Design of component composition of “ink” based
on cement for construction 3D printer
V. А. Poluektova
Physicotechnological properties of the mixture, the so-called “ink”, for a 3D construction printer are formulated. It is shown, that the structure must have unique rheological characteristics, regulated time of setting, good adhesion and early strength. It is defined that such material with the required properties can be received on the one hand by creation of composite material on the basis of two active agents: mineral binding and polymeric binding, and on the other hand ‒ by surface modifying of superplasticizer particles. Influence patterns of organic components (polymeric binding and superplasticizer) on cement matrix are received. The mobility of the mixture, setting time, strength characteristics and the microstructure of the polymer-cement composite are investigated. The patented composite material has been developed for innovative branch of construction on the basis of two active components – Portland cement and polyvinyl acetate dispersion. Due to phase boundary modifying of the colloid system the proposed composite possesses necessary plastic strength, high rate of setting, high early strength, crack resistance and some other properties necessary for three-dimensional printing of large-sized products and constructions without timbering.
Keywords: composite material, polymercement solution, quick-hardening solution, “ink” for the 3D printer, phloroglucinefurfural superplasticizer, polyvinyl acetate dispersion.
Poluektova Valentina — Belgorod State Technological University named after V.G. Shukhov (46 Kostyukova street, Belgorod, 308012, Russian Federation), PhD (Eng), assistant professor, specialist in the sphere of chemical modification of highly-concentrated mineral and polymineral dispersions. E-mail: email@example.com.
Poluektova V.А. Proektirovanie komponentnogo sostava “chernil” na osnove cementa dlya stroitel'nogo 3D-printera. [Design of component composition of “ink” based on cement for construction 3D printer]. Perspektivnye Materialy — Advanced Materials (in Russ), 2020, no. 2, p. 5 – 13. DOI: 10.30791/1028-978X-2020-2-5-13
Effect of oxygen nonstoichiometry on phase separation, structure and magnetic properties of the complex
oxide NdSr2Mn2O7 ± δ
O. M. Fedorova, L. B. Vedmid’, S. A. Uporov
For formation of different oxygen nonstoichiometry in oxide samples NdSr2Mn2O7 ± δ applied a two-step synthesis method, which allows to achieve different oxygen nonstoichiometry of the samples. Oxygen nonstoichiometry is formed by two methods: quenching at certain temperatures, and annealing at certain values of oxygen partial pressure. The value of oxygen nonstoichiometry determined by the mass emitted from the sample to oxygen during the decomposition of samples NdSr2Mn2O7 ± δ to simple oxides. Determined oxygen nonstoichiometry in NdSr2Mn2O7 ± δ when recording external parameters such as pressure and temperature. The study of samples NdSr2Mn2O7 ± δ using thermogravimetry and x-rays revealed phase separation — two phases with the same cation composition, having different oxygen content. For example, sample NdSr2Mn2O7 ± δ, tempered 1000 °C and having an oxygen nonstoichiometry +0.09 proposed crystallographic criterion of manifestation of phase separation in phases Ruddlesden-Popper (R-P) — a sharp change in the bond lengths of the manganese-oxygen. Measurement of the electrical resistance of DC in the samples NdSr2Mn2O7 ± δ were performed in the temperature range 5 – 300 K and magnetic fields up to 7 T standard 4-probe method. Magnetoresistive effect up to 400 % was found in the studied oxides, which is nonlinearly dependent on their oxygen nonstoichiometry.
Keywords: Ruddlesden-Popperphases, phase separation, structure, colossal magnetoresistive effect, oxygen nonstoichiometry.
Fedorova Olga — Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences (Ekaterinburg, 620016, Amundsen str., 101), PhD (Chem), senior researcher, specialist in the field of X-ray phase analysis of oxide materials. E-mail:firstname.lastname@example.org.
Vedmid’ Larisa — Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences (Ekaterinburg, 620016, Amundsen str., 101), PhD (Chem), senior researcher; Ural Federal University, (Ekaterinburg, 620002, Mira str., 19), senior researcher (specialist in the field of thermogravimetric analysis of oxide materials. E-mail: email@example.com.
Uporov Sergey — Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences (Ekaterinburg, 620016, Amundsen str., 101), PhD (Phys-Math), senior researcher; Ural Federal University, (Ekaterinburg, 620002, Mira str., 19), senior researcher, specialist in the analysis of magnetic properties of alloys and oxide materials. E-mail: firstname.lastname@example.org.
Fedorova O.M., Vedmid’ L.B., Uporov S.A. Vliyanie kislorodnoj nestekhiometrii na fazovoe rassloenie, strukturu i magnitnye svojstva slozhnogo oksida NdSr2Mn2O7 ± [Effect of oxygen nonstoichiometry on phase separation, structure and magnetic properties of the complex oxide NdSr2Mn2O7 ± ]. Perspektivnye Materialy — Advanced Materials (in Russ), 2020, no. 2, p.14 – 21. DOI: 10.30791/1028-978X-2020-2-14-21
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