Suspension Plasma Spraying for the Preparation of Perovskite Powders and Coatings

1997 ◽  
Author(s):  
G. Schiller ◽  
M. Müller ◽  
F. Gitzhofer
Keyword(s):  
Liquid Phase ◽  
Plasma Spraying ◽  
Inductively Coupled Plasma ◽  
Oxygen Plasma ◽  
Ethanol Solution ◽  
Suspension Plasma Spraying ◽  
Plasma Sheath ◽  
Molar Ratio ◽  
Inductively Coupled ◽  
Reactor Pressure

Abstract LaMnO3 powders and coatings have been prepared by reactive suspension plasma spraying (SPS) of MnO2 powders and LaCl3 solutions. A 40 kW inductively coupled plasma with an oxygen plasma sheath gas has been used. Water and ethanol have been tested as the liquid phase in the SPS process. High perovskite content (70-90%) has been achieved for both powders and coatings when spraying a suspension of fine MnO2 powder in a saturated ethanol solution of LaCl3 with a 1:1 molar ratio of La and Mn. Materials obtained by a 1100 °C oven treatment have been used as reference during the study. The reactor pressure was varied from 30 to 80 kPa. Low pressure was found to be necessary to suppress the formation of undesired phases in the powders and coatings obtained. A plasma post treatment of the coatings results in an increase of the perovskite content.

Preparation of Perovskite Powders and Coatings by RF-Suspension Plasma Spraying

1998 ◽  
Author(s):  
G. Schiller ◽  
M. Muller ◽  
F. Gitzhofer
Keyword(s):  
Plasma Spraying ◽  
Inductively Coupled Plasma ◽  
Oxygen Plasma ◽  
Ethanol Solution ◽  
Suspension Plasma Spraying ◽  
Plasma Sheath ◽  
Solid State Reactions ◽  
Molar Ratio ◽  
Inductively Coupled ◽  
Spray Process

Abstract Perovskite-type LaMnO3 powders and coatings have been prepared by a novel technique, the reactive suspension plasma spraying (SPS) using an inductively coupled plasma of about 40 kW plate power and an oxygen plasma sheath gas. Suitable precursor mixtures were found on the basis of solid state reactions, solubility and the phases obtained during the spray process. Best results were achieved by spraying a suspension of fine MnO2 powder in a saturated ethanol solution of LaCl3 with a 1:1 molar ratio of La and Mn. Low reactor pressure was helpful in order to diminish the amount of corrosive chlorine compounds in the reactor. As-sprayed coatings and collected powders showed perovskite contents of 70-90%. After a post-treatment with an 80% oxygen plasma an almost pure LaMnO3 deposit was achieved in the center of the incident plasma jet.

Suspension Plasma Spraying (SPS) of Cobalt Spinel

1997 ◽  
Author(s):  
G. Schiller ◽  
M. Müller ◽  
F. Gitzhofer ◽  
M.I. Boulos ◽  
R.B. Heimann
Keyword(s):  
Plasma Spraying ◽  
Inductively Coupled Plasma ◽  
Solid Phase ◽  
Spinel Phase ◽  
Rf Plasma ◽  
Dry Powders ◽  
Inductively Coupled ◽  
Cobalt Spinel ◽  
Chemical Conditions ◽  
Physical And Chemical

Abstract Fine (median size 6 μm and 0.3 μm) cobalt spinel (Co3O4) powders were processed suspended in a suitable liquid phase. Suspensions exceeding 50 wt.% solid phase content were successfully injected into an inductively coupled plasma. Spheroidized powders with large particle size (up to 80 μm) were prepared, and cobalt oxide coatings were produced by this novel RF-SPS method. The microstructural features of the coatings can be controlled by parameter optimization similarly to plasma spraying of dry powders. Numerous variations of the physical and chemical conditions of the process were performed in an attempt to overcome the main disadvantage of the process, i.e. the decomposition of the spinel phase to CoO. So far, the spinel phase could be reestablished only by a post-treatment of the deposited coatings with atomic oxygen in the RF plasma.

Improved Deposition Process of CVD-(Ba,Sr)TiO3 on Ru

2000 ◽  
Vol 655 ◽  
Author(s):  
M. Tarutani ◽  
T. Sato ◽  
M. Yamamuka ◽  
T. Kawahara ◽  
T. Horikawa ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Inductively Coupled Plasma ◽  
Deposition Process ◽  
Molar Ratio ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Bst Films ◽  
20 Nm ◽  
Uniform Composition

Abstract(Ba,Sr)TiO3 [BST] films were deposited by the flash vaporization CVD method with a unique liquid delivery system. An inductively coupled plasma mass spectrometry [ICP-MS] analysis revealed the decline of (Ba+Sr)/Ti molar ratio of the initial BST-layer on Ru. By readjusting the flow ratio of liquid sources and using a two-step deposition method, we obtained 30-nm-thick BST films with uniform composition profile, exhibiting good electrical properties. The leakage property, however, was severely deteriorated in BST films less than 24 nm thick. A SEM observation showed the presence of micro-roughness or micro-hillocks in these films, which were confirmed to be caused by Ru oxidation. Therefore, an annealing process of the Ru electrode was added for its planarization, and the CVD process was also improved. As a result, we obtained smooth and finely crystallized ∼ 20-nm-thick BST films with good electrical properties of equivalent SiO2 thickness (teq) ∼ 0.45 nm and leakage current < 1 × 10−7 A/cm2. We also measured properties of BST films deposited on the 3-D Ru electrode. The results are briefly discussed.

Fabrication of hybrid composites based on biomineralization of phosphorylated poly(ethylene glycol) hydrogels

2009 ◽  
Vol 24 (1) ◽  
pp. 50-57 ◽  
Author(s):  
Chan Woo Kim ◽  
Sung Eun Kim ◽  
Yong Woo Kim ◽  
Hong Jae Lee ◽  
Hyung Woo Choi ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Inductively Coupled Plasma ◽  
Hybrid Composites ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Poly Ethylene Glycol ◽  
3 Dimensional ◽  
Inductively Coupled ◽  
Poly Ethylene

A novel route to organic-inorganic composites was described based on biomineralization of poly(ethylene glycol) (PEG)-based hydrogels. The 3-dimensional hydrogels were synthesized by radical crosslinking polymerization of poly(ethylene glycol fumarate) (PEGF) in the presence of ethylene glycol methacrylate phosphate (EGMP) as an apatite-nuclating monomer, acrylamide (AAm) as a composition-modulating comonomer, and potassium persulfate (PPS) as a radical initiator. We used the urea-mediated solution precipitation technique for biomineralization of hydrogels. The apatite grown on the surface and interior of the hydrogel was similar to biological apatites in the composition and crystalline structure. Powder x-ray diffraction (XRD) showed that the calcium phosphate crystalline platelets on hydrogels are preferentially aligned along the crystallographic c-axis direction. Inductively-coupled plasma mass spectroscopy (ICP-MS) analysis showed that the Ca/P molar ratio of apatites grown on the hydrogel template was found to be 1.60, which is identical to that of natural bones. In vitro cell experiments showed that the cell adhesion/proliferation on the mineralized hydrogel was more pronounced than on the pure polymer hydrogel.

The Experimental Research on Uniformity of Argon Inductively Coupled Plasma at Different Cylinder Heights

2013 ◽  
Vol 724-725 ◽  
pp. 686-691
Author(s):  
Song Bai Wang ◽  
Xian Hui Zhang ◽  
Hong Zhe Wang ◽  
Lin Ying Liu ◽  
Ren Wu Zhou ◽  
...  
Keyword(s):  
Langmuir Probe ◽  
Inductively Coupled Plasma ◽  
Negative Ions ◽  
Plasma Sheath ◽  
Injection System ◽  
Dynamic Processes ◽  
Electronic Density ◽  
Inductively Coupled ◽  
Beam Injection ◽  
Two Factors

We report on the characteristics of argon inductively coupled plasma (ICP) for the ITER neutral beam injection system. In argon ICP, it was found by using Langmuir probe that the radial distribution of electronic density (Ne) was uniform while the radial distributions of both electron temperature (kTe ) and electric potential (VP) were non-uniform. The former depend on two factors: the variation of Ne was small, and the value of Ne was very large. The latter is owing to the generation and disappearance of the negative ions in the ICP, where the additional dynamic processes produce the instability. In addition, both kTe and VP profiles were very similar at the cylinder height H=14 cm, which proves the plasma sheath theory to some extent. Finally, both kTe and VP began flatter with the reduction of the cylinder height, which is owing to the decrease of the negative ions in the ICP.

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