bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal Spraying-Application and Development Trends
Authors: Hangong W. , Liuying W. 
Published: August 2022

Abstract
With high speed development of modern industry, the research and application of thermal spray technology made more progresses, the thermal spraying technology was applied more and more widely in industry fields. At the same time, the people pay more and more attention to the development of thermal spraying industry. In the paper, the development trends of thermal spray were presented on the basis of analyzing the research and application of thermal spraying technology. Spray particle velocity is developed to high velocity. Thermal spraying equipments is developed to multi-functional and accuracy and save energy and high efficiency. Spraying materials is developed to nano structured material, preparation of Nano Structured Coatings is one of directions of development of thermal spray. Thermal Spray has more widespread application prospect in aerospace, environmental protection and biological implant fields.
Thermal Spray Based Rapid Manufacturing, Part Refurbishing and Reengineering
Authors: Mohanty P.S. , Hart A. 
Published: August 2022

Abstract
The ability to respond timely and cost effectively is bringing rapid manufacturing techniques into the mainstream production/repair arena. The Army can benefit from such technologies to avoid long lead times and high costs of procuring and inventorying replacement parts. But, a technology that offers versatility in terms of product size, cost and the ability to fabricate production components rapidly is yet to be available. This paper describes thermal spray technologies as applied to rapid manufacturing, part refurbishing and reengineering. A hybrid thermal spray system that can deposit a variety of materials with high throughput and density has been developed. Several generic materials that can meet the functional requirements of many parts and at the same time can be easily deposited by a thermal spray technique are discussed. An expert system software assisting the operator from CAD information, reverse engineering to part refurbishing is presented. Examples on the use of multiple schemes to remanufacture a part are also discussed. These schemes offer new avenues to fabricate replacement parts and/or salvage damaged parts and can benefit the Army considerably.
Reengineering of Boiler Feed Pump using High Performance Coatings
Authors: Chandak A. , Balasubramanian G. 
Published: August 2022

Abstract
Boiler feed pumps (informally termed as mini turbine owing to its criticality) in thermal power plants are prone to normal wear and tear over a period of time, which leads to loss of pump efficiency and sometimes accidental failures resulting in heavy damages and prolonged shut downs. Re-engineering approach using High Performance Coatings by Plasma & HVOF processes, has recently enabled to add new world-class dimensions by reclamation & complete overhauling of Boiler Feed Pump Internal Cartridges (6“ LL Pacific Pumps Inc USA and 200 KHI, BHEL, India make), in order to obtain increased life cycle, maintain pump efficiency, De-accelerated wear rate. This was accomplished by establishing perfect interrelationship of cartridge assembly, providing exacting tolerances to meet functional and assembly requirement, and incorporating international standards for protective wear shielding by Plasma & HVOF technology on wear prone critical components. This paper describes the Re-engineering methodology adopted to improve the performance of the Boiler Feed Pump with the help of surface modification using plasma and HVOF coatings on critical components showing wear patterns, which led to the development of proprietary ceramic and cermets coatings after extensive laboratory and field trials. The Reengineered Boiler Feed Pumps are showing superior performance at one of the major power generating unit in Central India.
Manufacturing of Metal Foam Composites Through Multifunctional Coatings – The New Easy Foam-Process
Authors: Liebscher C. , Maurer M. , Zhao L. , Lugscheider E. 
Published: August 2022

Abstract
Especially, composites of aluminium metal foams are of high potential for lightweight applications in automotive, aerospace and general engineering because of their excellent ratio of low weight and high stiffness. To fulfill the industrial need for these new materials as soon as possible, a new integrated manufacturing process concept has been developed and studied at our institute. The new “easyFoam-process” concept consists of four basic steps: production of semi-finished parts via the powder metallurgical route, forming of the foamable semi-finished part into a near net shape by extrusion or any standard aluminium-forming process, coating of the surface by thermal spraying and foaming by inductive heating. Thus it’s feasible to provide a fast, continuous and efficient production of metal foam composites with highly reproducible properties, resulting in eminent advantages over current techniques for foam sandwich production in terms of degree of anisotropy, statistical spread in foam properties and production economy. This process is also the only one being able to produce a graded pore structure in symmetrical parts of PM-aluminium foams. The thermally sprayed coatings serve simultaneously as mould and as future multifunctional coating. In this paper, some results of our first study in coating the foamable Al-tubes and inductive heating the coated parts are presented.
High Resolution Microstructural Investigations of Interfaces Between Light Weight Alloy Substrates and Cold Gas Sprayed Coatings
Authors: Wielage B. , Podlesak H. , Grund T. , Wank A. 
Published: August 2022

Abstract
Investigations on interfaces between light weight alloys (aluminum AA7022 and magnesium AZ91) and optimized cold gas sprayed (CGS) zinc-based coatings are carried out. The analyses include standard optical and scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). By using TEM resolution within nanometric dimensions is realized. Investigations by SEM show areas of an intensive mixing between substrate and coating material with a number of different grey values due to element contrast. By EDXS analyses in a 1 µm broad transition zone increased zinc concentration compared to the substrate material is detected. TEM investigations prove that in this transition zone no homogeneous solid solution exists, but additionally submicron and nanosized intermetallic phases with different concentration of aluminum, zinc and magnesium are found. Due to these results an intensive mechanical interaction must take place at the substrate-coating interface during CGS. Thus bond strength does not only depend on physical and chemical adhesion or thin metallurgically affected zones, but also highly on effects of mechanical alloying.
Production of Freeform Net Shape Components by Cold Gas Dynamic Spray
Authors: Morgan R. , Pattison James , Celotto S. , O'Neill B. 
Published: August 2022

Abstract
This paper reports on the development of a cold spray system to be used as freeform fabrication production route. Cold Spray is seen as a preferential method for additive manufacture as the cold nature of the bonding removes detrimental thermally induced stresses. The Cold Gas Dynamic Manufacturing facility is the first of its kind, housed in a CNC machining centre with integrated high-speed machining spindle for back machining of deposit material to tolerance. The process enables the production of complex geometries including undercuts through the use of a two material delivery system fed by separate powder feeders. By this method one material is used as a sacrificial support structure and removed through post-process techniques. The process is fully numerically controlled. The process is conducted inside a chamber, such that all process gas is recaptured for purification and recycling. The paper will report on the various aspects of component production and will also detail strategies and techniques for building complex component shapes. Abstract only; no full-text paper available.
Kinetic Deposition of Ti Coatings Using Gas Atomized Ti Powder Particles
Authors: Zhao Z. , Gillispie B. , Han T. , Patel N. , Eesley G. , Mantese J. 
Published: August 2022

Abstract
The kinetic spray process is a coating process that involves impingement of a substrate by metallic particles at high velocities. In this work, we investigated the kinetically sprayed Ti coatings, which were deposited onto different metallic substrates using gas-atomized powders. The powder particles were characterized in terms of size distribution, morphology, hardness, and explosibilty index. The propellant gas used for coating deposition was compressed nitrogen. The substrates were placed inside an enclosure filled with nitrogen gas during deposition. It was observed that Ti coatings can be deposited at relatively high deposition efficiencies using large particles (median size~ 100 mm). Ti coatings with a wide range of thickness and good macroscopic appearance were readily prepared. The particle temperature appears to have strong effects on the coating formation; deposition efficiencies of ~90% were achievable. Microscopic examination of the coatings revealed deposited Ti particles with significantly lower deformation when compared to ductile materials such as Al and Cu. As a result, the Ti coatings exhibited a high degree of porosity. Several methods were exploited in order to make the Ti coatings denser, including the incorporation of heavy, hard particles for in-situ peening during the coating deposition, and post deposition laser heating. Abstract only; no full-text paper available.
Nano- and Microcrystalline Cold Spray Coatings
Authors: Shmyreva T. , Knapp J. , Sedov V. 
Published: August 2022

Abstract
The Cold Spray coatings have been sprayed from binary eutectic alloy – Al-12%Si and from the complex composition iron-based alloy. The atomized Al-Si powder had close to microcrystalline (grain size around 1micron) structure, the Fe alloy powder had amorphous-nanocrystalline structure. Aluminum-based alloy was also sprayed with addition of up to 10% of aluminum oxide powder. The coating structure and properties have been investigated using optical microscopy, scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, microcalorimetry, microhadness, tensile, bend, erosion and abrasion tests, and corrosion polarization tests. It has been shown that the Al-Si coatings have microcrystalline structure, and the Fe-based coating have amorphous-nanocrystalline structure similar but not identical to the feedstock powders. Cold Spray process has a specific mechanism to preserve the powders metastable structures. The coatings have enhanced hardness, wear and corrosion resistance. Abstract only; no full-text paper available.
Kinetically Sprayed Cu Coatings: Effects of Particle Characteristics
Authors: Zhao Z. , Gillispie B. , Han T. , Smith J. 
Published: August 2022

Abstract
The kinetic spray process is a coating process that involves impingement of a substrate by metallic particles at high particle velocities. During the last several years, significant advancements in the fundamental understanding of the process have been made at Delphi Research Labs, which allowed us to greatly to enhance our capability in spraying difficult-to-deposit materials, especially with relatively large particles as feedstock and compressed nitrogen as the propellant gas (a challenging combination). In this work, we investigated Cu coatings that were kinetically sprayed using large Cu particles (53-150 microns). The emphasis is placed on understanding the effect of powder particles on the coating formation by the kinetic spray process. The examined particle characteristics in the present study include particle size, shape and morphology, and microstructure. The results indicated that the coating formation by the kinetic spray process is controlled primarily by two fundamental variables of sprayed particles: particle velocity and particle temperature. Very large sized particles, in spite of their relatively low particle velocities (as a result of acceleration by nitrogen rather than helium), can be rendered to exhibit enhanced spray ability, comparable to smaller size particles. This can be achieved by properly controlling the particle temperatures. It is found that kinetic spray using large size Cu particles (~100 microns) can lead to dense Cu coatings, with 50-80% deposition efficiency. Abstract only; no full-text paper available.
Study of Magnetic Properties of Iron-Based Thermally Sprayed Coatings
Authors: Cherigui M. , Guessasma S. , Fenineche N.E. , Liao H. , Coddet C. , Craven J. 
Published: August 2022

Abstract
In this study, the magnetic properties of iron-based coatings obtained by HVOF thermal spraying were investigated. These properties were correlated to alloy type, heat treating temperature and coating thickness using artificial neural network method. Among coating characteristics, porosity is regarded as an influential parameter on the magnetic properties. Therefore, the role of the microstructure was particularly emphasized in this study. Magnetic properties, especially coercivity, showed a weak decrease with the addition of alloying elements. However, these properties remained nearly unchanged at high temperatures and for large coating thicknesses. Porosities are regarded as defects anchoring Bloch walls and consequently promoting an increase of coercivity.
Usefulness of 3-D Time Dependent Models and Steady 2-D Models in Plasma Spraying Engineering?
Authors: Mariaux G. , Vardelle A. , Fauchais P. 
Published: August 2022

Abstract
This paper presents a 2-D, steady and 3-D, time-dependent models of the atmospheric–pressure plasma spray process. The former focusses on plasma jet and particle behavior while the latter involves the modeling of plasma jet formation inside the nozzle and makes it possible to have some insight in anode erosion and coating geometry. Both models have been validated by comparing the predictions against experimental data. The input and expected output of both models will be discussed as their use in the engineering and operation of plasma spraying
Coatings Obtained by Low Pressure Plasma Spraying
Authors: Sokolov D.E. , Chwa S.-O. , Klein D. , Coddet C. , Nardin P. 
Published: August 2022

Abstract
Thermal sprayed protective coatings have gained widespread acceptance for a variety of industrials applications. This technology can be split into air plasma spraying (APS) and vacuum plasma spraying (VPS) according to the atmosphere during the deposition process. A number of advantages of VPS process such as avoiding oxidation or contamination of projectile, substrate and deposed coating; reducing the interaction between the plasma jet and the environment are obvious before the APS. The flexibility of process gives the largest possibility in aeronautics, gas turbine, medical field and other applications using different parameters, deposited and target materials. Low pressure plasma spraying (LPPS) is considered with some particular features so the range of pressure is about 10- 250 mbar, the dimensions of the plasma jet and its homogeneity are important. The adaptation of modern pumping and control systems allow to reduce the worked pressure to 0,1 mbar and to have conditions close to physical vapour deposition (PVD). This paper presents the results of the deposition of a copper alloy powder using the very low pressure plasma spraying performed by a new system developed in the LERMPS
Shock Wave Physical Mechanisms of Modulated Arc as Applied to Dusted Plasma Flows to Form the Coatings
Authors: Gutman-Goodman B.B. 
Published: August 2022

Abstract
This work is an attempt to understand the physical mechanisms lying on the basis of using DC torch modulation technology for spraying. The influence of the plasma disturbances created by means of arc current modulation and an influence of these disturbances on thermodynamic parameters and dynamic viscosity of the modulated plasma jet are carried out. Thus, the phenomena providing modulation effects, both as in the plasmatron itself as well as in the mechanisms influencing on the plasma technology parameters have become understandable. It was shown, that inserting hydrocarbons into the air plasma jet conduces to transition of the torch with vortex stabilization of the arc to the laminar spraying mode with a high coefficient use of powder. The obtained physical estimations are used for explanation of the coatings sprayed characteristics. In the article are described shortly the advantages and shortcomings of Plasma Spraying Technology, HVOF, Cold Spraying, Plasma Spraying with Modulation, Detonation Technologies. Each technology has important features like high velocity of spraying particles, melted spraying material and non - melted spraying material. However, these technologies have rigid requirements in regard with a size of spraying powder or wire. In one case it is possible to neglect these requirements (in a certain degree) in the case of Plasma Technology with Modulation which is a combination of all advantages of the above mentioned technologies and was applied to military and space technique.
The Influence of Post Heat-Treatment on the Wear Properties of Nano-Structured WC-Co Coatings
Authors: Kim J.H. , Baik K.H. , Seong B.G. , Hwang S.Y. 
Published: August 2022

Abstract
The potential of post heat-treatment to improve the wear properties of nanostructured WC-Co coatings was investigated in the present study. Since the nanostructured coatings are more susceptible to the detrimental reactions during spraying than their conventional counterparts, there is certain limitation in optimization of coating properties by adjusting process parameters. Post heat-treatment of nanostructured coatings can thus offer one solution to achieve further improvement in coating performance. Nanostructured WC-Co coatings prepared by HVOF spraying were heat-treated under various temperatures and their wear properties were compared to those of the as-sprayed condition. The influence of the post heat-treatment was discussed in terms of changes in microstructure, composition and hardness of the coatings. These results demonstrate that the wear resistance of the nanostructured WC-Co coatings can be improved without any degradation of the substrate properties by proper post heat-treatment process.
Microstructural Observation of the Sintering Behavior of Nanostructured Yttria Stabilized Zirconia
Authors: Racek O. , Berndt C.C. , Guru D. , Heberlein J. 
Published: August 2022

Abstract
Multilayer thermal barrier coatings are being investigated for high temperature applications by employing a strain accommodating interlayer. Plasma sprayed coatings of nanostructured feedstock have shown promise in this direction. Layers of nanostructured yttria stabilized zirconia (nano–YSZ) and conventional YSZ were deposited on mullite substrates using the triple torch plasma reactor (TTPR), and on NiCrAlY coated steel substrates using the Praxair SG-100 plasma torch. The coatings were heat treated and the microstructure evaluated. Heat treating the samples lead to the formation of larger pores with a significant proportion of partially molten particles. The porosity evolved from the partial sintering of the nano-agglomerates. Porosity change during the sintering process was measured and the microstructure observed using electron microscopy. The nanostructured coatings were compared to conventional YSZ coatings.
A Computational Heat and Mass Transfers Model for a Laser Pyrolysis Reactor
Authors: Amara M. , El Ganaoui M. , Hourlier D. 
Published: August 2022

Abstract
Recently the research about technical ceramics knows a renewed interest. The synthesis process of nanopowders plays a significant role in the production of such materials. This work, concerns particularly the synthesis of the nanopowders by laser pyrolysis. A numerical model is developed in order to understand the influence of the heat transfers occurring in the reactor and around the reaction zone, for a better control of the process. The study highlights the importance of the thermal transfer in the cell. A simple one dimensional analysis enabled us to define a stability condition of the flame function of the precursor flow rate and the cell pressure. The extended 3D calculations underline the complex fluid flow and heat transfer developing in the synthesis reactor.
Plasma Sprayed Oxide Surfaces in Aqueous Environments
Authors: Harju M. , Mäntylä T. , Areva S. , Järn M. , Halme J. , Rosenholm J.B. 
Published: August 2022

Abstract
Plasma sprayed oxide coatings are widely used in applications where the surface properties of the coatings dictate the performance of the coating. The knowledge of chemical surface properties of plasma sprayed oxide coatings is very limited and to our knowledge surface chemical studies of these coatings have not been published. Surface properties of common plasma sprayed oxide coatings exposed to water based electrolytes were evaluated using several surface sensitive techniques such as X-ray photoelectron spectroscopy (XPS) and electrophoretic mobility studies. The dissolution behaviour of the coating materials were studied using inductively coupled plasma-mass spectroscopy (ICP-MS). Other characterization techniques included X-ray diffraction (XRD) and scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS). The correlation between chemical stability, bulk and surface properties of the coatings were evaluated. Obtained results are compared with published values of traditionally manufactured oxide counterparts.
Cermet Coating by APS : Influence of the Ceramic Phase and the Particle Size Range on the Mechanical Properties
Authors: Syed A.A. , Denoirjean A. , Grimaud A. , Fauchais P. , Girardin D. 
Published: August 2022

Abstract
The cermet coatings constituted by a metallic phase mixed with a ceramic one allows obtaining coating properties with a wide range of variations. This is particularly interesting for graded coatings produced by APS technique with two different injection ports devoted to each kind of powder. By monitoring the powder feed rates independently it is relatively easy to obtain the requested composition and also the gradient as a function of the coating thickness. In the present work 600 ìm graded coatings were produced with 5 or 6 layers, each one with a specific composition. The hardness properties of the whole coating were evaluated by the Knoop technique. Also each layer was produced separately and characterized as well. These coatings were devoted to thermo-mechanical applications. In this work the metallic phase is always NiCr 80/20 wt% and the ceramic phase is zirconia doped with yttria or ceria as well as Al2TiO5. The powders used as a standard have a size range included between 40 and 10 µm. Smaller size ranges were evaluated to produce NiCr / ZrO2, Y2O3 graded coatings and were compared to those obtained with the standard powder. In this last part a post heat treatment of the coating was evaluated against the mechanical properties.