bluuebunny/crossref_metadata_2025 huggingface dataset:
Organizational Culture in University: A Bibliometric Analysis
Authors: Rosanti Feira A. , Udin Udin
Published: August 2022

Organizational culture as one of the important factors in the organization is a theme often discussed in the research. Many make organizational culture a variable which is then linked to other variables. Therefore, organizational culture research needs to be done to determine whether this topic is still relevant for research. In this paper, researchers are interested in seeing whether organizational culture is still a topic that still needs to be studied, especially organizational culture in universities. Given the times and the factors of external and internal organizational change, the question of organizational culture has become a topic that deserves further discussion. For this reason, research on the development trend of "Organizational Culture at the University" as a research theme is necessary. The method used is the Scopus search engine in random journals to identify related publications. Organizational culture is used as the main search keyword. The data obtained is then exported in RIS format and analyzed to obtain a research development map. The study also used data visualization software called VOSviewer to analyze the results, underlying relationships, and developing trends. The main finding of this study indicates that organizational culture in universities is experiencing a downward trend, and not many studies have addressed this theme. Hence this finding may be useful for similar research in the future.
Outcomes of COVID-19 in Children After Wide Distribution of COVID Vaccine, Albaha, Saudi Arabia
Authors: Almawazini Abdulmajid Mustafa , Alghamdi Ahmed Obaidalla , Alsharkawy Ali , Sehemi Matar Ahmed Al , Alghamdi Mohammed Ahmed , Alghamdi Njood Abdulaziz , Alghamdi Kholoud Mohammed , Alsakka Lara Muaffak , Alghmadi Nouf Abdullah , Almawazini Hazem , Almawazini Mohammad
Published: August 2022

Background: The WHO announced COVID-19 as a pandemic on 12 March 2020, and has become a major public health around the world. Objectives: The study aimed to evaluate clinical presentation and outcomes of COVID-19 cases after wide distribution of COVID vaccine. Methods: Cross sectional study, retrospective file review of the children aged less than 14 years, and confirmed by positive swab test to have COVID 19, from May 2021 to May 2022. Results: A total of 125 patients with positive tests were included in this study. Males made up 52.8% (66/125) of the population, while females made up 47.2% (59/125). The age group of 5–10 years was the most affected, with 46.2%. The common symptoms noted were fever 90.4%, followed by abdominal pain 45.6%, vomiting 44%, diarrhea 41.6%, running nose 39.2%, cough 36%, and headache 25%. Conjunctivitis (4%) and skin rash (1.6%) were the least common symptoms. Only four patients needed PICU admission. No mortality was reported in this study. Conclusions: The study concluded that the COVID severity became less with a short hospital course after wide distribution of the COVID vaccine. Male patients were more affected than female patients in the age group 5-10 years. Severe cases were associated with comorbidities.
Analyzing the What and How of United States Foreign Aid to Israel 2017-2020
Authors: Ramos Emilio , Hikmawan Rizky
Published: August 2022

The United States and Israel are two of the countries with the most unique relationship. The relationship between the two countries can be traced back to the very beginning of Israel's statehood. For most of modern history, a lot of conflicts involving Israel have erupted in the Middle East, some of which have endangered Israel's very existence. The unique relationship between the two countries has led the United States to view Israel as its main ally in the Middle East. Therefore, it is important for the United States to help Israel ensure its survival in this conflict-ridden region. One U.S. effort involves its foreign aid to Israel. Through this study, the authors attempt to explain the form and process of U.S. foreign aid to Israel in 2017-2020. This paper uses a qualitative method, with the data collected using document and internet-based methods. The primary data that are being used here are documents and reports on US foreign aid to Israel from 2017 to 2020 published directly by the US government. The findings show that the United States provided Israel with substantial military and non-military foreign aid in the period 2017-2020, and that the process of providing this aid is also progressing well.
Effects of intumescent flame retardant based on THEIC-based oligomeric ester as char forming agent on thermal，mechanical and flame retardant properties of HDPE composites
Authors: Khanal Santosh
Published: August 2022

In this study, a new phosphor-ester (TPE) was prepared by one-spot polycondensation of tris (2-hydroxyethyl) isocyanurate (THEIC) and phenyl phosphonic dichloride (PPDC) and used as a charring agent in combination with ammonium polyphosphate (APP) to develop new intumescent flame retardant (IFR) for high-density polyethylene (HDPE). The thermal and flame retardant properties of composites were investigated by thermogravimetric analysis (TGA), limiting oxygen index measurement (LOI), and cone calorimetry (CCT). At the same time, the morphology and chemical structure of the char residue were analyzed by scanning electron microscopy, Fourier transfer infrared spectroscopy, and laser Raman spectroscopy. The results showed the LOI value of the composite HD/APP/TPE containing 25 wt. % of APP/THE reaches 28.2 %. The CCT test suggested that the peak heat released rate (PHRR) of the flame retardant composite is decreased by 37 % compared to that of pure HDPE. The use of IFR based on APP and TPE produces a compact char residue that acts as a barrier for heat, oxygen, and volatile combustibles and protects the underlying polymer. Besides TPE can produce the PO-type radicals that show some gas phase flame retardant action. However, the tensile strength of the composites is still lower than that of pure polymer.
Extraction and Characterization of Cellulose from Agricultural Residues: Wheat Straw and Sugarcane Bagasse
Authors: Karn Anup , Thakur Sweta , Shrestha Bindra
Published: August 2022

Wheat straw and Sugarcane bagasse are agricultural as well as industrial wastes rich in lignocellulosic components that can be extracted easily and used as a renewable source of energy. The main aim of this present work was to explore the alternative source of cellulose extraction using simple, fast, and eco-friendly conditions. The process involves NaOH degradation, acid hydrolysis, and bleaching using hydrogen peroxide as a bleaching agent. The extracted compound was analyzed by XRD and FTIR techniques. The XRD peaks obtained were specific to cellulose Iβ which is a crystalline allomorph with a monoclinic structure. The crystallite size of cellulose obtained from sugarcane bagasse was 10.51 nm which is larger than the size of cellulose obtained from wheat straw i.e 4.04 nm. Cellulose from sugarcane bagasse showed a crystallinity index of 51.84 % whereas wheat straw showed only 17.94 %. The yield was slightly higher in wheat straw than in sugarcane bagasse. FTIR analysis in sugarcane bagasse showed a characteristic peak at 3255.84 cm-1 which is shifted to 3340 cm-1 in the case of wheat straw. This peak is due to the vibration of the –OH group in both of the materials. However, both of the materials showed the vibration of the C-O-C bond at 1033 cm-1.
Accounting for Consequences and Claims in Policy
Authors: Dolan Paul
Published: August 2022

Fully appraising any policy requires us to capture all of its ripple effects and not simply the size of the splash when the pebble of intervention hits the water. It also requires that we weight the value of those effects according to morally relevant characteristics of people, such as their age. In this chapter, I discuss the consequences that should feed into policy appraisal and the claims that different groups may have on resources.
Wellbeing in Public Policy: Contributions Based on Sen’s Capability Approach
Authors: Anand Paul
Published: August 2022

This chapter provides a brief introduction to the capability approach and its use in public policy-making around the world. Specifically, it shows the approach provides a definition of wellbeing and a framework for understanding how it is produced and distributed. It notes that the framework is useful across the entire life course and so helpful for understanding wellbeing in children and retirees as well as working age adults. The chapter then discusses the practical impacts of the approach on the development of monitoring systems in the OECD and UN where the Human Development Index paved the way for the globally adopted Sustainable Development Goals. It highlights the fact that behavioural and psychological factors are an important contributor to understanding how resources are converted into wellbeing.
Incorporating Wellbeing and Mental Health Research to Improve Pandemic Response
Authors: Daly Michael , Delaney Liam
Published: August 2022

This chapter discusses the potential for wellbeing research to be institutionalised into emergency response in the UK. We review the short and long-run wellbeing impacts of COVID-19 policies and argue for a wider scope of groups such as the Scientific Advisory Group for Emergencies (SAGE). The potential form of such response could be based both on emerging multi-dimensional societal wellbeing frameworks and on rapid and scalable policy appraisal capacities that incorporate wellbeing considerations.
Health and Disability Gaps in Political Engagement: A Short Review
Authors: Mattila Mikko
Published: August 2022

This review presents a short overview of the current state of research in the field of health, disability, and political engagement. I focus on the individual-level relationship between health and political behaviour or political attitudes. Most of the existing studies have analysed the effects of health or disability on electoral turnout, and almost all of these studies have found a negative association between poor health, disability, and turnout. The relationships between health and other forms of political participation are more complex; poor health and disability can actually promote certain types of participation (e.g., signing petitions or participation in social media). However, studies of political attitudes show that poor health and disability are connected to lower levels of trust and external political efficacy and that this disengagement may even lead, for example, to increased support for right-wing populist parties. In general, political actors and researchers need to be encouraged to implement new, more inclusive solutions to bridge the health and disability gaps in political engagement.
The dynamics of the planned number of sport events in game sports in the Ivano-Frankivsk region during 2020−2022
Authors: Lyseiko Kostiantyn , Yatsiv Yaroslav , Pityn Maryan , Hrecheskyi Oleh
Published: August 2022

The changes in the socio-economic system of Ukraine requires a scientific discussion of the established management mechanisms for the development of game sports in the regions. The study of the problem field according to the chosen subject of research made it possible to single out relatively independent directions of research. The first is related to the development of physical culture and sport in the regions, the second – to the development of individual sports or a group of game sports in general. The purpose: to find out the changes in the structure of the planned events in game sports in the Ivano-Frankivsk region during 2020−2022. Methods: theoretical analysis and generalization of data from scientific and methodical literature, analysis of documentary materials, methods of mathematical statistics. The content of the orders of the Sport Department of the Ivano-Frankivsk Regional State Administration on the "Unified calendar plan for sport competitions and training meetings of the region for Olympic sports" for 2020−2022 was studied. The results. Ping-Pong (23.1% − 2020 and 21.1% − 2021) and football (20.8% − 2020 and 21.1% of the total number of events from game sports, respectively, in 2021) among the total number of events from game sports have the largest shares by separate years. In 2022, there is one leader in the number of planned events among game sports − Ping-Pong (23.9% of the total number of events from game sports). During 2020−2022, tennis and rugby, which occupy the third and fourth places in the ranking, retain the leading positions in terms of shares of events among game sports. Conclusions. We received new data in view of the new socio-economic conditions of activity of physical culture and sports subjects, which indicate the dynamics of absolute and relative indicators of activities for the development of game sports at the regional level, in particular in the Ivano- Frankivsk region.
Adaptive reactions of the cardiovascular system in women of different somatotypes under the influence of classes of health-improving swimming
Authors: Miroshnichenko V. , Drachuk S. , Shvets O. , Pavlyk O.
Published: August 2022

It is known that representatives of different somatotypes have different training effects. The cardiovascular system is a limiting factor in the body's ability to exhibit aerobic and anaerobic lactatic productivity. Peculiarities of adaptation of the cardiovascular system of women of the first mature age of different somatotypes to recreational swimming classes were investigated in a fragmentary manner. 80 women aged 25-35 who had no experience in physical education and sports took part in the study. Swimming classes were held 3 times a week. The swimming program is focused on stimulating mainly the aerobic energy supply system. For the purpose of harmonious development, anaerobic exercises were performed in the second half of the main part. All subjects were conditionally divided into groups according to somatotype. Somatotype was determined by the Heath-Carter method. A decrease in heart rate and systolic blood pressure after dosed exercise was found in a group of women of different somatotypes and in a group of representatives of the endomorphic somatotype. In representatives of ectomorphic, endomorphic- mesomorphic and balanced somatotypes, there is a tendency to decrease heart rate and blood pressure after dosed loads. Such adaptation reactions are considered positive. Adaptation reactions of women aged 25-35 years under the influence of classes of health-improving swimming were manifested by a decrease in heart rate and systolic blood pressure after dosed physical exertion. Among representatives of different somatotypes, women of the endomorphic somatotype have more pronounced adaptation reactions of the cardiovascular system.
The Relation Between Temperature of Substrate and the Composition, Structure and Corrosion Resistance of the Zinc Coated Extruded Aluminum Multi-Void for Automotive Air Conditioning Unit
Authors: Huang X. , Wang R. , Zhang T.
Published: August 2022

The balanced flow type condenser is one of important part used in the air-conditioner of automobile. The manufacture needs the surface of aluminum multi-void to be coated with zinc. One of economical and efficient process is the automatic wire arc spray, in which the maintain of temperature and the in-process speed can make key effects on the quality of coatings. The relation between substrate temperature and the composition, structure and corrosion resistance of the coating of aluminum multi-void are mainly discussed to confirm the best in-process speed of aluminum multi-void, the maintain of temperature and the parameters of arc spraying. Abstract only; no full-text paper available.
Repair of Multi-Layered, Polymer-Based Thermal Spray Coatings
Authors: Gross K.A. , Yan F.Y. , Berndt C.C. , Simon G.P.
Published: August 2022

Polymeric coatings manufactured by thermal spray processes exhibit variable mechanical and adhesion properties that depend on their exact processing schedules. One important advantage of these coatings is that they can be readily repaired by re-spraying any delaminated or otherwise defective regions. In some instances the repaired region exhibits better mechanical attributes than the original coating. In this study the repairability of several classes of polymeric and polymer-ceramic composite coatings were investigated with a focus on the interfacial adhesion properties. The coatings include those of monolayer and bilayer ethylene methacrylic acid (EMAA), and CaCO3-EMAA composites. The coating thickness did not influence the interfacial adhesive strength between the coating and substrate; while a higher preheat temperature produced a greater interfacial cohesion for the monolayer coating on a metal substrate. The substrate preheat temperature played a dominant role concerning the peel strength of the coating. Greater peel strengths were achieved between polymers, at least twofold greater than that between the polymer and the steel substrate when the pre-heat temperature was greater than the melting point of the polymer. The peel strength of the composite coating decreased with filler content; both on the steel substrate and on a previously sprayed polymer coating. On the basis of these observations, the adhesion mechanism between polymers was explained with a model that relied on the formation of welding points.
Development of Durable Spray Coatings in Molten Aluminum Alloy
Authors: Mizuno H. , Kitamura J. , Osawa S. , Itsukaichi T.
Published: August 2022

A novel thermal spray material of MoB/CoCr with high durability in molten aluminum and/or zinc alloys has been developed to utilize for die casting parts and for galvanizing bath parts. The durability of the MoB/CoCr coatings prepared by high velocity oxy-fuel (HVOF) spraying has been investigated using a molten-metal immersing tester. It has been found that durability of the MoB/CoCr coating in the molten aluminum and Al-45%Zn alloys is much higher than that of the conventional surface treatments, such as physical vapor deposition, nitridation and spray coatings of conventional materials, such as WC/12%Co, WC/10%Co/4%Cr, Cr3C2/NiCr, Al2O3 and ZrO2-8%Y2O3. Preservation of the crystal structure and no decrease in coating thickness due to dissolution or delamination of the MoB/CoCr coating were seen after long term immersing test of about 600 hours. Further, the molten alloys were easily dropped from the specimens of the MoB/CoCr coatings during the immersing test, suggesting much lower reactivity. On the other hand, an adhesion of the alloys on the coating surface of other specimens was clearly observed. This means that the MoB/CoCr coating is excellent in increasing the lifetime of mechanical parts, which come into contact with molten metal and/or alloys.
Microstructure and Property of LTHVOF Sprayed Copper Coatings
Authors: Zha B. , Wang H. , Xu K.
Published: August 2022

LTHVOF(Low Temperature High Velocity Oxygen-Fuel) spray is developed by injecting nitrogen into the gun chamber. The flame temperature can be adjusted between 400K to 800K after cooling, which is identical to cold spray. Copper coatings were sprayed by LTHVOF. SEM photos show that the coatings are dense with a lamellar structure. X-ray diffraction pattern shows that there is no oxide in the coatings. LTHVOF may be another choice for coating production of low melt point metal and nanometer size materials.
The Cold Spray Process and Its Potential for Industrial Applications
Authors: Gärtner F. , Stoltenhoff T. , Schmidt T. , Kreye H.
Published: August 2022

Cold spraying has attracted serious attention since unique coating properties can be obtained by that process which are not achievable by conventional thermal spraying. This is due to the fact that coating deposition takes place without exposing the spray or substrate material to high temperatures and, in particular without melting of spray particles. Thus oxidation and other undesired reactions can be avoided. Spray particles adhere to the substrate only due to their high kinetic energy upon impact. For successful bonding powder particles have to exceed a critical velocity upon impact, which is dependent on properties of the particular spray material. This requires new concepts for the description of coating formation but also indicates applications beyond the market for typical thermal spray coatings. The present contribution is aimed to summarize the current ‘state of the art‘ in cold spraying and to demonstrate concepts for further process optimization. That concerns the management of impact velocities and temperatures as well as the development of powders tailored to the process. So far, a wide variety of different spray materials ranging from different metals or alloys to even metal matrix composites, has successfully been tested as promising coating material. All together, the advantages of cold spraying can enhance new applications in surface technologies.
Particle In-Flight Velocity Measurements from Particle Image Velocimetry in Cold Spray
Authors: Sansoucy E. , Richer P. , Taylor K. , Jodoin B. , Johnson M.
Published: August 2022

The cold spray process is a relatively new coating process by which protective coatings have been successfully applied. In this process, fine powder particles are accelerated in a supersonic gas jet towards a substrate. Experimental investigations show that successful bonding of the particles to the substrate is achieved only above a critical particle velocity at which point the particles possess sufficient kinetic energy to plastically deform upon impact. Consequently, one of the most important parameters in the cold spray process is the particle velocity prior to impact. In the present investigation, the Particle Image Velocimetry (PIV) technique have been implemented to a cold spray setup. The objective was to quantify the effects of the powder feed rate on the particle velocity. Fine metal particles were cold sprayed and in-flight particle velocities were measured using the PIV technique. This paper will discuss the implementation of the systems and present results illustrating the effects of powder feed rate on the particle in-flight velocity. Abstract only; no full-text paper available.
Alloying of Cold-Sprayed Al-Ti, Al-Ni Composite Films
Authors: Jung S.H. , Lee S.Y. , Lee H.Y. , Yu Y.H. , Ko K.H.
Published: August 2022

The Al-Ti, Al-Ni mixed powders were successfully coated by cold gas dynamic spray process (CDSP) and alloying behaviors of films after post-annealing were investigated. The particles were accelerated through a standard de Laval type of nozzle with 120psi (prior to enter). Instead of conventional He gas, the air was used as particle carrying gas. The as-purchased power size of Al, Ti, Ni, was 77, 44, and 3, respectively. The composition of Ti and Ni was varied from 10 and 30 wt%. The coated films were annealed at 600~630. in air or N2 atmosphere for 3 hrs. It was observed that Ni and Ti particles were finely dispersed and imbedded densely in Al matrix. After post annealing of Al-Ti and Al-Ni films, alloy phases such as the Al3Ti and Al3Ni phase were formed in the films. In case of Al-Ni films after annealing in air, the oxidation process seemed to retard the alloying of Al3Ni. However, after annealing in N2, the limitless alloying was proceeded until Ni particles were all consumed. In case of Al-Ti films, it was found that oxidation were virtually nonexistent even in air atmosphere. The formation of Al3Ti seemed to be limited by Al or Ti diffusion via preformed Al3Ti phase encapsulating Ti powder. In bond strength test, Al-Ti and Al- Ni composite films have higher adhesive bond strength up to 2~ 3 times more than pure Al coating due to massive crater formation of hard Ni or Ti particles. In conclusion, CDSP of Al-metal composite powder source can be a practical and economical way to prepare hard and adhesive Al-alloy thick films owing to stable and finely dispersed inter metallic compound formed in low Temperature annealing. Abstract only; no full-text paper available.
Production of Titanium Deposits by Cold Gas Dynamic Spray
Authors: Marrocco T. , McCartney D.G. , Shipway P.H. , Sturgeon A.J.
Published: August 2022

Over the past five years, interest in cold gas dynamic spraying (CGDS) has increased substantially. Considerable effort has been devoted to process development and optimization for low melting point metals such as copper and aluminium. This paper will describe work undertaken to expand the understanding of deposition of titanium by cold spray methods. CGDS deposits have been produced from commercially pure Ti. Using room temperature helium gas, a range of processing conditions, powder size ranges, substrates and substrate preparation methods have been employed to study their impact on deposition of powders. Scanning electron microscopy has been employed to examine deposit microstructures, and microhardness testing of deposits has been conducted. Samples for pull-off bond strength test have been prepared from a number of the more promising sets of parameters and adhesive strengths have been determined. Computational estimates of gas velocity and in-flight particle velocity have been made focusing specifically on the influence that these factors have on the process deposition efficiency. Differences will be discussed in terms of powder feedstock characteristics and the underlying physical and mechanical properties of the powders and substrates.
Effect of Heat Treatment on Properties of Cold Sprayed Coatings
Authors: Lagerbom J. , Mäkinen H. , Vuoristo P.
Published: August 2022

Cold spraying is a novel coating method in which coating is formed by mechanical deformation of sprayed metal particles. This heavy deformation causes structures, which need recrystallization heat-treatment in order to gain back the materials natural deformability. Aluminum, copper, nickel and Ni-20%Cr were cold sprayed and heat-treated at several temperatures. Coatings were sprayed using nitrogen as process gas. Substrate material was carbon steel. Heat-treatment temperatures were chosen from near room temperature to below coating materials melting temperature. As-sprayed and heat-treated coatings were characterized in microstructure, hardness, phase structure and electrical resistivity. It was found that 200ºC was enough to increase electric conductivity to 87% of pure copper. By heat treatment ductility was able to be increased and hardness subsequently decreased.
Finite Element Modelling of Acoustic Emission Behaviour of Thermally Sprayed WC-Co Coatings
Authors: Bansal P. , Shipway P.H. , Leen S.B.
Published: August 2022

The acoustic emission (AE) technique, when used with the four-point bend test, is potentially an effective method for characterization of the ductility and fracture behaviour of certain thermally sprayed coatings. Monitoring of AE during such tests on brittle coatings reveals that the rate of the occurrence of events with increasing load changes gradually over the duration of the test. In this work, finite element modelling (FEM) of a brittle coating on an elastic substrate in four-point bending is used to analyze the fracture behaviour of the coating and predict its AE behaviour. The results from the FE analysis show good agreement with experimental data from four-point bending of thermally sprayed WC-Co coatings.
Computational Simulations and Experimental Characterization of the Mechanical and Fracture Behaviour of Alumina-Glass Plasma Sprayed Coatings
Authors: Barbieri L. , Bolelli G. , Cannillo V. , Lusvarghi L. , Riccò S.
Published: August 2022

Plasma-sprayed alumina-waste glass composite coatings on ceramic substrates were produced. Two kinds of alumina powders, different alumina volume fractions, and two glass powders particle size distributions were tested. Post-process thermal treatments were performed. The coatings were characterized by SEM, XRD, Vickers microhardness, fracture toughness, abrasion resistance tests. Coatings superior to traditional tile glazes were obtained with as high as 50 vol.% of waste glass. Fine glass powders (<45µm) must be employed to achieve adequate toughness. A low-cost spray-dried alumina can be used instead of the expensive commercial powders. The thermal treatment enhances the coating properties. A FEM thermo-mechanical simulation was performed. Elastic modulus calculations show a definite coating anisotropy (higher mechanical properties in the longitudinal direction). Compressive residual stresses in the alumina and tensile ones in the glass are developed after the thermal treatment. Crack propagation studies based on Griffith model show cracks initiating from larger pores and propagating easily through the glass, thus explaining the coating toughening achieved through the employment of finer glass powders. Cracks are stopped by alumina; this effect is enhanced in the thermally treated coatings. The numerical and experimental (from indentation fracture toughness test) crack propagation patterns are in good agreement.
Modified Supersonic Nozzles for the Vacuum Plasma Spraying
Authors: Schwenk A. , Mihm S. , Nutsch G. , Wank A. , Gruner H.
Published: August 2022

Two new inner contours of de Laval nozzles (V70, V21) for F4 torch, which have already successfully been established for the Atmospheric Plasma Spraying (APS) are investigated for application under Vacuum Plasma Spraying conditions (VPS). Studies have been performed with regard to power efficiency, sound level and arc voltage fluctuations as well as coating quality and deposition efficiency for use of CoNiCrAlY powder as feedstock material. The results are compared to the commonly used standard VPS nozzle. CFD calculations and enthalpy probe measurements of plasma gas velocity and temperature distribution in the centreline of the supersonic plasma jets are carried out in order to get insight in the basic dependencies.
Constructive Aspects for the Application of Hard-Metal Coatings Using High Velocity Oxygen Fuel Flame Spraying (HVOF); Experience and Examples
Authors: Steinke T. , Bäker M. , Döring J.-E.
Published: August 2022

For 20 years now, the HVOF-method has been an industrially-established process for the application of hard-metal coatings to prevent wear phenomena from happening. A successful application combines the typical process parameters, conditions of materials and, above all, constructive frame conditions. In the following, we will present investigations for coating uneven outlines/contours such as edges, cavities or uneven surfaces. Furthermore, constructive frame conditions will be deduced from these and compared to our practical experience. The distribution of the layer thickness and its accessibility with the spray jet will be discussed as well. Here, we will have a closer look on which mechanical properties the basic substance has regarding hardness
Surface Preparation of Steel Substrates Using Grit-Blasting
Authors: Varacalle D.J. , Rhodaberger W. , Sampson E. , Guillen D.
Published: August 2022

The primary purpose of grit blasting for thermal spray applications is to ensure a strong mechanical bond between the substrate and the coating by the enhanced roughening of the substrate material. This study presents statistically designed experiments that were accomplished to investigate the effect of abrasives on roughness for A36/1020 steel. The experiments were conducted using a Box statistical design of experiment (SDE) approach. Three grit blasting parameters and their effect on the resultant substrate roughness were investigated. These include blast media, blast pressure, and working distance. The substrates were characterized for roughness using surface profilometry. These attributes were correlated with the changes in operating parameters. Twin-Wire Electric Arc (TWEA) coatings of aluminum and zinc/aluminum were deposited on the grit-blasted substrates. These coatings were then tested for bond strength. Bond strength studies were conducted utilizing a portable adhesion tester following ASTM standard D4541.
High Quality Coatings by VPS with Combined IC/DC-Spraying Technology
Authors: Gruner H. , Moens J. , Gruner Ph.
Published: August 2022

Direct current (DC) plasma spraying, in atmosphere (APS) or under vacuum condition (VPS), is a standard spraying technology to produce high performance coatings for important applications. Although inductive coupled (IC) plasma torches have been known since the early sixties, its use for industrial coating production remained limited due to the static gun requirement. An adequate substrate manipulation opens up the IC-spraying for its practical use. A VPS system was realized which combines IC- with DC-spraying. The potential of this new facility is highlighted by coatings of W and Yb2O3. The key parameters to achieve an optimized coating structure are explained.
Continuous Coating of Technical Textiles from “Coil to Coil”
Authors: Gadow R. , von Niessen K.
Published: August 2022

A pilot plant equipment for continuous coating of technical textiles is implemented to establish thermal spraying as a new and promising coating technique in the textile industry. In order to apply thermal spraying to temperature sensitive and flexible fiber structures two main difficulties have to be taken into account. First, the flexible structure of a textile fabric has to be fixed and stretched to achieve a sufficient mechanical support. Second, the kinetic and thermal energy of the molten particles and the hot gas jet may damage the fibers and their woven structure both mechanically and chemically. Special winding equipment is designed to allow various fabrics to be fixed and stretched in a way that enables the coating of wound fabrics from “coil to coil”. With this equipment even temperature sensitive fabrics, like cotton or polyester, but also aramide, carbon and oxide ceramic fabrics are coated by atmospheric plasma spraying or electric arc wire spraying in the case that higher deposition rates are required. Fabric coils up to a web width of 1500 mm can be coated continuously with a well-defined pre-stress in one single procedure.
Plasma Plume Condition Forming of Cascaded Type Plasma Guns
Authors: Hawley D. , Refke A. , Landes K.D.
Published: August 2022

In the thermal spray industry there remains a constant demand for more stable, controllable and economical processing devices. Most thermal spray applicators apply a wide range of materials especially those who are allied with the turbine markets. Each material coating specification requires a relatively specific range of velocity and temperature transferred to the powder particle to achieve the required material properties on the part. The plasma gun has become a dominant process tool in the turbine industry due to the wide range of parameters that are achievable with the basic tool. In addition, there are today a large number of individual plasma guns that are each known to provide excellent results with some, but not all coating requirements. In many cases the optimum gun running condition can never be achieved due to the interdependence of arc behavior and gas conditions. The turbine industry is currently largely populated with guns that are based on the technology as it was developed in the 1960’s. These guns are characterized by poor voltage stability with a large quasi periodic oscillation in the 3-5 kHz range as described by Bisson [1], with poor performance and life under more extreme operating conditions. A key element of any plasma gun is the nozzle geometry. The cascaded gun types as typified by the Triplex offer a unique opportunity to study and document a wide range of operational parameters, especially at extreme operating conditions.
Robotic Trajectory Autogeneration in Thermal Spraying
Authors: Deng S. , Liao H. , Zeng C. , Charles P. , Coddet C.
Published: August 2022

The quality of thermal spray coatings depends not only on the spray parameters but also on the gun trajectory. When using a robot, trajectory generation represents an important part of the work. Different workpieces require different spraying trajectories and even a same workpiece will require different spraying trajectories versus different spraying techniques. The purpose of this study was to develop a software toolkit to auto generate the spraying trajectory. Thermal Spray Toolkit is an add-in software of Robot Studio® which is a simulation and off-line programming software of ABB Company. This toolkit provides several projects of trajectory generation: spraying on a quadrilateral piece; spraying on a circular piece; spraying on a curved surface; etc. Furthermore, all the parameters of the trajectory are adjustable, such as traverse step; distance of overstep; etc. The results show that this development is reliable and applicable.
Calcium Phosphate Coatings Produced by Solution Precursor Plasma Spray
Authors: Garcia E. , Gan L. , Pilliar R. , Coyle T.
Published: August 2022

Calcium phosphate (Ca-P) coatings have been used as surface coatings on porous metallic implants in dentistry and orthopaedics for the last twenty years. These Ca-P coatings, nominally hydroxyapatite (HA), have been shown to promote bone fixation and osteconductivity on Ti and Ti alloy substrates used for those purposes. Such coatings can be formed by different methods including plasma spray. In addition to the well known advantages of the plasma spray technique to deposit coatings, a new version of this technique, i.e. solution precursor plasma spray (SPPS), has been reported to produce submicron/nanocrystalline structured coatings. Nanocrystalline HA coatings may improve the resorption of the coating in the body, avoiding the irritant effect of large particles which may be seen in current thermal sprayed HA coatings. The main purpose of this work was to study the suitability of a sol-gel Ca-P solution precursor (calcium nitrate tetrahydrate and ammonium dihydrogen phosphate) as feedstock for the air plasma spray (APS) coating technique. We report on the formation and the characteristics of the coatings so formed on Ti6Al4V substrates. The presence of different Ca-P crystalline and amorphous phases was assessed by X-ray diffraction analysis. The X-ray photoelectron spectroscopy technique was used to characterize the surface chemical composition of the Ca-P coatings. The microstructural features of the coatings were characterized by scanning/transmission electron microscopy combined with image analysis in order to evidence the presence of submicron/nanocrystalline Ca-P features. Final results are discussed in terms of the spraying parameters. Abstract only; no full-text paper available.
Cold Spray Deposition of Nanocrystalline Materials
Authors: Ajdelsztajn L. , Jodoin B. , Schoenung J.M.
Published: August 2022

This work describes recent progress in cold spray deposition of nanocrystalline metals and alloy. Gas-atomized powders (Ni and Aluminum alloys powder) were mechanically milled under liquid nitrogen to achieve a nanocrystalline grain size of the order of 10-30 nm. The powders were subsequently sprayed using a nozzle designed with a validated numerical model for cold spray technology. The resulting coatings were evaluated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), micro- and nanoindentation. TEM analysis shows that the nanocrystalline grain structure of the cryomilled feedstock powder was retained after the cold spray process. A significant increase in hardness was observed for all the cryomilled material when comparing with the conventional gas-atomized powder. The ability to use cold spray to produce nanocrystalline large deposits with low porosity (<1%) was also demonstrated in this work. Abstract only; no full-text paper available.
Thermal Shock Resistance of Thick Graded Nanostructured Zirconia-NiCoCrAlY Composite Coatings by Plasma Spraying
Authors: Yang H. , Wang H.G. , Cao X.P.
Published: August 2022

Thick Nanostructured PSZ- NiCoCrAlY graded TBCs were got by air plasma spraying. The results reveal the morphology and phase transformation of TBCs by means of SEM and XRD. The plasma spray process results in a characteristic layered structure consisting of lamellae, unmelted nano-particles and an inter-lamellar porosity. The test results of thermal shock show that the graded coatings have different failure behavior, which caused by thermal stress, radial cracks penetrating and substrate oxidation. The failure mode was the spallation of top coat due to thermal stress. The improved strain tolerance of the top coat was benefited from the high coating porosity, the segmentation cracking, the fine-splat size and the unmelted nanoparticles. It has been found that the lamella consists of nanoscale columnar grains parallel to the spraying direction.
Nanostructured and Conventional Titania Coatings for Abrasion and Slurry-Erosion Resistance Sprayed via APS, VPS and HVOF
Authors: Lima R.S. , Marple B.R. , Leblanc L.
Published: August 2022

In order to characterize the performance of nanostructured coatings during wear, nanostructured and conventional titania (TiO2) coatings were sprayed via three different thermal spray processes: APS, VPS and HVOF. Three distinct types of wear resistance were evaluated: dry-abrasion and slurry-erosion at 30° and 90°. The ranking of the wear performance of the different coatings varied for the three wear tests, except for the HVOF-sprayed nanostructured titania. The HVOF-sprayed nanostructured coating exhibited the highest wear resistance in all three types of wear. The different angles of erosion (30° and 90°) did not cause a change in the wear performance (ranking) of the HVOF-sprayed nanostructured coating, as was observed for the other coatings tested. The superior mechanical performance of the HVOF-sprayed nanostructured titania can be explained by observing the microstructure of the coating via high magnification SEM. These observations show that the nanostructured zones in the coating microstructure act as crack arresters, thereby increasing the coating toughness. The wear scars for the different coatings were also analyzed via SEM and used to help understand the wear performance of the different materials.
Magnetic Properties of HVOF Thermally Sprayed Coatings Obtained from Nanostructured Powders
Authors: Cherigui M. , Fenineche N.E. , Coddet C. , Gang J. , Grosdidier T.
Published: August 2022

Ultra fine grain Fe-Si based coatings were synthesised by HVOF thermal spraying of nanostructured powders obtained from mechanical milling. Magnetic measurements revealed a soft magnetic character for all the coatings. Additions of boron, niobium and copper were investigated. The thermal stability and the evolution of the coercivity with temperature were observed to be remarkable.
Phase Formation Mechanisms in Plasma Sprayed Hydroxyapatite Coatings
Authors: Sun L. , Berndt C.C. , Gross K.A.
Published: August 2022

Phase composition control is a prime concern for plasma sprayed hydroxyapatite [Ca10(PO4)6(OH)2; i.e., HA] coatings due to the complexity of both HA structure and plasma spray process. The present study aims to better understand the phase formation mechanism in the HA coating through compositional, structural and microstructural studies of HA coatings obtained from various spraying processes. A process model was established by considering both a single HA splat formation and coating buildup processes. Three HA recrystallization mechanisms were proposed on the basis of the temperature-time experiences of particles, their cooling rates, and the heat and hydroxyl accumulation during coating formation. The model explained very well the experimental results. It was concluded that crystallinity alone was not capable of reflecting the coating composition due to the existence of various portions of crystalline HA; i.e., unmelted, recrystallized and dehydroxylated HA, as well as the gradient compositional structure from the coating interface to the surface. Some newly formed nanocrystalline regions were also revealed in the coating microstructure.
Fluid Dynamic Stability of Plasma Spray Jets
Authors: Heberlein J. , Outcalt D. , Hallberg M. , Yang G. , Strykowski P. , Pfender E.
Published: August 2022

Instabilities of plasma spray jets have been a source of inconsistencies in coating properties. These instabilities can be minimized through the use of central injection torches or torches with fixed anode attachment. However, any low density ( < ~0.7) jet is globally unstable to small disturbances. Globally unstable jets are characterized by a short potential core, rapid spreading, and high entrainment, all of which are present in a plasma jet. Plasma jets have ratios of jet density to density of the surrounding gas on the order of 0.01, as well as rather low Reynolds numbers and thick boundary layers. In the present work, the instabilities are investigated through analysis of the disturbance growth in the shear layer between the plasma and the cold surrounding gas. These investigations are using two types of experiments, one consisting of a SG 100 spray torch with several optical diagnostic methods being applied to the shear layer analysis. The other experiment simulates the plasma jet at low temperatures by using a helium core jet exhausting into a sulfur hexafluoride (SF6) environment. The simulated plasma jet (SPJ) has a density ratio of 0.03. The simulated plasma jet (SPJ) allows controlled variation of the boundary layer through different fluid dynamic arrangements. It further allows use of diagnostics such as hot wire anemometry and PIV to clearly characterize the shear layer. Some of the characteristics of the shear layer are presented and comparisons between the plasma jet and the simulated plasma jet, and initial results on controlling the jet instability, are discussed. Abstract only; no full-text paper available.
Development and Properties of Tungsten-Based Coatings Sprayed by WSP(R)
Authors: Matejicek J. , Neufuss K. , Kolman D. , Chumak O. , Brozek V.
Published: August 2022

Plasma sprayed tungsten and tungsten-copper coatings are being developed for potential application as plasma facing materials for fusion reactors. Initial spray tests indicated difficulties in tungsten melting and in-flight oxidation. Numerical modeling was performed to help explain these issues. A complex study of the process and its products was performed, including: in-flight diagnostics, characterization of isolated splats, and structure, composition, thermal and mechanical properties of the coatings. Based on these results, the process was optimized, with respect to powder size and various spraying parameters, to improve melting of the particles, reduce oxidation and increase the deposition efficiency.
Plasma Sprayed Ultra High Temperature Ceramic Materials Tested in Simulated Operative Conditions
Authors: Tului M. , Valente T. , Marino G.
Published: August 2022

Thermal protection systems represent the key issue for the successful re-entry of a space vehicle. Future concepts for space launchers foresee sharp aerodynamic profiles as conventional aircrafts, which offers several advantages with respect to current blunt shapes. As a drawback, aerodynamic heat flux increases dramatically and state of art hot structures materials cannot withstand them. UHTC (Ultra High Temperature Ceramics) materials are very promising candidate materials for such applications. An innovative, proprietary methodology was developed to produce, by plasma spraying deposition, a ceramic composite containing SiC particles (25 wt %) dispersed in a ZrB2 matrix. With such a technique both coatings and self standing parts were fabricated. The present paper reports the results of a development activity aiming at testing plasma sprayed real scale components in simulated operative conditions by means of a Plasma Wind Tunnel. The results of the tests showed that plasma sprayed UHTC materials can withstand very high heat flux conditions in an oxidizing environment. Abstract only; no full-text paper available.