Structural characterization of Ti implanted AlN

1995 ◽  
Vol 10 (12) ◽  
pp. 3136-3142 ◽  
Author(s):  
M. Borowski ◽  
A. Traverse ◽  
J.P. Dallas
Keyword(s):  
Chemical Properties ◽  
Local Environment ◽  
Heat Of Formation ◽  
Implantation Process ◽  
Calculated Distribution ◽  
Final System ◽  
Post Implantation ◽  
Key Parameter

Sintered AlN ceramics were implanted by 1 × 1017 Ti/cm2 at an energy of 70 keV in order to investigate the role of the chemical properties of the implanted species on the phase formed during the implantation process. The implanted ions were found in a depth profile corresponding to the calculated distribution of the vacancies produced during the implantation process instead of the predicted ion profile. Identification of the local environment of Ti and of the resulting phase led us to conclude that Ti is surrounded by N after the collision cascade and forms TiN after post-implantation annealing. The TiN nucleus if formed by substitution of Al by Ti. Therefore, the heat of formation, which is more negative for TiN than for AlN, is found to be a key parameter to predict the final system.

scholarly journals Peculiar Structural Effects in Pure and Doped Functional Single Crystals of Complex Compositions

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2451
Author(s):  
Galina Kuz’micheva ◽  
Irina Kaurova
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Functional Materials ◽  
Local Environment ◽  
Structural Effects ◽  
Local Structures ◽  
Annealing Conditions ◽  
Activator Ions

Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained. A change in crystal symmetry due to crystal–chemical and growth reasons is considered. The use of structural analysis and X-ray absorption spectroscopy is substantiated to reveal the role of activator ions in the formation of statistical and local structures, respectively. A relationship between the distribution of activator ions over crystallographic sites and photoluminescent parameters of materials is established, which allows selecting optimal systems for the application. The combined results of studying single-crystal compounds of other classes (huntite, sillenite, whitlockite, garnet, tetragonal bronzes) allow formulating and summarizing structural effects that appeared in the systems and caused by various factors and, in many cases, due to the local environment of cations. A principal difference in the structural behavior of solid solutions and doped compounds is shown. The methodology developed for single-crystal samples of complex compositions can be recommended for the systematic structural studies of functional materials of different compositions.

scholarly journals Characterization of Thermally Annealed Sb Implanted Fused Silica

1993 ◽  
Vol 316 ◽  
Author(s):  
S.H. Morgan ◽  
Z. Pan ◽  
D.O. Henderson ◽  
S.Y. Park ◽  
R.A. Weeks ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Annealing Treatment ◽  
Local Environment ◽  
Fused Silica ◽  
Index Of Refraction ◽  
Oxide Glasses ◽  
Before And After ◽  
Nonlinear Index ◽  
Optical Behavior

ABSTRACTThe local environment of the polarizable ion in heavy metal oxide glasses is postulated to strongly influence the nonlinear response of these materials. We have previously observed that post-implantation thermal annealing changes the chemical properties of the implanted layer in a different fashion in Pb- and Bi- implanted SiO2. In this paper we report the optical behavior of Sb-implanted SiO2 as a function of annealing temperature and atmosphere. High purity fused silica substrates were implanted at room temperature to a dose of 6 × 1016 ions/cm2, and subsequently annealed at temperatures from 500 to 1000 C in argon and oxygen atmospheres. RBS, optical absorption (1.8 to 6.2 eV), infrared reflectance (450 to 5000 cm-1), and nonlinear index of refraction were measured before and after annealing. The results of these measurements indicate that annealing treatment significantly affects the local environment of the implanted Sb ions, and consequently the optical response.

scholarly journals High-energy resolution X-ray spectroscopy at actinide M4,5 and ligand K edges: what we know, what we want to know, what we can know

2021 ◽  
Author(s):  
Kristina Kvashnina ◽  
Sergei M Butorin
Keyword(s):  
Electronic Structure ◽  
Energy Resolution ◽  
Chemical Properties ◽  
High Energy ◽  
High Energy Resolution ◽  
X Ray

In recent years, scientists have progressively recognized the role of electronic structure in the characterization of chemical properties for actinide containing materials. High-energy resolution X-ray spectroscopy at the actinide M4,5...

Characterization of bond formation in SiC and Si3N4 implanted with Ti, Fe, and Co

2001 ◽  
Vol 16 (2) ◽  
pp. 512-523 ◽  
Author(s):  
Didier Zanghi ◽  
Agnès Traverse ◽  
Sébastien Gautrot ◽  
Odile Kaïtasov
Keyword(s):  
Absorption Spectroscopy ◽  
Bond Formation ◽  
Local Environment ◽  
Heat Of Reaction ◽  
X Ray ◽  
Implantation Process ◽  
X Ray Absorption

Ti, Fe, and Co ions were implanted in two ceramics, SiC and Si3N4, to reach concentrations on the order of 10% over a depth of about 50–60 nm. X-ray absorption spectroscopy was performed at the K edge of the implanted ions to identify their local environment at the end of the implantation process. Ti was found to form Ti–C and Ti–N bonds whereas Co and Fe precipitated and formed clusters in Si3N4. CoSi was detected in SiC whereas, in the same matrix, Fe clusters coexist with FeSi. A coherent interpretation of these results is given in terms of the heat of reaction for all possible systems. We also successfully interpret in the same way some results found in literature in the case of implanted oxides.

EXAFS investigation of the role of Cu on the chemical order and lattice distortion in L10Fe–Pt–Cu thin films

2014 ◽  
Vol 47 (5) ◽  
pp. 1722-1728 ◽  
Author(s):  
S. Laureti ◽  
C. Brombacher ◽  
D. Makarov ◽  
M. Albrecht ◽  
D. Peddis ◽  
...  
Keyword(s):  
Lattice Distortion ◽  
Structural Evolution ◽  
Local Environment ◽  
Linear Dichroism ◽  
Ternary Alloys ◽  
Chemical Order ◽  
Cu Content ◽  
Exafs Study

This work presents an extended X-ray absorption fine structure (EXAFS) characterization of ternary Fe–Pt–Cu alloys with different Cu content. The EXAFS measurements have been carried out at the CuKα and PtLIIIedges in order to describe the local environment around these elements in the Fe–Pt–Cu samples and to compare the structural evolution as a function of the Cu content. The EXAFS study, based on a substitutional model where the Cu atoms occupy Fe or Pt sites in the tetragonal structure, has been performed by using linear dichroism to enhance the sensitivity to differently oriented bonds and to gain a detailed description of the atomic environment. The study allowed the effects on the chemical order and lattice distortion induced by the Cu atoms to be distinguished experimentally. The determined positions of the Cu atoms in the chemically L10-ordered face-centred tetragonal lattice were correlated with the magnetic properties of Fe–Pt–Cu ternary alloys. In particular, the main effect of Cu atoms in the alloy is a linear reduction of thec/aratio, while the nonmonotonic behaviour of the chemical order is consistent with the variation of the magnetocrystalline anisotropy.

Synthesis and Characterization of Synthetic F-Mica Containing Glass-Ceramics in the System SiO2·Al2O3·B2O3·CaO·MgO·Li2O·(K,Na)2O·F

2004 ◽  
Vol 19 (4) ◽  
pp. 1234-1242 ◽  
Author(s):  
D.U. Tulyaganov ◽  
S. Agathopoulos ◽  
H.R. Fernandes ◽  
J.M.F. Ferreira
Keyword(s):  
Crystallization Temperature ◽  
Crystallization Process ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
Synthesis And Characterization ◽  
Na Ions ◽  
Anions And Cations ◽  
And Chemical Properties

Ions of Li, Na, K, and B were incorporated in Ca-mica, CaMg3Al2Si2O10F2. The crystallization process and the properties of the resulting glass-ceramics were experimentally determined, and the role of the anions and cations is discussed. According to the results, Li, K, and Na ions strongly affected the formation of the crystalline phases. Until 900 °C, pargasite and F-cannilloite amphiboles and KLi-mica were predominately crystallized. The two amphiboles are dissociated, yielding stable forsterite at 900 °C and Ca-mica and spinel at 950 °C. KLi-mica showed remarkable stability and growth within the investigated temperature range, until 1000 °C. The optimum crystallization temperature for the investigated glass-ceramics is between800 °C and 900 °C. The produced glass-ceramics exhibited capability for easy bulk crystallization, high whiteness, translucency, and mechanical and chemical properties suitable for several applications.

Non-Crystallographic Nanopores in Single Crystals: A New Approach in Nanomaterials Chemistry

2004 ◽  
Vol 443-444 ◽  
pp. 217-222
Author(s):  
Claus J.H. Jacobsen ◽  
Iver Schmidt ◽  
Michael Brorson ◽  
Astrid Boisen ◽  
Thomas W. Hansen ◽  
...  
Keyword(s):  
Single Crystals ◽  
Chemical Properties ◽  
Metal Sulfide ◽  
Building Blocks ◽  
New Approach ◽  
New Family ◽  
Physical And Chemical ◽  
And Chemical Properties

Nanomaterials are the building blocks of nanotechnology. Recently, nanotube materials have attracted considerable attention due to their unique physical and chemical properties. Here we discuss how nanotubes can be used as templates for preparation of a new family of materials, the nanoporous single crystals, and for the preparation of metal sulfide nanotube materials. Today, the characterization of these materials depends heavily on electron microscopy. However, as rational synthesis schemes are becoming available, more well-defined, homogeneous nanotube samples will be produced and the role of diffraction techniques may increase.

A “Green” Primary Explosive: Design, Synthesis, and Testing

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 885-892 ◽  
Author(s):  
Jie Tang ◽  
Dan Chen ◽  
Gen Zhang ◽  
Hongwei Yang ◽  
Guangbin Cheng
Keyword(s):  
Chemical Properties ◽  
High Heat ◽  
Heat Of Formation ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Design Synthesis ◽  
Metal Free ◽  
Detonation Velocity And Pressure ◽  
Physical And Chemical

This account presents the synthesis and the characterization of triazine-tetrazine nitrogen heterocyclic compounds. Some compounds were characterized by NMR and IR spectroscopy, mass spectrometry, differential scanning calorimetry (DSC), and single-crystal X-ray diffraction. The physical and chemical properties were obtained by EXPLO5 v6.01, gas pycnometer, BAM Fallhammer, BAM Friction tester, and several detonation tests. The results show that the new metal-free polyazido compound 3,6-bis-[2-(4,6-diazido-1,3,5-triazin-2-yl)-diazenyl]-1,2,4,5-tetrazine (4) with high heat of formation (2820 kJ mol–1/6130.2 kJ kg–1) and excellent detonation velocity and pressure (D = 8602 m s–1, P = 29.4 GPa) could be used as ingredient in secondary explosives. 3,6-Bis-[2-(4,6-diazido-1,3,5-triazin-2-yl)-hydrazinyl]-1,2,4,5-tetrazine (3) can detonate research department explosive (RDX, cyclonite) as a primer (Δf H m = 2114 kJ mol–1/4555.2 kJ kg–1, D = 8365 m s–1, P = 26.8 GPa), whose initiation capacity is comparable to that of the traditional primary explosive Pb(N3)2. Therefore, the metal-free compound 3 can potentially replace lead-based-primary explosives, which would be advantageous for the environment.1 Introduction2 Strategies to Form High-Nitrogen Compounds with High Heat of Formation3 Metal-Free Strategies to Prepare Primary Explosives4 Concluding Remarks

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

Sign in / Sign up

Export Citation Format

Share Document