fabrication of nanocomposites of Al-AlN, there are not yet the mastered technologies of industrial production of these composites. Azide technology of self-propagating high-temperature synthesis (SHS-AZ) using sodium azide NaN3 as a solid nitriding reagent allows you to get relatively inexpensive nanopowder of aluminum nitride in the form of nanofibers along with side salt of cryolite Na3AlF6, which can play the role of flux when working with molten aluminum. A new simple ex-situ method of introduction of AlN particles in the molten aluminum alloy in the form of a composite master alloy obtained by fusing together a flux carnallite KCl·MgCl2 with AlN nanopowder mixed with cryolite Na3AlF6 was proposed. Results of experiments on the application of the proposed method for obtaining nanocomposite with matrix made of aluminum-magnesium alloy AlMg6 containing up to 1 % of the reinforcing phase AlN are presented.

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4

UDA, Masahiro, Satoru OHNO, and Hideo OKUYAMA. "Preparation of Ultrafine Powders of AlN and (AlN+Al) by Nitrogen Plasma-Al Reaction." Journal of the Ceramic Association, Japan 95, no. 1097 (1987): 86–90. http://dx.doi.org/10.2109/jcersj1950.95.86.

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5

Uda, Masahiro, Satoru Ohno, and Hideo Okuyama. "Preparation of ultrafine powders of AlN and (AlN + Al) by nitrogen plasma-Al reaction." International Journal of High Technology Ceramics 3, no. 4 (January 1987): 333. http://dx.doi.org/10.1016/0267-3762(87)90101-9.

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6

Daud, Abdul Razak, and Mahamad Noor Wahab. "Microstructure and Phases of As-Cast and Heat-Treated Al-Si-Mg/AlN Composites Prepared by Stir Casting." Advanced Materials Research 501 (April 2012): 155–59. http://dx.doi.org/10.4028/www.scientific.net/amr.501.155.

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Al-Si-Mg/AlN composites were prepared by stir casting technique. The amount of AlN added to Al-Si-Mg alloy was from 2 to 10 wt%. As-cast composites were solutionised at 540 °C for 4 h, quenched in warm water, 60 °C then artificially aged at 180 °C for 4 h. The microstructure of Al-Si-Mg matrix alloy contained dendritic α-Al, needle-like Si and very little inter-metallic compounds. As-cast Al-Si-Mg/AlN composites have rounded α-Al phase and needle-like Si where AlN particles dispersed surrounding α-Al. Needle-like Si transformed to spheroid after artificial aging. The size of α-Al phases of heat-treated composites containing 2 and 5 wt% AlN was bigger than that of as-cast composites whereas the heat-treated Al-Si-Mg/10% AlN composite has thin and elongated dendritic α-Al phases, and larger AlN particles.

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7

Chen, Jie, Chonggao Bao, Yana Ma, and Zihan Chen. "Distribution control of AlN particles in Mg-Al/AlN composites." Journal of Alloys and Compounds 695 (February 2017): 162–70. http://dx.doi.org/10.1016/j.jallcom.2016.10.190.

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8

OGAWA, Soichi, Masatoshi KONDO, Masami SHIMIZU, Bohyom LEE, and Masatomo YASUDA. "Optical Properties of the Sputter-Deposited AlN/Al/AlN Multilayer Nanofilms." Journal of The Surface Finishing Society of Japan 64, no. 5 (2013): 311–14. http://dx.doi.org/10.4139/sfj.64.311.

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9

Chen, C. W., D. Y. Chen, C. Y. Hsu, Y. H. Chang, and K. H. Hou. "Spectrally selective Al/AlN/Al/AlN tandem solar absorber by inline reactive ac magnetron sputtering." Surface Engineering 27, no. 8 (September 2011): 616–22. http://dx.doi.org/10.1179/026708410x12786785573436.

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10

Tang, Y. B., Y. Q. Liu, C. H. Sun, and H. T. Cong. "AlN nanowires for Al-based composites with high strength and low thermal expansion." Journal of Materials Research 22, no. 10 (October 2007): 2711–18. http://dx.doi.org/10.1557/jmr.2007.0368.

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Based on the synthesis of a sufficient amount of AlN nanowires (AlN-NWs), AlN-NWs/Al composites with homogenously distributed AlN-NWs were fabricated. Microstructural observations reveal that the interface between AlN-NWs and Al matrix is clean and bonded well, and no interfacial reaction product was formed at the nanowire-matrix boundary. Mechanical properties including yield and tensile strength of the composites were improved with AlN-NWs volume fraction changing from 5 to 15 vol%, and the maximum yield and tensile strengths of the composite were about 6 and 5 times, respectively, as high as those of Al matrix. Meanwhile, AlN-NWs effectively decreased the coefficient of thermal expansion (CTE) of the composites, and the CTE of 15 vol% composite was about one half that of Al matrix. The results obtained suggest that AlN nanowire is a promising reinforcement for optimizing the mechanical and thermal properties of metal matrix composites.

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11

Watanabe, Yoshimi, Masaki Murase, Hisashi Sato, and Hideaki Tsukamoto. "Joining of AlN and Al with Compositional Graded Layer by Centrifugal Mixed-Powder Method." Materials Science Forum 941 (December 2018): 1978–83. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1978.

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In this study, joining of AlN and Al with compositional graded layer is made by centrifugal mixed-powder method (CMPM). The mixed-powder of AlN particles and Al particles is inserted into a spinning mold with bulk-shaped AlN, and then molten Al is poured into the spinning mold with the mixed-powder and bulk-shaped AlN. As a result, the molten Al penetrates into the space between the mixed-powder by the centrifugal force, and at the same time, the Al particles can be melted by heat from the molten Al. Then AlN and Al can be joined with compositional graded layer after solidification. Micromechanics-based analysis is also employed to understand the thermal stress relaxation by the compositional graded layer.

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12

Nagatomo, Yoshiyuki, Ryo Muranaka, Hiromasa Hayashi, Yoshirou Kuromitsu, and Noriyuki Kuwano. "Fracture Process of Aluminum/Aluminum Nitride Interfaces during Thermal Cycling." Materials Science Forum 638-642 (January 2010): 3895–900. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.3895.

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Al circuit substrates, which are composed of a sintered AlN plate and pure Al plate joined to both sides of the AlN plate, are used for semiconductor power devices. It is important to prevent fracture of the Al/AlN interface to ensure normal and stable device operation. In this study, the fracture process of Al/AlN interface during thermal cycling was investigated using advanced scanning electron microscopy (SEM). Al circuits joined to an AlN plate were plastically deformed with thermal cycling. Al grains were divided with the formation of sub-boundaries due to the plastic deformation. After 2000 thermal cycles, a crack was generated at edges of the Al/AlN interface and propagated gradually to the center of the substrate. Cross-sectional observation, using an angle selective backscattered electron detector (AsB), revealed that the Al grain size near the Al/AlN interface decreased to 3 m or less, and the crack proceeded along the Al grain boundaries. To clarify the temperature dependence of the fracture process, a repeated bending test was performed at various temperatures. Shear strains were induced at the Al/AlN interface by the repeated bending. The rate of crack propagation tends to be higher at higher temperatures for bending test. In substrates bent at 373 K or higher, the crack proceeded after the Al grains had been refined. These results indicate that fine-grained Al resulting from thermal cycling is formed by creep deformation and recrystallization at higher temperatures. Thus, improving the creep strength of the Al plate is thought to be effective for prevent cracking during thermal cycling. The effect of additive elements in the Al plate was also discussed in this study.

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13

Gao, Tong, Zengqiang Li, Yihan Bian, Qingfei Xu, Kaiqi Hu, Mengxia Han, and Xiangfa Liu. "Dispersing nano–AlN particles cluster by designing Al–Si–AlN/Mg diffusion couples and the preparation of AlN/Mg–Al composite." Materials Science and Engineering: A 766 (October 2019): 138347. http://dx.doi.org/10.1016/j.msea.2019.138347.

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14

Kangawa, Yoshihiro, and Koichi Kakimoto. "AlN synthesis on AlN/SiC template using Li-Al-N solvent." physica status solidi (a) 207, no. 6 (May 31, 2010): 1292–94. http://dx.doi.org/10.1002/pssa.200983566.

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15

Fang, Bin Xiang, Bo Quan Zhu, Wen Jie Zhang, Xue Dong Li, and Zheng Yun Fan. "Hydration Resistance of Al/AlN Bonded Corundum Based Multiphase Material." Key Engineering Materials 368-372 (February 2008): 1133–36. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1133.

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The Al/AlN bonded corundum based multiphase material was prepared by raw materials of fused alumina and metallic aluminum powder by in situ reaction at 1100°C for 3h in N2 . The XRD analysis showed that the mineral phases of prepared material are corundum, metallic aluminum and AlN respectively. The SEM investigation revealed that both tetragonal whiskers and hexagon powders of AlN were formed. The results of hydration tests indicated that the rate of weight gain and pulverization of the material were negligible and the ratio of residual crushing strength was kept at a high level. The XRD patterns of samples after hydration tests identified that the AlN phase still remained although a small amount of AlOOH and Al(OH)3 was formed due to the hydration of AlN. It is believed that the limited hydration of AlN should be contributed to the dissolution of O element to AlN. The hydration mechanism of AlN was discussed.

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16

SHAHIEN, MOHAMMED, MOTOHIRO YAMADA, TOSHIAKI YASUI, and MASAHIRO FUKUMOTO. "REACTIVE PLASMA NITRIDING OF AL2O3 POWDER IN THERMAL SPRAY." International Journal of Modern Physics: Conference Series 06 (January 2012): 546–51. http://dx.doi.org/10.1142/s2010194512003753.

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Among advanced ceramics, aluminum nitride ( AlN ) had attracted much attention in the field of electrical and structural applications due to its outstanding properties. However, it is difficult to fabricate AlN coating by conventional thermal spray processes directly. Due to the thermal decomposition of feedstock AlN powder during spraying without a stable melting phase (which is required for deposition in thermal spray). Reactive plasma spraying (RPS) has been considered as a promising technology for in-situ formation of AlN thermally sprayed coatings. In this study the possibility of fabrication of AlN coating by reactive plasma nitriding of alumina ( Al 2 O 3) powder using N 2/ H 2 plasma was investigated. It was possible to fabricate a cubic- AlN (c- AlN ) based coating and the fabricated coating consists of c- AlN , α- Al 2 O 3, Al 5 O 6 N and γ- Al 2 O 3. It was difficult to understand the nitriding process from the fabricated coatings. Therefore, the Al 2 O 3 powders were sprayed and collected in water. The microstructure observation of the collected powder and its cross section indicate that the reaction started from the surface. Thus, the sprayed particles were melted and reacted in high temperature reactive plasma and formed aluminum oxynitride which has cubic structure and easily nitride to c- AlN . During the coatings process the particles collide, flatten, and rapidly solidified on a substrate surface. The rapid solidification on the substrate surface due to the high quenching rate of the plasma flame prevents AlN crystal growth to form the hexagonal phase. Therefore, it was possible to fabricate c- AlN / Al 2 O 3 based coatings through reactive plasma nitriding reaction of Al 2 O 3 powder in thermal spray.

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17

Matsutani, Takaomi, Masato Kiuchi, Kiyotaka Shirouzu, Akihiro Yoshioka, Ryuichi Shimizu, and Sadayuki Takahashi. "Formation of Aluminum Nitride Film for High Power Soft X-Ray Source Using Ion-Beam Assisted Deposition Method." Solid State Phenomena 107 (October 2005): 43–46. http://dx.doi.org/10.4028/www.scientific.net/ssp.107.43.

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An aluminum nitride (AlN) target for Al-Kα X-ray source with high power and long service life has been developed by N2 + ions assisted Al vapor deposition method (IBAD). The AlN film formations were carried out at the Al deposition rate varied from 2.0 nm/s to 0.15 nm/s with a fixed low-energy N2 + ion of 1 keV. The films were deposited on Cu substrate at room temperature. The AlN films were characterized by an X-ray diffraction, an electron probe X-ray microanalysis and a Knoop-hardness measurement. The AlN deposited at the Al deposition rate of 0.5 nm has a N/Al ratio of 0.4, a Knoop-hardness of ~1500 and a low resistance of ~0.2 . Comparison of durability test between the AlN target and a conventional Al target was performed. It has been revealed, after 500 hours under an electron bombardment of 300 mA at 20 kV, that there were no change of morphology and X-ray intensity on the AlN-surface whilst cracks due to the heat-cycle fatigue covered the Al-surface.

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18

Li, Zengqiang, Tong Gao, Qingfei Xu, Huabing Yang, Mengxia Han, and Xiangfa Liu. "Microstructure and Mechanical Properties of an AlN/Mg–Al Composite Synthesized by Al–AlN Master Alloy." International Journal of Metalcasting 13, no. 2 (September 10, 2018): 384–91. http://dx.doi.org/10.1007/s40962-018-0261-0.

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19

Sugio, Kenjiro, Takuya Kawata, Yongbum Choi, and Gen Sasaki. "Evaluation of Interfacial Thermal Resistance of Al-AlN Composites by Using Image-Based Calculation." Materials Science Forum 1016 (January 2021): 1411–16. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1411.

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Interfacial thermal resistance of Al-AlN composites was evaluated by comparing the measured thermal conductivity and the simulated thermal conductivity. Al-10vol.%AlN and Al-20vol.%AlN composites were fabricated by spark plasma sintering. Effective thermal conductivity was measured with the steady state thermal conductivity measuring device. Effective thermal conductivity was also simulated by using FE-SEM image and the measured relative density. Comparing the measured thermal conductivity and the simulated thermal conductivity, interfacial thermal resistance in Al-AlN composites was evaluated as about 1.27-6.2510-9 m2K/W.

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20

A. Shlaka, Jamal, and Abbas H. Abo Nasria. "A Theoretical Study of H2S Toxic Gas Adsorption on Pristine and Doped Monolayer (AlN)21 Using Density Functional Theory." Journal of Kufa-Physics 12, no. 02 (December 10, 2020): 99–111. http://dx.doi.org/10.31257/2018/jkp/2020/120210.

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Been studying the interactions between graphene - like aluminium nitride P(AlN)21 nano ribbons doped and defect (AlN)21Sheet, Molecules and small toxic gas molecules ( H2S), were built for two different adsorption sites on graphene like aluminium nitride P(AlN)21. this was done by employing B3LYP density functional theory (DFT) with 6-31G*(d,p) using Gaussian 09 program, Gaussian viw5.0 package of programs and Nanotube Modeller program 2018. the adsorptions of H2S on P(AlN)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C)atoms-doped P(AL-N)19 (on atom) with (Ead) (-0.468eV),(-0.473 eV), (-0.457 eV), (-0.4478 eV) and (-0.454 eV), respectively, (Ead) of H2S on the center ring of the P(AL-N)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C,B)atoms-doped P(AL-N)19 sheet are (-0.280 eV),(-0.465 eV), (-0.405 eV), (-0.468 eV) and -0.282 eV), respectively, are weak physisorption . However, the adsorptions of H2S, on the ((AlN)20 -B and D- (AlN)19 -B), (on atom N and center ring the sheet) are a strong chemisorption because of the (Ead) larger than -0.5 eV, due to the strong interaction, the ((AlN)20-B and D-(AlN)19-B), could catalyst or activate, through the results that we obtained, which are the improvement of the sheet P(AlN)21 by doping and per forming a defect in, it that can be used to design sensors. DOI: http://dx.doi.org/10.31257/2018/JKP/2020/120210

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21

Costantino, Marc, and Carlo Firpo. "High pressure combustion synthesis of aluminum nitride." Journal of Materials Research 6, no. 11 (November 1991): 2397–402. http://dx.doi.org/10.1557/jmr.1991.2397.

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We report initial results on the synthesis of monolithic aluminum nitride by burning Al–AlN mixtures in high pressure nitrogen. The objective is to synthesize economically large, near-theoretical density AlN parts. In this work, we begin with compacted mixtures of 10 μm Al and 3 μm AlN powder formed into 7.62 cm diameter by 3.81 cm thick disks having densities up to 60% of theoretical. Then, at N2 pressures up to 180 MPa (26 000 psi), we ignite the disk on one face. The fraction of Al converted to AlN, density, and severity of macroscopic cracking vary with N2 pressure and heat transfer from the sample. Presently, products are inhomogeneous, showing regions of relatively high porosity, regions with no porosity but with AlN in a matrix of Al, and regions of nearly theoretical density AlN.

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22

Song, Yeong Hwan, Masakazu Tane, Takuya Ide, Yoshihiro Seimiya, Bo Young Hur, and Hideo Nakajima. "Effect of Foaming Temperature on Pore Morphology of Al/AlN Composite Foam Fabricated by Melt Foaming Method." Materials Science Forum 658 (July 2010): 189–92. http://dx.doi.org/10.4028/www.scientific.net/msf.658.189.

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Al foams whose matrix contains dispersed AlN particles (Al/AlN composite foams) were prepared by a melt foaming method, and the effect of foaming temperature on the pore morphology of the prepared foams was investigated. First, Al/AlN composites were prepared by non-compressive infiltration of Al powder compacts with molten Al alloy in nitrogen atmosphere. Next, the prepared composites were melted by induction heating and foamed at various temperatures using TiH2 powders as blowing agents. The porosity of prepared Al/AlN composite foams slightly decreases with increasing foaming temperature, and the pore morphology of the foam becomes homogeneous simultaneously. When the foaming temperature is 1123 K, homogeneous pores are formed in all over the ingot. This pore homogeneity is probably achieved by the stabilization of the foaming behavior due to the formation of Al3Ti particles in the melt and dispersion of AlN particles.

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23

CHUAH, L. S., Z. HASSAN, and H. ABU HASSAN. "INFLUENCE OF Al MONOLAYERS ON THE PROPERTIES OF AlN LAYERS ON Si (111)." Surface Review and Letters 16, no. 01 (February 2009): 99–103. http://dx.doi.org/10.1142/s0218625x09012354.

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High-quality aluminum nitride ( AlN ) layers with full width at half maximum (FWHM) values of 11 arcmin were grown by plasma-assisted molecular-beam epitaxy on Si (111) substrates. AlN nucleation layers are being investigated for the growth of GaN on Si . Growth using AlN buffer layers leads to Al -polar films, with surfaces strongly dependent on the flux conditions used. Flat surfaces can be obtained by growing as Al -rich as possible, although Al droplets tend to form. Before starting the AlN growth, a few monolayers of Al are deposited on the substrate to avoid the formation of Si 3 N 4. X-ray diffraction (XRD) techniques were employed to determine the surface and structural quality of the layers. XRD revealed that monocrystalline AlN was obtained. Best AlN films were obtained at high substrate temperatures (875°C) and III/V ratios close to stoichiometry.

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24

Liu, Peng, Hao Ran Geng, Zhen Qing Wang, Jian Rong Zhu, Fu Sen Pan, and Xiao Bin Dong. "Effect of AlN on Microstructure and Mechanical Properties of Mg-Al-Zn Alloy." Materials Science Forum 704-705 (December 2011): 1095–99. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.1095.

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Effects of AlN addition on the microstructure and mechanical properties of as-cast Mg-Al-Zn magnesium alloy were investigated using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile testing. Five different samples were made with different amounts of AlN(0wt%, 0.12wt%, 0.30wt%, 0.48wt%, 0. 60wt%). The results show that the phases of as-cast alloy are composed of α-Mg,β-Mg17Al12. The addition of AlN suppressed the precipitation of the β-phase. And, with the increase of AlN content, the microstructure of β-phase was changed from the reticulum to fine grains. When AlN content was up to 0.48wt% in the alloy, the β-phase became most uniform distribution. After adding 0.3wt% AlN to Al-Mg-Zn alloy, the average alloy grain size reduced from 102μm to 35μm ,the tensile strength of alloy was the highest. The average tensile strength increased from 139MPa to 169.91MPa, the hardness increased from 77.7HB to 98.4HB, but the elongation changes indistinctively. However, when more amount of AlN was added, the average alloy grain size did not reduce sequentially and increased to 50μm by adding 0.6wt% AlN and the β-phase became a little more. Keywords: Al-Mg-Zn alloy; AlN; β-Mg17Al12; Tensile strength

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Chintalapati, Sandhya, and Yuan Ping Feng. "Stable ferromagnetic state in Si-doped AlN with cation vacancies: Ab-initio study." International Journal of Computational Materials Science and Engineering 05, no. 03 (September 2016): 1650017. http://dx.doi.org/10.1142/s2047684116500172.

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The magnetic property of Si-doped AlN with Al-vacancy is studied using first principles calculations based on spin polarized density functional theory. The Si dopant alone does not introduce the magnetic moment in AlN. However, the doping of Si in AlN reduces the formation energy caused by Al-vacancy, and stabilizes the spin polarized state. The magnetic moments are mainly localized on N atoms surrounding the defect. The strong ferromagnetic state is obtained in AlN due to the combined role of Al-vacancy and Si-dopant.

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Lee, Kon-Bae, Seong-Hyeon Yoo, Yong-Hwan Kim, Chul-Woong Han, Sung-Ok Won, Jae-Pyung Ahn, and Hyun-Joo Choi. "A cost-effective route to produce Al/AlN composites with low coefficient of thermal expansion." Journal of Composite Materials 51, no. 20 (June 22, 2017): 2845–51. http://dx.doi.org/10.1177/0021998317716528.

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In this study, a novel process was developed to produce Al/AlN composites by infiltrating molten Al ingot into a mixture of Al and lamp carbon powders. The findings revealed that, during the process, Al2O3 on the surface of Al powder reacted with nitrogen gas and was transformed to AlN. The degree of nitridation was greatly enhanced by adding only less than 3 wt.% lamp carbon, because lamp carbon could act as a dispersion agent as well as a reduction agent. The Al-based composites containing in situ AlN phases showed coefficient of thermal expansion values of ∼11 × 10−6/℃, which were comparable to those of composites containing 60% ex situ AlN particles.

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ZHUANG, QINQIN, JUNYONG KANG, SHUPING LI, and WEI LIN. "SURFACTANT EFFECT OF In ON THE MOVPE GROWTH OF Al- AND N-POLAR AlN." Surface Review and Letters 24, no. 06 (November 23, 2016): 1750081. http://dx.doi.org/10.1142/s0218625x17500810.

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Al- and N-polar AlN have been grown by metalorganic vapor phase epitaxy (MOVPE) with the assistance of In dopant and characterized by in situ interferometry, ellipsometry, scanning electron microscopy, atomic force microscopy, and X-ray diffractometry. The growth of Al-polar AlN is faster with smoother surfaces than the N-polar ones, which is explained by theoretical calculations. The surfactant effect of In is confirmed by improving the growth rate and surface flatness without getting into the epilayer. Additionally, In is also favorable for reducing the density of dislocations and improving the crystalline quality, especially that of Al-polar AlN. The results suggest that using In surfactant to grow the Al-polar AlN epilayer leads to a better crystal quality under proper pre-growth treatments, low- and high-temperature AlN growth conditions.

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28

Wang, Z. Q., and C. J. Chen. "Preparation of Al-Ti-N Master Alloy Grain Refiner for Al." Advanced Materials Research 452-453 (January 2012): 721–25. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.721.

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An Al-Ti-N master alloy was prepared through the addition of AlN and Ti powders into pure Al melt heated in an induction furnace. This master alloy shows a higher grain refinement effect for pure Al than Al-Ti due to the formation of TiN and/or AlxTiyNz particles in the Al matrix. DTA, SEM and XRD results suggest that TiN and/or AlxTiyNz particles start to form at about 970°C during heating the Al-Ti-AlN powder mixture.

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29

Sung, Mei-Chen, Ya-Fen Wang, Shang-Che Chen, and Cheng-Hsien Tsai. "Two-Stage Plasma-Thermal Nitridation Processes for the Production of Aluminum Nitride Powders from Aluminum Powders." Materials 12, no. 3 (January 24, 2019): 359. http://dx.doi.org/10.3390/ma12030359.

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The synthesis of aluminum nitride (AlN) powders is traditionally done via the thermal nitridation process, in which the reaction temperature reaches as high as 960 °C, with more than several hours of reaction time. Moreover, the occurrence of agglomeration in melting Al particles results in poor AlN quality and a low efficiency of nitridation. In this study, an atmosphere-pressure microwave-plasma preceded the pre-synthesis process. This process operates at 550 °C for 2–10 min with the addition of NH4Cl (Al: NH4Cl = 1:1) for generating a hard AlN shell to avoid the flow and aggregation of the melting Al metals. Then, the mass production of AlN powders by the thermal nitridation process can be carried out by rapidly elevating the reaction temperature (heating rate of 15 °C/min) until 1050 °C is reached. X-Ray Diffractometer (XRD) crystal analysis shows that without the peak, Al metals can be observed by synthesizing AlN via plasma nitridation (at 550 °C for 2 min, Al: NH4Cl = 1:1), followed by thermal nitridation (at 950 °C for 1 h). Moreover, SEM images show that well-dispersed AlN powders without agglomeration were produced. Additionally, the particle size of the produced AlN powder (usually < 1 μm) tends to be reduced from 2–5 μm (Al powders), resulting in a more efficient synthesizing process (lower reaction temperature, shorter reaction time) for mass production.

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30

Pee, Jae Hwan, Jong Chul Park, Kwang Taek Hwang, Soo Ryong Kim, and Woo Seok Cho. "Properties of AlN Powder Synthesized by Self-Propagating High Temperature Synthesis Process." Key Engineering Materials 434-435 (March 2010): 834–37. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.834.

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The synthesis of AlN via self-propagating high-temperature synthesis (SHS) was attempted, using various ratio of Al powder mixed with AlN powder as diluents. Al and AlN powder mixtures with various weight ratios were ignited a nitrogen atmosphere with various amounts of carbon as additives. High crystalline AlN by SHS were successfully synthesized. The microstructure development during the reaction and the influence of these additives were determined by SEM and XRD analysis. A mechanism for the formation of high purity AlN with a very low content of residual oxygen (<0.8wt %) was proposed.

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31

Yadav, S. K., J. Wang, and X. Y. Liu. "Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers." Journal of Applied Physics 119, no. 22 (June 13, 2016): 224304. http://dx.doi.org/10.1063/1.4953593.

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32

Yang, Ruike, Chuanshuai Zhu, Qun Wei, and Zheng Du. "Phase stability, mechanical and optoelectronic properties of two novel phases of AlN." Modern Physics Letters B 31, no. 18 (June 14, 2017): 1750201. http://dx.doi.org/10.1142/s0217984917502013.

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Two novel aluminum nitride (which is bct-AlN at ambient pressure, and h-AlN at higher pressure) were predicted using first-principles calculations. The mechanical and phonon dispersion results indicate that bct-AlN is mechanically and dynamically stable at zero pressure, h-AlN phase can be stabilized by increasing pressure and it is mechanically and dynamically stable at 10 GPa. bct-AlN is more favorable than rs-AlN in thermodynamics at ambient pressure. Our calculated band gap of bct-AlN is 5.85 eV. It can be used as semiconductor device and optoelectronic device due to its inherent wide direct band gap. For bct-AlN, the shortest Al–N bond length is 1.8476 Å and its bond order index is 1.28, which shows that strong covalent bonds are formed between Al atoms and N atoms. Moreover, the anisotropy of Young’s modulus and optical properties can be noticed obviously for bct-AlN.

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33

Zdunek, Krzysztof, Katarzyna Nowakowska-Langier, Rafal Chodun, Jerzy Dora, Sebastian Okrasa, and Ewa Talik. "Optimization of gas injection conditions during deposition of AlN layers by novel reactive GIMS method." Materials Science-Poland 32, no. 2 (June 1, 2014): 171–75. http://dx.doi.org/10.2478/s13536-013-0169-6.

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AbstractIn 2011, we proposed a novel magnetron sputtering method. It involved the use of pulsed injection of working gas for the initiation and control of gas discharge during reactive sputtering of an AlN layer (Gas Injection Magnetron Sputtering — GIMS). Unfortunately, the presence of Al-Al bonds was found in XPS spectra of the AlN layers deposited by GIMS onto Si substrate. Our studies reported in this paper proved that the synchronization of time duration of the pulses of both gas injection and applied voltage, resulted in the elimination of Al-Al bonds in the AlN layer material, which was confirmed by the XPS studies. In our opinion the most probable reason of Al-Al bonds in the AlN layers deposited by the GIMS was the self-sputtering of the Al target in the final stage of the pulsed discharge.

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34

Yu, Seung Hoon, and Kwang Seon Shin. "Fabrication of Aluminum/Aluminum Nitride Composites by Reactive Mechanical Alloying." Materials Science Forum 534-536 (January 2007): 181–84. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.181.

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Various reactions and the in-situ formation of new phases can occur during the mechanical alloying process. In the present study, Al powders were strengthened by AlN, using the in-situ processing technique during mechanical alloying. Differential thermal analysis and X-ray diffraction studies were carried out in order to examine the formation behavior of AlN. It was found that the precursors of AlN were formed in the Al powders and transformed to AlN at temperatures above 600oC. The hot extrusion process was utilized to consolidate the composite powders. The composite powders were canned in an Al can and then extruded at elevated temperatures. The microstructure of the extrusions was examined by SEM and TEM. In order to investigate the mechanical properties of the extrusions, compression tests and hardness measurements were carried out. It was found that the mechanical properties and the thermal stability of the Al/AlN composites were significantly greater than those of conventional Al matrix composites.

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35

Jin, Sheng Li, Ya Wei Li, Jing Liu, Yuan Bing Li, Lei Zhao, Xiao Hua Liu, Yu Ee Ni, and Ze Ya Li. "Microstructure and Phase Composition of AlN/Al Composite Fabricated by Directed Melt Nitridation." Key Engineering Materials 368-372 (February 2008): 977–79. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.977.

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AlN/Al ceramic composite was fabricated by directed melt nitridation of pure Al block covered with 10wt% Mg powder at 1300°C in a high purity flowing N2. Microstructure and phase composition of the composite were investigated by scanning electron microscopy with energy dispersive spectroscopy and X-ray diffraction. Results showed that AlN is the main phase in the composite and its lattice parameters of a and c are 3.1110Å and 4.9806Å, respectively. The phase composition of the composite changes along the growth direction and a gradient sandwich structure forms. The surface of the composite is made up of a dense and thin nodular AlN layer, underneath which an AlN/Al layer appears, followed by an AlN/Al/MgAl2O4 layer. Thermodynamic calculations predicted the formation of possible phases with the addition of Mg. It suggested that the content of Mg at the reaction frontier of nitridation is considerably lower to 0.15wt% where MgAl2O4 was stable, because of escape and reaction exhaustion of Mg. Once Mg is lower than 0.05wt%, only a dense AlN layer can exist, which prevents the further nitridation of Al melt.

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36

Wahab, Mahamad Noor, Mariyam Jameelah Ghazali, and Abdul Razak Daud. "Effect of Aluminum Nitride Addition on Dry Wear Properties of Al-11%Si Alloy Prepared by Stir Casting Process." Advanced Materials Research 264-265 (June 2011): 614–19. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.614.

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Dry wear properties of aluminum nitride (AlN) reinforced aluminum-11% silicon alloy (Al-11%Si) was studied using a pin-on-disc configuration wear tester. Different weight percentages of AlN (0 – 10 wt.%) powder were added to the Al-Si alloy, melt and stir cast via bottom pour technique to form composites of Al-Si alloy/AlN. The dry sliding wear test were performed at a room temperature (27°C), under 25N and 70N load with fixed velocity of 1ms-1 and sliding distance between 1 to 5 km. The addition of 10 wt% of AlN improved wear resistance of Al-Si alloy by 72% and 130% indicated by volume loss for 25N and 70N load respectively. Mixed-wear mechanism of delamination, adhesion and abrasion was observed for the composite when applied loads were 25N and 70N while delaminating mechanism was dominance for Al-Si matrix alloy. Both Al-Si alloy with and without AlN reinforced found with FE element from counter-face disk that shows material transfer was significant.

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37

Shen, Qiang, Z. D. Wei, Mei Juan Li, and Lian Meng Zhang. "Densification and Thermal Conductivity of Y₂O₃-Doped AlN Ceramics by Spark Plasma Sintering." Key Engineering Materials 352 (August 2007): 227–31. http://dx.doi.org/10.4028/www.scientific.net/kem.352.227.

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AlN ceramics doped with yttrium oxide (Y2O3) as the sintering additive were prepared via the spark plasma sintering (SPS) technique. The sintering behaviors and densification mechanism were mainly investigated. The results showed that Y2O3 addition could promote the AlN densification. Y2O3-doped AlN samples could be densified at low temperatures of 1600-1700oC in 20-25 minutes. The AlN samples were characterized with homogeneous microstructure. The Y-Al-O compounds were created on the grain boundaries due to the reactions between Y2O3 and Al2O3 on AlN particle surface. With increasing the sintering temperature, AlN grains grew up, and the location of grain boundaries as well as the phase compositions changed. The Y/Al ratio in the aluminates increased, from Y3Al5O12 to YAlO3 and to Y4Al2O9. High-density, the growth of AlN grains and the homogenous dispersion of boundary phase were helpful to improve the thermal conductivity of AlN ceramics. The thermal conductivity of 122Wm-1K-1 for the 4.0 mass%Y2O3-doped AlN sample was reached.

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38

Wahab, Mahamad Noor, Mariyam Jameelah Ghazali, and Abdul Razak Daud. "Effect of Aluminum Nitride (AlN) Addition on Wear and Mechanical Properties of Al-Si Alloy Composites Fabricated by Stir Casting Process." Key Engineering Materials 462-463 (January 2011): 307–12. http://dx.doi.org/10.4028/www.scientific.net/kem.462-463.307.

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The effect of AlN addition in Al-Si alloy composites on the mechanical properties and dry wear behaviour were studied using pre-selected parameter conditions. In this work, high purity of AlN powders with different weight percentage of 5, 7 and 10 were used as reinforced materials for the composites. Morphology of the reinforced composite indicated that both silicon grains and inter-metallic compounds were surrounded by the AlN particles. The presence of AlN in the Al-Si alloy showed a significant improvement in tensile properties in which 7wt% of AlN addition increased up to 25% compared to those of without any reinforcements. Fracture morphologies with small dimples, tear ridges and necking features indicated that ductile fractures had occurred on the Al-Si composites. At 25N load, alloys with 5wt% of AlN exhibited high wear resistances whereas at 70N, alloys with 10wt% of AlN showed a great improvement in wear resistance. SEM investigation also revealed that the presence of wear was also marked with prominent grooves, craters and scoring marks. Overall, alloys with 7wt% AlN addition possessed great improvement in hardness, tensile and wear resistance properties.

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39

Ren, Hui Hui, Rong Wu, Ji Kang Jian, Chu Chen, and Abduleziz Ablat. "Al Vacancy Induced Room-Temperature Ferromagnetic in Un-Doped AlN." Advanced Materials Research 772 (September 2013): 57–61. http://dx.doi.org/10.4028/www.scientific.net/amr.772.57.

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Room-temperature ferromagnetism has been found in AlN grown by direct arc discharge method using the direct reaction of Al powder with N2 gas. The observed room-temperature ferromagnetism which arises from the aluminum vacancy is intrinsic properties in AlN. The results could rule out oxygen impurities as the main cause of magnetic origin in AlN. First-principles calculations reveal that spontaneous spin polarization creates with a 3.0 uBlocal moment for AlN and magnetic originate from the polarization of the unpaired 2p electrons of N surrounding the Al vacancy. The aluminum vacancy induced may be applicable to other Ш-V nitride semiconductors in turning their magnetism.

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40

Huang, Jow-Lay, and Ching-Hsiung Li. "Microstructure and mechanical properties of aluminum nitride-aluminum composite." Journal of Materials Research 9, no. 12 (December 1994): 3153–59. http://dx.doi.org/10.1557/jmr.1994.3153.

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In a new approach to sinter Al/AlN composites in an overpressure environment of Al, the effects of sintering temperature and Al content on the microstructure, density, shrinkage, and mass gain were investigated. Fracture behavior and toughness were correlated with microstructure and composition of Al/AlN composites.

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41

Subramani, Shanmugan, and Mutharasu Devarajan. "Structural and surface analysis of chemical vapor deposited boron doped aluminum nitride thin film on aluminum substrates." Materials Science-Poland 37, no. 3 (September 1, 2019): 395–403. http://dx.doi.org/10.2478/msp-2019-0056.

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AbstractChemical vapor deposition (CVD) process was conducted for synthesis of boron (B) doped aluminum nitride (B-AlN) thin films on aluminum (Al) substrates. To prevent melting of the Al substrates, film deposition was carried out at 500 °C using tert-buthylamine (tBuNH2) solution delivered through a bubbler as a nitrogen source instead of ammonia gas (NH3). B-AlN thin films were prepared from three precursors at changing process parameters (gas mixture ratio). X-ray diffraction (XRD) technique and atomic force microscope (AFM) were used to investigate the structural and surface properties of B-AlN thin films on Al substrates. The prepared thin films were polycrystalline and composed of mixed phases {cubic (1 1 1) and hexagonal (1 0 0)} of AlN and BN with different orientations. Intensive AlN peak of high intensity was observed for the film deposited at a flow rate of the total gas mixture of 25 sccm. As the total gas mixture flow decreased from 60 sccm to 25 sccm, the crystallite size of AlN phase increased and the dislocation density decreased. Reduced surface roughness (10.4 nm) was detected by AFM for B-AlN thin film deposited on Al substrate using the lowest flow rate (25 sccm) of the total gas mixture.

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42

Park, Jong Keuk, Yong Hwa Chung, Young Do Kim, and Young Joon Baik. "Effect of Nanoscale Multilayered Structurization on Hardness and Wear Resistance in Al-Cr-N Coating." Solid State Phenomena 124-126 (June 2007): 1305–8. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.1305.

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Al-Cr-N coatings were deposited on Si substrate by unbalanced magnetron (UBM) sputtering with Al and Cr targets and Ar and N2 reactive gases at substrate bias of -50V. At a fixed chamber pressure of 0.8 Pa, the microstructure of the coatings was changed from AlN/CrN nanoscale multilayered structure to (Al,Cr)N mixed single layered one with the increase of rotation speed of substrate holder. The residual compressive stress of AlN/CrN nanoscale multilayered coating was higher than that of (Al,Cr)N single layered coating. For the AlN/CrN nanoscale multilayered coating, the residual compressive stress was reduced with increase in total pressure of reactive gases. The AlN/CrN nanoscale multilayered coatings with higher residual compressive stress showed higher hardness and wear resistance.

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43

Song, Xiu Feng, Ren Li Fu, Hong He, and De Liu Wang. "Structure and Dielectric Properties of AlN Multilayered Film on Al Substrate." Key Engineering Materials 368-372 (February 2008): 1383–85. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1383.

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AlN multilayered films were deposited on Al substrates using RF reactive magnetron sputtering with Al targets under Ar and N2 atmosphere. Circles of deposition and annealing were repeatedly performed. Macrostructure observations, crystallographic analyses and dielectric property measurements were carried out. The grains of AlN film had a worm-like shape. When the number of layers (and cycles) increased, the (100) and (110) oriented grains weakened and the structure of film changed into (002) and (101) oriented. The capacity–frequency (C-f) curves of Cu-AlN-Al-Cu capacitors, measured at 100 Hz - 1 MHz, showed that the dielectric constant and the dielectric loss of AlN decrease with increasing number of cycles, attributed to annealing processes that influences film microstructure and the orientation of worm-like shape grains.

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44

Lu, Yuan, Jing Long Li, Jian Feng Yang, Qiang Zheng Jing, Jing Jing Li, and Peng Li. "Squeeze Cast Co-Continuous AlN/Al Composites." Materials Science Forum 788 (April 2014): 580–87. http://dx.doi.org/10.4028/www.scientific.net/msf.788.580.

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The co-continuous AlN composites with different Al contents were fabricated through the squeeze casting of porous AlN preform with varied porosities obtained by carbothermal reduction. The effects of volume fraction of Al phase and the heat treatment temperature on the mechanical properties of composites were investigated. The change of the mechanical properties of composites with the Al content was in line with the mixed rule. With an increase in the Al content, the fracture toughness increased, the Vickers hardness and the flexural strength decreased. The toughen mechanism of composites included ductile rupture and microcrack toughening. The avoiding of excessive interface reaction between AlN and Al was beneficial to the mechanical properties of composites. With an increase in the heat treatment temperature, the stress and the dislocation due to mismatch in the coefficients of thermal expansion increased, the fracture toughness decreased, the vickers hardness and the flexural strength increased.

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45

Chedru, M., G. Boitier, Jean Vicens, Jean-Louis Chermant, and B. L. Mordike. "Al-AlN Composites Elaborated by Squeeze Casting." Key Engineering Materials 132-136 (April 1997): 1006–9. http://dx.doi.org/10.4028/www.scientific.net/kem.132-136.1006.

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46

Oya-SEIMIYA, Yoshihiro, Keiji ONODERA, Toshihisa YAMAGUCHI, and Tetumori SHINODA. "In-situ formation of AlN/Al composite." Journal of Japan Institute of Light Metals 57, no. 9 (2007): 405–10. http://dx.doi.org/10.2464/jilm.57.405.

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47

Paul, Rajat Kanti, Kap-Ho Lee, Byong-Taek Lee, and Ho-Yeon Song. "Formation of AlN nanowires using Al powder." Materials Chemistry and Physics 112, no. 2 (December 2008): 562–65. http://dx.doi.org/10.1016/j.matchemphys.2008.05.096.

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48

Liang, H. F., L. G. Meng, and C. L. Liu. "Electroforming of continuous Al-AlN granular films." Applied Surface Science 255, no. 5 (December 2008): 3159–63. http://dx.doi.org/10.1016/j.apsusc.2008.09.019.

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49

Kent, Damon, Graham B. Schaffer, Ma Qian, and Zhen Yun Liu. "Formation of Aluminium Nitride during Sintering of Powder Injection Moulded Aluminium." Materials Science Forum 618-619 (April 2009): 631–34. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.631.

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A TEM study of aluminium nitride formed during sintering of powder injection moulded aluminium under nitrogen is presented. A polycrystalline layer consisting of fine, rod-shaped crystallites of hexagonal AlN formed on the Al powder surfaces. The grain boundaries exhibit a double layer of AlN separated by a thin layer of Al. The structure of the AlN is characterised and its influence upon sintering discussed.

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50

HAN, S. M., S. Y. KIM, D. C. CHOO, J. I. JUNG, T. W. KIM, K. H. YOO, Y. H. JO, et al. "ELECTRONIC PARAMETER AND SUBBAND STRUCTURE VARIATIONS DUE TO AN EMBEDDED AlN POTENTIAL BARRIER LAYER IN Al0.3Ga0.7N/GaN HETEROSTRUCTURES." Surface Review and Letters 14, no. 04 (August 2007): 807–11. http://dx.doi.org/10.1142/s0218625x07010305.

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Carrier density of a two-dimensional electron gas (2DEG) in Al 0.3 Ga 0.7 N / GaN and Al 0.3 Ga 0.7 N / AlN / GaN heterostructures was investigated by performing Shubnikov-de Haas (SdH) measurements. The angular-dependent SdH measurements and the fast Fourier transformation results for the SdH data indicated 2DEG occupation of one subband in the triangular potential wells. The carrier densities of the 2DEGs in the Al 0.3 Ga 0.7 N / AlN / GaN and the Al 0.3 Ga 0.7 N / GaN heterostructures at 1.5 K, determined from the SdH data, were 1.28 × 1013 and 1.12 × 1013 cm-2, respectively. The electron carrier density of the 2DEG in the Al 0.3 Ga 0.7 N / GaN heterostructure with an AlN embedded potential barrier layer was larger than that in the Al 0.3 Ga 0.7 N / GaN heterostructure. The electronic subband energies, the wave functions, and the Fermi energies in the Al 0.3 Ga 0.7 N / AlN / GaN and Al 0.3 Ga 0.7 N / GaN heterostructures were calculated by using a self-consistent method taking into account spontaneous and piezoelectric polarizations.

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Journal articles on the topic 'Al/AlN'

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