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M. Kupková, M. Hrubovčáková, M. Kabátová and M. Kupka

Abstract

Elemental iron and manganese powders were blended to form mixtures containing 25, 30 and 35wt.% Mn. Mixtures were compressed into prismatic bars and sintered. Some of the bars were repressed and resintered. Compared to a bar pressed and sintered once, the bar pressed and sintered twice possessed a higher relative density, a higher bending stiffness, and a grid microindentation data set with a lower variance. Bars were immersed in Hank's solution for eight weeks. After this procedure, the bending stiffness were found reduced for all bars except for those pressed, sintered and only repressed, the bending stiffness of which remained unchanged. The repressing has most likely closed up throats connecting the clusters of pores with the free surface of a bar, reducing thus a surface area exposed to a corrosive attack. The resintering has opened up those throats, the electrolyte could fill accessible pores and corrosion weakened the near-surface material, reducing thus a bar's bending stiffness.

Open access

Elena Valentina Stoian, Vasile Bratu, Cristiana Maria Enescu and Dan Nicolae Ungureanu

Abstract

Aim of the study is to present the technological process of obtaining cast iron with lamellar graphite for use in the manufacture of cylinder liners, and to identify the main alloying elements and track their influence on the mechanical properties of cast iron with lamellar graphite.

Also paper presents analysis of 20 batches of cast iron with lamellar graphite, which are made of cylinder liners, in terms of chemical composition and the mechanical properties.

After the analysis of the 20 castings of cast iron Fc 250 it is observed that: the increase in the carbon content shows a decrease of the tensile strength and hardness of the gray cast iron; the increase in silicon content shows a decrease in hardness and tensile strength. Decreasing the amount of graphite and especially the alloy of silicon iron lead to hardness increase 1% Si increases hardness by 50 HB). A statistical analysis has been performed on the data obtained that accounts for changes in alloying additions. A modeling and optimization of mechanical properties (tensile strength and hardness) was performed according to the percentages of carbon, silicon and manganese. Mathematical modeling found that the hardness and traction resistance of the cast iron decreased with the increase in carbon, silicon and manganese content.

Open access

Prapawan Thongsri

Abstract

Calcium manganese oxide (CaMnO3) polycrystalline was synthesized by solid state reaction (SSR) and hot-press (HP) methods. The powder of CaCO3 and MnO2 were mixed by ball milling then calcined at 850°C for 10 h and hotpressing at 850 °C for 1 h to obtain the CaMnO3 samples. The crystallography of the samples was analyzed by the X-ray diffraction (XRD). The microstructures of the samples were observed by scanning electron microscope (SEM). It was found that, the sintering process influence the crystalline perfection and have a direct impact on the mechanical properties of CaMnO3 and their aging behavior. The values of the effective elastic modulus was 6 GPa and Flexural strength was 0.417 MPa of CaMnO3 were found to be in the range of corresponding values for high performance and possibility fabricated n-type thermoelectric leg.

Open access

E. Lichańska, P. Kulecki and K. Pańcikiewicz

-Mn-(Mo)-(Cr)-C Sintered Structural Steels, 2004 [8] Fiał, C., Dudrova, E., Kabatova, M., Kupkova, M., Selecka, M., Sułowski, M., Ciaś, A.: Arch. Metall. Mater., vol. 60, 2015, p 783 [9] Ciaś, A., Czarski, A.: Arch. Metall. Mater., vol. 58, 2013, no. 4, p. 1045 [10] Zhang, Z., Frisk, K., Salwén, A., Sandström, R.: Powder Metall., vol. 47, 2004, no. 3, p. 239 [11] Lindsley, B., James, WB. In: Euro PM 2010 Florence, no. 5, 2010, p. 1 [12] Salak, A., Selecká, M.: Manganese in powder metallurgy steels, 2012 [13] Dudrova, E., Kabátová, M. In: Workshop

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Ileana Nicoleta Popescu, Ruxandra Vidu and Vasile Bratu

-969. [4] H. Hermawan, H. Alamdari, D. Mantovani, D. Dube, Iron-manganese: new class of metallic degradable biomaterials prepared by powder metallurgy, Powder Metall. 51(2008) 38–45. [5] Ayşe Eda Onar and Koray Gençoğlan, Biomaterials (lecture), Muğla Sıtkı Koçman University. [6] D. Vojtech, J. Kubasek, J. Serak, P. Novak, Mechanical and corrosion properties of newly developed biodegradable Zn-based alloys for bone fixation, Acta Biomaterialia, 7(9)(2011)3515-3522. [7] F.Y. Zhou, B.L. Wang, et.al., Microstructure, corrosion behavior and cytotoxicity of

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Veronika Varga, Katalin Bélafi-Bakó, Dávid Vozik and Nándor Nemestóthy

.12.016 [9] Karaffa, L.; Diaz, R.; Papp, B.; Fekete, E.; Sandor, E.; Kubicek, C. P.: A deficiency of manganese ions in the presence of high sugar concentrations is the critical parameter for achieving high yields of itaconic acid by Aspergillus terreus , Appl. Microbiol. Biotechnol. , 2015 99 (19), 7937–7944 DOI: 10.1007/s00253-015-6735-6 [10] MagalhȈ aes, A. I.; de Carvalho, J. C.; Ramírez, E. N. M.; Medina, J. D. C.; Soccol, C. R.: Separation of Itaconic Acid from Aqueous Solution onto Ion-Exchange Resins, J. Chem. Eng. Data, 2016 61 (1), 430–437 DOI: 10

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Zsolt Valicsek, Melitta P. Kiss, Melinda A. Fodor, Muhammad Imran and Ottó Horváth

.; Wankmüller, A.: Photophysical and photocatalytic behavior of cobalt(III) 5,10,15,20-tetrakis(1- methylpyridinium-4-yl)porphyrin, Inorg. Chem. Commun. , 2014 50 , 110–112 DOI: 10.1016/j.inoche.2014.10.029 [6] Fodor, M.A.; Horváth, O.; Fodor, L.; Vazdar, K.; Grampp, G.; Wankmüller, A.: Photophysical and photochemical properties of manganese complexes with cationic porphyrin ligands: Effects of alkyl substituents and micellar environment, J. Photochem. Photobiol. A , 2016 328 , 233–239 DOI: 10.1016/j.jphotochem.2016.06.011 [7] Major, M.M.; Horváth, O.; Fodor