Opracowanie procedury rentgenowskiej analizy strukturalnej materiałów wielofazowych zawierających fazy niestechiometryczne i nanometryczne

W rozprawie zaproponowano procedurę analizy materiałów wielofazowych przy wykorzystaniu połączonych metod Toraya i Rietvelda. Połączenie to polega na wstępnej analizie dyfraktogramów metodą Toraya i późniejszym wykorzystaniu wyznaczonych wartości parametrów sieciowych i szerokości połówkowej linii dyfrakcyjnych jako danych wejściowych w metodzie Rietvelda. Stwierdzono, że stosowanie wymienionej procedury okazuje się niezbędne do analizy materiałów z fazami niestechiometrycznymi i nanometrycznymi. Względna dokładność ilościowej analizy fazowej przy zawartościach faz powyżej 30 %wag. jest rzędu 1-5%, dokładność ta malała do 10-15% przy zawartościach faz rzędu 8-15%wag. Przy wzroście stopnia dyspersji krystalitów do skali nanometrów i zawartościach faz rzędu 62,5 %wag. dokładność zmalała dwukrotnie. W przypadku niewielkiej ilości (10-12,5 %wag) faz nanometrycznych dokładność zmniejszyła się trzykrotnie. Stwierdzono, że dla materiałów z fazami międzymetalicznymi i ceramicznymi funkcja pseudo-Voigta lepiej opisuje profil linii dyfrakcyjnych od faz mikrokrystalicznych, podczas gdy funkcja Pearsona VII od faz nanokrystalicznych. Stwierdzono, że zarówno dla materiałów testowych jak i technicznych charakteryzujących się nakładaniem refleksów dyfrakcyjnych wysoko i niskosymetrycznych faz o wysokiej dyspersji krystalitów, przy wykorzystaniu połączonych metod Toraya i Rietvelda istnieje możliwość szerszej i dokładniejszej analizy parametrów sieciowych, rozmiaru krystalitów i zniekształceń sieciowych oraz zawartości faz

Study on crystallization phenomenon and thermal stability of binary Ni-Nb amorphous alloy

In this paper, a ribbon of binary Ni–Nb amorphous alloy was prepared by the melt spinning technique. Glass transition and crystallization phenomenon of the alloy were investigated by differential scanning calorimetry. Thermal properties of the ribbon of binary Ni–Nb upon heating and cooling were analysed by DTA at a heating/ cooling rate of 0.5 K s-1 under the purified argon atmosphere. The thermal stability of Ni–Nb amorphous alloy was studied by using an X-ray diffractometer equipped with an in situ heating system. The structure and fracture morphology of the ribbons were examined by X-ray diffraction and scanning electron microscopy methods

Effect of high energy ball milling on the structure and phase decomposition of the ultiferroic Bi5Ti3FeO15 ceramics

The paper presents the results of the Bi5Ti3FeO15 multiferroic phase stability analysis during high-energy ball milling aimed at obtaining fine dispersion ceramic powder. The X-ray diffraction and transmission electron microscopy methods were used to analyse the structure and verify the degree of crystallite dispersion. Structural data analysis was carried out using the Rietveld method. To carry out the analysis of the morphology, the scanning electron microscopy was used. The results that were obtained showed that the high energy ball milling process results in the decomposition of the initial ceramics, where finally Bi5Ti3FeO15 and Bi are obtained. An increase in the proportion of the amorphous phase and an increase in the dispersion of the grains and crystallites of the powder that occurs with an increase in the milling time were observed[…

Processing, Microstructure and Dielectric Properties of the Bi5Ti3FeO15 Ceramic

The aim of the present work is the analysis of microstructure, dielectric permittivity and thermal properties analysis of Bi5Ti3FeO15 ceramics obtained by two methods. The studied Bi5Ti3FeO15 ceramics were prepared by conventional synthesis and hot uniaxial pressing reaction from the conventional mixture of oxides, viz. TiO2, Fe2O3, Bi2O3. The studied material has layered perovskite like structures, first described by Aurivillius in 1949 and Subbaro in 1969. The ceramic Bi5Ti3FeO15 is known to contain a series of compounds with the general formula: Bim+1Fem¡3Ti3O3m+3. The X-ray diffraction methods were used for qualitative phase analysis of studied samples. The morphology was analyzed by scanning electron microscopy method. The thermal properties of the studied materials were measured using the differential thermal analysis at a constant heating rate of 15 K/min under an argon protective atmosphere. Thermal dependence of dielectric permittivity was studied between room temperature and 1137 K

Role of Sn as a Process Control Agent on Mechanical Alloying Behavior of Nanocrystalline Titanium Based Powders

In this study, the e ects of Sn as a process control agent (PCA) on the final powder sizes, morphology, homogenization and alloying process of a new titanium alloy were investigated. Two kinds of powders, Ti10Ta8Mo and Ti10Ta8Mo3Sn (wt %), were prepared using a mechanical alloying process. For the Ti10Ta8Mo3Sn (wt %) alloy, the Sn element was used as PCA to enhance the milling process in the planetary ball mill. The milling process of both compositions was carried out with 200 rpm for 10, 15, 20, 40, 60, 80 and 100 h. The results confirmed that using Sn as a proces control agent can result in a relatively good size distribution and better yield performance compared to samples without Sn addition. The phase analysis using X-ray di raction proved the formation of the nanocrystalline phase and the partial phase transformation from to nanocrystalline phases of both alloy compositions. The Scaning Electron Micoscope- Backscattered Electrons SEM-BSE results confirmed that the use of Sn as the PCA can provide a better homogenization of samples prepared by at least 60 h of ball milling. Furthermore, the presence of Sn yielded the most uniform, spheroidal and finest particles after the longest milling time

The effect of mixed doping on the microstructure and electrophysical parameters of the multi-component PZT-type ceramics

This article belongs to the Special Issue The Electrophysical Properties of Ceramic Materials. Guest editor: Prof. Dariusz BochenekThis work shows the influence of admixture on the basic properties of the multicomponent PbZr1-xTixO3 (PZT)-type ceramics. It presents the results of four compositions of PZT-type material with the general chemical formula, Pb0.99M0.01((Zr0.49Ti0.51)0.95Mn0.021Sb0.016W0.013)0.9975O3, where, in the M position, a donor admixture was introduced, i.e., samarium (Sm3+), gadolinium (Gd3+), dysprosium (Dy3+) or lanthanum (La3+). The compositions of the PZT-type ceramics were obtained through the classic ceramic method, as a result of the synthesis of simple oxides. The X-ray di raction (XRD) pattern studies showed that the obtained multicomponent PZT materials have a tetragonal structure with a P4mm point group. The microstructure of the obtained compositions is characterized by a well crystallized grain, with clearly visible grain boundaries. The composition with the admixture of lanthanum has the highest uniformity of fine grain microstructure, which positively affects its final dielectric and piezoelectric properties. In the multicomponent PZT-type ceramic, materials utilize the mixed (acceptor and donor) doping of the main compound. This dopiong method has a positive effect on the set of the electrophysical parameters of ceramic materials. Donor dopants W6+ (at positions B) and M3+ = Sm3+, Gd3+, Dy3+, and La3+ (at positions A) increase the dielectric and piezoelectric properties, while the acceptor dopant Sb3+ (at positions B) increases the time and temperature stability of the electrophysical parameters. In addition, the suitable selection of the set of admixtures improved the sinterability of the ceramic samples, as well as resulted in obtaining the required material with good piezoelectric parameters for the poling process. This research confirms that all ceramic compositions have a set of parameters suitable for applications in micromechatronics, for example, as actuators, piezoelectric transducers, and precision microswitches.1. Haertling, G.H. Ferroelectric ceramics: History and technology. J. Am. Ceram. Soc. 1999, 82, 797–818. 2. King, T.G.; Preston, M.E.; Murphy, B.J.M.; Cannell, D.S. Piezoelectric ceramic actuators: A review of machinery applications. Precis. Eng. 1990, 12, 131–136. 3. Tressler, J.F.; Alkoy, S.; Newnham, R.E. Piezoelectric sensors and sensor materials. J. Electroceram. 1998, 2, 257–272. 4. Bochenek, D.; Zachariasz, R.; Niemiec, P.; Ilczuk, J.; Bartkowska, J.; Brzezińska, D. Ferroelectromagnetic solid solutions on the base piezoelectric ceramic materials for components of micromechatronics. Mech. Syst. Signal Process. 2016, 78, 84–90. 5. Bochenek, D.; Niemiec, P.; Adamczyk, M.; Skulski, R.; Zachariasz, R.; Wodecka-Duś, B.; Machnik, Z. The multicomponent PZT-type ceramics for micromechatronic applications. Arch. Metall. Mater. 2017, 62, 667–672. 6. Mishra, S.K.; Singhi, A.P.; Pandey, D. Thermodynamic nature of phase transitions in Pb(ZrxTi1−x)O3 ceramics near the morphotrpic phase boundary. II. Dielectric and piezoelectric studies. Philos. Mag. 1997, 76, 213–226. 7. Soares, M.R.; Senos, A.M.R.; Mantas, P.Q. Phase coexistence region and dielectric properties of PZT ceramics. J. Eur. Ceram. Soc. 2000, 20, 321–334. 8. Tzou, H.S.; Lee, H.-J.; Arnold, S.M. Smart materials, precision sensor/actuators, smart structures, and structronic systems. Mech. Adv. Mater. Struct. 2004, 11, 367–393. 9. Prabu, M.; Shameem Banu, I.B.; Gobalakrishnan, S.; Chavali, M. Electrical and ferroelectric properties of undoped and La-doped PZT (52/48) electroceramics synthesized by sol–gel method. J. Alloys Compd. 2013, 551, 200–207. 10. Bochenek, D.; Niemiec, P.; Szafraniak-Wiza, I.; Dercz, G. Comparison of electrophysical properties of PZT-type ceramics obtained by conventional and mechanochemical methods. Materials 2019, 12, 3301. 11. Bochenek, D.; Niemiec, P.; Korzekwa, J.; Durtka, B.; Stokłosa, Z. Microstructure and properties of the ferroelectric-ferromagnetic PLZT-ferrite composites. Symmetry 2018, 10, 59. 12. Kong, L.B.; Zhang, T.; Ma, J.; Boey, F. Progress in synthesis of ferroelectric ceramic materials via high-energy mechanochemical technique. Prog. Mater. Sci. 2008, 53, 207–322. 13. Bartkowska, J.A. The magnetoelectric coupling effect in multiferroic composites based on PZT-ferrite. J. Magn. Magn. Mater. 2015, 374, 703–706. 14. Siddiqui, M.; Mohamed, J.J.; Ahmad, Z.A. Structural, piezoelectric, and dielectric properties of PZT-based ceramics without excess lead oxide. J. Aust. Ceram. Soc. 2019, doi:10.1007/s41779-019-00337-3. 15. Bartkowska, J.A.; Bluszcz, J.; Zachariasz, R.; Milczuk, J.; Bruś, B. Domain wall motion effect in piezoelectric ceramics. J. Phys. IV 2006, 137, 19–21. 16. Kalema, V.; Çamb, I.; Timuçina, M. Dielectric and piezoelectric properties of PZT ceramics doped with strontium and lanthanum. Ceram. Int. 2011, 37, 1265–1275. 17. Texier, N.; Courtois, C.; Traianidis, M.; Leriche, A. Powder process influence on the characteristics of Mn, W., Sb, Ni-doped PZT. J. Eur. Ceram. Soc. 2001, 21, 1499–1502. 18. Fernandez, J.F.; Moure, C.; Villegas, M.; Duran, P.; Kosec, M.; Drazic, G. Compositional fluctuations and properties of fine-grained acceptor-doped PZT ceramics. J. Eur. Ceram. Soc. 1998, 18, 1695–1705. 19. Bhattacharya, K.; Ravichandran, G. Ferroelectric perovskites for electromechanical actuation. Acta Mater. 2003, 51, 5941–5960. 20. Lines, M.E.; Glass, A.M. Principles and Applications of Ferroelectrics and Related Materials; Oxford Classics Series; Oxford University Press: Oxford, UK, 2001. 21. Moulson, A.J.; Herbert, J.M. Electroceramics: Materials, Properties, Applications; Chapman and Hall: New York, NY, USA, 1990. 22. Uchino, K. Ferroelectric Devices, 2nd ed.; CRC Press/Taylor and Francis: Boca Raton, FL, USA, 2010. 23. Uchino, K.; Giniewicz, J.R.; Micromechatronics; Marcel Dekker, Inc.: New York, NY, USA, 2003. 24. Karapuzha, A.S.; James, N.K.; Khanbareh, H.; van der Zwaag, S.; Groen, W.A. Structure, dielectric and piezoelectric properties of donor doped PZT ceramics across the phase diagram. Ferroelectrics 2016, 504, 160–171. 25. Xu, Y. Ferroelectric Materials and Their Applications; North-Holland: Amsterdam, The Netherlands, 1991. 26. Jaffe, B.; Cook, W.R.; Jaffe, H. Piezoelectric Ceramics; Academic Press: London, UK, 1971. 27. Surowiak, Z.; Bochenek, D.; Czekaj, D.; Gavrilyachenko, S.V.; Kupriyanov, M.F. Piezoceramics transducers with high thermal stability of the resonance frequency. Ferroelectrics 2002, 273, 119–124. 28. Khacheba, M.; Abdessalem, N.; Hamdi, A.; Khemakhem, H. Effect of acceptor and donor dopants (Na, Y) on the microstructure and dielectric characteristics of high curie point PZT-modified ceramics. J. Mater. Sci.-Mater. Electron. 2020, 31, 361–372, doi:10.1007/s10854-019-02535-y. 29. Chu, S.-Y.; Chen, T.-Y.; Tsai, I.T.; Water, W. Doping effects of Nb additives on the piezoelectric and dielectric properties of PZT ceramics and its application on SAW device. Sens. Actuators A-Phys. 2004, 113, 198–203. 30. Shung, K.K.; Cannata, J.M.; Zhou, Q.F. Piezoelectric materials for high frequency medical imaging applications: A review. J. Electroceram. 2007, 19, 141–147. 31. Shannigrahi, S.R.; Tay, F.E.H.; Yao, K.; Choudhary, R.N.P. Effect of rare earth (La, Nd, Sm, Eu, Gd, Dy, Er and Yb) ion substitutions on the microstructural and electrical properties of sol-gel grown PZT ceramics. J. Eur. Ceram. Soc. 2004, 24, 163–170. 32. Garg, A.; Agrawal, D.C. Effect of rare earth (Er, Gd, Eu, Nd and La) and bismuth additives on the mechanical and piezoelectric properties of lead zirconate titanate ceramics. Mater. Sci. Eng. B 2001, 86, 134–143. 33. Bongkarn, T.; Rujijanagul, G. Effect of excess lead oxide on phase transitions and physical properties of perovskite lead barium zirconate ceramics. Ferroelectrics 2007, 358, 67–73. 34. Gao, X.; Xue, J.; Wang, J.; Yu, T.; Shen, Z.-X. Sequential combination of constituent oxides in the synthesis of Pb(Fe1/2Nb1/2)O3 by mechanical activation. J. Am. Ceram. Soc. 2002, 85, 565–572. 35. Rietveld, H.M. A profile refinement method for nuclear and magnetic structures. J. Appl. Cryst. 1969, 2, 65–71. 36. Yu, T.; Shen, Z.X.; Toh, W.S.; Xue, J.M.; Wang, J.J. Size effect on the ferroelectric phase transition in SrBi2Ta2O9 nanoparticles. J. Appl. Phys. 2003, 94, 618–620. 37. Williamson, G.K.; Smallman, R.E., III. Dislocation densities in some annealed and cold-worked metals from measurements on the X-ray debye-scherrer spectrum. Philos. Mag. 1956, 1, 34–46. 38. Gantassi, A.; Essaidi, H.; Boubaker, K.; Bernède, J.C.; Colantoni, A.; Amlouk, M.; Manoubi, T. Physical investigations on (In2S3)x(In2O3)y and In2S3-xSex thin films processed through In2S3 annealing in air and selenide atmosphere. Mater. Sci. Semicond. Proc. 2014, 24, 237–248. 39. Wang, D.; Jin, H.; Yuan, J.; Wen, B.; Zhao, Q.; Zhang, D.; Cao, M. Mechanical reinforcement and piezoelectric properties of PZT ceramics embedded with nano-crystalline. Chin. Phys. Lett. 2010, 27, 047701. 40. Lin, H.; Cao, M.; Yuan, Y.; Wang, D.; Zhao, Q.; Wang, F. Enhanced mechanical behavior of lead zirconate titanate piezoelectric composites incorporating zinc oxide nanowhiskers. Chin. Phys. B 2008, 17, 4323–4327. 41. Bokov, A.A.; Ye, Z.G. Recent progress in relaxor ferroelectrics with perovskite structure. J. Mater. Sci. 2006, 41, 31–52. 42. Cross, L.E. Relaxor ferroelectrics. Ferroelectrics 2011, 76, 241–267. 43. Balusamy, R.; Kumaravel, P.; Renganathan, N.G. Dielectric and electrical properties of lead zirconate titanate. Der Pharma Chemica 2015, 7, 175–185. 44. Smolensky, G.A. Ferroelectrics with diffuse phase transition. Ferroelectrics 1984, 53, 129–135. 45. Bochenek, D.; Surowiak, Z.; Krok-Kowalski, J.; Poltierova-Vejpravova, J. Influence of the sintering conditions on the physical proprieties of the ceramic PFN multiferroics. J. Electroceram. 2010, 25, 122–129. 46. Raymond, O.; Font, R.; Suárez-Almodovar, N.; Portelles, J.; Siqueiros, J.M. Frequency-temperature response of ferroelectromagnetic PbFe1/2Nb1/2O3 ceramics obtained by different precursors. Part I. Structural and thermo-electrical characterization. J. Appl. Phys. 2005, 97, 084107. 47. Isupov, V.A. Nonlinearity of the concentration dependence of the Curie temperature in ferroelectric perovskite solid solutions. Phys. Status Solidi A 2000, 181, 211–218. 48. Wong, G.H.L.; Chua, B.W.; Li, L.; Lai, M.O. Processing of thermally stable doped perovskite PZT ceramics. J. Mater. Process. Technol. 2001, 113, 450–455. 49. Yang, K.; Huang, X.; Huang, Y.; Xie, L.; Jiang, P. Fluoro-polymer@BaTiO3 hybrid nanoparticles prepared via RAFT polymerization: Toward ferroelectric polymer nanocomposites with high dielectric constant and low dielectric loss for energy storage application. Chem. Mater. 2013, 25, 2327–2338. 50. Rayssi, C.; Kossi, S.E.; Dhahri, J.; Khirouni, K. Frequency and temperature-dependence of dielectric permittivity and electric modulus studies of the solid solution Ca0.85Er0.1Ti1-xCo4x/3O3 (0x 0.1). RSC Adv. 2018, 8, 17139. 51. Bochenek, D., Niemiec, P.; Skulski, R.; Brzezińska, D. Electrophysical properties of PMN-PT-ferrite ceramic composites. Materials 2019, 12, 3281. 52. Prokopalo, O.I. Conductivity and anomalous polarization in ceramic ferroelectrics with perovskite structure. Ferroelectrics 1976, 5, 683–685. 53. Dih, J.J., Fulrath, R.M. Electrical conductivity in lead zirconate-titanate ceramics. J. Am. Ceram. Soc. 1978, 61, 448–451. 54. Li, M.; Pietrowski, M.J.; De Souza, R.A.; Zhang, H.; Reaney, I.M.; Cook, S.N., Kilner, J.A.; Sinclair, D.C. A family of oxide ion conductors based on the ferroelectric perovskite Na0.5Bi0.5TiO3. Nat. Mater. 2013, 13, 31–35. 55. Osak, A. AC low frequency conductivity in PZT PFS ferroelectric ceramics. Tech. Trans. 2017, 1, 173–185. 56. Scott, J.F. Ferroelectrics go bananas. J. Phys. Condens. Matter 2008, 20, 021001. 57. Paik, H.; Hwang, H.; No, K.; Kwon, S.; Cann, D.P. Room temperature multiferroic properties of single-phase (Bi0.9La0.1)FeO3–Ba(Fe0.5Nb0.5)O3 solid solution ceramics. Appl. Phys. Lett. 2007, 90, 042908. 58. Kour, P.; Sinha, S.K. Dielectric, ferroelectric and piezoelectric properties of La3+ substiuted PZT ceramics. Digest J. Nanomater. Biostruct. 2012, 7, 1327–1332. 59. Kong, L.B.; Ma, J.; Huang, H.T.; Zhu, W.; Tan, O.K. Lead zirconate titanate ceramics derived from oxide mixture treated by a high-energy ball milling process. Mater. Lett. 2001, 50, 129–133

Structural and quantitative analysis of die cast AE44 magnesium alloy

Purpose: The main objective of this study was development of determination of phase fraction methodology in cast magnesium alloy containing aluminum and rare earth elements. Design/methodology/approach: The study was conducted on magnesium alloy containing 4 %wt. aluminum and 4 %wt. mixture of rare earth elements (mischmetal) in the as-cast condition. The mischmetal includes cerium, lanthanum, neodymium and praseodymium. In this study, several methods were used such as: optical light microscopy, quantitative metallography, scanning electron microscopy and X-ray diffraction. The Rietveld method with Hill and Howard procedure was applied for determination of lattice parameters and phase abundance. Findings: The microstructure of investigated alloy consists of α-Mg solid solution, globular, lamellar and acicular precipitations of Al11RE3 and Al2RE phases. The results show that the accurate determination of phase contents in AE44 alloy can not perform using quantitative metallography. In this purpose X-ray investigations should be applied. Research limitations/implications: Developed methodology will be used to quantitative phase analysis of investigated alloy after creep tests and die cast with different parameters. Practical implications: AE44 magnesium alloy is used in automotive industry. Moreover, this alloy has a new potential application and results of investigations may be useful for preparing optimal technology of die casting. Originality/value: Procedure described in this paper may be useful as the best experimental techniques for quantitative phase analysis of the intermetallic phases occurring in the AE series magnesium alloys

Application of mechanical activation in synthesizing multiferroic Pb(Fe1/2Nb1/2)O3 powders

In the study, the method of high-energy powder milling – mechanical activation (MA) was used for synthesizing Pb(Fe1/2Nb1/2)O3 (PFN) powders. For the purpose of comparing the influence of high-energy milling on PFN synthesis, two groups of powder samples were used. The first mixture consisting of simple oxide powders; the second one consisting of compound oxide powders. The obtained powders were subjected to structural analysis with the use of XRD and Mossbauer spectroscopy. Tests revealed that during the process of high-energy milling of initial constituents a partial synthesis of PFN material phases occurs. By comparing the two methods of PFN synthesizing it may be stated that mechanical activation in the case of a simple oxide mixture (PFN1) is equally effective as for a compound oxide mixture (PFN2).[1] Y. X u, Ferroelectric materials and their applications. North – Holland, Amsterdam 1991. [2] S.L. S w a r t z, V.E. W o o d, Condensed Matter News 1, 4-14 (1992)[3] E.G. F e s e n k o, A.Ya. D a n c i g e r, O.N. R a z u -m o v s k a y a, Novye piezokeramicheskie materialy, RGU, Rostov-na-Donu, 1983. [4] O. R a y m o n d, R. F o n t, N. S u a r e z, J. P o r -t a l l e s, J. M. S i q u e i r o s, Ferroelectrics 294, 141 (2003). [5] K. S i n g h, S.A. B a n d, W.K. K i n g e, Ferroelectrics 306, 179 (2004). [6] X. G a o, J. X u e, J. W a n g, Journal of the American Ceramic Society 85, 565 (2002). [7] D. B o c h e n e k, Z. S u r o w i a k, Journal of Alloys and Compounds 480, 732-736 (2009). [8] D. B o c h e n e k, J. D u d e k, The European Physical Journal – Special Topics 154, 1 19-22 (2008). [9] D. B o c h e n e k, R. Z a c h a r i a s z, Archives of Metallurgy and Materials, 54, 903-910 (2009). [10] D. B o c h e n e k, Journal of Alloys and Compounds 504, 508-513 (2010). [11] B.D. S t o j a n o v i c, A.Z. S i m o e s, C.O. P a i -v a - S a n t o s, C. J o v a l e k i c, V.V. M i t i c, J.A. V a r e l a, Journal of the European Ceramic Society 25, 1985-1989 (2005). [12] J.S. B e n j a m i n, Scientific American 234, 40-43 (1976). [13] A.S. K h i m, X. J u n m i n, J. W a n g, Journal of Alloys and Compounds 343, 156-163 (2002). [14] X.S. G a o, J.M. X u e, T. Y u, Z.X. S h e n, J. W a n g, Materials Chemistry and Physics 75, 211-215 (2002). [15] J. W a n g, D.M. W a n, J.M. X u e, W.B. N g, Singapore Patent 9801566-2, 1998. [16] J. W a n g, D.M. W a n, J.M. X u e, W.B. N g, Journal of the American Ceramic Society 82, 477 (1999). [17] D. D e r c z, J. D e r c z, K. P r u s i k, A. H a n c, L. P a j ą k, J. I l c z u k, Archives of Metallurgy and Materials, 54, 741-745 (2009). [18] L.B. K o n g, J. M a, H.T. H u a n g, W. Z h u, O.K. T a n, Materials Letters 50, 129-133 (2001). [19] D. B o c h e n e k, Z. S u r o w i a k, J. K r o k - K o w a l -s k i, J. P o l t i e r o v a - V e j p r a v o v a, Journal of Electroceramics 25, 122-129 (2010). [20] Y. Y a n g, H.B. H u a n g, J.-M. L i u, Z.G. L i u, Ferroelectrics 280, 75-82 (2002)

Microstructure investigations of Co-Si-B alloy after milling and annealing

Purpose: The work presents the microstructure characterization of Co77Si11,5B11,5 metallic glass after high-energy ball milling and heat treatment processes. Design/methodology/approach: The studies were performed on ribbon prepared by melt spinning and this ground in high-energy vibratory ball mill. The tested ribbon and obtained powders were also annealed in specified heat treatment conditions. The morphology of the powder particles of milled ribbon was analyzed by using the confocal laser scanning microscope. The methods of X-ray diffraction were used for the qualitative phase analysis. The parameters of the individual diffraction line profiles were determined by PRO-FIT Toraya procedure. The average crystallite sizes and lattice distortions for Co phase were estimated using Williamson-Hall method. Findings: The studied Co77Si11.5B11.5 metallic glass in annealed state contains hexagonal Co crystalline phases emerged in amorphous matrix. The crystallite size of Co phase in as-cast sample lies in nanoscale. After annealing process the crystallite size increases to 72 nm and diminishes to 46 nm in the powder sample after 30 hours of milling. The milling causes decrease of the crystallite size and increase of lattice distortions of crystalline phase. The powder particles after 30 hours of milling are of spherical shape. Practical implications: The powder particles obtained after milling process of Co-based metallic glass could be suitable components in production of ferromagnetic nanocomposites. Originality/value: The obtained results confirm the utility of applied investigation methods in the microstructure analysis of powder materials with nanocrystalline phases. Keywords: X-ray phase analysis; Toraya procedure; High

Barium ferrite powders prepared by mechanical alloying and annealing

Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatment. Design/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container during which their collisions occur. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM). Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases. The X-ray vestigations of tested mixture milled for 30 hours and annealed at 950 °C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force (HC) for mixture of powders annealed at 950 °C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. The arithmetic mean of diameter of Fe2O3 and BaCO3 mixture powders after 30 hours of milling is about 6.0 μm. Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable components to produce sintered and elastic magnets with polymer matrix. Originality/value: The results of tested barium ferrite investigations by different methods confirm their utility in the microstructure and magnetic properties analysis of powder materials