scholarly journals Computer-Controlled Detonation Spraying: Flexible Control of the Coating Chemistry and Microstructure

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1244 ◽  
Author(s):  
Vladimir Yu. Ulianitsky ◽  
Dina V. Dudina ◽  
Alexandr A. Shtertser ◽  
Igor Smurov
Keyword(s):  
Chemical Properties ◽  
Ceramic Composites ◽  
Detonation Spraying ◽  
Gaseous Mixtures ◽  
Flexible Control ◽  
Variable Chemical ◽  
Computer Controlled ◽  
Detonation Gun ◽  
Chemical And Phase Compositions ◽  
Novel Applications

This article is a focused review aimed to describe the potential of the computer-controlled detonation spraying (CCDS) for producing and designing coatings with variable chemical and phase compositions and microstructure and promising properties. The development of the detonation spraying method is briefly analyzed from a historical perspective and the capabilities of the state-of-the art facilities are presented. A key advantage of the CCDS is the possibility of using precisely measured quantities of the explosive gaseous mixtures for each shot of the detonation gun and different oxygen to fuel ratios, which can create spraying environments of different chemical properties—from severely oxidizing to highly reducing. The significance of careful adjustment of the spraying parameters is shown using material systems that are chemically sensitive to the composition of the spraying environment and temperature. Research performed by the authors on CCDS of different materials—metals, ceramics, intermetallics and metal-ceramic composites is reviewed. Novel applications of detonation spraying using the CCDS technology are described.

Influence of Surface Condition on the Bonding Strength of Thermal Sprayed Coatings

1997 ◽  
Author(s):  
V.Yu. Ulianitsky ◽  
J.A. Nikolaev ◽  
T.P. Gavrilenko ◽  
M.C. Kim ◽  
J.W. Hong
Keyword(s):  
Bonding Strength ◽  
Substrate Surface ◽  
Surface Condition ◽  
Surface Preparation ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Substrate Material ◽  
Detonation Spraying ◽  
Wide Scale ◽  
Detonation Gun

Abstract The role of surface roughness in coating adhesion mechanism is studying for detonation spraying. Roughness was produced by conventional grit blasting, D-gun blasting and was formed as a result of spraying of high-adhesive thin layer of detonation coating. Cermet and alloy powders were sprayed by detonation gun Ob. The coating bonding strength measurements show the WC+25Co adhesion to be above 200 MPa independently of a substrate surface preparation. Contrary, NiCrSiB coatings are very sensitive to surface conditions their adhesion varies from 180 MPa to zero. As-sprayed alloy particles fail in adherence because of insufficient energy to fuse substrate material at a flat surface. Only developed (wide scale) roughness may be fused partially by these particles for their bonding to the substrate. Otherwise, high heated cermet particles do not need special surface preparation (except cleaning) for fusion of substrate material to provide high bonding with it. The wide scale and ball shape roughness, which is similar to the self-reproduced coating roughness, provides the best conditions for the coating bonding and it is recommended as the purpose of surface treatment before thermal spray coating.

scholarly journals Novel Applications of Nanoparticles in Nature and Building Materials

2021 ◽  
Author(s):  
Juyoung Ha
Keyword(s):  
Chemical Weathering ◽  
Building Materials ◽  
Mine Drainage ◽  
Bulk Material ◽  
Chemical Properties ◽  
Future Research ◽  
Natural Environments ◽  
Weathering Processes ◽  
Different Types ◽  
Novel Applications

Nanoparticles are assemblies of atoms in the size range less than 100 nanometers. At these length scales, the properties of particles may deviate significantly from those of the equivalent bulk material indicating that changes in physical and chemical properties of materials depend on the dimensions of the particle. The presence of mineral nanoparticles has been reported in a range of natural environments. Such nanoparticles can arise from a variety of mechanisms, including chemical weathering processes, precipitation from relatively saturated solutions in hydothermal and acid mine drainage environments, evaporation of aqueous solutions in soils, and biological formation by a variety of different microorganisms. Furthermore, recent increased applications of nanoparticles in different types of industries, including construction and building material manufacturing, have caused prevalent occurrences of different types of synthetic nanoparticles in the environment. In this chapter, a comprehensive reviews on occurrences and observations of naturally and anthropogeniccally generated nanoparticles in the environment and their characterization techniques will be discussed along with directions and suggestions for the future research topics and areas for nanomaterials.

Studies on some solodic soils in north-eastern Queensland. 1. Morphological and chemical characteristics

1970 ◽  
Vol 10 (44) ◽  
pp. 334 ◽  
Author(s):  
BJ Crack ◽  
RF Isbell
Keyword(s):  
Chemical Properties ◽  
Summer Rainfall ◽  
Sampled Data ◽  
Nitrogen And Phosphorus ◽  
North Eastern ◽  
Variable Chemical ◽  
Calcium Magnesium ◽  
Major Chemical ◽  
Low Nitrogen ◽  
Phosphorus Levels

Morphological and chemical data are presented for solodic and solodized-solonetz soils occurring in north-eastern Queensland under a strongly seasonal summer rainfall. Mean annual totals range from 26 in, to 70 in. The soils have slightly acid sandy to loamy A horizons, often strongly bleached, and abruptly underlain by hard dense clay R horizons which are strongly alkaline at depth. Profiles show variable chemical properties but many surface elements show relatively little variability within or between areas sampled. Data for such elements may be interpolated for sites within the area studied. Major chemical features are low nitrogen and phosphorus levels which show little variation between areas sampled. The exchangeable calcium : magnesium ratio of surface soils is narrow but values do not suggest deficiencies or imbalance. In the subsoils magnesium and sodium are the dominant exchangeable cations. Exchangeable and acid-extractable potassium values are variable in surface horizons, and data indicate sufficiency in the lower rainfall areas with likelihood of deficiency under higher rainfall. The soils have several adverse physical properties.

Exfoliating silica bilayers via intercalation at the silica/transition metal interface

2021 ◽  
Author(s):  
Mengen Wang ◽  
Jorge Anibal Boscoboinik ◽  
Deyu Lu
Keyword(s):  
Transition Metal ◽  
Molecular Sieves ◽  
Density Functional ◽  
Chemical Properties ◽  
Large Area ◽  
Surface Protection ◽  
Potential Applications ◽  
Chemical Reaction Mechanisms ◽  
Novel Applications ◽  
Physical And Chemical

Abstract The growth of the silica (SiO2) bilayer (BL) films on transition metal (TM) surfaces creates a new class of two-dimensional (2D) crystalline, self-contained materials that interact weakly with the TM substrate. The BL-silica/TM heterojunction has shown unique physical and chemical properties that can lead to new chemical reaction mechanisms under the sub-nm confinement and broad potential applications ranging from surface protection, nano transistors, molecular sieves to nuclear waste removal. Novel applications of BL-silica can be further explored as a constituent of van der Waals assembly of 2D materials. Key to these applications is an unmet technical challenge to exfoliate and transfer BL-silica films in a large area from one substrate to another without material damage. In this study, we propose a new exfoliation mechanism based on gas molecule intercalation from density functional theory studies of the BL-silica/TM heterojunction. We found that the intercalation of O atoms and CO molecules at the BL-silica/TM interface weakens the BL-silica – TM hybridization, which results in an exponential decrease of the exfoliation energy against the interface distance, as the coverage of interfacial species increases. This new intercalation mechanism opens up the opportunity for non-damaging exfoliation and transfer of large area silica bilayers.

Diverse silver(i) sulfobenzoate coordination polymers and their recycling property as homogeneous catalyst in oxygenation of sulfide

RSC Advances ◽  
2014 ◽  
Vol 4 (28) ◽  
pp. 14691-14699 ◽  
Author(s):  
Ai-Qing Ma ◽  
Long-Guan Zhu
Keyword(s):  
Coordination Polymers ◽  
Chemical Properties ◽  
Homogeneous Catalyst ◽  
Benzene Rings ◽  
Variable Chemical

Four silver sulfobenzoate coordination polymers with bpmb ligands were prepared. The variable positions of sulfonate groups on benzene rings gave rise to different coordination polymers and variable chemical properties.

scholarly journals Cyclodextrins: Structural, Chemical, and Physical Properties, and Applications

2021 ◽  
Vol 3 (1) ◽  
pp. 1-31
Author(s):  
Benjamin Gabriel Poulson ◽  
Qana A. Alsulami ◽  
Abeer Sharfalddin ◽  
Emam. F. El Agammy ◽  
Fouzi Mouffouk ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Chemical Properties ◽  
Aqueous Solubility ◽  
Industrial Applications ◽  
Physical And Chemical Properties ◽  
To Come ◽  
Novel Applications ◽  
Physical And Chemical ◽  
And Chemical Properties

Due to their unique structural, physical and chemical properties, cyclodextrins and their derivatives have been of great interest to scientists and researchers in both academia and industry for over a century. Many of the industrial applications of cyclodextrins have arisen from their ability to encapsulate, either partially or fully, other molecules, especially organic compounds. Cyclodextrins are non-toxic oligopolymers of glucose that help to increase the solubility of organic compounds with poor aqueous solubility, can mask odors from foul-smelling compounds, and have been widely studied in the area of drug delivery. In this review, we explore the structural and chemical properties of cyclodextrins that give rise to this encapsulation (i.e., the formation of inclusion complexes) ability. This review is unique from others written on this subject because it provides powerful insights into factors that affect cyclodextrin encapsulation. It also examines these insights in great detail. Later, we provide an overview of some industrial applications of cyclodextrins, while emphasizing the role of encapsulation in these applications. We strongly believe that cyclodextrins will continue to garner interest from scientists for many years to come, and that novel applications of cyclodextrins have yet to be discovered.

scholarly journals Mechanical and Microstructural Response of Aluminum Composites Reinforced with Ceramic Micro-Particles

2021 ◽  
Vol 5 (9) ◽  
pp. 228
Author(s):  
José A. Castillo-Robles ◽  
Alicia P. Dimas-Muñoz ◽  
José A. Rodríguez-García ◽  
Carlos A. Calles-Arriaga ◽  
Eddie N. Armendáriz-Mireles ◽  
...  
Keyword(s):  
Tungsten Carbide ◽  
Aluminum Matrix ◽  
Chemical Properties ◽  
Ceramic Composites ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Aluminum Composites ◽  
Micro Particles ◽  
The Matrix ◽  
Physical And Chemical

Aluminum matrix composites have recently taken an important role in advanced applications because they have a good combination of physical and chemical properties. For this reason, in this work, aluminum composites, with additions of ceramic particles (mullite or tungsten carbide), were manufactured in order to determine the effect of those particles on the mechanical properties and microstructure of aluminum. The manufacture of the composites was carried out by means of powder metallurgy. We studied composites with additions of 0.5 and 1 vol.% of the respective ceramic. Composites were sintered at 580 and 601 °C, which corresponds to 88 and 91% of the melting point of aluminum, respectively. Observations in SEM, together with EDX analysis, confirm that mullite particles are located at intragranular and transgranular positions of the aluminum matrix, while tungsten carbide particles were found mostly at intragranular areas of the matrix. From the analysis of the studied ceramics, it was found that with the use of mullite, there are greater improvements in the hardness and elastic modulus of the manufactured composite.

Ceramics and Ceramic Composites: Opportunities and Cooperative Research Modes

1985 ◽  
Vol 60 ◽  
Author(s):  
John B. Wachtman
Keyword(s):  
Critical Mass ◽  
Chemical Properties ◽  
Ceramic Composites ◽  
List Type ◽  
Type Number ◽  
Cooperative Research ◽  
Science And Engineering ◽  
Research Areas ◽  
Layer Structures ◽  
University Industry

AbstractCeramics and ceramic composites are a rapidly evolving category of materials capable of being tailored to have unique combinations of electrical, optical, mechanical, and chemical properties that make them essential and irreplacable in many engineering applications. Conventional ceramics have both enabled and enhanced many important aspects of our modern technological society; the next generation of ceramics will play a further enabling role for still higher performance devices.A briefing panel of the National Academies of Science and Engineering recently identified four areas into which promising research areas for advanced ceramics can be grouped: 1.New thin films and layer structures with improved properties.2.Exploration of completely new, multicomponent ceramic crystal structures and composites.3.The mechanical behavior of ceramics and tough composites.4.Ceramic processing of large parts and assemblies.Three mechanisms for achieving critical mass in ceramics research were recommended: 1.University/industry programs.2.A summer institute.3.A large interdisciplinary center.

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