• Title/Summary/Keyword: Al-AlN system

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AlN preparation by Self-propagation High-temperature Synthesis (SHS) in Al-N2 and Al-N2-AIN system (Al-N2와 Al-N2-AlN계에서 고온자전연소법에 의한 AlN 합성)

  • 이재령;이익규;안종관;김동진;안양규;정헌생
    • Journal of Powder Materials
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    • v.11 no.4
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    • pp.294-300
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    • 2004
  • This study for preparation of aluminum nitride (AlN) with high purity was carried out by self-propagating high-temperature synthesis method in two different systems, $Al-N_{2}$ and $Al-N_{2}$-AlN, with the change of nitrogen gas pressure and dilution factor. On the occasion of $Al-N_{2}$ system, unreacted aluminum was detected in the product in spite of high nitrogen pressure, 10 MPa, This may be caused by obstructing nitrogen gas flow to inner part of molten and agglomerate of aluminum, formed in pre-heating zone. In $Al-N_{2}$-AlN system, AlN with a purity of 95% or ever can be prepared in the condition of $f_{Dil}\geq0.5$, $P_{N_{2}}\geq$ 1 MPa, and the purity can be elevated to 98% over in the condition of $f_{Dil}$ = 0.7 and $P_{N_{2}}$ = 10 MPa.

A Study on the Phase Transformations of (TiAl)N Films Deposited by TFT Sputtering System (TFT(Two-Facing-Targets) 스퍼터장치에 의해 증착된 (TiAl)N 박막의 상변태에 관한 연구)

  • Han, Chang-Suk
    • Journal of the Korean Society for Heat Treatment
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    • v.18 no.5
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    • pp.281-287
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    • 2005
  • Titanium aluminium nitride((TiAl)N) film is anticipated as an advanced coating film with wear resistance used for drills, bites etc. and with corrosion resistance at a high temperature. In this study, (TiAl)N thin films were deposited both at room temperature and at elevated substrate temperatures of 573 to 773 K by using a two-facing-targets type DC sputtering system in a mixture Ar and $N_2$ gases. Atomic compositions of the binary Ti-Al alloy target is Al-rich (25Ti-75Al (atm%)). Process parameters such as precursor volume %, substrate temperature and Ar/$N_2$ gas ratio were optimized. The crystallization processes and phase transformations of (TiAl)N thin films were investigated by X-ray diffraction, field-emission scanning electron microscopy. The microhardness of (TiAl)N thin films were measured by a dynamic hardness tester. The films obtained with Ar/$N_2$ gas ratio of 1:3 and at 673 K substrate temperature showed the highest microhardness of $H_v$ 810. The crystallized and phase transformations of (TiAl)N thin films were $Ti_2AlN+AlN{\rightarrow}TiN+AlN$ for Ar/$N_2$ gas ratio of 1:3, $Ti_2AlN+AlN{\rightarrow}TiN+AlN{\rightarrow}Ti_2AlN+TiN+AlN$ for Ar/$N_2$ gas ratio of 1:1 and $TiN+AlN{\rightarrow}Ti_2AlN+TiN+AlN{\rightarrow}Ti_2AlN+AlN{\rightarrow}Ti_2AlN+TiN+AlN$ for Ar/$N_2$ gas ratio of 3:1. The above results are discussed in terms of crystallized phases and microhardness.

Preparation of AlN Powder by Combustion Reaction in the System of Al-AlN-NH4Cl (Al-AlN-NH4Cl 계에서 연소반응에 의한 AlN 분말의 제조)

  • Min, Hyun-Hong;Won, Chang-Whan
    • Journal of the Korean Ceramic Society
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    • v.43 no.7 s.290
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    • pp.445-450
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    • 2006
  • The preparation of AlN powder by SHS in the system of $Al-AlN-NH_4Cl$ was investigated in this study. In the preparation of AlN powder, the effect of gas pressure and the composition such as Al, AlF, and additive in mixture on the reactivity were investigated. At 60 atm of the initial inert gas pressure in reactor, the optimum composition for the preparation of pure AlN was 35 wt%Al+5 wt% $NH_4Cl+60wt%$AlN. The AlN powder synthesized in this condition was a single phase AlN with a whisker morphology.

Microstructural and Mechanical Characterization of Nanocomposite Ti-Al-Si-N Films Prepared by a Hybrid Deposition System (하이브리드 증착 시스템에 의해 합성된 나노복합체 Ti-Al-Si-N 박막의 미세구조와 기계적 특성)

  • 박인욱;최성룡;김광호
    • Journal of the Korean institute of surface engineering
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    • v.36 no.2
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    • pp.109-115
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    • 2003
  • Quaternary Ti-Al-Si-N films were deposited on WC-Co substrates by a hybrid deposition system of arc ion plating (AIP) method for Ti-Al source and DC magnetron sputtering technique for Si incorporation. The synthesized Ti-Al-Si-N films were revealed to be composites of solid-solution (Ti, Al, Si)N crystallites and amorphous Si3N4 by instrumental analyses. The Si addition in Ti-Al-N films affected the refinement and uniform distribution of crystallites by percolation phenomenon of amorphous silicon nitride, similarly to Si effect in TiN film. As the Si content increased up to about 9 at.%, the hardness of Ti-Al-N film steeply increased from 30 GPa to about 50 GPa. The highest microhardness value (~50 GPa) was obtained from the Ti-Al-Si-N film haying the Si content of 9 at.%, the microstructure of which was characterized by a nanocomposite of nc-(Ti,Al,Si) N/a$-Si_3$$N_4$.

Microstructure, Mechanical, Oxidation and Corrosion Properties of Zr-Al-N Coatings Synthesized by the Hybrid Coating System (하이브리드 코팅 시스템에 의해 합성된 Zr-Al-N 박막의 미세구조와 기계적 특성, 산화 특성, 부식특성)

  • Choi, Hasong;Jang, Jaeho;An, Eunsol;Kim, Kwang Ho
    • Journal of the Korean institute of surface engineering
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    • v.46 no.6
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    • pp.242-247
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    • 2013
  • Zr-Al-N coatings were synthesized by the hybrid coating system combining arc ion plating and DC magnetron sputtering from a Zr and an Al target in argon-nitrogen atmosphere, respectively. By changing the power applied on the Al cathodes, the Zr-Al-N coatings with various Al contents were deposited. The microstructure and chemical compositions of the Zr-Al-N coatings were studied by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM). With increasing of Al content in the coatings, the solid solution (Zr, Al)N crystallites were observed in the Zr-Al-N coatings. The nanohardness of the Zr-Al-N coatings exhibited a maximum value of 42 GPa for the Zr-Al (7.9 at.%)-N, and decreased with further increase in Al content in the coatings. The oxidation and corrosion behavior of the Zr-Al-N coatings revealed better properties compared than those of ZrN coatings due to the formation of a solid solution.

Synthesis of AlN-SiO2-Al2O3 System (AlN-SiO2-Al2O3계로부터 AlN-Polytypes의 제조)

  • 박용갑;장병국
    • Journal of the Korean Ceramic Society
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    • v.26 no.1
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    • pp.31-36
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    • 1989
  • In order to synthesize AlN-polytypes from AlN-SiO2-Al2O3 system, composition A (AlN/SiO2/Al2O3=1/0.3/0.05, mole ratio) and composition B(AlN-SiO2-Al2O3=1/0.2/0.05, mole ratio) were used. AlN-polytypes were produced by nitriding the mixture at 175$0^{\circ}C$~190$0^{\circ}C$ under N2 atmosphere. For lower reaction temperature, 15R phase was produced and in the case of higher reaction temperature, AlN phase was only produced. As each composition was heated at 185$0^{\circ}C$ in N2 atmosphere, produced main phases were 15R phase for composition A and 21R phase for composition B respectively. The fracture surfaces of produced reactants showed porous skeleton structure.

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Effects of AlN Ratio on Microstructure of AlN Films Grown by PAMBE (PAMBE를 이용하여 성장된 AlN 박막의 미세구조에 미치는 Al/N 비율 영향)

  • 홍성의;한기평;백문철;조경익;윤순길
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.12
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    • pp.972-978
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    • 2001
  • Some effects of Al/N ratio on microstructure of AlN films grown on Si(111) substrates by PAMBE were investigated. Al/N ratio was controlled by rf power of N$_2$ plasma source system. Al excess or N excess conditions were obtained below or above 350 W rf power, respectively. Surface roughness and morphology of AlN film grown at Al/N=1.0 showed the best result. Under Al excess condition, it was suggested that excess Al atoms which did not contribute to the growth of AlN film prevent the normal crystal growth and make abnormal growth of some columns. However, under N excess condition, it was explained that some of the excess active N source turned into gas state and then desorbed out from substrate.

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Preparation of Aluminum Nitride from an Alkoxide and its Properties (알콕사이드로부터 AlN분말의 합성 및 분말 특성)

  • 이홍림;박세민;조덕호
    • Journal of the Korean Ceramic Society
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    • v.26 no.1
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    • pp.100-108
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    • 1989
  • Aluminum hydroxides were prepared by the alkoxide hydrolysis method using Al-isopropoxide as a starting material and NH4OH as a catalytic agent. When Al-isopropoxide was hydrolyzed in a H2O-NH3 system, only Al(OH)3 was obtained over all pH values. However, AlOOH was formed besides Al(OH)3 when Al-isopropoxide was hydrolyzed in a H2O-NH3-isopropyl alcohol system. The AlOOH/Al(OH)3 ratio was increased as the isopropyl alcohol content was increased. The hydroxides, Al(OH)3 and AlOOH, obtained in this study and the commerical products, $\alpha$-Al2O3 and AlOOH were subjected to the carbothermal reduction and nitridation reaction to product AlN powder, using carbon black as a reducing agent under N2 atmosphere at various temperatures. AlN was synthesized from the obtained Al(OH)3 and the commercial AlOOH at 145$0^{\circ}C$, however, synthesized from the obtained AlOOH and the commercial alpha-alumina at 135$0^{\circ}C$. The temperature difference is assumed to be attributed to the reactivity of those powders. AlN powder prepared from the Al-isopropoxide was observed to have the narrower particle size distribution than that prepared from the commercial $\alpha$-Al2O3 or AlOOH.

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The Properties of GaN Grown by BVPE Method on the Si(111) Substrate with Pre-deposited Al Layer (Al 박막이 증착 된 Si(111) 기판 위에 HVPE 방법으로 성장한 GaN의 특성)

  • Shin Dae Hyun;Baek Shin Young;Lee Chang Min;Yi Sam Nyung;Kang Nam Lyong;Park Seoung Hwan
    • Journal of the Korean Vacuum Society
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    • v.14 no.4
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    • pp.201-206
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    • 2005
  • In this work, we tried to improve the fabrication process in HVPE (Hydride Vapor Phase Epitaxy) system by using Si(111) substrate with pre-deposited Al layer. PL measurements was done for samples with and without pre-deposited Al on Si and it was also examined the dependence of the optical characteristic properties on AlN buffer thickness for GaN/AIN/Al/Si. A sample with thin Al nucleation layer on Si substrate reveals a better optical property than the other. And it suggests that the thickness for AlN buffer layer with thin Al nucleation layer on Si(111) substrate is most proper about $260{\AA}$ to grow GaN in HVPE system. The surface morphology of GaN clearly shows the hexagonal crystallization. The XRD pattern showed strong peak at GaN{0001} direction.

Microstructures, mechanical properties, and tribological behaviors of Cr-Al-N, Cr-Si-N, and Cr-Al-Si-N coatings by a hybrid coating system (하이브리드 시스템을 이용한 Cr-Al-N, Cr-Si-N, Cr-Al-Si-N 코팅막의 미세구조와 기계적 특성과 마찰 거동에 관한 연구)

  • Yun, Chang-Seong;Kim, Gwang-Ho
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2007.11a
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    • pp.128-129
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    • 2007
  • Cr-Al-N, Cr-Si-N 그리고 Cr-Al-Si-N 코팅막을 WC-Co 모재위에 AIP법과 DC 마그네트론 스퍼터링 법을 결합한 하이브리드 시스템을 이용하여 합성하였으며, Si함량에 따른 Cr-Al-Si-N 코팅막의 미세구조, 기계적 특성과 마찰 거동에 관해 비교 연구하였다. Cr-Si-N(${\sim}35GPa$)과 Cr-Al-Si-N(${\sim}55GPa$) 코팅막의 경도값은 CrN(${\sim}23GPa$)과 Cr-Al-N(${\sim}25GPa$) 코팅막과 비교하여 각각 증가하였고, CrN(${\sim}0.50$)과 Cr-Al-N(${\sim}0.84$)의 평균 마찰계수는 Si 함량이 9 at.% 일때, Cr-Si-N(${\sim}0.30$)과 Cr-Al-Si-N(${\sim}0.57$)으로 각각 감소하였다.

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