Home Rapid Synthesis of Metallic Reinforced in Situ Intermetallic Composites in Ti-Al-Nb System via Resistive Sintering
Article Open Access

Rapid Synthesis of Metallic Reinforced in Situ Intermetallic Composites in Ti-Al-Nb System via Resistive Sintering

  • Mediha İpek , Tuba Yener EMAIL logo , Gözde Ç. Efe , Ibrahim Altınsoy , Cuma Bindal and Sakin Zeytin
Published/Copyright: September 3, 2018

Abstract

Intermetallics are known as a group of materials that draws attention with their features such as ordered structure, high temperature resistance, high hardness and low density. In this paper, it is aimed to obtain intermetallic matrix composites and also to maintain some ductile Nb and Ti metallic phase by using 99.5% purity, 35-44 μm particle size titanium, niobium and aluminium powders in one step via recently developed powder metallurgy processing technique - Electric current activated/assisted sintering system (ECAS). In this way, metallic reinforced intermetallic matrix composites were produced. Dominant phases of TiAl3 and NbAl3 which were the first compounds formed between peritectic reaction of solid titanium, niobium and molten aluminum in Ti-Al-Nb system during 10, 30 and 90 s for 2000 A current and 1.5-2.0 voltage were detected by XRD and SEM-EDS analysis. Hardness values of the test samples were measured by Vickers indentation technique and it was detected that the hardnesses of intermetallic phases as 411 HVN whereas ductile metallic phase as 120 HVN.

1 Introduction

Due to their regular structure and covalent bonding, intermetallics exhibit high elastic modulus, maintain high strength at high temperatures and are resistant to creep, recrystatlization and corrosion [1, 2, 3, 4, 5]. Titanium and niobium aluminides show particular interest due to their high specific strength. The greatest limitation of practical use is their fragility at low temperatures [6]. For this reason, the processing of alloys has become a major challenge in the development of these alloys by increasing low temperature ductility [2, 7, 8, 9]. Therefore, for optimization of room-temperature toughness, microstructural modifications are required [4, 7, 8, 9]. In-situ toughening is an alternative technique to enable a combination of brittle intermetallic matrix with a ductile metallic phase in one step [8, 10, 11, 12]. Some conventional methods such as, casting, melting, mechanical alloying techniques or self-propagating high-temperature synthesis (SHS) can be used for manufacturing intermetallic [8, 13]. To produce metallic-reinforced intermetallic-based composites, the pressure-assisted electric-current- activated sintering method is an alternative method. The use of ECAS for consolidating samples not only provides a faster heating time and shorter dwell time but also gives lower sintering temperatures [8, 10, 11, 14, 15, 16].

The starting materials used in our study is metallic Nb, Al and Ti powders. From this perspective it is high importance to describe phases within Ti-Al, Nb-Al phase diagram in terms of production conditions. The Nb-Al phase diagram (Figure 1.a), shows three intermediate phases: NbAl3 (D022, TiAl3-type tetragonal); σ (D8b, also denoted Nb2Al); and Nb3Al (A15, denoted δ) [8, 17]. Among these aluminides NbAl3 with its high melting point (1680°C), low density (4.54 g/cm3), is attractive as a potential material for high-temperature applications [8, 13]. Ti-Al phase diagram (Figure 1.b) depicts a number of intermediate phases. TiAl2 forms at 1215°C from Ti5Al11 and is stable at low temperatures and forms peritectically at 1460°C. (βTi) [body-centered cubic (bcc), also denoted β] and liquid undergo a peritectic reaction at 1490°C to yield (αTi), (close-packed hexagonal, also denoted α). Ti3Al, commonly called α2, has the D019 [17, 18]. TiAl3 (D022-type tetragonal) forms peritectically at 1387°C and decomposes eutectoidally at 735°C [4, 17]. TiAl3 has the lowest density among Ti-Al family, of 3.4 g/cm3, the highest micro hardness of 465–670 kg/mm2 and the best oxidation resistance even at 1000°C [9, 19].

Figure 1 Phase diagram (a) Nb-Al, (b) Ti-Al [20].
Figure 1

Phase diagram (a) Nb-Al, (b) Ti-Al [20].

The aim of this work was a precise description of the production of Nb-Ti in situ reinforced intermetallic matrix composites from metallic Ti, Al and Nb powders in one step resistive sintering method in a very short process time without using any controlled atmosphere. Special attention was paid to peritectical reactions of intermediate phases occur during production of intermetallic matrix zone. Especially it is aimed to produce NbAl3-TiAl3 intermetallics as matrix because of its superior properties mentioned above.

2 Experimental Procedures

Powders of titanium (35-44μm size and of purity >99.5%), aluminum (35-44 μm size and of purity >99.8%) and niobium (35-44μm size and of purity >99.8%) were used as starting materials. The powders were initially blended to the desired composition of Ti–30Al–50Nb (wt.%). Ti, Al and Nb powders were ball milled at room temperature at a rotation speed of 200 rpm for 2 h milling times. Process parameter are shown in Table 1. After ball milling process, powder mixture was cold-pressed before sintering, to form a cylindrical compact in a metallic die under a uniaxial pressure of 200MPa. Dimensions of the compact were 15mm diameter and 5 mm thickness. The production of intermetallic compound was performed via electric current activated sintering technique in an open atmosphere at 2000 A, for 10, 30 and 90 second using the electric-current-activated sintering technique in an open-atmosphere ECAS system, as shown in Figure 2. After the sintering, the specimens were unloaded and cooled to room temperature.

Table 1

Process Parameters.

Sample codeWt.%Current (A)Voltage (V)Holding Time (s)
C120Ti–30Al–50Nb20001.5 – 2.010
C230
C390

Figure 2 Schematic representation of ECAS system.
Figure 2

Schematic representation of ECAS system.

The microstructure and chemical composition of the samples were analysed using scanning electron microscopy (SEM) (Model JEOL JSM-6060, FEI Co., Japan) with energy dispersive spectroscopy (EDS). X-Ray diffraction (XRD (Model D/MAX-B/2200/PC, Rigaku Co., Japan) was used to identify phases formed in the specimens with a wavelength of 1.5418 A over a 2θ range of 10–80o with Cu-Kα source radiation. The micro-hardness of the test materials was measured using by a Vickers indentation technique with a load of 0.98 N using Leica WMHT-Mod model Vickers hardness instrument.

Ethical approval: The conducted research is not related to either human or animals use.

3 Results and Discussion

3.1 SEM-EDS Analyses

The morphologies of Ti, Al and Nb powders are shown in Figure 3. Metallic Al powder particles are generally spherical with a diameter of 10 μm. Some of particles are agglomerated and it is clear that the grain size is thinner than 35-40 μm. Unlike aluminum powder, Ti and Nb powder have sharp irregular corners and the grain size is more than 40 μm. For Nb powder, it is seen that the grain size range is quite wide. Very fine powder particles are also present in the structure.

Figure 3 SEM Migrographs of (a) Ti, (b) Al, (c)Nb powders.
Figure 3

SEM Migrographs of (a) Ti, (b) Al, (c)Nb powders.

Typical backscattered electron (BSE) micrographs of samples are given in Figure 4. As can be seen in the micrograph of the C1-coded sample (Figure 4a), the sintering time of 10 s is not enough for the reaction of metallic powders, almost no bonding occurred between metallic Ti, Nb and Al yet. The Nb-rich phases give rise to the brightest image because Nb has the highest atomic number (41) of the elements present. Ti (22)-rich areas also lighter than Al(13). Al gives rise to the darkest image because it has the lowest atomic number then it can be said that the dark gray matrix consists of aluminum [9]. The reaction between the phases rapidly started at the C2 sample which was obtained by raising the reaction time from 10 s to 30 s (Figure 4b). In addition to the intermetallic TiAl3 phase TiAl and Nb2Al phases were formed in the body. However, it is clear that the metallic niobium phase still does not react sufficiently. When it comes to 90 s (Figure 4c), new phases can be easily detected such as NbAl3 around ductile niobium particulates. C3 sample composed of not only brittle TiAl3 and NbAl3 phases but also metallic ductile Ti and Nb phases as desired. TiAl3 phases present gray image due to Ti atoms replaced by Al atoms from liquid aluminum [9].

Figure 4 SEM Micrographs of (a) C1, (b) C2 and (c) C3 sample.
Figure 4

SEM Micrographs of (a) C1, (b) C2 and (c) C3 sample.

Nb2Al and TiAl3 are produced from peritectical reactions [17]. Nice micrographs of peritectial transformation of Nb2Al phase can be seen in Figure 5. Generally, the term peritectic refers to reactions in which a liquid phase reacts with at least one solid phase to form one new solid phase [21]. This reaction can be written as:

Figure 5 Peritectial reaction of Nb-Al phases.
Figure 5

Peritectial reaction of Nb-Al phases.

α+Lβ(peritecticreaction)(1)

Here, in our study, L refers to liquid aluminium, and β is Nb. In this type of reaction, because the Nb phase surrounds the solid α particles (new solid phase Nb2Al), as shown in Figure 5, α atoms must diffuse through the Nb crust to reach the liquid for the reaction to continue. However, diffusion through the solid phase is much slower than diffusion through a liquid. As the peritectic reaction continues, the α layer gets thicker and the reaction slows down even more. Unless the cooling rate is very slow, a cored segregated structure will result [21].

Among the Ti-Al binary system as mentioned in introduction section, it can be seen that several intermetallic compounds, such as Ti3Al, TiAl, TiAl2 and TiAl3, form in the Ti-Al system. Many studies involving synthesis of titanium aluminides showed that TiAl3 formed prior to the formation of any other titanium aluminides present in this system [9, 10]. From EDS analysis of C3 sample, it can be detected that the dominant phase is as TiAl3 reaction phase between Al and Ti. Initial processing stage, titanium, which is reinforced to maintain ductile phase in the composite as well as to produce intermetallic [10, 15]. But it is seen from EDS analyses, almost all metallic titanium transformed to intermetallic. Titanium is only available in a small area within small islands.

When it comes to niobium, besides brittle intermetallic matrix formation, Nb is also analyzed in the composite as metallic ductile form as it is desired. Unreacted Nb particles play important role in ductility of the composite [8, 10]. Another dominant phase in the matrix is NbAl3.

SEM-Map analyses of C3 sample is given in Figure 7. This analysis is important in terms of showing that there is almost no oxidation in the composite structure even though it is carried out in an open atmosphere. ECAS allows reactions to occur in much shorter times and at lower temperatures than conventional production methods [14, 22]. Thus, short-term processing interferes with possible oxidation during formation of intermetallic. According to Map analyses it is clear that niobium aluminide and titanium aluminides is homogeneously distributed in the matrix. In addition, that unreacted ductile metallic niobium can be seen in the analyses.

Figure 6 EDS Analyses of C3 Sample.
Figure 6

EDS Analyses of C3 Sample.

Figure 7 SEM-Map Analyses of C3 sample.
Figure 7

SEM-Map Analyses of C3 sample.

The main phases in the composite are detected as Nb, Ti, TiAl3 and NbAl3 from XRD analyses (Figure 8). Looking at the XRD analysis of the C2 sample (at the bottom), it is seen that the Nb phase peaks is higher than the intermetallic phase. For C3 sample, as the temperature increased, niobium phase became more reactive and the formation of intermetallic phase increased. Increasing with the intermetallic phase the composites hardness also increased from 120±25 HV to 411±65 HV. This high hardness value can be attributed to dense structure of intermetallic composite. The different hardness values for the different production conditions indicate the strong effect of microstructure variations on the mechanical behavior [22].

Figure 8 XRD Analyses of C2 and C3 sample.
Figure 8

XRD Analyses of C2 and C3 sample.

TiAl intermetallic compound was approximately 200 HV [22]. Depends on the production conditions intermetallic usually contain pores. This pores result decreasing the hardness values.

It is possible to increase the amount of Nb in the work to be done in the future and decrease the amount of Ti so that the aluminum reacts with the niobium before the titanium so that more niobium is consumed and the hardness is increased.

4 Conclusion

The following results can be derived from the present study:

NbAl3 and TiAl3 based intermetallic compound coatings produced by the one-step pressure-assisted electric current- activated sintering (ECAS) method have a low porosity in open atmosphere for 90 s. The phases formed in the composite included NbAl3, TiAl3 and Nb, Ti as major phases and some other intermetallic phases also detected such as TiAl, Nb2Al in SEM-EDS analyses. These findings were confirmed by XRD analysis. Peritectical reaction has not completed for 90 s. Some unreacted ductile niobium particles has remained in the body. Thus it can be succeed to produce metallic reinforced in situ intermetallics by resistive sintering. The Vickers microhardness values for intermetallic composites increases from 120 ± 20 HV to 450 ± 65 HV by increasing the holding time in the process by ensuring the formation of a higher proportion of intermetallic phases

Acknowledgements

The authors thank expert Fuat Kayis and Murat Kazanci, technicians Ersan Demir and Erkut Tas and special appreciation is expressed to Tunahan Kart, Doğukan Şenkal, Sinan Bakan and Gurkan Tarakci of Sakarya University for assisting with experimental studies.

  1. Conflict of interest: Authors state no conflict of interest.

References

[1] Geng J., Gantner G., Oelhafen P., Datta P.K., Initial oxidation of Ti–Al intermetallics: an in situ MXPS study, Appl. Surf. Sci., 2000, 158, 64–74.10.1016/S0169-4332(99)00583-8Search in Google Scholar

[2] Dutkiewicz J., Maziarz W., Heinrich H., Kostorz G., Structure of Ti–Al–Nb intermetallics produced by mechanical alloying aod hot-pressing techniques, Mater. Chem. Phys., 2003, 81, 414–416.10.1016/S0254-0584(03)00036-1Search in Google Scholar

[3] Cinca N., Lima C.R.C., Guilemany J.M., An overview of intermetallics research and application: Status of thermal spray coatings, J. Mater. Res. Technol., 2013, 2, 75–86.10.1016/j.jmrt.2013.03.013Search in Google Scholar

[4] Djanarthany S., Viala J.-C., Bouix J., An overview of monolithic titanium aluminides based on Ti 3 Al and TiAl, Mater. Chem. Phys., 2001, 72, 301–319.10.1016/S0254-0584(01)00328-5Search in Google Scholar

[5] Yener T., Yener S.C., Zeytin S., Electromagnetic-shielding effectiveness and fracture behavior of laminated (Ni-NiAl3) Composites, Mater. Tehnol., 2016, 50, 899–902.10.17222/mit.2015.189Search in Google Scholar

[6] Wang T., Zhang J., Thermoanalytical and metallographical investigations on the synthesis of TiAl3 from elementary powders, Mater. Chem. Phys., 2006, 99, 20–25.10.1016/j.matchemphys.2005.08.075Search in Google Scholar

[7] Wu H., Fan G.H., Cui X.P., Geng L., Qin S.H., Huang M., A novel approach to accelerate the reaction between Ti and Al, Micron, 2014, 56, 49–53.10.1016/j.micron.2013.10.005Search in Google Scholar

[8] Aybey M., Yener T., Ipek M., Zeytin S., Effect of holding time on the production of Nb-NbAl3 intermetallic composites via electric-Current-activated sintering, Mater. Tehnol. 2017, 51, 55-58.10.17222/mit.2015.179Search in Google Scholar

[9] Wang P., Li H., Qi L., Zeng X., Zuo H., Synthesis of Al-TiAl3 compound by reactive deposition of molten Al droplets and Ti powders, Pro. Nat. Sci.-Mater., 2011, 21, 153–158.10.1016/S1002-0071(12)60049-5Search in Google Scholar

[10] Yener T., Zeytin S., Production and Characterization of Niobium Toughened Ti-TiAl 3 Metallic-Intermetallic Composite, Acta Phys. Pol. A, 2017, 132, 941-943.10.12693/APhysPolA.132.941Search in Google Scholar

[11] Yener T., Okumus S.C., Zeytin S., In Situ Formation of Ti-TiAl 3 Metallic-Intermetallic Composite by Electric Current Activated Sintering Method, Acta Phys. Pol. A, 2015, 127, 917–920.10.12693/APhysPolA.127.917Search in Google Scholar

[12] Robert M.H., Urtiga Filho S.L., Mechanical properties of Al⍰ NbAl 3 in situ composites, J. Mater. Process. Technol., 1997, 64, 335–341.10.1016/S0924-0136(96)02584-8Search in Google Scholar

[13] Gauthier V., Bernard F., Gaffet E., Munir Z.A., Larpin J.P., Synthesis of nanocrystalline NbAl 3 by mechanical and field activation, Intermetallics, 2001, 9, 571–580.10.1016/S0966-9795(01)00040-1Search in Google Scholar

[14] Orrù R., Licheri R., Locci A.M., Cincotti A., Cao G., Consolidation/synthesis of materials by electric current activated/assisted sintering, Mater. Sci. Eng. R Rep., 2009, 63, 127–287.10.1016/j.mser.2008.09.003Search in Google Scholar

[15] Yener T., Zeytin S., Synthesis and characterization of metallic-intermetallic Ti-TiAl3, Nb-Ti-TiAl3 composites produced with Electric-Current-Activated Sintering (ECAS), Mater. Tehnol., 2014, 48, 847–850.Search in Google Scholar

[16] Yener S.C., Yener T., Mutlu R., A Process Control Method for the Electric Current Activated/Assisted Sintering System Based on the Container Consumed Power and Temperature Estimation, J. Therm. Anal. Calorim., 2018, In Press, 10.1007/s10973-018-7453-ySearch in Google Scholar

[17] Raghavan V., Al-Nb-Ti (aluminum-niobium-titanium), J. Phase Equilib. Diffus., 2005, 26, 360–368.10.1007/s11669-005-0089-1Search in Google Scholar

[18] Lee J., Gao W., Li Z., He Y., Corrosion behaviour of Ti3Al and Ti3Al–11 at.% Nb intermetallics, Mater. Lett., 2003, 57, 1528–1538.10.1016/S0167-577X(02)01018-2Search in Google Scholar

[19] Rohatgi A., Harach D.J., Vecchio K.S., Harvey K.P., Resistance-curve and fracture behavior of Ti–Al3Ti metallic–intermetallic laminate (MIL) composites, Acta Mater., 2003, 51, 2933–2957.10.1016/S1359-6454(03)00108-3Search in Google Scholar

[20] ASM Handbook, Volume 3, Alloy phase diagrams, ASM international, Materials Park, Ohio, 1992.Search in Google Scholar

[21] Campbell F.C., Peritectic Alloy Systems, Phase Diagrams: Understanding the Basics, ASM International, Materials Park, Ohio, 2012.10.31399/asm.tb.pdub.9781627083102Search in Google Scholar

[22] Yoruk G., Ozdemir O., The evaluation of NiAl- and TiAl-based intermetallic coatings produced on the AISI 1010 steel by an electric current-activated sintering method, Intermetallics, 2012, 25, 60–65.10.1016/j.intermet.2012.02.006Search in Google Scholar

Received: 2018-01-21
Accepted: 2018-05-22
Published Online: 2018-09-03

© 2018 Mediha İpek et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Articles in the same Issue

  1. Regular Articles
  2. The effect of CuO modification for a TiO2 nanotube confined CeO2 catalyst on the catalytic combustion of butane
  3. The preparation and antibacterial activity of cellulose/ZnO composite: a review
  4. Linde Type A and nano magnetite/NaA zeolites: cytotoxicity and doxorubicin loading efficiency
  5. Performance and thermal decomposition analysis of foaming agent NPL-10 for use in heavy oil recovery by steam injection
  6. Spectroscopic (FT-IR, FT-Raman, UV, 1H and 13C NMR) insights, electronic profiling and DFT computations on ({(E)-[3-(1H-imidazol-1-yl)-1-phenylpropylidene] amino}oxy)(4-nitrophenyl)methanone, an imidazole-bearing anti-Candida agent
  7. A Simplistic Preliminary Assessment of Ginstling-Brounstein Model for Solid Spherical Particles in the Context of a Diffusion-Controlled Synthesis
  8. M-Polynomials And Topological Indices Of Zigzag And Rhombic Benzenoid Systems
  9. Photochemical Transformation of some 3-benzyloxy-2-(benzo[b]thiophen-2-yl)-4Hchromen-4-ones: A Remote Substituent Effect
  10. Dynamic Changes of Secondary Metabolites and Antioxidant Activity of Ligustrum lucidum During Fruit Growth
  11. Studies on the flammability of polypropylene/ammonium polyphosphate and montmorillonite by using the cone calorimeter test
  12. DSC, FT-IR, NIR, NIR-PCA and NIR-ANOVA for determination of chemical stability of diuretic drugs: impact of excipients
  13. Antioxidant and Hepatoprotective Effects of Methanolic Extracts of Zilla spinosa and Hammada elegans Against Carbon Tetrachlorideinduced Hepatotoxicity in Rats
  14. Prunus cerasifera Ehrh. fabricated ZnO nano falcates and its photocatalytic and dose dependent in vitro bio-activity
  15. Organic biocides hosted in layered double hydroxides: enhancing antimicrobial activity
  16. Experimental study on the regulation of the cholinergic pathway in renal macrophages by microRNA-132 to alleviate inflammatory response
  17. Synthesis, characterization, in-vitro antimicrobial properties, molecular docking and DFT studies of 3-{(E)-[(4,6-dimethylpyrimidin-2-yl)imino]methyl} naphthalen-2-ol and Heteroleptic Mn(II), Co(II), Ni(II) and Zn(II) complexes
  18. M-Polynomials and Topological Indices of Dominating David Derived Networks
  19. Human Health Risk Assessment of Trace Metals in Surface Water Due to Leachate from the Municipal Dumpsite by Pollution Index: A Case Study from Ndawuse River, Abuja, Nigeria
  20. Analysis of Bowel Diseases from Blood Serum by Autofluorescence and Atomic Force Microscopy Techniques
  21. Hydrographic parameters and distribution of dissolved Cu, Ni, Zn and nutrients near Jeddah desalination plant
  22. Relationships between diatoms and environmental variables in industrial water biotopes of Trzuskawica S.A. (Poland)
  23. Optimum Conversion of Major Ginsenoside Rb1 to Minor Ginsenoside Rg3(S) by Pulsed Electric Field-Assisted Acid Hydrolysis Treatment
  24. Antioxidant, Anti-microbial Properties and Chemical Composition of Cumin Essential Oils Extracted by Three Methods
  25. Regulatory mechanism of ulinastatin on autophagy of macrophages and renal tubular epithelial cells
  26. Investigation of the sustained-release mechanism of hydroxypropyl methyl cellulose skeleton type Acipimox tablets
  27. Bio-accumulation of Polycyclic Aromatic Hydrocarbons in the Grey Mangrove (Avicennia marina) along Arabian Gulf, Saudi Coast
  28. Dynamic Change of Secondary Metabolites and spectrum-effect relationship of Malus halliana Koehne flowers during blooming
  29. Lipids constituents from Gardenia aqualla Stapf & Hutch
  30. Effect of using microwaves for catalysts preparation on the catalytic acetalization of glycerol with furfural to obtain fuel additives
  31. Effect of Humic Acid on the Degradation of Methylene Blue by Peroxymonosulfate
  32. Serum containing drugs of Gua Lou Xie Bai decoction (GLXB-D) can inhibit TGF-β1-Induced Epithelial to Mesenchymal Transition (EMT) in A549 Cells
  33. Antiulcer Activity of Different Extracts of Anvillea garcinii and Isolation of Two New Secondary Metabolites
  34. Analysis of Metabolites in Cabernet Sauvignon and Shiraz Dry Red Wines from Shanxi by 1H NMR Spectroscopy Combined with Pattern Recognition Analysis
  35. Can water temperature impact litter decomposition under pollution of copper and zinc mixture
  36. Released from ZrO2/SiO2 coating resveratrol inhibits senescence and oxidative stress of human adipose-derived stem cells (ASC)
  37. Validated thin-layer chromatographic method for alternative and simultaneous determination of two anti-gout agents in their fixed dose combinations
  38. Fast removal of pollutants from vehicle emissions during cold-start stage
  39. Review Article
  40. Catalytic activities of heterogeneous catalysts obtained by copolymerization of metal-containing 2-(acetoacetoxy)ethyl methacrylate
  41. Antibiotic Residue in the Aquatic Environment: Status in Africa
  42. Regular Articles
  43. Mercury fractionation in gypsum using temperature desorption and mass spectrometric detection
  44. Phytosynthetic Ag doped ZnO nanoparticles: Semiconducting green remediators
  45. Epithelial–Mesenchymal Transition Induced by SMAD4 Activation in Invasive Growth Hormone-Secreting Adenomas
  46. Physicochemical properties of stabilized sewage sludge admixtures by modified steel slag
  47. In Vitro Cytotoxic and Antiproliferative Activity of Cydonia oblonga flower petals, leaf and fruit pellet ethanolic extracts. Docking simulation of the active flavonoids on anti-apoptotic protein Bcl-2
  48. Synthesis and Characterization of Pd exchanged MMT Clay for Mizoroki-Heck Reaction
  49. A new selective, and sensitive method for the determination of lixivaptan, a vasopressin 2 (V2)-receptor antagonist, in mouse plasma and its application in a pharmacokinetic study
  50. Anti-EGFL7 antibodies inhibit rat prolactinoma MMQ cells proliferation and PRL secretion
  51. Density functional theory calculations, vibration spectral analysis and molecular docking of the antimicrobial agent 6-(1,3-benzodioxol-5-ylmethyl)-5-ethyl-2-{[2-(morpholin-4-yl)ethyl] sulfanyl}pyrimidin-4(3H)-one
  52. Effect of Nano Zeolite on the Transformation of Cadmium Speciation and Its Uptake by Tobacco in Cadmium-contaminated Soil
  53. Effects and Mechanisms of Jinniu Capsule on Methamphetamine-Induced Conditioned Place Preference in Rats
  54. Calculating the Degree-based Topological Indices of Dendrimers
  55. Efficient optimization and mineralization of UV absorbers: A comparative investigation with Fenton and UV/H2O2
  56. Metabolites of Tryptophane and Phenylalanine as Markers of Small Bowel Ischemia-Reperfusion Injury
  57. Adsorption and determination of polycyclic aromatic hydrocarbons in water through the aggregation of graphene oxide
  58. The role of NR2C2 in the prolactinomas
  59. Chromium removal from industrial wastewater using Phyllostachys pubescens biomass loaded Cu-S nanospheres
  60. Hydrotalcite Anchored Ruthenium Catalyst for CO2 Hydrogenation Reaction
  61. Preparation of Calcium Fluoride using Phosphogypsum by Orthogonal Experiment
  62. The mechanism of antibacterial activity of corylifolinin against three clinical bacteria from Psoralen corylifolia L
  63. 2-formyl-3,6-bis(hydroxymethyl)phenyl benzoate in Electrochemical Dry Cell
  64. Electro-photocatalytic degradation of amoxicillin using calcium titanate
  65. Effect of Malus halliana Koehne Polysaccharides on Functional Constipation
  66. Structural Properties and Nonlinear Optical Responses of Halogenated Compounds: A DFT Investigation on Molecular Modelling
  67. DMFDMA catalyzed synthesis of 2-((Dimethylamino)methylene)-3,4-dihydro-9-arylacridin-1(2H)-ones and their derivatives: in-vitro antifungal, antibacterial and antioxidant evaluations
  68. Production of Methanol as a Fuel Energy from CO2 Present in Polluted Seawater - A Photocatalytic Outlook
  69. Study of different extraction methods on finger print and fatty acid of raw beef fat using fourier transform infrared and gas chromatography-mass spectrometry
  70. Determination of trace fluoroquinolones in water solutions and in medicinal preparations by conventional and synchronous fluorescence spectrometry
  71. Extraction and determination of flavonoids in Carthamus tinctorius
  72. Therapeutic Application of Zinc and Vanadium Complexes against Diabetes Mellitus a Coronary Disease: A review
  73. Study of calcined eggshell as potential catalyst for biodiesel formation using used cooking oil
  74. Manganese oxalates - structure-based Insights
  75. Topological Indices of H-Naphtalenic Nanosheet
  76. Long-Term Dissolution of Glass Fibers in Water Described by Dissolving Cylinder Zero-Order Kinetic Model: Mass Loss and Radius Reduction
  77. Topological study of the para-line graphs of certain pentacene via topological indices
  78. A brief insight into the prediction of water vapor transmissibility in highly impermeable hybrid nanocomposites based on bromobutyl/epichlorohydrin rubber blends
  79. Comparative sulfite assay by voltammetry using Pt electrodes, photometry and titrimetry: Application to cider, vinegar and sugar analysis
  80. MicroRNA delivery mediated by PEGylated polyethylenimine for prostate cancer therapy
  81. Reversible Fluorescent Turn-on Sensors for Fe3+ based on a Receptor Composed of Tri-oxygen Atoms of Amide Groups in Water
  82. Sonocatalytic degradation of methyl orange in aqueous solution using Fe-doped TiO2 nanoparticles under mechanical agitation
  83. Hydrotalcite Anchored Ruthenium Catalyst for CO2 Hydrogenation Reaction
  84. Production and Analysis of Recycled Ammonium Perrhenate from CMSX-4 superalloys
  85. Topical Issue on Agriculture
  86. New phosphorus biofertilizers from renewable raw materials in the aspect of cadmium and lead contents in soil and plants
  87. Survey of content of cadmium, calcium, chromium, copper, iron, lead, magnesium, manganese, mercury, sodium and zinc in chamomile and green tea leaves by electrothermal or flame atomizer atomic absorption spectrometry
  88. Biogas digestate – benefits and risks for soil fertility and crop quality – an evaluation of grain maize response
  89. A numerical analysis of heat transfer in a cross-current heat exchanger with controlled and newly designed air flows
  90. Freshwater green macroalgae as a biosorbent of Cr(III) ions
  91. The main influencing factors of soil mechanical characteristics of the gravity erosion environment in the dry-hot valley of Jinsha river
  92. Free amino acids in Viola tricolor in relation to different habitat conditions
  93. The influence of filler amount on selected properties of new experimental resin dental composite
  94. Effect of poultry wastewater irrigation on nitrogen, phosphorus and carbon contents in farmland soil
  95. Response of spring wheat to NPK and S fertilization. The content and uptake of macronutrients and the value of ionic ratios
  96. The Effect of Macroalgal Extracts and Near Infrared Radiation on Germination of Soybean Seedlings: Preliminary Research Results
  97. Content of Zn, Cd and Pb in purple moor-grass in soils heavily contaminated with heavy metals around a zinc and lead ore tailing landfill
  98. Topical Issue on Research for Natural Bioactive Products
  99. Synthesis of (±)-3,4-dimethoxybenzyl-4-methyloctanoate as a novel internal standard for capsinoid determination by HPLC-ESI-MS/MS(QTOF)
  100. Repellent activity of monoterpenoid esters with neurotransmitter amino acids against yellow fever mosquito, Aedes aegypti
  101. Effect of Flammulina velutipes (golden needle mushroom, eno-kitake) polysaccharides on constipation
  102. Bioassay-directed fractionation of a blood coagulation factor Xa inhibitor, betulinic acid from Lycopus lucidus
  103. Antifungal and repellent activities of the essential oils from three aromatic herbs from western Himalaya
  104. Chemical composition and microbiological evaluation of essential oil from Hyssopus officinalis L. with white and pink flowers
  105. Bioassay-guided isolation and identification of Aedes aegypti larvicidal and biting deterrent compounds from Veratrum lobelianum
  106. α-Terpineol, a natural monoterpene: A review of its biological properties
  107. Utility of essential oils for development of host-based lures for Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), vector of laurel wilt
  108. Phenolic composition and antioxidant potential of different organs of Kazakh Crataegus almaatensis Pojark: A comparison with the European Crataegus oxyacantha L. flowers
  109. Isolation of eudesmane type sesquiterpene ketone from Prangos heyniae H.Duman & M.F.Watson essential oil and mosquitocidal activity of the essential oils
  110. Comparative analysis of the polyphenols profiles and the antioxidant and cytotoxicity properties of various blue honeysuckle varieties
  111. Special Issue on ICCESEN 2017
  112. Modelling world energy security data from multinomial distribution by generalized linear model under different cumulative link functions
  113. Pine Cone and Boron Compounds Effect as Reinforcement on Mechanical and Flammability Properties of Polyester Composites
  114. Artificial Neural Network Modelling for Prediction of SNR Effected by Probe Properties on Ultrasonic Inspection of Austenitic Stainless Steel Weldments
  115. Calculation and 3D analyses of ERR in the band crack front contained in a rectangular plate made of multilayered material
  116. Improvement of fuel properties of biodiesel with bioadditive ethyl levulinate
  117. Properties of AlSi9Cu3 metal matrix micro and nano composites produced via stir casting
  118. Investigation of Antibacterial Properties of Ag Doped TiO2 Nanofibers Prepared by Electrospinning Process
  119. Modeling of Total Phenolic contents in Various Tea samples by Experimental Design Methods
  120. Nickel doping effect on the structural and optical properties of indium sulfide thin films by SILAR
  121. The effect mechanism of Ginnalin A as a homeopathic agent on various cancer cell lines
  122. Excitation functions of proton induced reactions of some radioisotopes used in medicine
  123. Oxide ionic conductivity and microstructures of Pr and Sm co-doped CeO2-based systems
  124. Rapid Synthesis of Metallic Reinforced in Situ Intermetallic Composites in Ti-Al-Nb System via Resistive Sintering
  125. Oxidation Behavior of NiCr/YSZ Thermal Barrier Coatings (TBCs)
  126. Clustering Analysis of Normal Strength Concretes Produced with Different Aggregate Types
  127. Magnetic Nano-Sized Solid Acid Catalyst Bearing Sulfonic Acid Groups for Biodiesel Synthesis
  128. The biological activities of Arabis alpina L. subsp. brevifolia (DC.) Cullen against food pathogens
  129. Humidity properties of Schiff base polymers
  130. Free Vibration Analysis of Fiber Metal Laminated Straight Beam
  131. Comparative study of in vitro antioxidant, acetylcholinesterase and butyrylcholinesterase activity of alfalfa (Medicago sativa L.) collected during different growth stages
  132. Isothermal Oxidation Behavior of Gadolinium Zirconate (Gd2Zr2O7) Thermal Barrier Coatings (TBCs) produced by Electron Beam Physical Vapor Deposition (EB-PVD) technique
  133. Optimization of Adsorption Parameters for Ultra-Fine Calcite Using a Box-Behnken Experimental Design
  134. The Microstructural Investigation of Vermiculite-Infiltrated Electron Beam Physical Vapor Deposition Thermal Barrier Coatings
  135. Modelling Porosity Permeability of Ceramic Tiles using Fuzzy Taguchi Method
  136. Experimental and theoretical study of a novel naphthoquinone Schiff base
  137. Physicochemical properties of heat treated sille stone for ceramic industry
  138. Sand Dune Characterization for Preparing Metallurgical Grade Silicon
  139. Catalytic Applications of Large Pore Sulfonic Acid-Functionalized SBA-15 Mesoporous Silica for Esterification
  140. One-photon Absorption Characterizations, Dipole Polarizabilities and Second Hyperpolarizabilities of Chlorophyll a and Crocin
  141. The Optical and Crystallite Characterization of Bilayer TiO2 Films Coated on Different ITO layers
  142. Topical Issue on Bond Activation
  143. Metal-mediated reactions towards the synthesis of a novel deaminolysed bisurea, dicarbamolyamine
  144. The structure of ortho-(trifluoromethyl)phenol in comparison to its homologues – A combined experimental and theoretical study
  145. Heterogeneous catalysis with encapsulated haem and other synthetic porphyrins: Harnessing the power of porphyrins for oxidation reactions
  146. Recent Advances on Mechanistic Studies on C–H Activation Catalyzed by Base Metals
  147. Reactions of the organoplatinum complex [Pt(cod) (neoSi)Cl] (neoSi = trimethylsilylmethyl) with the non-coordinating anions SbF6– and BPh4
  148. Erratum
  149. Investigation on Two Compounds of O, O’-dithiophosphate Derivatives as Corrosion Inhibitors for Q235 Steel in Hydrochloric Acid Solution
Downloaded on 30.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/chem-2018-0095/html?lang=en
Scroll to top button