Dilatometric Method Research Articles

Poly complexes based unsaturated β-diketones and rare earth elements for optoelectronics

ABSTRACTThe complexes of samarium(III) with 2-methyl-5-phenylpenten-1-3,5-dione (mphpd) Sm(mphpd)3·2H2O and 2,6-dymethyl-heptene-1-3,5-dione (hdmhpd), Sm(hdmhpd)m were synthesized. The polycomplexes on their basis [Sm(mphpd)3]n, [Sm(hdmhpd)m]n and copolymers with styrene Sm(mphpd)3-co-styrene in ratio 5:95 were obtained by free-radical polymerization and the kinetics of polymerization was studied by dilatometric method at the first time. The method of dynamic light scattering and the results of electronic microscopy showed that the obtained polymer systems are nanoscale. The luminescent spectra of obtained metal complexes in solid state are investigated and analyzed. The electroluminescent spectra of organic planar heterostructure ITO/PEDOT:PSS/{[Sm(mphpd)3]n[Styrene]m}/Al are examined.

Study on technology characteristics materials based on polysulfone

The research covers rheological characteristics of melts of polysulfones of domestic brand PSF-190 and foreign brand Udel P-1700 at temperatures ranging from 290 to 360°C. The values of activation energy of viscous flow of polysulfone melts at different temperatures are presented. The flow behavior indexes of melts of polysulfones PSF-190 and Udel P-1700 were determined. For the first time thermal stability curves over a wide temperature range were obtained, and formulas for describing them were presented. Temperature modes for processing the studied polysulfones were suggested. The dependency of density and volume in the temperature range from 23 to 320°C were obtained by the dilatometric method. Besides, constants and coefficients of the state equation of linear thermal expansion were calculated.

(Invited) Engineering Electronic and Electrochemical Nanoscale Oxides

Oxides are playing an increasing critical role as functional components in the fields of energy conversion/storage, microelectronics, displays, sensors/actuators and catalysis. In turn, their electrical (ionic & electronic), optical, magnetic and catalytic properties depend sensitively on their defect structure and oxygen nonstoichiometry, typically frozen in during processing, and rarely well defined. This is particularly true for thin films and nanoparticles/wires, where conventional methods, appropriate to bulk materials, do not apply. In this presentation, we review in-situ optical, electrochemical and dilatometric methods, developed or refined in our laboratory, to monitor, analyze and control nonstoichiometry, defect equilbria, transport and optical properties of oxide thin films and nano-sized particles. Examples will include materials of interest as electrodes in fuel cells, and as components of chemical sensors, oxidation catalysts and electronic memory devices.

Investigation of thermal linear expansion for nanostructured Si0.8Ge0.2P0.022 in wide temperature range

The results of investigation of thermal linear expansion for high temperature thermoelectric material nanostructured Si0.8Ge0.2P0.022 n-type with maximum thermoelectric figure of merit Z = 0.98 10-3 K are presented. Investigations were carried out by dilatometric method in the temperature range from 300 to 1220 K in dynamic heating and cooling regimes with using of infrared radiation source. Temperature dependence of thermal linear expansion coefficient (TLEC) was analyzed. The average value of TLEC for Si0.8Ge0.2P0.022 was determined, which is equal to ∼5.9·10-6 K-1.

Thermal expansion and thermal diffusivity properties of Co-Si solid solutions and intermetallic compounds

The thermal expansion of Co-Si solid solutions and intermetallic compounds was measured via dilatometric method, compared with the results of first-principles calculations, and their thermal diffusivities were investigated using laser flash method. The length changes of rapidly solidified Co-Si alloys are larger than those of slowly solidified alloys when temperature increases to around 1000K due to the more competitive atom motion. The coefficient of thermal expansion (α) of Co-Si alloy increases with an increasing Si content, except that the coefficient of thermal expansion of Co95Si5 influenced by both metastable structure and allotropic transformation is lower than that of Co90Si10 at a higher temperature. The thermal expansion abilities of Co-Si intermetallic compounds satisfy the relationship of Co2Si>CoSi>CoSi2, and the differences of the coefficients of thermal expansion between them increase with the rise of temperature. The thermal diffusivity of CoSi2 is evidently larger than the values of other Co-Si alloys. If temperature exceeds 565K, their thermal diffusion abilities are CoSi2>Co95Si5>Co90Si10>Co2Si>CoSi. All the coefficient of thermal expansion and thermal diffusivity variations with temperature satisfy linear or polynomial relations.

Transport properties of the sodium-yttrium-silicate glasses

The influence of yttrium oxide on the transport properties and chemical stability of sodium silicate glasses is investigated. The seven sodium-yttrium silicate glass compositions were synthesised. There are three composition with Na2O/Y2O3=6.5 and four with permanent Na2O content with 5 to 8mol% of Y2O3. The thermal behaviour of the glasses was studied with dilatometric and DSC methods. The research into the electrical characteristics of the glass has shown that their electrical conductivity is in the range of 5×10−8–10−6S/cm at 25°C and 10−3S/cm at 300°C. It is shown that the hydrolytic resistance increases when growing the Y2O3 concentration in the glass composition at constant Na2O content.

Evaluation of thiol-ene photo-curable resins using in rapid prototyping

Purpose The purpose of this paper is to evaluate the properties of several thiol-acrylate photosensitive systems and compare with corresponding acrylate free-radical systems. The potential stereolithography applications of thiol–ene photosensitive systems are also discussed. Design/methodology/approach In the both thiol–ene and acrylate free-radical photosensitive systems, various key performances were characterized. The function group conversions were characterized by real-time Fourier transform infrared spectroscopy. The tension strength was determined according to the standard ASTM D638-2003, the flexible strength was determined according to ASTM D790-07 and the hardness was measured according to ASTM D2240-05. The volume shrinkage was measured by dilatometer method. The glass transition temperature was analyzed by differential scanning calorimeter. Findings As adding mercapto propionates into acrylate system, the inhibition of polymerization by oxygen was controlled and the flexible performance was improved. In addition, the photosensitive resin showed better tension strength, higher elongation at break and lower volume shrinkage. Among the four mercapto propionates, rigid TEMPIC showed most obvious affect, followed hexa-functional DPMP, tetra-functional PETMP and tri-functional TMMP. Originality/value Although the thiol–ene photosensitive resin has unmatched advantages in performance, there are no reports on the thiol–ene photosensitive resin in the stereolithography application. In this study, thiol–ene photopolymerization material was first tentatively implemented in stereolithography area. Several critical performance parameters were compared between thiol–ene and acrylate free-radical photosensitive systems.

Complex-Radical Terpolymerization of Maleic Anhydride (Styrene), Allyl Propionate and Methyl Methacrylate

<p>The radical terpolymerization reactions of the acceptor-donor-acceptor and donor-acceptor-donor systems, maleic anhydride (MA)-allyl propionate (AP)-methyl methacrylate (MMA) and styrene (St)-MMA-AP, had been studied. The terpolymerizations were carried out in methyl ethyl ketone at 60-75 °C in the presence of 2,2’-azoisobutyronitrile (ABIN) used as the initiator. Some kinetic parameters and copolymerization constants - for both, system were determined by dilatometric and Kelen-Tudos or Seiner-Lift methods. The obtained results are discussed in terms of the free monomer and complex chain growth models. It is shown that terpolymerization was carried out at a stage close to binary copolymerization of MA...AP complex with free MMA and St...MMA complex with AP in the both studied system, respectively. These systems are also used as model for interpretation of cyclocopolymerization mechanism in allyl methactylate-MA (or St) system. DTA and TGA analyses indicated the relatively high thermal stability of St-MMA-AP terpolymer. It is shown that this terpolymer decomposes through a one-step reaction at 310 °C, however MA-AP-MMA terpolymer decomposes through a multi-step reactions at 150, 260 and 310 °C.</p>

Influence of Zinc on the Surface Tension, Density and Molar Volume of (Ag-Sn)eut +Zn Liquid Alloys

The dilatometric and maximum bubble pressure methods were applied for the measurements of the density and surface tension of liquid (Ag-Sn)eut+Zn lead-free solders. The experiments were carried out in the temperature range from 515 to 1223 K for the alloys of the zinc concentration equaling 0.01, 0.02, 0.04, 0.05, 0.1 and 0.2 of the mole fraction. It was found that the temperature dependence of both the density and the surface tension could be thought as linear, so they were interpreted by straight line equations. The experimental data of the molar volume of the investigated alloys were described by the polynomial dependent on the composition and temperature.Calculations of the surface tension by Butler’s equation were conducted and confronted with the experimental data. Some significant deviations between the experimental and the calculated surface tension were observed. They reached almost 40 mNm-1. The observed changes of the density and surface tension caused by the zinc addition to the Ag-Sn eutectic were discussed with the consideration of the thermodynamic properties and the influence of a small quantity of impurities in a protective gas atmosphere.

Influence of Cooling Rate on Phase Transformation of a α+β Titanium Alloy

Effect rules of cooling rate on phase transformation and microstructure of a α+β titanium alloy were studied by thermal dilatometer method. Specimens under different cooling rates from 0.05°C/s to 2.5°C/s were analyzed by using X-ray diffraction (XRD), optical micrograph (OM) and Vickers micro-hardness. The results showed that the starting temperature of β to α phase transformation gradually decreased with the increase of cooling rate. The finishing temperature of β to α phase transformation firstly decreased and then increased with the increase of cooling rate. The typical lamellar structures were observed under the cooling rates from 0.05°C/s to 0.2°C/s. The layer thickness of α phase became thinner and the precipitation content of α phase reduced under the cooling rate of 0.5°C/s. The α phase was fine acicular and the precipitation content of α phase reduced obviously under the cooling rate of 2.5°C. The effect rule of cooling rate on micro-hardness was that the value of micro-hardness firstly decreased and then increased with the cooling rate increasing.

Electrical conductivity and glass transition temperature (Tg) measurements on some selected glasses used for nuclear waste immobilization

Borosilicate glass, alumino-borosilicate glass, barium borosilicate glass and lead borosilicate glasses were prepared by melting the glass forming reagents of the respective glass compositions in air ambience. The glasses were characterised by powder X-ray diffractometry. The electrical conductivity of these four glasses was measured by impedance measurements. The conductivities were attributed mainly due to conduction of Na+ ion in the glass network and were in the range of 9.92×10−9–1.74×10−3Ω−1cm−1 at 400–900K. The activation energies of conduction for these glasses were found to be 0.96±0.01eV for borosilicate glass, 1.19±0.01eV for alumino-borosilicate glass, 1.19±0.01eV for barium borosilicate glass and 1.24±0.01eV for lead borosilicate glass. Diffusion coefficient of the conducting species (Na+-ion) was calculated from the conductivity values using Nernst Einstein equation, and the values were in the range of 5.28±0.03×10−13–1.78±0.01×10−8cm2s−1. Glass transition temperatures of these glasses were measured by differential scanning calorimetry as well as by dilatometric methods. Tg measured by differential scanning calorimetry were found to be 813±4, 820±4, 785±4 and 749±4K for borosilicate glass, alumino-borosilicate glass, barium borosilicate glass and lead borosilicate glass respectively, and Tg measured by dilatometric method was 799±5, 818±5, 781±5 and 742±5K for borosilicate glass, alumina-borosilicate glass, barium borosilicate glass and lead borosilicate glass respectively.

Identification of Phase Transformations During Heating and Cooling for High Iron Chromium Alloy by Dilatometric Method

The phase transformations occur in metals and alloys involves important changes in microstructures according to chemical composition and kinetic of transformations in alloy ,this work deals with many operations and investigation, especially dilatometric test , which enable the achievement of important results for the aim of research. Phase transformation points during heating and cooling by different rates (2-100) C◦/min , for high CR-Fe with high Cr , using dilatometric tests . these tests showed that cooling of this alloy from (950)C◦ , had more than phase transformation during cooling at rate (2-50)C◦/min . while only one transformation –martinsite –during cooling at a rate of (100)C◦/min , as no other transformation at that low temperature . This transformation has high importance to obtain high ,strength, hardness and wear resistance .Those properties are useful for many applications. The phase transformation points of alloy enable the choose of heat treatment required to get the suitable properties. The important results achieved by heating and cooling rates were indication of phase transformation and the time periods of those transformations .

Electrophoretic deposition of a self-stabilizing suspension based on a nanosized multi-component electrolyte powder prepared by the laser evaporation method

This work presents the results of study of non-aqueous suspensions based on a solid state electrolyte Се0.8(Sm0.75Sr0.2Ba0.05)0.2O2-δ (CSSBO) prepared by the method of high-energy material dispersion–laser evaporation of the ceramic target. The thermal behavior of the powder was studied by thermogravimetric and differential thermal analysis (TG-DTA); the sintering kinetic was investigated by the dilatometric method. Electrokinetic study showed that the powders with nanoparticles that had an average diameter of 15nm formed a self-stabilizing suspension with a high value of ζ-potential (+31mV) in the isopropanol/acetylacetone (50/50vol.%) dispersing medium. The CSSBO thin films (2μm) that deposited on the dense electrode substrate of La2NiO4+δ (LNO) after sintering for 6h at 1400°C had a uniform microstructure with an average grain size of 4μm and total conductivity of 0.1S/cm at 650°C.

Thermal properties of hot-pressed aluminum nitride–graphene composites

This paper concerns the modification of thermal properties of aluminum nitride polycrystalline ceramic material with high thermal conductivity coefficient. The way to change these properties was to distribute graphene particles in the high-conductive matrix. The composite material was hot-pressed at 1900 °C under 25 MPa pressure. The applied pressure allowed to orient the graphene particles and obtain an anisotropy of thermal conductivity. The microstructural observations were made by SEM method. The phases of the matrix were analyzed by XRD measurements, and the existence of graphene was confirmed by Raman spectroscopy. The quantity of graphene in the material after hot-pressing process was determined by thermogravimetric examinations in air flow. The thermal phase stability was checked by differential scanning calorimetry with mass change record. The thermal expansion coefficient was measured by dilatometric method. The thermal diffusivity and thermal conductivity were measured in various directions of the material. The results showed that the anisotropy of thermal conductivity exceeds 100 % for material with 10 mass% of graphene (GPLs). The introduced 2D particles caused a decrease of this parameter in the parallel direction to the load applied during the hot-pressing process.

Simple optical method for measuring free shrinkage

ObjectivesA simple optical method for measuring polymerization shrinkage of dental composites is compared with an established dilatometer. MethodsFive restorative composites were used to test the methods: Filtek Supreme Ultra (3M ESPE), Filtek LS (3M ESPE), Premise (Kerr), Gradia Direct (GC), and GC Kalore (GC). Uncured composites were attached to sandblasted silane-treated glass slides. The slides were placed sample side inside a mercury-filled dilatometer (ADAF). The mercury levels were recorded as the materials were light-cured through the glass-slides (40s). Mercury levels, which correlated with volumetric shrinkage, were recorded for 60min (N=6). For the optical method, uncured composite was placed on a smooth silicone platform. A pre-polymerization image was captured under a stereomicroscope, and the specimen was light-cured (40s). Post-polymerization images were captured at 2, 10, 60, and 90min (N=10). Composite outlines were traced to obtain projected surface areas (ImageJ) and volumetric shrinkage was calculated. Results were analyzed using two-way ANOVA (α=0.05) and Pearson Correlation tests. Shrinkage deformation for both methods was modeled using finite element analysis. ResultsVolumetric shrinkage at 60min ranged between 1.24% and 2.24% for dilatometer and 1.35–2.68% for optical methods. Optical method shrinkage was consistently higher than the dilatometer (P=.0001), but the ranking of the composites was the same (Pearson Correlation Coefficient 0.9997). Finite element analysis showed that lower shrinkage values of the dilatometer method could be attributed to bonding of its samples. SignificanceThe optical method using a general-purpose stereomicroscope and public-domain software is a simple and accurate alternative to measure free shrinkage.

Density Of The Copper-Rich Cu-Pb-Fe Alloys

AbstractDensity of the copper-rich corner of the ternary Cu-Pb-Fe alloys was determined with the dilatometric method. Investigated alloys had constant copper content equal to 0.9, 0.8 and 0.7 mole fraction, and varied iron concentration up to 0.1 mole fraction. A model predicting the density of ternary solution from knowledge of density of pure component and the excess of molar volume for limiting binaries is proposed.

Estimation of Thermal Expansion of Silica Refractory Based on its Mineralogy

The paper examines the possibility of estimation of Thermal Expansion (TE) of silica refractory up to 1000°C, based on its mineral contents, particularly SiO2 polymorphs. For that purpose a very accurate quantitative X-ray diffractometric (QXRD) method for estimation of quartz, cristobalite, and tridymite and an optical method for Si glass were standardized in the authors’ laboratory. The total TE caused by these Si polymorphs up to 1000°C was found to be almost equal to that estimated by the conventional dilatometric method showing differences in the third decimal place only. The method is much quicker than the dilatometric method.

Получение полистирольных суспензий заданной дисперсности

<p>Polystyrene suspensions were synthesized by emulsion polymerization of styrene in the presence of small additive (3% by weight) of polymethylmethacrylate (as stabilizer). The additive is not compatible with the formed polystyrene. Formed suspensions have narrow size distribution of the polymer granules with a diameter of 0.3-0.4 microns.</p><p>The kinetics of polymerization were studied by dilatometric method. There was determined the rate of reaction. Dispersed composition of the polymer suspensions was studied by electrophoretic light scattering. There were found the optimal conditions for obtaining the above-mentioned polystyrene suspensions, which are: phase ratio monomer/water – 1:25, initiator concentration – 2%, the reaction temperature – 70°C.</p><p>Obtained polystyrene suspension particles may be used as adsorbent-carriers of various bioligands (live cells, antibodies, viruses) for visualizing during the rapid analysis and identification by optical microscopy.</p>

Investigation of the Continuous Cooling Transformations in Rotor Steel 30CrNi4MoV

A diagram of continuous-cooling transformations in rotor steel 30Cr2Ni4Mo (30Kh2N4MF) in the range of cooling rates from 0.01 to 10 K/sec is plotted with the help of a dilatometric method. The changes in the morphology of the products of transformation of austenite and in the Vickers hardness, which occur upon growth in the cooling rate, are studied and analyzed.

Determination of retained austenite content in Fe–Cr–Ni weld metal

Several techniques, including dilatometry, X-ray diffraction, electron backscattering diffraction and magnetisation measurement, were applied and compared in order to reliably determine the retained austenite content of Fe–Cr–Ni steel weld metal. In this work, based on a proposed novel numeric solution for martensite transformation kinetics, it was found that the dilatometric method presented consistent results along with the magnetisation method in the quantification of mechanically unstable or stable retained austenite. By contrast, the X-ray diffraction method was inaccurate and time-consuming for the measurement of mechanically unstable retained austenite. However, the X-ray diffraction method was relatively successful when the retained austenite was mechanically stable. In addition, the magnetisation method seemed to be the only reliable way to detect small amounts (less than 5 vol.-%) of retained austenite in Fe–Cr–Ni weld metal.