bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Torch Hardware and Operating Parameters on Oxy-Acetylene Powder Flame Spray Heat Flux
Authors: Cates J.W. , Urrea D.A. , Hall A.C. , Neiser R.A. , Smith M.F. , Beatty D.E. , Mayer A.J. , Roemer T.J. , Hirschfeld D.A. , Cook D.J. 
Published: September 2022

Abstract
The effect of torch hardware, operating parameters, and powder type on substrate surface heat flux was quantitatively investigated using calorimeters. The Sulzer-Metco 6P oxyacetylene torch with two nozzles and two air caps and the Alamo PG-550 torch were studied using designed experiments to show the effects of total combustible gas flow, oxy-fuel ratio, air flow, and standoff distance on surface heat flux. Air caps which directed cooling air toward the flame produced lower heat flux than air caps providing gun cooling. For the 6P torch, nozzle geometry did not have a significant effect on heat flux. With low air flow rates, both torches exhibited similar heat fluxes. At high air flows, the surface heat flux of the PG-550 was larger than that of the 6P.
High Speed Visualization and Plume Characterization of Hybrid Spray Process
Authors: Stanisic J. , Kosikowski D. , Mohanty P.S. 
Published: September 2022

Abstract
The hybrid spray process that combines arc-spray with HVOF/plasma jet, has recently demonstrated its effectiveness in the deposition of functionally gradient coatings. This approach aims at exploiting the attributes of both the arc-spray technique combined with those of the HVOF/APS technique. This paper presents high speed visualization and plume characterization of an Arc/HVOF hybrid spray gun as well as a twin-wire arc spray gun. The physics of atomization in hybrid spray process is examined using high-speed camera. A DPV-2000 particle diagnostics sensor is used to measure particle velocity, temperature, size and distribution. The influence of feed material, arc-spray parameters, and the jet parameters on the particle characteristics is presented. The differences in the in-flight characteristics between the hybrid and the twin wire arc process have been discussed aided by the observed atomization phenomena with the high speed camera.
Prospect for Plasma Spray Process On-Line Control Via Artificial Intelligence (Neural Networks and Fuzzy Logic)
Authors: Kanta A.F. , Montavon G. , Planche M.P. , Coddet C. 
Published: September 2022

Abstract
Parametric drifts and fluctuations occur during plasma spraying. These drifts and fluctuations originate especially from the electrode wear and intrinsic plasma jet instabilities: the plasma net power varies in this case modifying significantly its thermodynamic properties and transport coefficients hence modifying the momentum and heat transfers to the particles. It is possible to control the in-flight particle characteristics by adjusting continuously the operating parameters, in particular the power parameters. Due to the large amplitudes of these drifts and fluctuations, the strategy to adopt will depend on the required corrections to apply to the particle characteristics. Developing a reliable controller requires: (i) implementation of reliable sensors to accurately diagnose in-flight particle characteristics but also some other parameters, such as surface temperature during spraying; (ii) development of a robust command, to insure the stability of the control system. Fuzzy logic permits to define parametric correction rules and the command can be based on these algorithms; (iii) linking of the robust command to a predictive model. Artificial neural networks, among other artificial intelligence protocols such as genetic algorithms, proved to be able to predict in-flight particle and coating characteristics; (iv) validation of the corrections with an extensive database used as a reference. Coupling neural protocols to fuzzy logic should permit the development of such an independent controller which could adjust in real time the operating parameters as a function of the measured in-flight particles to manufacture a coating with identical conditions among its entire thickness. This paper aims at presenting the methodology and the controller and at simulating the spray operation.
Evaluation of Adhesion Strength and Residual Stress of HVOF Sprayed Metallic Coatings
Authors: Yokoyama K. , Watanabe M. , Kuroda S. , Gotoh Y. 
Published: September 2022

Abstract
The purposes of the present study are firstly to establish a reliable experimental method to evaluate the adhesion strength and secondly to reveal the relationship between the adhesion strength and the residual stress in the coatings. SUS304 stainless steel coatings were deposited on low carbon steel substrates by HVOF spraying. Two types of samples were fabricated. One is a cylindrical shape for the adhesion test and the other has a rectangular dimension for residual stress evaluation. The tensile adhesion tests were carried out by modifying the conventional test method. Circumferential interface cracks were introduced by putting carbon thin layer on the substrate before spraying, and the edge of the substrate was masked to prevent undesirable deformation during spraying. The interface fracture toughness was estimated from the load at failure and the width of carbon area in radial direction (corresponding to the crack length) by finite element analysis. The residual stress was evaluated by measuring the relaxed strain at the substrate surface for reduction of the coating thickness. Thinning of the coatings was performed by polishing. It was possible to evaluate the adhesion strength of SUS304 steel coatings with good reproducibility for the samples deposited under various spray conditions. The correlations between adhesion strength and residual stress will be discussed.
MoB/CoCr Spray Coating with Higher Durability in Molten Al and Al-Zn Alloys
Authors: Mizuno H. , Aoki I. , Tawada S. , Kitamura J. 
Published: September 2022

Abstract
MoB/CoCr, a novel thermal spray material, with high durability in molten Al and/or Al-Zn alloys has been developed to utilize for die casting parts of Al alloy, and for hot continuous dipping roll in Zn and Al-Zn plating lines. The durability of the MoB/CoCr coatings prepared by high velocity oxy-fuel (HVOF) spraying has been investigated using a molten metal immersion tester. The immersion tests revealed that the MoB/CoCr coating has much higher durability without dissolution in the Al alloys than conventional spray coatings, such as WC/12%Co and WC/10%Co/4%Cr, as well as various other surface modification methods. The MoB/CoCr coating also has showed higher durability in the molten Al-Zn alloy when the coefficient of thermal expansion (CTE) of the substrate is similar to that of the MoB/CoCr. The lifetime of the coating on stainless 316L substrate, widely used as the hot continuous dipping roll, was insufficient because of the generation of cracks due to a large difference in the CTE between the MoB/CoCr coating and substrate. Basic anneal examinations have revealed that optimization of coating structure by changing undercoat material and its thickness is effective to improve the lifetime.
Plasma Transferred Arc Deposition of Beryllium
Authors: Hollis K. , Bartram B. , Withers J. , Storm R. , Massarello J. 
Published: September 2022

Abstract
The exceptional properties of beryllium (Be) including low density and high elastic modulus, make it the material of choice in many defense and aerospace applications. However, health hazards associated with Be material handling limit the applications that are suited for its use. Innovative solutions that enable continued use of Be in critical applications while addressing worker health concerns are highly desirable. Plasma Transferred Arc solid freeform fabrication is being evaluated as a Be fabrication technique for civilian and military space based components. Initial experiments producing beryllium deposits are reported here. Deposit shape, microstructure and mechanical properties are reported.
Plasma Spray Formed Yttrium Oxide Crucibles
Authors: Hollis K. , Bartram B. 
Published: September 2022

Abstract
Plasma spray forming ceramic components on a mandrel provides a way of net shape forming of difficult to machine materials. In addition, the structure of plasma sprayed ceramics contains fine porosity that improves strain accommodation as compared to sintered ceramics. However, plasma spray forming causes complex stress states in materials that may lead to cracking during spraying or during separation from the mandrel. Monitoring surface temperatures by infrared videography and controlling deposit surface temperature by directed cooling can be used to minimize thermal gradients and minimize part cracking. Control of thermal stresses is also necessary for proper separation of the sprayed part from the mandrel. Details of the plasma spray forming of yttrium oxide crucibles show how temperature monitoring, directed cooling, and robot manipulation are used to produce a crack free crucible.
Novel Nickel-Cermet Hardcoatings
Authors: Sherman A. , Garrett W. , Conklin M. 
Published: September 2022

Abstract
Current thermal spray chrome replacement and hardfacing materials primarily use WC or Cr3C2 as hardphase materials and contain chrome. A series of cermet alternatives based on lower weight and cost ceramic particles including alumina, silicon carbide, boron carbide and titanium nitride were applied via HVOF and tested for wear and frictional properties under various loading conditions. Furthermore, based upon highly promising initial results, thermal spray particle designs were modified for lower cost and improved performance.
Wear Behaviour of APS and HVOF Sprayed Ceramic Coatings
Authors: Bolelli G. , Cannillo V. , Lusvarghi L. , Turunen E. , Varis T. , Fält T. , Hannula S.-P. 
Published: September 2022

Abstract
Plasma sprayed oxides are effective coatings against wear and corrosion. Low particle velocity in the plasma jet causes a limited interlamellar cohesion. HVOF-sprayed ceramic coatings emerged as an improved alternative. In this paper, microstructural characteristics and tribological performances of HVOF sprayed Al2O3, nanostructured Al2O3 and Cr2O3 coatings are compared to reference plasma-sprayed Al2O3 and Cr2O3. The microstructure is analysed by SEM, EDS and XRD. Hardness and fracture toughness are investigated by instrumented indentation and elastic modulus by 3-point bending. Steel wheel and rubber wheel tests have been used to assess dry particle abrasion resistance. Sliding wear resistance is tested by pin-on-disk at room temperature and at 400°C, against SiC and 100Cr6 steel balls. HVOF-sprayed coatings are denser and have better interlamellar cohesion thanks to increased particle velocity. They are harder, tougher, possess a higher elastic modulus and lower porosity. Dry particles abrasion resistance is definitely superior to plasma-sprayed ceramics due to higher toughness; sliding wear resistance is higher, particularly at 400°C.
Correlation between Process Maps of HVOF-Sprayed WC-Co Coatings and Wear Resistance
Authors: Valarezo A. , Choi W.B. , Gouldstone A. , Sampath S. 
Published: September 2022

Abstract
The general method of process maps to understand and control thermal spray processes has been applied to monitor the deposition of WC-Co by high velocity oxygen fuel (HVOF). A selected number of particle state conditions (velocity and temperature) has been performed to produce a variety of coatings. Microstructure, mechanical properties, and wear resistance were evaluated and compared. A second order process map for sliding wear, impacting particle erosion and abrasive wear control can be constructed from the process map to provide the limits within which the particle state can be changed to achieve a predefined coating specification. The mechanisms behind the wear resistance are discussed within the framework of wear maps –third order process map-in the context of analysis of inter splat de-bonding, mechanical properties of the coating, and delamination failure.
Effect of Torch Hardware on Oxy-Acetylene Powder Flame Spray Performance
Authors: Urrea D.A. , Cates J.W. , Hall A.C. , Neiser R.A. , Smith M.F. , Hirschfeld D.A. , Mayer A.J. , Beatty D.E. , Roemer T.J. 
Published: September 2022

Abstract
The effect of hardware on operating parameters and the resultant coating are qualitatively known; however, the quantitative effects have not been well defined. This study quantitatively characterizes particle temperature and velocity for the Sulzer-Metco 6P oxy-acetylene torch with 3 different nozzles and 3 air caps and also, the Alamo PG-550 then relates those data to particle diagnostics, deposition efficiency and coating microstructure. Both torches were evaluated using statistically designed experiments where the process inputs of oxy-fuel ratio, total combustible gas flow, and standoff distance were varied. Both torches can access similar regions of particle temperature - particle velocity space. Increasing total combustible gas flow increased particle velocity with little effect on particle temperature. Increasing oxy-fuel ratio decreased particle temperature with little effect on particle velocity. Higher particle velocity and particle temperature conditions yielded denser, less porous coatings. Flame cooling air caps increase the particle speed while decreasing particle temperature. Nozzles which inject powder directly into the flame jets significantly increase particle temperature as compared to nozzles which do not. Deposition efficiency is shown to not only be affected by particle temperature and particle velocity where hotter and faster usually increase efficiency, but is also dependent on the distribution of particles within the plume.
Properties of SiC-Reinforced Aluminum Alloy Coatings Produced by the Cold Spray Deposition Process
Authors: Sansoucy E. , Ajdelsztajn L. , Jodoin B. , Marcoux P. 
Published: September 2022

Abstract
SiC-reinforced Al-12Si alloy coatings were produced using the Cold Gas Dynamic Spraying deposition process. Feedstock powder mixtures containing 20% and 30% vol. of particulate SiC were used. The composite coatings’ bond strengths and microstructures were evaluated, as well as the porosity and the SiC content. It was found that approximately 45% of the SiC particulate blended with the aluminum alloy was embedded in the coatings. The SiC was homogeneously distributed inside the Al-12Si matrix. Particle velocity measurements revealed that the addition of up to 30% vol. of SiC did not change the Al-12Si particle velocities.
Densification of Ti Coatings by Bi-modal Size Distribution of Feedstock Powder During Warm Spraying
Authors: Kawakita J. , Watanabe M. , Kuroda S. , Katanoda H. 
Published: September 2022

Abstract
Warm Spray has demonstrated that it could fabricate comparatively dense metal coatings keeping with high purity during the atmospheric process. Its key technology is the control of the temperature of the supersonic combustion jet prior to supplying feedstock. So far, even titanium (Ti), known as one of materials difficult for the atmospheric process, could be deposited with less oxidation and higher density of the resulting coatings. For instance, the porosity and oxygen content of two coatings obtained were 2.3 vol% and 0.28mass%, and 1.1vol% and 0.92mass%, respectively. Further densification of Ti coatings was achieved by bi-modal size distribution of feedstock powder upon Warm Spraying in this study. When bigger Ti particles were mixed with the usual feedstock powder under 45 µm, the coating porosity was decreased to 0.8vol% simultaneously with the low oxygen content of 0.26mass%, which was comparable to the level of feedstock powder. This densification is caused by the balance of the enhancement of the peening effect by big particles and of optimization of the filling rate of the big and small particles.
A Three-Dimensional Analysis of the Cold Spray Process: Effect of Substrate Location and Shape
Authors: Samareh B. , Dolatabadi A. 
Published: September 2022

Abstract
A three dimensional model of a Cold Gas Dynamic Spray system with a peripheral non-axisymmetric powder feeder is studied in this work. It is found that the stagnation pressure alternates for different substrate stand-off distances due to the nature of the supersonic flow interaction with the substrate. One can find the optimum substrate location for any given operating condition which results in minimum pressure buildup on the substrate. The three-dimensional analysis shed more light on the complex gas and particle flow fields generated due to the three-dimensional particle injection process. Additionally, the three-dimensional model allows us to further investigate the effect of practical substrate shapes (such as convex and concave) on the flow field and consequently to determine the optimum conditions to deposit coating particles.
Deformation Behavior and Properties of a CuZrTiNi BMG Kinetic Spray Coating
Authors: Kim J.S. , Xiong Y.M. , Lee C. , Choi H.S. , Kim H.J. 
Published: September 2022

Abstract
The deformation behavior and mechanical properties of a Cu54Zr22Ti18Ni6 bulk metallic glass during and after deposition by kinetic spraying were investigated. The bulk metallic glass feedstock particles were manufactured by inert gas atomization and were subsequently deposited onto mild steel substrates by means of kinetic spraying at different powder carrier gas temperatures [room temperature, 450°C (within the supercooled liquid region), and 550°C (above crystallization temperature)]. In addition, the phase compositions of the feedstock and as-sprayed BMG coatings were investigated using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), and Transmitted Electron Microscopy (TEM). With an increase of the powder feed temperature, it was deduced that more intimate contact of the particles with the substrate was achieved which decreased the porosity of the resulting coating. However, crystallizations, which seemed to be induced by severe deformation and accumulated heat, were observed at localized regions in the coating. In addition, micro-hardness and bond strength were affected by the crystallization degree of the as-sprayed coatings
Examination of the Estimating Approaches for the Critical Velocity in Cold Spraying
Authors: Li C.-J. , Yang G.-J. , Li C.-X. , Bang H.S. , Bang H.S. , Li W.-Y. 
Published: September 2022

Abstract
The particle critical impact velocity is a key parameter in cold spraying. The appropriate estimation of this critical velocity benefits the optimization of coating deposition in terms of deposition efficiency. The critical velocity can be estimated experimentally through measuring the relation between deposition efficiency and particle velocity. A recent study has revealed that the critical velocity can be estimated by the velocity resulting in the onset of adiabatic shear instability through numerical simulation of particle impact. However, it was found that the critical velocities of a pure metal material obtained by different investigators through simulation were significantly different. No reasonable explanation was provided to such difference. In the present paper, the critical velocities reported in the literature for Cu powder as a typical material were reviewed. The factors influencing the critical velocity were examined. The numerical simulation methods employed in the limited literature were also examined for a better understanding of the factors that influence the simulated results. A reasonable estimation method was proposed by using the numerical critical velocity.
DYMET Technology Evolution and Application
Authors: Kashirin A. , Klyuev O. , Buzdygar T. , Shkodkin A. 
Published: September 2022

Abstract
High requirements of Cold Gas Dynamic Spray (GDS) process caused the development of low pressure DYMET technology. The technology and equipment evolution is presented and discussed. Modern portable low pressure DYMET equipment may be easily applied for various technical problem solutions. Multiple applications are briefly described.
Improvement of Plasma Gun Performance using Comprehensive Fluid Element Modeling: Part 2
Authors: Molz R. , McCullough R. , Hawley D. , Muggli F. 
Published: September 2022

Abstract
Utilization of a comprehensive validated computer model of a thermal spray process enables an ability to improve, optimize, and fine tune the performance of that thermal spray process. A validated model of the Sulzer Metco TriplexPro 200 plasma gun has been used to improve the performance of the actual gun in terms of enhancing gas flow dynamics, thermal management, and overall performance in terms of a robust design. Internal changes to the gun geometry using the model have extended the life of the hardware beyond any current plasma gun. In addition the model has permitted the investigation of the fundamental operation of the gun, specific to the behavior and path of the arcs, as well as the ability to operate the plasma gun, under simulation, in operating regimes that currently cannot be supported by the physical hardware. The model has been run at gas pressures above 14 bar and/or voltages above 300V that currently cannot be obtained with the physical hardware due to equipment limitations to evaluate the potential to extend the operating window of the Sulzer Metco TriplexPro 200 gun beyond current levels in terms of particle velocity and temperature. The end result is an improved process tool for applying thermal spray coatings from high temperature ceramics to relatively colder and faster carbides and alloys.
Modeling and Diagnostic Study of a Supersonic Impinging Plasma Flow Near the Surface of a Substrate
Authors: Xue S. , Lakaf Y. , Gravelle D. , Boulos M.I. 
Published: September 2022

Abstract
A consistent thermal and chemical non-equilibrium model for inductive supersonic plasma flow, developed recently, is applied to the modelling of pure argon supersonic plasma flow, which impinges on a substrate below the Mach 1 nozzle. The model considers the ionization of argon atom and the corresponding recombination but the second order ionization is ignored and plasma charge neutrality is assumed. The transport and mass diffusion coefficients are computed using the collision cross-section data, published by Devoto and Murphy and the computations of transport properties are fully coupled with the calculation of the plasma flow fields. The model treats the subsonic discharge region above the supersonic nozzle and the supersonic region below the nozzle together. Two different turbulent models are incorporated into the model to describe the supersonic plasma flow. The modeled radial and axial profiles of electron and heavy species temperatures and electron number densities near the substrate are then compared to those measured by the method of optical emission spectroscopy and finally the most realistic model is identified.