Morphology, Structure and Catalytic Properties of Pd-CeO2/Al2O3 Catalysts for Methane Oxidation and Coats Based Thereon

2019 ◽  
Vol 19 (3) ◽  
pp. 206-218
Author(s):  
N. V. Shikina ◽  
O. Yu. Pod’yacheva ◽  
A. V. Ishchenko ◽  
S. R. Khairulin ◽  
T. B. Tkachenko ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Cold Spraying ◽  
Scaling Up ◽  
Metal Foil ◽  
Active Components ◽  
Alumina Layer ◽  
Energy Devices ◽  
Metal Foils ◽  
Oxidation Of Methane ◽  
Gas Dynamic

Morphologies and structures of catalytic compositions and coats based thereon were studied using Pd-CeO2/Al2O3 calcined at 100, 500, 1000 °C and the coats prepared by gas dynamic cold spraying onto a metal foil. It was established that the methods for preparation of the initial catalytic composition and for introduction of the active components to the coat influenced the phase composition, particle size and activity to oxidation of methane. The introduction of the active components by impregnation of the pre-deposited alumina layer was shown to provide the uniform distribution of Pd and Ce through the support profile, formation of nanosize PdO particles and of the interacting phases between the catalyst and support components. The impregnated catalyst was most active to oxidation of methane. The method for preparation of the coats has no limitations in scaling-up and, therefore, can be widely used for production of full-size catalysts on metal foils to be used for various energy devices.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

scholarly journals Finite Element Modelling and Validation of Thermomechanical Behaviour for Layered Aluminium Parts Made by Composite Metal Foil Manufacturing

2018 ◽  
Vol 2 (4) ◽  
pp. 68 ◽  
Author(s):  
Javaid Butt ◽  
Mohammad Ghorabian ◽  
Abed Ahmed ◽  
Hassan Shirvani
Keyword(s):  
Finite Element ◽  
Tensile Properties ◽  
Thermal Effects ◽  
Finite Element Modelling ◽  
Corrosion Testing ◽  
Metal Foil ◽  
Element Modelling ◽  
Metal Foils ◽  
Dog Bone ◽  
Thermomechanical Behaviour

The paper presents finite element modelling and thermomechanical analysis on the tensile properties of layered aluminium 1050 metal foil parts made by composite metal foil manufacturing. In this paper, a three-dimensional finite element model was developed and validated through experiments to analyse thermal effects on the tensile properties of 200-μm-thick aluminium 1050 metal foils. The effects of thermal stress and strain were studied by carrying out transient thermal analysis on the heated plates used to join the 200-μm-thick metal foils together using a special brazing paste. A standard tensile test at ambient temperature was carried out on the resulting layered dog bone specimens to analyse the thermal effects on the individual layers of metal. The investigations were precisely designed to assess the effect of heat provided amid the brazing operation to join the metal thwarts together as a layered structure and whether it assumed a part in affecting the tensile properties of the final products when contrasted to a solid aluminium 1050 dog bone specimen of the same dimensions. Corrosion testing was also carried out on dog bone specimens made from varying thickness foils (50 μm, 100 μm, and 200 μm) of aluminium 1050 to assess the effect of corrosion on the tensile strength and elongation. The results showed that the specimens did not face the problem of galvanic corrosion of the foil–bond interface. Microstructural analysis was also carried out to analyse the fracture modes of the tested specimens after corrosion testing.

Formation of Alumina Layer on Ti Alloy for Artificial Hip Joint

2014 ◽  
Vol 614 ◽  
pp. 200-205 ◽  
Author(s):  
Rohit Khanna ◽  
Tomiharu Matsushita ◽  
Tadashi Kokubo ◽  
Hiroaki Takadama
Keyword(s):  
Heat Treatment ◽  
Hip Joint ◽  
Thick Layer ◽  
Cold Spraying ◽  
Ti Alloy ◽  
Good Adhesion ◽  
Time Duration ◽  
Alumina Layer ◽  
Artificial Hip Joint ◽  
Artificial Hip

The purpose of this research is to form a layer of alumina on Ti-6Al-4V alloy for hip joint by deposition of Al layer on the Ti alloy and its subsequent oxidation. In this work, a thick layer of Al was deposited onto the Ti alloy by cold spraying. The reaction layer of Al3Ti was formed by heat treatment of cold sprayed Al at 640°C in air/Ar atmosphere to ensure a good adhesion between cold sprayed Al layer and the Ti alloy. A thick Al3Ti layer formed by heat treatment of Al layer at 640°C for 12 h in air, was subjected to heat treatment at 850°C for 96 h in air to form a-alumina and Al2Ti. Thus, alumina scales can be formed on the top surface of the Ti alloy and can be densified by increasing the time duration of heat treatment.

Nanocomposites Based Upon Alumina and Zirconia Pillared Clays Loaded with Transition Metal Cations and Clusters of Precious Metals: Synthesis, Properties and Catalysis of NOx Selective Reduction by Hydrocarbons

1999 ◽  
Vol 581 ◽  
Author(s):  
Vladislav A. Sadykov ◽  
R. V. Bunina ◽  
G. M. Alikina ◽  
V. P. Doronin ◽  
T. P. Sorokina ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Nitrogen Oxides ◽  
Transition Metal ◽  
Catalytic Properties ◽  
Precious Metals ◽  
Selective Reduction ◽  
Pillared Clays ◽  
Active Components ◽  
Synthesis Properties ◽  
Nitrogen Oxides Reduction

ABSTRACTThermally stable alumina and zirconia pillared clays loaded with copper and cobalt cations and silver nanoparticles were synthesized. The structural and surface features of these nanosystems were studied and compared with those of bulk analogs -partially stabilized zirconias and γ-alumina loaded with the same active components. Specificity of the catalytic properties of nanocomposites in the reactions of nitrogen oxides reduction by propane, propylene and decane in the excess of oxygen appears to be determined both by the degree of interaction between pillars and active components and the type of reducing agent.

Effects of WC12Co Content on Wear Behavior of NiCoCrAlY Coating by Cold Gas Dynamic Spraying

2014 ◽  
Vol 1004-1005 ◽  
pp. 747-750
Author(s):  
Sheng Qiang Feng ◽  
Cun Long Wang ◽  
Bing Ma ◽  
Lang Cui
Keyword(s):  
Wear Resistance ◽  
Magnesium Alloy ◽  
Dry Friction ◽  
Wear Behavior ◽  
Cold Spraying ◽  
Friction Condition ◽  
High Density ◽  
Cold Gas Dynamic Spraying ◽  
Gas Dynamic ◽  
Cold Gas

The NiCoCrAlY+WC12Co coating with high density was prepared on the surface of the magnesium alloy by cold spraying. Effects of the WC12Co content on the wear behavior of coating were studied. The results showed that, under the dry friction condition, the weightlessness of wear of the coating with 20%WC12Co was smallest. The weightlessness of wear of the coating with 10%WC12Co was worse than that with 20%WC12Co. However, the weightlessness of wear of the coating without any WC12Co was worst among the three coatings. After the frictional experiment for 20 minutes, the weightlessness of wear of coating without any WC12Co was 10mg. Compared with that of coatings with 10%WC12Co and 20%WC12Co, the weightlessness of wear was lower than 35% and 54%, respectively. Obviously, the coating with 20%WC12Co had the capacity of the weightlessness of wear resistance. Consequently, the more the coating with WC12Co was, the higher the capacity of the weightlessness of wear resistance was.

scholarly journals A comparative review on cold gas dynamic spraying processes and technologies

2019 ◽  
Vol 6 ◽  
pp. 25 ◽  
Author(s):  
Sunday Temitope Oyinbo ◽  
Tien-Chien Jen
Keyword(s):  
New Technology ◽  
Cold Spraying ◽  
Industrial Applications ◽  
Cold Gas Dynamic Spraying ◽  
Future Research ◽  
Gas Dynamic ◽  
Comparative Review ◽  
Wide Range ◽  
High Fatigue ◽  
Cold Gas

Cold gas dynamic spraying (CGDS) is a relatively new technology of cold spraying techniques that uses converging-diverging (De Laval) nozzle at a supersonic velocity to accelerate different solid powders towards a substrate where it plastically deforms on the substrate. This deformation results in adhesion to the surface. Several materials with viable deposition capability have been processed through cold spraying, including metals, ceramics, composite materials, and polymers, thereby creating a wide range of opportunities towards harnessing various properties. CGDS is one of the innovative cold spraying processes with fast-growing scientific interests and industrial applications in the field of aerospace, automotive and biotechnology, over the past years. Cold gas spraying with a wide range of materials offers corrosion protection and results in increases in mechanical durability and wear resistance. It creates components with different thermal and electrical conductivities than that substrates would yield, or produces coatings on the substrate components as thermal insulators and high fatigue-strength coatings, and for clearance control, restoration and repairing, or prostheses with improved wear, and produces components with attractive appearances. This review extensively exploits the latest developments in the experimental analysis of CGDS processes. Cold gas dynamic spraying system, coating formation and deposit development, description of process parameter and principles, are summarized. Industrial applications and prospectives of CGDS in future research are also commented.

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