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The formation of pyrochlores during plasma spraying of REO and zirconia oxides powder mixture

Kubaszek Tadeusz, Nowak Wojciech J., Pędrak Paweł, Góral Marek, Rybus Kinga, Ślemp Karol

Journal of Mechanical and Energy Engineering

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2019

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Vol. 3, No 2

141--147

EN

The pyrochlores are the promising low-thermal conductive materials for Thermal Barrier Coatings applications. In present work the concept of pyrochlore formation during APS spraying of ZrO2 and ReO was analyzed. The specially prepared agglomerated mixtures of ZrO2 with Nd2O3, Yb2O3, Er2O3 and Gd2O3 oxides were plasma sprayed using A60 plasma torch on NiCoCrAlY-type bond coat. The influence of plasma gasses composition on coatings’ microstructure was investigated. The results of XRD phase analysis proved formation of pyrochlores from Gd2O3 +ZrO2 and Nd2O3+ZrO2 mixtures. The formation of Er4O12Zr3 from Er2O3+ ZrO2 mixture as well as Zr3Yb4 from Yb2O3+ ZrO2 powder was detected. The presence of pure rare earth oxides (REO) and zirconia oxides was observed in all types of sprayed coatings. The microstructural assessment showed differences in porosity and thickness of obtained ceramic coatings depending of type of REO oxides. The analysis of results showed that it is possible to obtain pyrochlore ceramic coatings from pure oxides mixture. The plasma energy was not efficient for full formation of pyrochlores, therefore the presence of pure oxides was observed.

2

Zasadowość katalizatorów a ich aktywność w reakcji metanolizy oleju sojowego

Skrzyńska E., Kądziołka A.

Czasopismo Techniczne. Chemia

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2011

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R. 108, z. 2-Ch

221-234

PL

W niniejszym artykule zbadano aktywność katalityczną wybranych tlenków metali ziem rzadkich w procesie transestryfikacji oleju sojowego metanolem. największą aktywność (91-100% konwersji oleju) wykazały katalizatory: KOH/CeO[2], K[2]CO[3]/CeO[2] i KnO[3]/CeO[2]. Właściwości fizykochemiczne tlenków metali ziem rzadkich określono w oparciu o metodę wskaźników Hammetta. Dowiedziono, że aktywność katalizatorów korelowała z ich mocą zasadową.

EN

In this paper the catalytic activity of selected rare earth metal oxides was investigated in the transesterification reaction of soybean oil with methanol. The highest catalytic activity (91-100% conversion of oil) was observed over KOH/CeO[2], K[2]CO[3]/CeO[2] and KnO[3]/CeO[2]. The physicochemical properties of the rare earth metal oxides were analyzed by Hammett's indicators method. It was proved that the activities of the catalysts correlated with their basic strength.

3

Broadband dielectric spectroscopy of Al/Lu2O3/Al thin film sandwiches

Wiktorczyk T.

Materials Science Poland

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2009

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Vol. 27, No. 4/2

1179--1187

EN

The paper focuses on the dielectric characterization of electron beam deposited lutetium oxide thin films sandwiched between aluminium electrodes. The complex capacitance characteristics were recorded in the frequency domain (from 10 žHz to 10 MHz) with a dielectric response analyser. The influence of the temperature, the insulator thickness and sample ageing on C´(?) and C"(?) characteristics was examined. It was shown that high frequency/low temperature dielectric data are assigned to the volume of lutetium oxide film, whereas the low frequency/high temperature results are connected with M/I interfaces. The width of near electrode regions (Schottky barriers) was estimated (? ? 2.6-4.7 nm).

4

Rare Earth Silicate Formation: A Route Towards High-k for the 22 nm Node and Beyond

Mitrovic I. Z., Hall S.

Journal of Telecommunications and Information Technology

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2009

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nr 4

51-60

EN

Over the last decade there has been a significant amount of research dedicated to finding a suitable high-k/metal gate stack to replace conventional SiON/poly-Si electrodes. Materials innovations and dedicated engineering work has enabled the transition from research lab to 300 mm production a reality, thereby making high-k/metal gate technology a pathway for continued transistor scaling. In this paper, we will present current status and trends in rare earthbased materials innovations; in particular Gd-based, for the high-k/metal gate technology in the 22 nm node. Key issues and challenges for the 22 nm node and beyond are also highlighted.

5

Broadband dielectric spectroscopy of ALl/Lu2O3/Al thin film sandwiches.

Wiktorczyk T.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2007

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Vol. 46, nr 19

82-85

EN

The paper focuses on the dielectric characterization of electron-beam deposited lutetium oxide thin films sandwiched between aluminium electrodes. The complex capacitance characteristics were measured in the frequency domain (from 10/xHz to 10MHz) with dielectric response analyser. The influence of the temperature, the insulator thickness and sample aging on C'(u>) and C"((D) characteristics was examined. It was shown that high-frequency/low-temperature dielectric data are assigned to the volume of lutetium oxide film, whereas the low-frequency/high-temperature results are connected with M/I interfaces. The width of near-electrode regions (Schottky barriers) was estimated (k = 2.6-4.7 nm).

6

Wpływ sumy tlenków lantanowców na stabilizację wysokotemperaturowych faz ZrO2.

Żurek Z., Gil A., Bednarska I., Żmudzińska-Żurek B.

Szkło i Ceramika

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2001

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R. 52, nr 5

18-22

PL

Przedmiot badań stanowiły proszki ZrO2 otrzymane metodą współstrącania, zawierające do 15% mol. stabilizującego dodatku w postaci sumy tlenków lantanowców. Przeprowadzono pomiary derywatograficzne dla czystego Zr(OH)4 oraz wszystkich pozostałych układów Zr(OH)4+mLn(OH)3 (m=3, 5, 8, 12, 15% mol.), które obejmowały termiczną analizę różnicową (DTA) i analizę termograwimetryczną (DT). Badano wpływ temperatury prażenia na skład fazowy proszku ZrO2 mającego różne ilości stabilizującego dodatku. Określono wpływ ilości sumy lantanowców na wielkość ziaren Zr(OH)4 i ZrO2. Przeprowadzono obserwacje morfologii powierzchni proszków za pomocą mikroskopu skaningowego SEM, pomiary powierzchni właściwej metodą BET oraz pomiar objętości porów metodą Langmuira.

EN

The object of the investigation were ZrO2 powders, prepared by co-precipitation method. ZrO2 powders contained up to 15% mol of the stabilizing additive, considered as a sum of rare earth oxides. The influence of roasting point on the phase content of ZrO2 powder with different amounts of stabilizing additives was tested. The influence of grain dimensions Zr(OH)4 and ZrO2 according to different amounts of stabilizing additives was tested as well. The thermogravimetry measurements of pure Zr(OH)4 and all other systems of Zr(OH)4+mLn(OH)3 (m=3, 5, 8, 12, 15% mol.) were carried out. Morphology observations of powder surfaces of Zr(OH)4 and ZrO2 were made by scanning microscope SEM. The measurements of specific surface area by BET and volume of pores by Langmuire method were carried out.