bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbide Containing Materials for Hard Chromium Replacement by HVOF-Spraying
Authors: Kirsten A. , Oechsle M. , Moll R.F. 
Published: August 2022

Abstract
Hard chromium, electrochemical deposited, is a widely used and established coating solution for surface protection against wear and corrosion as well as for decorative applications. Due to the possibility to coat bulk goods also, this technique is well suitable to protect small pieces and mass-produced goods. However, the most disadvantage of that technique is the appearance of highly carcinogenic hexa-valence chromium. Because of human health and environmental aspects the replacement of this coating technique is more and more required. At least for bigger parts with larger surfaces H(igh) V(elocity) O(xy) F(uel) -spraying can already produce competitive coatings to galvanic hard chromium with equal or even better properties. Especially thermal sprayed carbide coatings with in terms of corrosion resistance tailored metallic matrices offering the best potential to replace hard chromium in various applications. Beside of the material properties also the spraying conditions have essential influence on the corrosion resistance of those coatings. The present paper will give an overview of different carbide containing materials for HVOF-spraying and their properties with special respect to the replacement of galvanic hard chromium. The closest attention will be on the corrosion resistance of HVOF-coatings of those materials in different aqueous solutions compared with hard chromium. For a liquid fuel high velocity spraying system also the trends will be shown in which way the spraying parameters are influencing the general corrosion behaviour of such coatings. Those tendencies by conviction of the authors are also transferable to other HVOF systems.
Analysis of Thermal Fluxes Transferred by an Impinging HVOF Jet
Authors: Bolot R. , Verdy C. , Coddet C. , Cornu D. , Choulant M. 
Published: August 2022

Abstract
In the present paper, both CFD computations and experiments were carried out in order to quantify thermal fluxes from an impinging HVOF jet. The case of a CDS gun fed by natural gas is considered. Standoff distances ranging from 50 mm up to 300 mm were investigated. The CFD model implements a 2-layer extension to the Chen-Kim k-? turbulence model for a better quantification of thermal exchanges with the front body surface. Experiments were performed using two different methods. The first device incorporates two square calorimeters positioned side by side. It was elaborated in order to attempt defining the radial profile of the transferred thermal flux. Additionally, an infrared thermal camera was used to measure the front part surface temperature.
Nanoreinforced HVOF-Sprayed Ceramic Coatings
Authors: Turunen E. , Varis T. , Hannula S.-P. , Keskinen J. , Lintunen P. , Fält T. 
Published: August 2022

Abstract
HVOF thermal spraying has been developed to deposit dense Al2O3-coatings with improved protective properties for various applications. Nanocrystalline coatings have been found to offer better thermal shock resistance, lower thermal conductivity and better wear resistance than their conventional counterparts. In this paper we describe the development of nanocrystalline Al2O3 and Al2O3-Ni -coatings, where the grain size of Al2O3 has been decreased and a few percents of nickel has been added in order to toughen the coating. Coatings were manufactured by HV- 2000 HVOF using spray parameters determined based on the on-line spray diagnostics. Parameters were selected aiming at different melting stages of the powder. The resulting microstructure of the coatings and its influence on the coating properties is discussed
Influence of Post Heat Treatment on Microstructure and Wear Properties of Thermally Sprayed WC-Co Coatings
Authors: Vuoristo P. , Laurila J. 
Published: August 2022

Abstract
In this study we studied the influence of post heat treatment of thermally sprayed WC-Co coatings on coating microstructure, phase structure and wear resistance. The coatings were prepared from two different spray powders by detonation gun process, with two different spray conditions. The as-sprayed coatings showed very different microstuctures and wear properties. After heat treatment, the coatings showed very similar good wear performance, although the phase structures showed large differences. Abstract only; no full-text paper available.
High Rate Deposition of Protective Coatings by High Power Diode Laser (HPDL)
Authors: Naumann T. , Scharek S. , Nowotny S. , Vuoristo P. , Tuominen J. , Latokartano J. , Vihinen J. 
Published: August 2022

Abstract
Laser cladding is a surface treatment technology in which thick, dense and metallurgically adhered metallic layers are deposited on various structural steels with relatively low heat input, high accuracy and reproducibility. Laser cladding processes used in industrial cladding are largely based on the use of CO2 or Nd:YAG lasers. High power diode lasers (HPDL) with rectangular beam spots are regarded as ideal laser sources for laser cladding processes, due to their compact size, high electrical to optical efficiency, easy operation, and low investment and running costs. In laser cladding of large surface areas, the affectivity of the laser cladding process becomes more important, i.e. high laser powers, wide laser beam spots, and high coating material feedrates are regarded as beneficial. In order to optimise the cladding process for such applications, special attention has to be put on devices used to deliver the coating power to the process. In the present work, various parameters in effective HPDL cladding are described and new approaches to optimised HPDL cladding process are described. The performance of a new HPDL cladding powder delivery nozzle will be presented and discussed. Abstract only; no full-text paper available.
Characteristics of BSCCO Thin Films Fabricated by using the Layer by Layer Deposition and Evaporation Deposition Method
Authors: Cheon M.W. , Park Y.-P. 
Published: August 2022

Abstract
The BSCCO thin film fabricated by using the layer by layer deposition method was compared with the BSCCO thin film fabricated by using the evaporation method. Reevaporation in the form of Bi atoms or Bi2O3 molecules easily bring out the deficiency of Bi atoms in thin film due to the long sputtering time of the layer by layer deposition. On the other hand, the respective atom numbers corresponding to BSCCO phase is concurrently supplied on the film surface in the evaporation deposition process and leads to BSCCO phase formation. Also, it is cofirmed that by optimizing the deposition condition, each single phase of the Bi2201 phase and the Bi2212 phase can be fabricated, the sticking coefficient of Bi element is clearly related to the changing of substrate temperature and the formation of the Bi2212 phase.
Corrosion Resistance and Microstructure of Arc-Sprayed Zn-Al and Zn-Al-Mg Coatings
Authors: Liu Yan , Zi-Xin Zhu , Yong-Xiong Chen , Xu B. , Ma Shining , Li Z. 
Published: August 2022

Abstract
In this study, cored wires and high velocity arc spraying technique (HVAS) were applied to produce Zn-Al and Zn-Al-Mg alloy coatings on low carbon steel substrates. The microstructures and mechanical properties were studied by SEM, EDS, XRD, and Vickers micro-indentor. The electrochemical corrosion behaviors of Zn-Al and Zn- Al-Mg coatings were investigated comparing with Zn and Al coatings in 5%NaCl. The results show that, Zn-Al and Zn-Al-Mg coatings have good quality of uniform microstructure and low porosity. The corrosion resistance of Al coating deteriorated rapidly after nearly 16h immersion, and then kept at a relative stable value. In the contrast, the corrosion potential of the coatings containing Zn decreased a little and then increased towards the noble potential. The potentiodynamic polarization tests show that the icorr value of Zn-Al coating changed greatly at different steps, and it trended to increase continuously which may imply that the coating is easy to be corroded. Comparatively, no obvious change had been found in the Zn-Al-Mg coating which may indicate that the corrosion resistance enhanced with the addition of Mg, and the role of Mg appears to be associated with the self sealing process. Abstract only; no full-text paper available.
Stress Gradients in Plasma Sprayed Chromia Coatings
Authors: Dubsky J. , Materna A. , Chraska P. , Prask H.J. , Gnaeupel-Herold T. 
Published: August 2022

Abstract
It is generally known that plasma sprayed coatings exhibit rather a low strength thanks to their characteristic microstructure with porosity and microcracks. To determine the role of varying types of deformation in different parts of the coatings profile, 1.8 mm thick chromia coatings on a steel substrate were made using WSP plasma spray. Stress gradients were then measured "in-situ" on a four-point bending device during bend deformation of the coated beam using neutron diffraction. Only compressive loading in coatings increased the resulting stresses. From the plot of stresses vs. applied strain (linear dependence) the Young’s moduli of the substrate and the coating were determined. Both values agree well with those obtained by mechanical testing. In general it is believed that, in a simplified way, interlamellar voids (cohesion defects) roughly parallel to the substrate decrease the tensile strength in the direction perpendicular to the substrate, while intralamellar cracks, roughly perpendicular to the substrate, significantly affect the Young’s modulus of coating. It is supposed that the tensile deformation of coatings opens the cracks and no stress increase is observed. On the other hand the applied compressive deformation in the coating closes the intralamellar microcracks and the internal stresses increase, as suggested by obtained results.
High Crystallinity Degree Hydroxyapatite Coatings using HVOF Spraying
Authors: Fernández J. , Guilemany J.M. , Gaona M. 
Published: August 2022

Abstract
Biomaterial coatings must have high degrees of crystallinity and phase purity, good adhesive and cohesive integrity and adequate porosity to promote bone ingrowth. The most used coating method is atmospheric plasma spraying. However, the main drawback of this technique is the generation of an amorphous phase and other calcium phosphate phases after the spraying process, which are not present in the feedstock and are not desirable. The use of HVOF as a process for obtaining hydroxyapatite coatings on Ti-6Al-4V was used successfully. With optimised HVOF process parameters, coatings with similar bond strength to plasma sprayed HAp coatings, good microstructure and higher crystallinity degree than atmospheric plasma sprayed ones where hydroxyapatite was the only crystalline phase present were obtained. Coating characteristics were analysed with XRD, EDS, SEM, FTIR which indicated that the coatings had a high degree of crystallinity and good bond strength. Moreover, in vitro response were also evaluated and the strength of the coating to the substrate.
On the Influence of the Substrate Hardness on Cold-Sprayed Nickel Coating
Authors: Raletz F. , Ezo’o G. , Brenot P. , Vardelle M. 
Published: August 2022

Abstract
Cold spray process is an emerging technique that produces high density coatings. Particles are carried by a supersonic gas stream through a De Laval nozzle and, finally, impact on a substrate with high kinetic energy. Low gas temperatures make it possible to maintain sprayed material in solid state during the whole process. Beyond a given velocity, called “particle critical velocity”, particles can bind to the surface and create a coating. This velocity is clearly dependent on both sprayed material and substrate properties. This study deals with the investigation of the influence of the substrate hardness on nickel coating properties. Substrates with different hardness but same chemical composition were used. Samples are then coated with pure nickel or NiCrAlY under the same operating conditions. The measurements of some coating properties and process parameters (deposition efficiency (D.E.), level of porosity, micro hardness) allow the analysis of the effect of substrate hardness on sprayability. It was found that only D.E. is widely influenced by hardness of the substrate. It decreases drastically (especially for NiCrAlY) since hardness of the substrate is higher than hardness of the particle. Porosity level and coating hardness remain constant whatever substrate hardness is.
Study of Laser Ablation in Conjunction with Wire Arc Spraying of Al-5Mg Coating Onto 7075 Al Alloy
Authors: Arsenault B. , Gougeon P. , Coddet C. 
Published: August 2022

Abstract
In order to broader thermal spraying applications and reduce constraints and time due to conventional surface preparation before thermal spraying, the PROTAL process was developed over the last decade. This process integrates laser ablation, using a Q-switched Nd-YAG laser to prepare the surface simultaneously to the coating build-up during Plasma or HVOF Spraying. The present paper aimed at evaluating the feasibility to use the Protal technology in conjunction with the Twin Wire Arc deposition (Arc spraying) onto the 7075 Aluminum based alloy and to define the optimal Protal process parameters. Coating adhesion, micro-gap at coating-substrate interface and the coating residual stresses are evaluated. The Protal parameters investigated are: the laser energy density onto the substrate and the coating layers, the number of laser passes and the time delay between the laser impact. This study results indicate that it is feasible to use the Protal technology in-situ with the Arc spray process in spite of the challenging overspray and the large plume size of the Arc process. Good adherence and absence of interface micro-gap is obtained with an appropriate range of laser energy density to ablate the substrate. The use of a low energy ablation prior each coating layers reduces coating tensile residual stresses and improves furthermore the bond strength. The elimination of the process ablation dust and overspray dust prior the coating deposition onto the plane substrate was found critical to obtain a good bond strength. This research results from collaboration between the LERMPS in France and National Research Council Canada. Abstract only; no full-text paper available.
Suitability of High Power Diode Laser for Plasma-Augmented-Laser-Cladding (PALC)
Authors: Wilden J. , Bergmann J.P. , Aicher M. , Dolles M. 
Published: August 2022

Abstract
Laser cladding offers several advantages as low dilution, low thermal influence and distortion of the components and a fine microstructure due to the high cooling rate. Nevertheless the set of laser cladding in the industrial production is nowadays limited to few applications, as the efficiency of laser sources is still too low and the running costs are too high. The absorption behaviour of metal surfaces, as for example steel, towards diode laser (up to approx. 42%) is very high compared to Nd:YAG (approx. 35%) and CO2-Laser sources (approx. 11%), so that some benefits can be expected. One of the disadvantages of diode laser was the low intensity and the difficulty to couple it in a fibre. The development of the last years reached to overcome these boundaries. High power diode lasers are nowadays available till 6 kW and can be coupled in fibres, allowing an easier processing. Investigations regarding laser alloying with high power diode laser confirm the appreciable reliability of this laser class. In order to improve efficiency of laser surface processing the hybrid process plasma-augmented-laser-cladding (PALC) with an Nd:YAG laser source was presented and confirmed that due to the pre-heating of the powder through the plasma transferred arc and the activation of the metallic surface a higher processing velocity (factor three) and efficiency could be reached by summing only one third of the energy with a PTA-equipment. Further more when processing with higher velocity the energy loss due to conductivity decreases so that a further positive increase of efficiency can be depicted. The suitability of fibre coupled high power diode laser for PALC hasn’t yet been investigated, even if the set of this laser type would be very advantageous. In this paper investigations regarding the process design and the necessary set up of the hybrid PALC-process with a 3 kW fibre coupled high power diode laser and wire coating metal are reported.
In-Flight Particle Diagnostic of Water Stabilized Plasma Spray Process
Authors: Chraska T. , Neufuss K. , Oberste-Berghaus J. , Lamontagne M. , Moreau C. 
Published: August 2022

Abstract
Individual particles of various ceramic materials sprayed by water stabilized plasma torch (WSP) were characterized in flight by an optical sensing device DPV-2000. Temperature, velocity, and diameter of individual particles were measured at the center of particle plume and maps of the particle plume cross-section were acquired as well. Plasma jet and consecutively particle plume of the WSP torch is much larger compared to gas stabilized torches and even larger than the maximum span of the DPV-2000 sensing head. In summary, temperatures of particles varied from 2000 to 2600°C and their velocities from 60 to 140 m/s depending on the powder feedstock cut size, particle density, feeding distance, spraying distance, and feed rate. The last three parameters were varied to study their effect on the particle states and their distribution in the plasma jet and to correlate these results with selected properties of the corresponding coating. Some of the spraying parameter effects are difficult to interpret, nevertheless, general trends have been established.
Characterization of the Particle Jet of Different HVOF Guns by Means of LDA
Authors: Wank A. , Wielage B. , Grund T. , Rupprecht C. , Zimmermann S. , Landes K. 
Published: August 2022

Abstract
For constant conditions concerning substrate state, feedstock and environment properties of thermal spray coatings depend only on temperature and velocity of particles at impact on the substrate. Two different HVOF spraying guns, the kerosene fuel system Tafa JP5000 with radial powder injection and the ethylene fuel system Sulzer Metco Diamond Jet Hybrid 2700 with axial powder feeding, are characterized concerning the evolution of space resolved velocity and density of particles by LDA. Also influence of process parameter variations is examined. The region of shock diamonds is studied specifically. The influence of different characteristics concerning impact velocity and trajectories on the coatings microstructure is determined by means of optical microscopy and microhardness testing.
Diagnostic and Microstructure of FeSi Coatings Sprayed by HVOF
Authors: Cherigui M. , Fenineche N.E. , Moulla L. , Elkedim O. , Coddet C. 
Published: August 2022

Abstract
Amorphous metallic alloys can be produced by rapid quenching from the metallic liquid at sufficient cooling rates to suppress the nucleation and growth of crystalline phases. The cooling rates required depend on the alloy constitution; generally the necessary values are in the order of 106 Ks-1[1]. There has been considerable interest in the manufacture of Fe-based metallic glasses because they possess attractive combinations of properties such as high hardness, good abrasive wear resistance together with enhanced corrosion resistance and good magnetic properties. However, in order to achieve these cooling rates in metallic alloy melts, samples less than 50 ƒÝm thick must be suddenly brought into good thermal contact with an efficient heat sink. Hence, these amorphous alloys are frequently produced in the form of ribbon or powder. An alternative approach consists to employ thermal spraying to deposit the alloys directly onto a substrate, in the form of a protective coating about 200 ƒÝm thick. In this study, FeSi powder was chosen as feedstock material. It is characterized by its good magntic properties [2- 7]. In order to control temperature and velocity of the in-flight particles during the coating deposition, on-line measurement of flame sprayed FeSi particles were performed with high-speed two-color pyrometer used especially for the spray forming process. In the same time, a wide band spectral pyrometer (LAND INFRARED) was used to monitor the coating surface temperature to ensure achieving good cooling rates. X-ray diffraction patterns show that the FeSi coatings structure present a crystalline phase and magnetic measurements indicate the soft ferromagnetic character of this last. Abstract only; no full-text paper available.
Modeling of an YSZ Coating Building and Thermomechanical Behavior during Plasma-Spraying
Authors: Patru J. , Fauchais P. , Bianchi L. , Hugot F. 
Published: August 2022

Abstract
Plasma coating performances and lifetimes may be ruined during service conditions because of uncontrolled residual stress development within the coating. This study presents the results of a CAST3M thermomechanical numerical model which purpose is to simulate the different residual stresses development within the duplex coating-substrate during the coating built up and its comparison with the experimental results. To achieve the thermal spray process understanding all the thermal fluxes transferred to a metallic beam and surrounding temperatures were measured so as to provide the CAST3M model with precise boundary conditions, corresponding to a specific geometry. The residual stresses were experimentally determined by the in situ curvature measurement and, afterwards, by the hole drilling method. The plasma torch stand-off distance, the relative torch/substrate velocity and the substrate material were considered as the parameters of this study. The main results concern the substrate temperature and deflection during the preheating stage, the thermal energy transferred by the molten splats to the substrate together with the quenching stress and the development of thermal stress during the final cooling.
Study on the Photo Catalytic Ability of Plasma Splayed TiO2-HAP Compound Coatings
Authors: Miyano Y. , Shibata Y. , Murai K. , Kikuchi Y. , Ohmori A. 
Published: August 2022

Abstract
The photo catalytic TiO2 coatings on biodegradable plastic (polybutylene succinate: PBS) were prepared by using plasma splaying techniques. It is reported that there is a possibility that the performance of photo catalytic TiO2 coating may be advanced by addition of absorption ability [1]. It is also well known that the extraordinary absorption ability of HAP (hydroxyapatite) [2]. In this study, to investigate the influence of the addition of absorption ability to the coatings, not only pure anatase TiO2 powder but also two types of TiO2-HAP compound powder (TiO2- 10wt.%HAP, TiO2-30wt.%HAP) were used as thermal splay materials. The microstructure of coatings was characterized with SEM and XRD analysis, and some photo catalytic ability of coatings as a functional material was evaluated. One was the air purification performance of the coatings through the photo degradation of acetaldehyde gas, and the other was the sterilization performance to bacteria. In not only pure anatase TiO2 powder condition, but also in TiO2-10wt.%HAP and in TiO2-30wt.%HAP powder condition, the high anatase ratio which was approximately 95% were verified. In terms of decomposition ability to acetaldehyde gas, TiO2-10wt.%HAP coating was predominate to the others. This result indicates the addition of absorption ability. In terms of sterilization ability to bacteria and bacteria absorption, TiO2-HAP compound powder coatings showed a good performance.