Solid state synthesis of Bi0.4Sr0.6FeO3 powder for SOFC applications

We report on the synthesis of Bi0.4Sr0.6FeO3 powder with cubic structure by solid state reaction (mechanical milling and calcination) from Bi2O3, SrCO3 and Fe2O3 stoichiometric ratios. Milled powder mixtures were heat treated between 775∘C and 825∘C for 30 and 60 min in oxygen atmosphere and characterized by X-ray diffraction (XRD), impedance as well as Mössbauer spectroscopy. The cubic phase of Bi0.4Sr0.6FeO3 was successfully obtained in samples milled for only 2 h and a subsequent calcination at 800∘C. Irrespective of milling time, heat treatments at lower temperatures (775∘C) still show spurious phases such as Sr0.23Bi0.76O1.1 (30 min) and Sr0.53Bi1.72O3 (60 min). Impedance spectroscopy show high values (105–109) Ω indicating strong structural bond between the atoms of the system and activation energies for the strontium ion around 04 eV. These results show a single dynamic behavior in a range from 1 to 2*105 Hz enabling data adjustment and analysis to a RC circuit. Conductivity results normally show a behavior that obeys the universal law of Jonscher’s relaxation (σ = σ Dc + α ω n) with values for the exponent n (0.8 < n < 1) typical in these structures. Mössbauer spectrometry measurements reveal that the hyperfine magnetic field of the precursors and milled powders corresponds to hematite 512 T. After the thermal treatment of the samples, the mean hyperfine field decreases to 489 ± 0.5 T showing the Bi and Sr atoms diffusion, (non- magnetic) in Fe2O3. While the result of isomer shift corresponds to a Fe+3 oxidation state irrespective of the heat treatmen

HVOF-sprayed HAp/S53P4 BG composite coatings on an AZ31 alloy for potential applications in temporary implants

Bioactive thermal spray coatings produced via high-velocity oxygen fuel spray (HVOF) from hydroxyapatite (HAp) and bioactive glasses (BG) have the potential to be employed on temporary implants due to the ability of both HAp and BG to dissolve and promote osseointegration, considering that both phases have different reaction and dissolution rates under in-vitro conditions. In the present work, 75% wt. HAp - 25% wt. S53P4 bioactive glass powders were HVOF-sprayed to obtain HAp/S53P4 BG composite coatings on a bioresorbable AZ31 alloy. The study is focused on exploring the effect of the stand-off distance and fuel/oxygen ratio variation as HVOF parameters to obtain stable structural coatings and to establish their effect on the phases and microstructure produced in those coatings. Different characterization techniques, such as scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy, were employed to characterize relevant structural and microstructural properties of the composite coatings. The results showed that thermal gradients during coating deposition must be managed to avoid delamination due to the high temperature achieved (max 550 °C) and the differences in coefficients of thermal expansion. It was also found that both spraying distance and oxygen/fuel ratio allowed to keep the hydroxyapatite as the main phase in the coatings. In addition, in-vitro electrochemical studies were performed on the obtained HAp/S53P4 BG composite coatings and compared against the uncoated AZ31 alloy. The results showed a significant decrease in hydrogen evolution (at least 98%) when the bioactive coating was applied on the Mg alloy during evaluation in simulated body fluid (SBF)

Magnetic character study of Fe-Mn-Al, Fe-Ni and Fe-Si alloys

IP 1106-05-222-99aleadas / M.M. Rico y G.A. Perez Alcazar. -- En: Revista colombiana de fisica. -- Vol. 32, no. 1 (2000); p.;ARTICULO(S) EN REVISTA: Estudio comparativo de aleacionesFe0.70'--xMnxAI0.30 fundidas y mecanicamente;'- Room temperature magnetic properties of the mechanicallyalloyed Fe0.8-xAl0.2 system / J. Restrepo, G. A.;Perez Alcazar, J. M. Gonzalez. - En: Latin american simposiumonsolid state physics (15 : 1999 Nov. 1-5 :;Cartagena de Indias, Colombia). - Cartagena : (s. l.), 1999. 28cm. - Magnetic and structural study of;Fe0.7--xMnxAl0.3 mechanically alloyed alloys. / M. M. Rico, G.A. Perez Alcazar, J. M. Gonzalez, A. Hernando.;- En: Latin american simposium on solid state physics (15: 1999 Nov. 1-5: Cartagena de Indias, Colombia). -;Cartagena : (s.l.), 1999. 28 cm. - Magnetic and structuralpropiertes of Fe1--x Alx alloyns produced by;mechanics alloying. / Y. Rojas, D. Oyola, G. A. Perez Alcazar.-En: Latinamerican simposium on solid state;physics (15 : 1999 Nov. 1-5 : Cartagena de Indias, Colombia).-Cartagena: (s. l.), 1999. 28 cm. -;Mechanical alloying of ductile FeMnAlCCu samples. / B. Cruz, G.A. Perez Alcazar. - En: International;symposium on metastable, mechanically alloyed and nanocrystalline materials (2001 : Jun. 24-29 : Michigan;Union, University of Michigan). -- Michigan Union, UniversityofMichigan: 2001. 28 cm. - Influence of B;content on the structural and magnetic properties of Fe60Mn10Al30--xBx prepared by mechanical alloying. / M.;M. Rico, J. Sort, S. Suriñach, J. M. Greneche, G. A. PerezAlcazar, J. S.Muñoz, M. D. Baro. - En:;International symposium on metastable, mechanically alloyed andnanocrystalline materials (2001 : Jun. 24-29 :;Michigan Union, University of Michigan). -- Michigan Union, University ofMichigan : 2001. 28 cm. - Sintering;of Fe0.50Mn0.412Al0.075C0.01Cu0.003 alloys. / B. Cruz, G.A.Perez Alcazar, J. D. Ardisson, Waldemar A. A.;Macedo. - En: International symposium on metastable, mechanically alloyedand nanocrystalline materials (2001;: Jun. 24-29 : Michigan Union, University of Michigan). --Michigan Union,University of Michigan : 2001. 28;cm. - Magnetic properties of mechanically alloyed FexMn0.70--xAl0.30 x '=0.40 and 0.45 alloys. / M. M. Rico,;G. Medina, G. A. Perez Alcazar, J. S. Muñoz, S. Surinach,M. D.Baro. - En: First seeheim conference on;magnetism (2001 : sept. 9-13 : Seeheim, Germany). -- Seeheim,Germany : 2001. 28 cm. - Mossbauer study of;FeXMn.0.65--XAl0.35 disordered alloys series / Claudia Gonzalez,J. M. Greneche, G. A. Perez Alcazar. - En:;International conference on the applications of the mossbauereffect (2001: sep. 2-7 : Institute of Physics).;67--82. -- ISSN Caracterizacion mossbauer de diferentes minerales auriferos colombianos / Ligia E. Zamora, M.;Fajardo, J. Mojica, G.A. Perez Alcazar, J.A. Tabares y A.Bohorquez. -- En: Revista colombiana de fisica. --;Vol. 32, no.1 (2000); p. 136--140. -- Magnetic Propertiesof FexMn0.3AI0.7--x (0.275 < x < 0.525) disordered;alloys / Ligia E. Zamora, G. A. Perez Alcazar, J. A. Tabares,A.Bohorquez, J. F. Marco, J. M. Gonzalez. - En:;Journal phys matter. - No. 12 (2000); p. 611--621. -- Magneticpropertiesof Fe0.9--qMn0.1AIq disordered;alloys: theory / J. Restrepo, A. Perez Alcazar. - En: Physicalreview B. -Vol. 61, no. 9 (Mar 1 2000); p.;5880--5883. -- Interpretation based on a binomial method of thehyperfinefield distributions of disordered;Fe0.9--xMn0.1AIx alloys / J. Restrepo, G. A. Perez Alcazar. -En: Journalof magnetism and magnetic materials.;- No. 213 (2000); p. 135--142. -- Magnetic properties of disordered Fe0.9--xAIx alloys / J. Restrepo, G. A.;Perez Alcazar. -- En: Journal of applied physics. - Vol. 87, No.10 (May 15 2000); p. 7425--7429. -- Room;temperature magnetic properties of quenched disordered FeAI alloys: a simulational study / J. Restrepo, G. A.;FexMn0.70--xAl030 (x '= 0.40 and 0.45) alloys Vol. 189, no.3 (2002); p. 811--816. -- Site diluted quantum;heisenberg spin model applied to the magnetic properties of Fe--Al disordered alloys / M. Salazar, Ligia E.;Zamora, G. A. Perez Alcazar, J. A. Plascak, W. R. Aguirre.'- en:Physica B. - No. 320 (2002); p. 236--238. --;Magnetic properties of the FexMn0.600--xAl0.400, 0.200 < xz 0.600, disordered alloy series / C. Gonzalez, G.;A. Perez Alcazar, Ligia E. Zamora, Jesus A Tabares, J. M.Greneche. - En:J. phys condens. Matter. - No. 14;(2002); p. 6531--6542. -- Development of magnetic softnessinhigh energyball milling alloyed Fe50B50 / J. M.;Gonzalez, G. A. Perez Alcazar, Ligia E. Zamora, J. A. Tabares,A. Bohorquez, J. R. Gancedo. - En: Journal of;magnetism and magnetic materials. -- PONENCIA(S) EN CONGRESO:Evolucion de las propiedades fisicas durante la;sinterizacion del sistema Fe0.45Mn0.25Al0.30 preparado pormezcla elemental / M. Medina, G. A. Perez Alcazar,;Y. Aguilar. -- En: Congreso nacional de fisica (19 : 2001sep.24-28 : Manizales, Colombia). -- Manizales;:Universidad Nacional de Colombia, 2001. - 28 cm. -- Analisisestructuralde la serie Fe60Mn10Al30-xBx(2<x<10);preparado por aleamiento mecanico / M.M. Rico, J. Sort, D.Baro,S. Suriñach, J.M. Greneche, G. A. Perez;Alcazar. -- En: Congreso nacional de fisica (19 : 2001 sep. 24-28 : Manizales, Colombia). -- Manizales :;Universidad Nacional de Colombia, 2001. - 28 cm. -- Propiedadesmagneticasy estructurales de aleaciones;Fe1--xAlx producidas por aleamiento mecanico / D. Oyola Lozano,Y. Rojas Martinez, H. Bustos Rodriguez. - En:;Congreso nacional de fisica (19 : 2001 sep. 24-28 : Manizales,Colombia).'-- Manizales : Universidad nacional;de Colombia, 2001. - 28 cm. - A random bond ising model appliedto the magnetic properties of Fe0.6--xMnxAl0.4;FexMn0.70--xAl030 (x '= 0.40 and 0.45) alloys / M.M. Rico,G. Medina, G. A.Perez Alcazar, J. S. Muñoz, S.;from guachinte mine in Colombia. / F. Reyes, G. A. Perez Alcazar, J. M. Barraza, A. Bohorquez, J. A. Tabares,;N. L. Speciali. - En: Lacame (2002 : sep. 23), -- (s. l.)2002.'- Mossbauer and X--RAY Characterization of;Fe0.2Mn0.4Al0.4 mechanically powders. / Claudia Gonzalez,J. M.Greneche,G. A. Perez Alcazar, J. A. Tabares.;- En: Lacame (2002 : Sep. 23), -- (s. l.) 2002. - Study oftheevolution in the iron oxide synthesis by a;hydrothermal process. / E. Delgado, A. Bohorquez, G. A. PerezAlcazar, A.Bolaños. - En: Lacame (2002 : sep.;23), -- (s. l.) 2002. - On the analysis of the mossbauer spectraof the rust converted by tannic and;phosphoric acids. / C. A. Barrero, J. F. Rios, A.L Morales, A.Bohorquez,G. A. Perez Alcazar. - En: Lacame;(2002 : sep. 23), -- (s. l.) 2002. - Study of the changesinduced in the surface of FeNi alloys below the;invar Ni concentration by AN oxidative process using cems/ J.A. Tabares,A. Cortes, G. A. Perez Alcazar, A.;Bohorquez. - En: Lacame (2002 : sep. 23), -- (s. l.) 2002.- Constructionand improvement of an spherical;electrostatic electron energy analyser for depth selectiveconversion electron mossbaur spectroscopy. / J. A.;Tabares, W. Castro, G. A. Perez Alcazar, A. Bohorquez. En:Lacame (2002 :sep. 23), -- (s. l.) 2002. --;Thermal driven and ball milled haematite to magnetite transformations. / J.D. Betancur, J. Restrepo, J. Mazo;Baro. - En: Journal of metastable and nunocrystalline materials.- Vol. 10(2000); p. 565--570. -- A;comparative study on the magnetic properties of arc meltedandball milledFe0.9--xMn0.1Aix alloys / J.;Restrepo, G. A. Perez Alcazar, J. M. Gonzalez. - En: Hyperfineinteractions. - No. 134 (2001); p. 27--35. --;Magnetic properties of the mechanically alloyed (Fe0.85Mn0.15)0.3Cu0.7 system / J. Restrepo, A. L. Morales, J.;M. Gonzalez, G. A. Perez Alcazar, G. Medina, C. A. Barrero, J.Tobon, G. Perez, O. Ornache, J. D. Betancur, M.;A. Giraldo. - En: Hyperfine interactions. - No. 134 (2001); p.199--206. -'- Influence of the B content On the;structural and magnetic properties of Fe60Mn10Al30--xBx preparedby mechanical alloying / M.M. Rico, J. Sort,;S. Suriñach, J. S. Muñoz, J. M. Greneche, G. A. Perez Alcazar,M. D. Baro.- En: Materials science forum. -;Vols. 386--388 (2002); p. 497--502. -- Magnetic and structuralpropertiesof mechanically alloyed; Institute of Physics : (s.l.), 2001 - Magnetic and structuralproperties of Fe-Mn-Al alloys produced by;mechanical alloying. / G. A. Perez Alcazar, Ligia E. Zamora, J.A. Tabares, A. Bohorquez. - En: Lacame (2002 :;Sept. 23), -- (s. l.) 2002. - Bulk magnetic properties ofFe0.5Mn0.1Al0.4disordered alloys: Experiment and;monte carlo simulation. / J. Restrepo, Claudia Gonzalez, G. A.Perez Alcazar, J. M. Greneche, O. Arnache. -;En: Lacame (2002 : sep. 23), -- (s. l.) 2002. - Nb effecton theproperties of the system Fe0.6Mn0.1Al0.3. /;Ligia E. Zamora, G. A. Perez Alcazar, J. M. Greneche, J. F. Valderruten. -En: Lacame (2002 : sep. 23), -- (s.;l.) 2002. - Study by surface spectroscopies of corrosion behaviour fermanal alloys in humic medias contamined;with SO2. / V. F. Rodriguez, A. Bohorquez, G. A. Perez Alcazar,J. A. Jimenez, J. R. Gancedo. - En: Lacame;(2002 : sep. 23), -- (s. l.) 2002. - Quantification of pyriticsulfur of one Colombian coal by mossbauer;spectroscopy. / F. Reyes, G. A. Perez Alcazar, J. M. Barraza,A.Bohorquez, J. A. Tabares. - En: Lacame (2002;: sep. 23), -- (s. l.) 2002. - Enhanced binomial method for hyperfine field distributions of the mechanically;alloyed Fe--Si system. / H. Sanchez Sthepa, J. Restrepo, M. Fajardo, G. A.Perez Alcazar. - En: Lacame (2002 :;sep. 23), -- (s. l.) 2002. - Characterization of mineral matterby mossbauer spectroscopy and XRD of coals;Perez Alcazar, D. P. Landau. -- En: Journal of applied physics.-- Vol. 87, no. 9 (May 1 2000); p. 6528--6530.;'-- Room temperature magnetic properties of the mechanically alloyed Fe0.8--xMnxAI0.2 system / J. Restrepo, G.;A. Perez Alcazar, J. M. Gonzalez. - En: Phys. Stat. sol. -No.220 (2000);p. 429--434. -- Hyperfine magnetic;field distributions of Fe0.8--qMnqAI0.2 disordered alloys:interpretationin a local model / J. Restrepo, G.;A. Perez Alcazar. - En: Phys. Stat. sol. - No. 220 (2000);p.395--399. --Magnetic and structural study of;mechanically alloyed Fe0.7--xMnxAI0.3 / M.M. Rico, Ligia E. Zamora, G. A.Perez Alcazar, J. M. Gonzalez, A.;Hernando. - En: Phys. Stat. sol. - No. 220 (2000); p. 445--448.'-- Magnetic and structural behavior of;mechanically alloyed FexMn0.912--xAI0.075Cu0.003 alloys with 0.50 < x <0.80 / B. Cruz, G. A. Perez Alcazar, Y.;Aguilar. - En: Phys. Stat. sol. - No. 220 (2000); p. 381--383.-'- Effect of milling time and composition on;the magnetic and estructural properties of the system FexMn0.95AL0.05 (0.40 < x < 0.50 / R. Rodriguez, G. A.;Perez Alcazar. - En: Phys. Stat. sol. - No. 220 (2000); p.441--444. -- Arandom bond ising model applied to;the magnetic properties of FexMn0.6--xAI0.4 disordered alloys/Ligia E. Zamora, G. A. Perez Alcazar, A.;Bohorquez. - En: Phys. Stat. sol. - No. 220 (2000); p. 363'--367.'-- Description in a local model of the;magnetic field distributions of mechanically alloyed Fe--Si (3.5wt%) / H.Sanchez Sthepa, J. Restrepo, M.;Fajardo, G. A. Perez Alcazar. - En: Phys. Stat. sol. - No.220(2000); p.347--349. -- Mossbauer spectroscopy;and X--ray diffraction study of FexMn0.70--xAl0.30 (0.40 <x <0.70) alloys prepared by mechanical alloying /;M.M Rico, M. H. Medina Barreto, G. A. Perez Alcazar. -- En: Hyperfine interactions. - No. 128 (2000); p.;503--510. -- Magnetic phase diagram of the FexMn0.60--xAi0.40(0.20 < x <0.60) alloys mechanically alloyed;for 48 hours / C. Gonzalez, G. Medina, J. M. Greneche, G.A. Perez Alcazar, S. Suriñach, J. S. Muñoz, M. D.;Suriñach, M. D. Baro. - En: Phys. Stat. sol. -- Magnetic and structural properties of mechanically alloyed;cm. - Description in a local model of the magnetic field distributions ofmechanically alloyed and melting;Fe-Si (3.5% wt.) alloys / H. Sanchez Sthepa, J. Restrepo,W. Barona, M. Fajardo, G. Perez Alcazar. - En: Latin;american simposium on solid state physics -- (15 : 1999 Nov. 1-5: Cartagena de Indias, Colombia). - Cartagena;: (s. l.), 1999. 28 cm. -- Magnetic and structural behaviour ofmecanically alloyed;FexMn0.912--xAl0.075C0.01Cu0.03 alloys with 0.50 '= x '= 0.80 /B.Cruz, G.A. Perez Alcazar, Y. Aguilar. - En:;Latin american simposium on solid state physics (15 : 1999Nov.1-5 : Cartagena de Indias, Colombia). -;Cartagena : (s. l.), 1999. 28 cm. -- Hyperfine magnetic fielddistributions of Fe0.8--qMnqAl0.2 disordered;alloys: interpretation in a local model / J. Restrepo, G.A. Perez Alcazar'- en: Latin American simposium On;solid state physics (15 : 1999 Nov. 1-5 : Cartagena de Indias,Colombia).- Cartagena : (s. l.), 1999. 28 cm.; Effect of milling time and composition On the magneticandstructuralproperties of the system;FexMn0,95--xAl0,05 0,40 '= x '= 0,50. / Ruby Rodriguez, G. A. Perez Alcazar.'- en: Latin American simposium On;disordered alloys / Ligia E. Zamora, G. A. Perez Alcazar,A. Bohorquez. -En: Latin american simposium on;solid state physics (15 : 1999 Nov. 1-5 : Cartagena de Indias,Colombia).- Cartagena : (s. l.), 1999. - 28;solid state physics (15 : 1999 Nov. 1-5 : Cartagena de Indias,Colombia).- Cartagena : (s. l.), 1999. 28 cm

Biota Colombiana Volumen 18 No. 1 (2017)

Volumen 18 Número 1 de la revista Biota ColombianaBogotá, Colombi