X-Ray Diffraction of Iron Containing Samples: The Importance of a Suitable Configuration

2017 ◽  
Vol 262 ◽  
pp. 545-548 ◽  
Author(s):  
Yvonne M. Mos ◽  
Arnold C. Vermeulen ◽  
Cees N.J. Buisman ◽  
Jan Weijma

X-ray diffraction (XRD) is a commonly used technology to identify crystalline phases. However, care must be taken with the combination of XRD configuration and sample. Copper (most commonly used radiation source) is a poor match with iron containing materials due to induced fluorescence. Magnetite and maghemite are analysed in different configurations using copper or cobalt radiation. Results show the effects of fluorescence repressing measures and the superiority of diffractograms obtained with cobalt radiation. Diffractograms obtained with copper radiation make incontestable phase identification often impossible. Cobalt radiation on the other hand yields high quality diffractograms, making phase identification straightforward.

1995 ◽  
Vol 401 ◽  
Author(s):  
Yoshihiko Shibata ◽  
Naohiro Kuze ◽  
Masahiro Matsui ◽  
Masaki Kanal ◽  
Tomoji Kawai

AbstractThin LINbO3 films are deposited on (001) sapphire and (001) LiTaO3 substrates by using pulsed excimer-laser ablation. These films are evaluated by high-resolution X-ray diffraction (HRXRD) analysis. Strained LiNbO3 films in which the a-axis is longer and the c-axis is shorter than those of LiNbO3 single crystals are deposited on the sapphire substrates. On the other hand, extremely high-quality LiNbO3 films in which the a-axis of the films is the same as that of substrates are grown on the LiTaO substrates. X-ray rocking curves for the (006) reflection showed very narrow full width at half maximum (FWHM) of 208 arcsec for the films on the sapphire substrates, and 9 arcsec for the films on LiTaO3 substrates.


MRS Advances ◽  
2018 ◽  
Vol 3 (64) ◽  
pp. 3971-3978 ◽  
Author(s):  
O.E. Villanueva-Perez ◽  
I. Mejía ◽  
V. García-García ◽  
A. Bedolla-Jacuinde

ABSTRACTLow density (LD) steels have shown particular characteristics in terms of mechanical properties and microstructure, since they have high strength, high ductility and density reduction up to 18%. On the other hand, the addition of microalloying elements such as Ti and B generate hardening by solid solution and precipitation, as well as grain refinement effect. LD steels generate nano-sized kappa phase precipitated from the austenite matrix, and these advanced steels can reach strength and elongation up to 780 MPa and 60%, respectively. The main objective of this research work is the metallographic, structural and mechanical characterization of a LD steel microalloyed with Ti/B in as-cast and -homogenized conditions. For this purpose a Fe-27Mn-7Al-1.2C (%wt) LD steel microalloyed with Ti/B was melted in a vacuum-induction furnace and cast in metallic mold. LD-Ti/B steel samples were homogenized at 1100 °C during 20, 50, 100, 150 and 200 minutes followed by water quenching. Metallographic, structural and mechanical characterization was carried out by optical (LOM) and scanning electron (SEM) microscopy, X-ray diffraction (XRD) and microhardness Vickers testing (HV10), respectively. In general, results showed a typical dendritic microstructure with average grain size of 1256 μm in the as-cast condition. On the other hand, the as-homogenized condition showed an austenitic equiaxial microstructure with average grain size from 164 to 940 μm. Austenite, ferrite and kappa phases were detected by X-ray diffraction (XRD). Also, second-phase particles such as AlN, TiC and MnS were detected by LOM and SEM-EDS analysis. LD steel microalloyed with Ti/B exhibited the highest microhardness Vickers value (235 HV10) in the as-cast condition, whilst in the as-homogenized condition microhardness gradually decreases from 223 to 198 HV10 as holding time increases.


2006 ◽  
Vol 61 (11) ◽  
pp. 1413-1420 ◽  
Author(s):  
Mohamed I. Hegab ◽  
A. M. Moustafa

The very reactive α-oxo-thioketone derivatives 2a - d, generated via thermolysis of spirobenzopyran- 3’,2-[1,3,4]oxadithiino[5,6-c]benzopyran-4’-ones 1a - d, reacted with 2,3-dimethyl-1,3-butadiene and 1,3-cyclohexadiene under [4+2]-cycloaddition to afford spirobenzopyran-3’,6-thiapyran-4’-one adducts 3a - d and spirobenzopyran-3’,3-thiabicyclo[2.2.2]oct-5-en-4’-one adducts 4a - d, respectively. On the other hand, the reaction of α-oxo-thioketones 2a - d with isoprene afforded regioselectively only 3-methyl-thiapyran derivatives 5a - d. Single crystal X-ray diffraction studies of 4b, 4c, and 5a give a good support for the established structure.


1989 ◽  
Vol 03 (05) ◽  
pp. 447-451
Author(s):  
M.A.K.L. DISSANAYAKE ◽  
K. TENNEKONE ◽  
O.A. ILEPERUMA ◽  
S.H.S.P. SAMARAPPULI

A new superconducting phase has been found in a mixed system prepared from the YBa 2 Cu 3 O 7−δ and Bi 2 CaSr 2 Cu 2 O 9−δ high-T c materials. The new compound shows an onset of resistivity transition at ~100 K and zero resistivity below ~50 K. Powder X-ray diffraction pattern of the new compound differs completely from those of YBa 2 Cu 3 O 7−δ and Bi 2 CaSr 2 Cu 2 O 9−δ. The materials prepared using a mixture of the oxides and carbonates with identical cation stoichiometric ratios, on the other hand, does not exhibit superconductivity.


1955 ◽  
Vol 38 (5) ◽  
pp. 575-580 ◽  
Author(s):  
Eric Ponder

The investigation of two thermal properties of red cells throws some light on whether sickling is a process involving the crystallization of a relatively insoluble hemoglobin. These properties are the specific heat and the heat of compression, both of which would be expected to become numerically less if the hemoglobin of the red cell were to crystallize. In the case of paracrystalline rat red cells, which give spacings at 45 A and 58 A by x-ray diffraction, the specific heat is reduced to 85 per cent of that of the normal red cells, and the heat of compression is only about 75 per cent of that found for the normal red cell. In the case of the red cell sickled by a reduction of the O2 tension, the specific heat and the heat of compression are substantially the same as found for the normal red cell. This is an argument against sickling being the result of a crystallization process, and supports the observation that sickled cells do not give x-ray spacings. The result is compatible, on the other hand, with sickling being the result of the formation of an oriented and birefringent gel.


1996 ◽  
Vol 61 (9) ◽  
pp. 1321-1334 ◽  
Author(s):  
Pavel Vojtíšek ◽  
Ivana Císařová

A number of compounds which can by their stoichiometry be classified into several groups have been prepared by reaction of tris(N-piperidinomethyl)phosphine oxide (tppo) with Zn(II) and Cd(II) salts. The structure of two Zn(II) complexes differing by their Zn : tppo ratio and of one Cd(II) complex has been determined by the X-ray diffraction technique. The results show that in all the cases tppo is bound as divalent chelate N,O-donor, but the geometry of coordination sphere of M(II) decisively affects the steric arrangement of the five-membered chelate ring. Structures of the compounds studied are entirely different from those of Zn(II) complexes of sterically less demanding P,P-dimethyl-P-aminomethylphosphine oxide (dmao). On the other hand, the way of coordination of tppo is the same as that found in the case of the Co(II) complex of tris(N,N-dimethylaminomethyl)phosphine oxide.


2017 ◽  
Vol 3 (3) ◽  
pp. 49
Author(s):  
Joseph Gunawan ◽  
Dede Taufik ◽  
Veni Takarini ◽  
Zulia Hasratiningsih

Comparison self-synthesized dental porcelain between feldspar from Pangaribuan and Sukabumi. Dental porcelain material as one of the esthetic indirect restorations in Indonesia is mostly imported. In fact, Indonesia is really rich of natural raw materials, including feldspar, silica, and kaolinite. The aim of this study is to synthesize the dental porcelain made from Indonesia’s two different originates, which are Pangaribuan and Sukabumi. This study was prepared by fritting and sintering the mixture of 65% wt feldspar (from Sukabumi and Pangaribuan), 25% wt silica, 5% wt kaolinite, and 5% wt potassium salt. The porcelains obtained were evaluated using X-Ray Diffraction (XRD). The results revealed that quartz and leucite were found in the composition of Pangaribuan sand that successfully showed more translucencies compared to Sukabumi sand which only imparted quartz on its component. This study shows that dental porcelain from Pangaribuan sand is successfully self-synthesized, on the other hand Sukabumi sand has not been successfully synthesized. These findings develop on a good prospect of esthetic dental porcelain made from Indonesian natural sand. ABSTRAKBahan porselen kedokteran gigi sebagai salah satu restorasi indirek estetik di Indonesia kebanyakan didatangkan dari luar negeri. Indonesia sebenarnya sangat kaya dengan bahan baku porselen kedokteran gigi seperti felspar, silika, dan kaolin. Tujuan penelitian ini adalah melakukan sintesis porselen kedokteran gigi dari 2 jenis pasir alam Indonesia yaitu Pangaribuan dan Sukabumi. Komposisi yang digunakan yaitu 65% wt felspar, 25% wt silika, 5% wt kaolin, dan 5% wt garam kalium, dicampur kemudian dilakukan fritting serta sintering. Dua komposisi porselen dibuat dengan bahan dasar berbeda yaitu felspar dari Pangaribuan dan Sukabumi. Kedua porselen yang telah disintering kemudian dievaluasi menggunakan X-Ray Diffraction (XRD). Hasilnya adalah kuarsa dan leusit ditemukan pada porselen dengan komposisi pasir Pangaribuan yang juga memberikan hasil lebih translusen secara visual dibandingkan dengan porselen dengan komposisi pasir Sukabumi yang hanya memperlihatkan hasil kuarsa. Hal ini menunjukkan bahwa porselen dengan komposisi bahan dasar pasir Pangaribuan berhasil disintesis dibandingkan komposisi bahan dasar pasir Sukabumi.Penemuan ini dapat memberikan peluang yang baik dalam pembuatan porselen kedokteran gigi yang berasal dari pasir alam Indonesia. 


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
María Laura Vera ◽  
Mario Roberto Rosenberger ◽  
Carlos Enrique Schvezov ◽  
Alicia Esther Ares

The bio- and hemocompatibility of titanium alloys are due to the formation of a TiO2layer. This natural oxide may have fissures which are detrimental to its properties. Anodic oxidation is used to obtain thicker films. By means of this technique, at low voltages oxidation, amorphous and low roughness coatings are obtained, while, above a certain voltage, crystalline and porous coatings are obtained. According to the literature, the crystalline phases of TiO2, anatase, and rutile would present greater biocompatibility than the amorphous phase. On the other hand, for hemocompatible applications, smooth and homogeneous surfaces are required. One way to obtain crystalline and homogeneous coatings is by heat treatments after anodic oxidation. The aim of this study is to evaluate the influence of heat treatments on the thickness, morphology, and crystalline structure of the TiO2anodic coatings. The characterization was performed by optical and scanning electron microscopy, X-ray diffraction, and X-ray reflectometry. Coatings with different colors of interference were obtained. There were no significant changes in the surface morphology and roughness after heat treatment of 500°C. Heat treated coatings have different proportions of the crystalline phases, depending on the voltage of anodic oxidation and the temperature of the heat treatment.


1992 ◽  
Vol 7 (4) ◽  
pp. 215-218 ◽  
Author(s):  
Sidney S. Pollack ◽  
Gregory J. McCarthy ◽  
Jean M. Holzer

AbstractPowder diffraction patterns have been calculated for nine isostructural rhombohedral M2(SO4)3 (M = Sc, Ti, V, Cr, Fe, Ga, Y, Rh, In) phases, and for four isostructural monoclinic M2(SO4)3 (M = V, Fe, In, Tl) phases. The pattern for monoclinic Fe2(SO4)3 is the first reported for this phase. Because structure data are available only for the two Fe2(SO4)3 polymorphs, the powder patterns of the other trivalent metal sulfates were approximated using the structure data of the isostructural Fe phases with the scattering factors and previously determined cell parameters of the various metal sulfates. These calculated patterns are termed an approximation by isostruduralism.The calculated patterns were used to evaluate reference powder data for these phases in the Powder Diffraction File (PDF). All but two of the PDF patterns were found to differ substantially from the calculated patterns in the stronger peaks used for identification, and to be missing weak peaks that may be confused for impurities during phase identification.


1990 ◽  
Vol 45 (3-4) ◽  
pp. 307-312 ◽  
Author(s):  
Koji Yamada ◽  
Takashi Matsui ◽  
Tomoko Tsuritani ◽  
Tsutomu Okuda ◽  
Sumio Ichiba

Abstract In a series of MSnI3 compounds (M = K, NH4 , Rb, Cs, CH3NH3) two types of coordination around the central Sn(II) were found by 127I-NQR and powder X-ray diffraction techniques. They are square pyramidal (for M = NH4 , Rb) and octahedral (for M = CH3NH3). CsSnI3 , on the other hand, showed a drastic structural change of the anion at 425 K from a square pyramid to a regular octahedron. Associated with this phase transition, the electrical conductivity increased from 4 x 10-3 S cm-1 to about 102 S cm-1 . This metallic modification was characterized by 127I-NQR and 119Sn Mössbauer spectroscopy.


Sign in / Sign up

Export Citation Format

Share Document