Chemical Stability of Vb2 and ZrB2 with Aluminum

1990 ◽  
Vol 181 ◽  
Author(s):  
L. E. Halperin ◽  
E. Kolawa ◽  
Z. Fu ◽  
M-A. Nicolet
Keyword(s):  
Thin Films ◽  
Chemical Stability ◽  
Rf Sputtering ◽  
Heat Of Reaction ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystallization Reaction ◽  
Exothermic Chemical Reaction

ABSTRACTThe chemical stability of boride thin films with aluminum is investigated. Only two diborides, VB2 and HfB2 have a positive heat of reaction which makes them potential candidates for thermodynamically stable diffusion barriers between Al and Si. Thin films of VB2, and ZrB2 for comparison, prepared by rf sputtering of composite targets were chosen for this study. Multilayer samples of these borides and aluminum were investigated by differential scanning calorimetry to determine if, according to calculations, a reaction between Al and the borides takes place, and to measure the heat of reaction. We find that an exothermic chemical reaction occurs between ZrB2 and Al and that an exothermic crystallization reaction takes place in the VB2 and Al sample. The reaction products were determined using X-ray diffraction.

scholarly journals Partial Reduction/Re-Oxidation Processing of Y-Ba-Cu-O Sputtered Thin Films

1989 ◽  
Vol 169 ◽  
Author(s):  
F.H. Garzon ◽  
J. G. Beery ◽  
D. K. Wilde ◽  
I. D. Raistrick
Keyword(s):  
Thin Films ◽  
Rf Sputtering ◽  
Partial Reduction ◽  
Rf Power ◽  
X Ray Diffraction ◽  
X Ray ◽  
Post Annealing ◽  
Residual Oxygen ◽  
Ceramic Targets ◽  
Substrate Temperatures

AbstractThin films of Y‐Ba‐Cu‐O were produced by RF sputtering of YBa2Cu3O7‐x ceramic targets, using a variety of plasma compositions, RF power levels, and substrate temperatures. Post annealing of these films in oxygen produced superconducting films with Tc values between 40‐60 K, broad transition widths and semiconductor‐like electrical behavior above Tc. Subsequent annealing at 850°C in an inert gas with a residual oxygen partial pressure of ≤10 ppm followed by an oxygen anneal produced high quality thin films: Tc> 85 K with narrow transition widths. The structure and morphology of these films during reduction‐oxidation processing were monitored using X‐ray diffraction and electron microscopy.

scholarly journals The Dehydrogenation Mechanism and Reversibility of LiBH4 Doped by Active Al Derived from AlH3

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 559 ◽  
Author(s):  
Qing He ◽  
Dongdong Zhu ◽  
Xiaocheng Wu ◽  
Duo Dong ◽  
Xiaoying Jiang ◽  
...  
Keyword(s):  
Reaction Products ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Scanning Calorimetry ◽  
Mass Spectral Analysis ◽  
X Ray ◽  
Mass Spectral ◽  
Al Composite ◽  
Dehydrogenation Mechanism

A detailed analysis of the dehydrogenation mechanism and reversibility of LiBH4 doped by as-derived Al (denoted Al*) from AlH3 was performed by thermogravimetry (TG), differential scanning calorimetry (DSC), mass spectral analysis (MS), powder X-ray diffraction (XRD), scanning electronic microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results show that the dehydrogenation of LiBH4/Al* is a five-step reaction: (1) LiBH4 + Al → LiH + AlB2 + “Li-Al-B-H” + B2H6 + H2; (2) the decomposition of “Li-Al-B-H” compounds liberating H2; (3) 2LiBH4 + Al → 2LiH + AlB2 + 3H2; (4) LiBH4 → LiH + B + 3/2H2; and (5) LiH + Al → LiAl + 1/2H2. Furthermore, the reversibility of the LiBH4/Al* composite is based on the following reaction: LiH + LiAl + AlB2 + 7/2H2 ↔ 2LiBH4 + 2Al. The extent of the dehydrogenation reaction between LiBH4 and Al* greatly depends on the precipitation and growth of reaction products (LiH, AlB2, and LiAl) on the surface of Al*. A passivation shell formed by these products on the Al* is the kinetic barrier to the dehydrogenation of the LiBH4/Al* composite.

Stability of Nitrogen in Sputtered Iron Nitride thin films and Multilayers

1997 ◽  
Vol 475 ◽  
Author(s):  
H. Chatbi ◽  
M. Vergnat ◽  
J. F. Bobo ◽  
L. Hennet
Keyword(s):  
Thin Films ◽  
Thermal Desorption ◽  
Rf Sputtering ◽  
Iron Nitride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Desorption Spectrometry

ABSTRACTDifferent phases of FeN thin films and Fe/FeN multilayers were prepared by reactive rf sputtering. The release of nitrogen and the crystallographic transformations during annealing were monitored by thermal desorption spectrometry and X-ray diffraction experiments. Finally, the diffusivity of nitrogen in the γ-Fe4N phase was evaluated.

Crystallization of Amorphous Si In Al/Si Multilayers

1991 ◽  
Vol 230 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Layered Structure ◽  
Heat Of Reaction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Amorphous Si

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.

scholarly journals The Dehydrogenation Mechanism and Reversibility of LiBH4 Doped by Active Al* Derived from AlH3

2019 ◽  
Author(s):  
Qing He ◽  
Dongdong Zhu ◽  
Xiaocheng Wu ◽  
Duo Dong ◽  
Xiaoying Jiang ◽  
...  
Keyword(s):  
Reaction Products ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Scanning Calorimetry ◽  
Mass Spectral Analysis ◽  
X Ray ◽  
Mass Spectral ◽  
Al Composite ◽  
Dehydrogenation Mechanism

A detailed analysis of the dehydrogenation mechanism and reversibility of LiBH4 doped by active Al* derived from AlH3 was performed by thermogravimetry (TG), differential scanning calorimetry (DSC), mass spectral analysis (MS), powder X-ray diffraction (XRD), scanning electronic microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that the dehydrogenation of LiBH4/Al* is a five-step reaction: (1) LiBH4 + Al → LiH + AlB2 + “Li-Al-B-H” + B2H6 + H2; (2) the decomposition of "Li-Al-B-H" compounds liberating H2; (3) 2LiBH4 + Al → 2LiH + AlB2 + 3H2; (4) LiBH4 → LiH + B + 3/2H2; (5) LiH + Al → LiAl + 1/2H2. And the reversibility of LiBH4/Al* composite is based on equation as follows: LiH + LiAl + AlB2 + 7/2H2 ↔ 2LiBH4 + 2Al. The extent of dehydrogenation reaction between LiBH4 and Al* greatly depends on the precipitation and growth of reaction products (LiH, AlB2 and LiAl, etc.) on the surface of Al*. A passivation shell of Al* formed by these products is the kinetic barrier to the dehydrogenation of LiBH4/Al* composite.

PREFERABLE ORIENTATION OF CRYSTALLINE THIN-FILM OF MODIFIED BNN SYSTEM

1989 ◽  
Vol 03 (06) ◽  
pp. 465-470 ◽  
Author(s):  
MASAYUKI TSUKIOKA ◽  
TASUKU MASHIO ◽  
MASAJI SHIMAZU ◽  
TAKESHI NAKAMURA
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Stainless Steel ◽  
Steel Substrate ◽  
Rf Sputtering ◽  
Polished Surface ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Analyses

Using rf-sputtering method, modified BNN ( Ba 2 NaNb 5 O 15) thin-films, which are highly aligned, were prepared on a polished surface of a stainless steel plate and on a polished silicon wafer. It was found that preferably aligned thin-films were successfully obtained only when modified Nb-rich BNN target was used. Preferable orientation of these thin-films was confirmed by X-ray diffraction measurement. In order to find the correlation between preferable orientation and separation from plasma center, X-ray measurement was carried out at several points on the thin-film sputtered on a long stainless steel substrate (5×100 mm ). The result indicated that preferable orientation was dominant near the position of plasma center. In order to distinguish whether the strong X-ray peak observed in the preferably aligned BNN thin-film is due to (200) peak of Nb 2 O 5 or (440) peak of BNN, X-ray measurements and the following quantitative analyses; fluorescent X-ray, ICP (Induced Coupled Radio Frequency Plasma) and an Atomic Absorption Method, were carried out for films sputtered from Nb-rich BNN target. The results reveal that the thin-films include considerable quantity of barium and sodium. This suggests that the highly aligned thin-film is composed of modified BNN and not Nb 2 O 5.

The Calcination Temperature Effect on the Phase Formation of the PZT Ceramic: How the same Calcination Temperature, Result in Different Phase’s Formation

2021 ◽  
Vol 406 ◽  
pp. 256-264
Author(s):  
Mohammed Mahdi ◽  
M. Kadri
Keyword(s):  
Thin Films ◽  
Calcination Temperature ◽  
Relative Intensity ◽  
Molar Mass ◽  
Rf Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metallic Oxides ◽  
Xrd Patterns ◽  
Sputtering System

First, the metallic oxides of PbO, TiO2 and ZrO2 were mixed following (2, 1, 1) molar mass respectively. Then 4 samples were separated (S1, S2, S3 and S4). the first one S1 was subjected to calcination treatments at 600, 700 and 800 °C however, the S2 was treated at 700 °C only, the S3 at 800 °C and S4 at 850 °C. The X ray diffraction of the samples reveals important difference in the phases obtained, at 600 °C the quadratic riche phase of PbTiO3 was mainly observed on sample S1, after the treatment at 700 °C and 800°C, the same XRD patterns were obtained with the same peaks positions and the relative intensity. However the S2 revels different pattern from S1 at 700 °C relative to the formation of the Pb(Zr0.75, Ti0.25)O3 Rhombohedral riche phase. The S3 XRD results reveal also different pattern from S1 at 800 °C relative to the formation of Pb (Zr0.58, Ti0.42) O3 near the Morphotropic phase boundary (MPB) and the S4 confirm these finding. Thin films grown from the S1 and S4 used as target in the RF sputtering system, show important difference in the PZT stoichiometry obtained which is relative to Pb (Zr0.44, Ti0.56) located in the quadratic riche phase and Pb (Zr0.52, Ti0.48) O3 near the MPB respectively.

Microstructure and Thermal Features of a-Si:H and nc-Si:H Thin Films Produced by Rf Sputtering

2006 ◽  
Vol 514-516 ◽  
pp. 23-27
Author(s):  
V. Thaiyalnayaki ◽  
M.Fátima Cerqueira ◽  
Francisco Macedo ◽  
João Alves Ferreira
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Thermal Properties ◽  
Rf Sputtering ◽  
Nanocrystalline Silicon ◽  
Transport Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicon Thin Films ◽  
Thermal Features

Amorphous and nanocrystalline silicon thin films have been produced by reactive r.f. sputtering and their microstructure, optical and thermal properties were evaluated. A good correlation was found between the microstructure determined by Raman spectroscopy and X- ray diffraction and the thermal transport parameters.

Structural Transitions in Titanium/Amorphous-Silicon Multilayers

1989 ◽  
Vol 163 ◽  
Author(s):  
E. Ma ◽  
L.A. Clevenger ◽  
C.V. Thompson ◽  
R.R. DeAvillez ◽  
K.N. Tu
Keyword(s):  
Thin Films ◽  
Exothermic Reaction ◽  
Heat Of Formation ◽  
Structural Transitions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Calorimetric Analysis ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

We report a quantitative investigation of silicidation in Ti/amorphous-Si thin-films using Differential Scanning Calorimetry (DSC), thin-film X-ray diffraction and Cross-sectional Transmission Electron Microscopy (XTEM). Multilayered thin films were used to facilitate calorimetric observation of the heat released or absorbed at many reacting interfaces. It is shown that calorimetric analysis, combined with structural analysis using X-ray diffraction and XTEM, is effective in providing both kinetic and thermodynamic information about interdiffusion reactions in thin films. The present paper describes experimental results for multilayers with an atomic concentration ratio of 1 Ti to 2 Si and modulation periods ranging from 10 to 60 nm. A thin amorphous titanium suicide layer was found to exist between the as-deposited Ti and a-Si layers. Heating the multilayer film caused the amorphous Ti-silicide to grow over a broad temperature range by an exothermic reaction. An endothermic relaxation occurs during the late stage of amorphous suicide growth. Heating to temperatures over 800K causes C49-TiSi2 to form at the a-si1icide/a-Si interface. Temperatures at which all the above structural transitions occur vary with modulation period. Analysis of the DSC data indicates an activation energy of 3.1 eV for the formation of C49-TiSio, which is attributed to both the nucleation and the early growth of the suicide. The heat of formation for C49-TiSi2 from a reaction of a-silicide and a-Si was found to be -30±5KJ/mol. Nucleation appears to be the controlling step in C49-TiSi2 formation.

In-Situ Characterisation of Precipitation in AI-Cu thin films

1999 ◽  
Vol 562 ◽  
Author(s):  
J. P. Lokker ◽  
A. J. Bottger ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Thin Films ◽  
Differential Scanning Calorimetry ◽  
Bulk Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Enthalpy Changes ◽  
Thin Foils ◽  
Lower Temperature

ABSTRACTThe precipitate formation occurring in Al-Cu thin foils with copper concentrations of either 1.15 at.% or 0.3 at.%, has been studied. In-situ X-ray diffraction analysis and differential scanning calorimetry are applied to determine the phases formed and the enthalpy changes in the same samples. Both X-ray diffraction and differential scanning calorimetry indicate that the precipitation behaviour of thin films (about 500 nm thickness) differs significantly from that of bulk material. In the films studied the precipitation of Al2Cu occurs at a much lower temperature than expected on the basis of the (bulk) phase diagram. Moreover, no intermediate phases are observed prior to Al2Cu precipitation. Also the amount of Cu in solid solution (0.20 at%Cu) observed by electron-probe micro-analysis after slowly cooling from 500°C to room temperature, exceeds the solubility of bulk Al-Cu.

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