Borchers, Christine

[["dc.bibliographiccitation.firstpage","80"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Thermochimica Acta"],["dc.bibliographiccitation.lastpage","84"],["dc.bibliographiccitation.volume","493"],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Khomenko, T. I."],["dc.contributor.author","Leonov, Alexander V."],["dc.contributor.author","Morozova, Olga S."],["dc.date.accessioned","2018-11-07T11:24:22Z"],["dc.date.available","2018-11-07T11:24:22Z"],["dc.date.issued","2009"],["dc.description.abstract","Structural changes of commercial TiH2 were studied using interrupted temperature desorption spectroscopy and X-ray diffraction techniques to understand the mechanism of its degradation under non-equilibrium conditions. Rapid cooling on different stages of temperature-programmed heating allowed to study the intermediate phase compositions that evolve upon cooling from the high-temperature phase beta Ti(H). The phase transformation sequence is described as a number of consecutive reactions corresponding to the observed desorption peaks. Phases delta TiH2-x, gamma TiH, and the solid solution alpha Ti(H) were found to be intermediates in the epsilon TiH2 --> alpha Ti transformation when the latter is interrupted. Additional evidence for the thermodynamic stability of gamma TiH is given. (C) 2009 Elsevier B.V. All rights reserved."],["dc.description.sponsorship","RFBR [07-03-00610]; INTAS [05-1000005-7672]"],["dc.identifier.doi","10.1016/j.tca.2009.04.011"],["dc.identifier.isi","000269098300014"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/56388"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1872-762X"],["dc.relation.issn","0040-6031"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Interrupted thermal desorption of TiH2"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","104904"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Journal of Applied Physics"],["dc.bibliographiccitation.volume","110"],["dc.contributor.author","Shkvarin, A. S."],["dc.contributor.author","Yarmoshenko, Yu M."],["dc.contributor.author","Zatsepin, Nadia A."],["dc.contributor.author","Dolgikh, V. E."],["dc.contributor.author","Kurmaev, Ernst Z."],["dc.contributor.author","Nemnonov, S. N."],["dc.contributor.author","Cherkashenko, V. M."],["dc.contributor.author","Skorikov, N. A."],["dc.contributor.author","Morozova, Olga S."],["dc.contributor.author","Borchers, Christine"],["dc.date.accessioned","2018-11-07T08:49:51Z"],["dc.date.available","2018-11-07T08:49:51Z"],["dc.date.issued","2011"],["dc.description.abstract","Titanium is well known as a light-weight hydrogen storage material that is applied as a component of hydrogen storage composites together with Mg and other metals. Amorphous boron, boron nitride, and graphite were used as additives to improve Ti-H(2) reactivity during ball-milling due to its anti-sticking and matrix-forming properties. The chemical state and local electronic structure of Ti atoms were studied by hard x-ray emission spectroscopy (XES). We have measured fluorescent Ti K beta(5) (4p -> 1s transition) x-ray emission spectra, which are very sensitive to the local surroundings of exciting atoms, and found additional features coinciding in energy with spectra of reference samples TiB(2), TiN, and TiC. Based on these measurements, it is concluded that atoms of additives form chemical bonding with Ti due to the occupation of interstitials in the host Ti-lattice. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3662200]"],["dc.description.sponsorship","Research Council of the Russian Federation [NSH-1929.2008.2]"],["dc.identifier.doi","10.1063/1.3662200"],["dc.identifier.isi","000297943700133"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21554"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0021-8979"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Effect of additives on titanium-hydrogen interaction under ball milling of Ti powder probed by hard x-ray emission spectroscopy"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","309"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Journal of Alloys and Compounds"],["dc.bibliographiccitation.lastpage","312"],["dc.bibliographiccitation.volume","483"],["dc.contributor.author","Morozova, Olga S."],["dc.contributor.author","Khomenko, T. I."],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Leonov, Alexander V."],["dc.contributor.author","Kurmaev, Ernst Z."],["dc.contributor.author","Moewes, A."],["dc.date.accessioned","2018-11-07T11:25:35Z"],["dc.date.available","2018-11-07T11:25:35Z"],["dc.date.issued","2009"],["dc.description.abstract","Mechanically activated TiH2/h-BN, TiH2/C and TiH2/B mixtures was studied by temperature-programmed desorption, X-ray diffraction, transmission electron microscopy and X-ray emission spectroscopy. Ball milling in the presence of additives results in a modification of hydrogen occupation sites. Additional Ti-N, Ti-C or Ti-B bonds from chemical bonding of Ti with interstitial N, C and B atoms, are formed in TiH2 due to contact of TiH2 nanoparticles with the respective additive matrix materials. Mixed configurations around Ti atoms with proportional combination of local Ti-H and Ti-N, Ti-C or Ti-B bonds significantly decrease the thermal stability of TiH2. The effect is most pronounced when boron is the additive. (C) 2008 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jallcom.2008.08.093"],["dc.identifier.isi","000270619600075"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/56655"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Sa"],["dc.publisher.place","Lausanne"],["dc.relation.conference","14th International Symposium on Metastable and Nano-Materials"],["dc.relation.eventend","2007-08-30"],["dc.relation.eventlocation","Corfu, Greece"],["dc.relation.eventstart","2007-08-26"],["dc.relation.issn","0925-8388"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Effect of N, C and B interstitial atoms on local bonding structure in mechanically activated TiH2/h-BN, TiH2/C, and TiH2/B mixtures"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","240"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Journal of Alloys and Compounds"],["dc.bibliographiccitation.lastpage","246"],["dc.bibliographiccitation.volume","395"],["dc.contributor.author","Kurmaev, Ernst Z."],["dc.contributor.author","Morozova, Olga S."],["dc.contributor.author","Khomenko, T. I."],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Nemnonov, S. N."],["dc.contributor.author","Harada, Y."],["dc.contributor.author","Tokushima, T."],["dc.contributor.author","Osawa, H."],["dc.contributor.author","Takeuchi, T."],["dc.contributor.author","Shin, S."],["dc.date.accessioned","2018-11-07T10:59:22Z"],["dc.date.available","2018-11-07T10:59:22Z"],["dc.date.issued","2005"],["dc.description.abstract","The local bonding structure of mechanically activated TiH2 and TiH2/graphite mixture is studied by means of temperature-programmed desorption (TPD), X-ray emission- and absorption-spectroscopy. Ball milling of TiH2 in the presence of graphite results in a modification of the hydrogen occupation sites. Additional Ti-C bonds from chemical bonding of Ti with carbon, which occupies octahedral interstitials, appears in TiH2 due to intimate contact between graphite and TiH2 nanoparticles embedded into an amorphous graphite matrix. Mixed configurations around Ti atoms with proportional combination of local Ti-H and Ti-C bonds significantly decrease the thermal stability of TiH2. © 2004 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jallcom.2004.11.031"],["dc.identifier.isi","000229410600044"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/50682"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0925-8388"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Local bonding structure in mechanically activated TiH2 and TiH2 plus graphite mixture"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Journal of Nanoparticle Research"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Martin, May L."],["dc.contributor.author","Vorobjeva, Galina A."],["dc.contributor.author","Morozova, Olga S."],["dc.contributor.author","Firsova, Alla A."],["dc.contributor.author","Leonov, Alexander V."],["dc.contributor.author","Kurmaev, Ernst Z."],["dc.contributor.author","Kukharenko, Andrey I."],["dc.contributor.author","Zhidkov, Ivan S."],["dc.contributor.author","Cholakh, Seif O."],["dc.date.accessioned","2018-11-07T10:05:41Z"],["dc.date.available","2018-11-07T10:05:41Z"],["dc.date.issued","2016"],["dc.description.abstract","Catalytic systems designated for preferential oxidation of CO in the presence of H-2 are prepared by ball milling of Cu and CeO2, a simple and cheap onestep process to synthesize such catalysts. It is found that after 60 min of milling, a mixture of 8 wt.% Cu-CeO2 powders exhibits CO conversion of 96% and CO selectivity of about 65% at 438 K. Two active oxygen states, which are not observed in case of pure CeO2, were detected in the nanocomposite lattice and attributed to the presence of Cu in surface sites as well as in subsurface bulk sites. Correspondingly, oxidation of CO to CO2 was found to occur in a two-stage process with T-max approximate to 395/460 K, and oxidation of H-2 to H2O likewise in a two-stage process with T-max approximate to 465/490 K. The milled powder consists of CeO2 crystallites sized 810 nm agglomerated to somewhat larger aggregates, with Cu dispersed on the surface of the CeO2 crystallites, and to a lesser extent present as Cu2O."],["dc.identifier.doi","10.1007/s11051-016-3640-6"],["dc.identifier.isi","000390063800003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38948"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1572-896X"],["dc.relation.issn","1388-0764"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Cu-CeO2 nanocomposites: mechanochemical synthesis, physico-chemical properties, CO-PROX activity"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5869"],["dc.bibliographiccitation.issue","15"],["dc.bibliographiccitation.journal","The Journal of Physical Chemistry. C, Nanomaterials and interfaces"],["dc.bibliographiccitation.lastpage","5879"],["dc.bibliographiccitation.volume","112"],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Morozova, Olga S."],["dc.contributor.author","Khomenko, T. I."],["dc.contributor.author","Leonov, Alexander V."],["dc.contributor.author","Postnikov, A. V."],["dc.contributor.author","Kurmaev, Ernst Z."],["dc.contributor.author","Moewes, A."],["dc.contributor.author","Pundt, A."],["dc.date.accessioned","2018-11-07T11:16:03Z"],["dc.date.available","2018-11-07T11:16:03Z"],["dc.date.issued","2008"],["dc.description.abstract","The effect of h-BN additive on hydrogen sorption by Ti under mechanical treatment in H-2/He flow and on the thermal stability of Ti-hydride produced during milling were studied using kinetic, structural, microscopic, and spectroscopic techniques and theoretical first-principles calculations. The results obtained were compared with the corresponding properties of pure Ti and Ti with graphite additive. Like graphite, hexagonal BN was found to be an effective additive to improve the hydrogen sorption capacity of Ti. New types of occupation sites available for hydrogen, very similar to those detected for Ti/C, were observed. These sites are characterized by a low H-2 desorption temperature: 630-670 K instead of similar to 1000 K."],["dc.identifier.doi","10.1021/jp077582s"],["dc.identifier.isi","000254883100029"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54505"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1932-7447"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Effect of h-BN additive on hydrogen sorption by Ti under mechanical treatment in H-2/He flow"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","10341"],["dc.bibliographiccitation.issue","20"],["dc.bibliographiccitation.journal","The Journal of Physical Chemistry B"],["dc.bibliographiccitation.lastpage","10347"],["dc.bibliographiccitation.volume","109"],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Leonov, Alexander V."],["dc.contributor.author","Khomenko, T. I."],["dc.contributor.author","Morozova, Olga S."],["dc.date.accessioned","2018-11-07T10:59:48Z"],["dc.date.available","2018-11-07T10:59:48Z"],["dc.date.issued","2005"],["dc.description.abstract","The effect of graphite admixture on hydrogen sorption-desorption properties of mechanically activated electron microscopy, temperature-programmed reaction, and temperature-programmed desorption techniques. The major effect of graphite addition was found to be the formation of microporous carbon matrix particles containing randomly distributed titanium particles only several nanometers in diameter. This powder architecture enhances hydrogen transport to the titanium surface without hindrances and promotes titanium-hydrogen interaction by modifying the titanium surface and subsurface layers with interstitial carbon atoms."],["dc.identifier.doi","10.1021/jp0406870"],["dc.identifier.isi","000229296600064"],["dc.identifier.pmid","16852253"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/50782"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1520-6106"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Stimulating effect of graphite admixture on hydrogen sorption - Desorption properties of mechanically activated titanium powder"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1843"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","The Journal of Physical Chemistry B"],["dc.bibliographiccitation.lastpage","1848"],["dc.bibliographiccitation.volume","106"],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Leonov, Alexander V."],["dc.contributor.author","Morozova, Olga S."],["dc.date.accessioned","2018-11-07T10:31:46Z"],["dc.date.available","2018-11-07T10:31:46Z"],["dc.date.issued","2002"],["dc.description.abstract","The effect of mechanical activation on the structural and chemical transformations in the zirconium-carbon-hydrogen system was studied using X-ray powder diffraction, transmission electron microscopy and kinetic techniques. A zirconium-graphite mixture was subjected to high-energy impact milling in a permanent hydrogen flow. A two-stage process was observed: first, the formation of tetragonal epsilon-ZrH1.8-2 accompanied by carbon amorphization, and second the decomposition of epsilon-ZrH1.8-2 synthesized at the first stage to cubic delta-ZrH1.6 + gamma-ZrH + alpha-Zr. In the first stage, the size of the hydride particles decreased drastically to only a few nanometers dispersed in larger particles of amorphous carbon, while in the second stage the newly formed Zr particles compacted again to gain the size of microns, while the carbon partially crystallized. While the first stage is governed by the fast reaction kinetics of hydrogen with zirconium, the second stage is governed by the greater affinity of zirconium to carbon as compared to hydrogen."],["dc.identifier.doi","10.1021/jp0125505"],["dc.identifier.isi","000174189000003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44193"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1520-6106"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Mechanical activation of structural and chemical transformations in a ZR-C-H system in two stages"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","757"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Current Nanoscience"],["dc.bibliographiccitation.lastpage","769"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Khomenko, T. I."],["dc.contributor.author","Leonov, Alexander V."],["dc.contributor.author","Morozova, Olga S."],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Shkvarin, A. S."],["dc.contributor.author","Kurmaev, Ernst Z."],["dc.contributor.author","Moewes, A."],["dc.date.accessioned","2018-11-07T08:50:49Z"],["dc.date.available","2018-11-07T08:50:49Z"],["dc.date.issued","2011"],["dc.description.abstract","Morphological, structural and chemical evolution in Ti/B/H-2 system is studied in detail as a function of mechanical treatment. Ti/B powder continuously changes both in composition and morphology during ball-milling in H-2 flow: The powder composition varies from Ti/B to TiH2-x/B causing a change in mechanical properties. The role of boron additive also changes from preventing the Ti nanoparticles from sticking together in the early stages to a matrix material participating in Ti - B interface reactions in the intermediate and final stages of the process. Boron atoms participating in the formation of nanoscopic holes give rise to new H states in the hydride by changing the local atomic state of Ti atoms. The dynamics of the formation of these sites and the redistribution of hydrogen between different types of occupation sites in dependence of phase composition and milling time of the powders are also studied."],["dc.identifier.doi","10.2174/157341311797483817"],["dc.identifier.isi","000299678400013"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21779"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1573-4137"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Boron Enhanced Synthesis of Ti-hydride Nanoparticles by Milling Ti/B in Hydrogen Flow"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","043509"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Journal of Applied Physics"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Morozova, Olga S."],["dc.contributor.author","Borchers, Christine"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T08:45:54Z"],["dc.date.available","2018-11-07T08:45:54Z"],["dc.date.issued","2010"],["dc.description.abstract","Positron annihilation spectroscopy was employed for defect studies of \"Ti\"-based nanocomposites prepared by high-energy ball milling and consisting of Ti nanoparticles separated by hexagonal boron nitride (h-BN) or boron (B) additive. The size distribution of nanoscopic holes in nanocomposites was determined directly from measurement of ortho-positronium (Ps) lifetimes. Chemical environment of defects was characterized using coincidence Doppler broadening. It was found that size of nanoscopic holes is reduced with increasing milling time in H(2)/He atmosphere and also probability of Ps formation in holes decreases. At the same time the Ti content in the vicinity of holes increases. This can be explained by (i) increased intermixing of Ti particles with h-BN or B additive and by (ii) filling the nanoscopic holes with absorbed hydrogen. Analysis of obtained results showed that both these processes take place during milling of nanocomposites. In addition, it was found that the effect of filling the nanoscopic pores with hydrogen is enhanced in TiH(2) milled with h-BN or B in He atmosphere. Comparison of nanocomposites with h-BN and B additive showed that sufficiently long milling time leads to a similar size distribution of nanoscopic holes in Ti/h-BN and Ti/B, despite the fact that it differs substantially in the initial powders. However, density of nanoscopic holes in Ti/B is significantly lower than in Ti/h-BN nanocomposites."],["dc.identifier.doi","10.1063/1.3305790"],["dc.identifier.isi","000275028900025"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20560"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0021-8979"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Size distributions of nanoscopic holes in Ti/h-BN and Ti/B nanocomposites"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]