bluuebunny/crossref_metadata_2025_split huggingface dataset:
Current and Next-Generation Titanium Blade Compatible Compressor Abradable Coatings
Authors: Sporer D. , Wilson S. 
Published: January 2023

Abstract
Compressor abradables coming into operational contact with bare, un-tipped titanium alloy rotor blades over a wide range of incursion conditions require excellent cuttability in order to avoid blade tip damage by wear and over-heating. This is more easily achieved for low temperature systems that can make use of low shear strength aluminum matrices than for compressor abradables operating closer to the maximum allowable temperature of advanced titanium alloy blade materials. In this case the rotor path linings will have to incorporate higher temperature resistant Ni and Co alloy matrices. To that end the availability of abradable coatings capable of operating at up to 550°C while showing little thermal ageing effects and excellent abradability over their entire service life can influence the compressor blade material selection and therefore compressor weight and performance characteristics. This paper provides an overview of titanium blade friendly compressor abradable concepts. Particular emphasis will be placed on the abradability of in-service and next-generation coatings designed for use up to the temperature capability of Ti blade rotor materials and beyond. Candidate coatings are also screened for other performance criteria such as thermal cyclic resistance and ageing behaviour.
Integrated Study of APS YSZ Coatings with Different Spray Angle
Authors: Chen Y.K. , Tan Y. , Tessarini S. , Sampath S. 
Published: January 2023

Abstract
Spray parameters play an important role on the microstructure and properties of plasma sprayed coatings. Parameters such as spray distance, plasma gas flow and current, raster speed and spray angle all can be varied. In this paper, an integrated study to investigate the effects and influences of spray angle on properties of yttria-stabilized zirconia coatings was carried out with spray angles of 60°, 75° and 90° (to the substrate surface). In situ coating property sensor (ICP) based on beam curvature measurements was used to measure the evolving stress and elastic moduli of the resultant coatings and combined with other characterization tools for thermophysical property and microstructure analysis, such as laser flash and scanning electron microscopy (SEM). The results indicate that the coating with 60° spray angle had the lowest thermal conductivity and more compliant structure. This study seeks to understand the mechanism for this effect and will provide important insight into parametric sensitivities on complex spray parts.
Role of Process Conditions on the Interfacial Fracture Toughness of Plasma Sprayed Zirconia
Authors: Okajima Y. , Nakamura T. , Sampath S. 
Published: January 2023

Abstract
Adhesive strength of the plasma-sprayed thermal barrier coating (TBC) is one of the most important parameters which influence the reliability during service. In the past, numerous test methods were reported to measure the coating adhesion. However, most of them require careful and time consuming preparation. Consequently, limited information could be obtained to establish the relationship between the processing conditions and the adhesive property. To produce more measurements using a simpler procedure, the interfacial indentation test and the modified tensile adhesive test are examined. In this paper, the interfacial fracture toughness of the plasma-sprayed ZrO2 coatings, deposited on Al substrates, were evaluated by these two tests. In order to study the effects of the powder injection, samples were sprayed with various carrier gas flow rates. The test results show a certain correlation between the melting index and the interfacial fracture toughness. In addition, variations between the results obtained from the two different methods are discussed.
High Velocity Suspension Flame Sprayed (HVSFS) Bioactive Coatings for Biomedical Applications
Authors: Stiegler N. , Killinger A. , Gadow R. 
Published: January 2023

Abstract
Thermal spraying of suspensions containing particles of submicron or nano-size offers new possibilities in functional coating development and enables new application fields. Spraying of suspensions containing bioceramic materials by hypersonic flame spraying (HVSFS), result in coatings with a refined microstructure. A layer thickness ranging from 10 - 50 µm can be achieved. Thermally sprayed HAp coatings are widely used for various biomedical applications due to the fact that HAp is a bioactive, osteoconductive material capable of forming a direct and firm biological fixation with surrounding bone tissue. Bioceramic coatings (e.g. Hydroxyapatite HAp, Tricalcium Phosphate TCP or Bioglass) were thermally sprayed on Ti plates by high-velocity suspension flame spraying. The deposited coatings were mechanically characterized. The bond strength of the layer composites was analyzed by the pull-off method and compared for different spraying conditions.
Design of Experiments Analysis of Flame Sprayed PCL/PMMA Bioactive Coatings
Authors: Chebbi A. , Stokes J. 
Published: January 2023

Abstract
Bioactive coatings are proven to enhance bone regeneration, implant integration and act as drug-delivery systems following bone replacement surgeries. Polycaprolactone (PCL) was used in this study as coating material due to its superior biocompatibility and biodegradability. Polymethyl-methacrylate (PMMA) was used as an additive in order to improve the flowability of the PCL powder. The processing technique used to obtain polymeric coatings was oxy-acetylene flame spraying. Seeing that biodegradable polymers were not thoroughly investigated in the past, a Design of Experiments (DoE) analysis was necessary in order to understand the effects of spraying parameters on coating characteristics (thickness, roughness, adhesion, wettability) and to be able to optimize the coating properties for specific requirements. The polymer matrix was sprayed onto titanium substrates. The statistical analysis was followed by FTIR spectroscopy, which showed that the coatings underwent little chemical degradation. Finally, biocompatibility tests showed that cells proliferated well on the flame sprayed polymer coatings, which confirms that the coating technique used did not affect the biological performance of the material.
Modeling of Phenomena Occurring in Plasma Jet at Suspension Spraying of Hydroxyapatite Coatings
Authors: Delluc G. , Pateyron B. , Pawłowski L. , Calve N. , Denoirjean A. 
Published: January 2023

Abstract
The phenomena occurring after injection of water-ethanol suspension of fine hydroxyapatite powder are simulated numerically. The mathematical modeling starts with the calculation of the map of velocity and temperature of working plasma gases. The map is calculated by taking into account the evaporation of the liquids included in the suspension. The suspension is injected through a mechanical injector into the anode-nozzle of the SG-100 torch. The plasma was generated with the use of working gases composed of 45 slpm of Ar and 5 slpm of H2 and with the electric power input of 30 kW. The initial droplets of suspension were supposed to be spherical with a diameter equal to that of the injector, i.e., 500 µm. The trajectory of suspension was calculated until the evaporation of liquids. Then, the simulation of the movement and heating of solid hydroxyapatite (HA) started. The HA powder was home synthesized and exhibited a bimodal size distribution with two maxima around 3 and 10 µm. The equations describing the momentum and heat transfer from hot gas to the solids took into account the small size of solid particles. In particular, the thermophoresis force, as well as, the drag coefficient modified for non-continuum effect were used in the calculation of the trajectory of small particles. Similarly, the non-continuum effect was considered in the calculation of heat transfer. The obtained trajectories were tentatively correlated with the microstructure of the suspension plasma sprayed HA coatings.
Fabrication of Aluminum-Alumina Metal Matrix Composite Coatings Via Cold Gas Dynamic Spraying at Low Pressure Followed by Friction-Stir Processing
Authors: Hodder Kevin , Gerlich Adrian , Villafuerte Julio , McDonald André 
Published: January 2023

Abstract
Cold gas dynamic spraying (“cold spraying”) at low pressure (150 psig) was used to fabricate Al-Al2O3 metal-matrix composite (MMC) coatings onto 6061 Al alloy. The powder contained -45 µm Al stock powder admixed with -10 Al2O3 in fractions ranging from 0-90 wt%. Scanning electron microscopy (SEM), Vickers microhardness testing, and image analysis were conducted on the as-sprayed coatings. The coatings were then friction-stir processed (FSP) using a milling machine and a 12 mm diameter cylindrical tool. Microhardness testing, SEM, and image analysis were then repeated to study the effect that FSP had on the MMC coating hardness. Hardness increased with increasing fraction of Al2O3 in the feedstock powder, resulting in a maximum as-sprayed coating hardness of 85 HV when 90 wt% Al2O3 is used. After FSP, the hardness of the MMC fabricated from a 90 wt% Al2O3 powder blend increased to a maximum of 140 HV. SEM micrographs showed that the as-sprayed MMC coatings contained Al2O3 particles that had been trapped between the larger Al particles. FSP succeeded in redistributing the Al2O3 particles, decreasing the mean free interparticle distance and increasing the probability of load sharing between the reinforcing particles. It was suggested that this redistribution may be the primary reason for hardness improvement in the MMC coatings.
Deposition of Amorphous Aluminium Powder Using Cold Spray
Authors: Koh P.K. , Cheang P. , Loke K. , Yu S.C.M. , Ang S.M. 
Published: January 2023

Abstract
Deposition of amorphous aluminium powder using cold spray technology as a corrosion prevention measure was studied. Amorphous aluminium (Al-Ni-Ce) powder was successfully deposited on 7000-series aluminium substrates using cold spray parameters of 1.7 MPa under compressed air and temperature of 450°C. The coatings were subjected to tensile bond strength measurement and comparative studies with cold sprayed pure Al6061 coatings were conducted. The results obtained showed that the amorphous aluminium coatings exhibited better adhesive strength. In addition, salt-water immersion test was conducted. The Al-Ni-Ce coating not only demonstrated better corrosion resistance but also exhibited evidence of passivation of surface imperfections such as scratches in the coatings.
Research on Corrosion Behavior of Cold Sprayed Copper Coating on Aluminum Substrate
Authors: Guosheng Huang , Daming Gu , Xiangbo Li , Lukuo Xing , Hongren Wang 
Published: January 2023

Abstract
Due to its low processing temperature, cold-sprayed coatings tend to exhibit many advantages over traditional thermal sprayed coatings, such as, lower porosity, oxidation and residual stress levels. These characteristics impart the improved anti-corrosion performance of the cold-sprayed coatings. However, it is not known how much these factors influence the corrosion performance of them. In addition, there are few results on the electrochemical behavior difference between cold and thermally sprayed coatings. In this article, as-deposited cold-sprayed copper, aluminum bulk material, arc-sprayed copper and pure copper are tested with electrochemical methods to compare their electrochemical behaviors in natural seawater. The electrochemical methods included the potential-dynamic polarization curve and electrochemical impedance spectrum. The results indicated that there is no significant difference in the corrosion potential between cold-sprayed and bulk copper materials. The potential of cold-sprayed copper is much different from that of the arc-sprayed one. Polarization curves indicated that the corrosion rate is significantly higher for arc-sprayed copper. The electrochemical impedance spectrum shows that there is no difference in electrode interface structure between cold-sprayed and bulk copper materials. Based on these results it is inferred that the higher corrosion rate for arc-sprayed copper was caused by its high porosity level and oxidation degree.
Kinetic Metallization Repair of Alclad
Authors: Tapphorn R. , Gabel H. , Hashimoto K. , Crowe T. 
Published: January 2023

Abstract
Cladding is a common method of providing corrosion protection of aluminum alloys, which forms an anodic layer in direct and intimate contact with the alloy sheet during cold roll processing. A structural aluminum alloy is clad in a thin layer of a higher purity alloy that is more galvanically reactive. Common examples include 1230 clad on 2024, and 7072 clad on 6061 and 7075. If this clad layer is damaged or removed the underlying structural alloy is exposed and susceptible to corrosion and/or stress corrosion cracking. Kinetic Metallization is a low temperature deposition technique compliant with MIL-STD-3021 that enables repair or replacement of worn or damaged clad layers. Aluminum or Al-Trans coatings are deposited as a new clad coating, and can be subsequently polished to the same mirror finish as the original clad surfaces. This paper presents the techniques developed for repairing worn or damaged Al clad surfaces using the economical Kinetic Metallization process and the qualification tests performed to date for various feedstock powder formulations (Ref 1).
Phase Transformation of Cold-Sprayed Ni/Al-Al2O3 Composite Coatings during Post-Spraying Annealing Treatment
Authors: Yang G.-J. , Zhao S.-N. , Li C.-X. , Li C.-J. 
Published: January 2023

Abstract
NiAl-Al2O3 intermetallics based composite coatings were prepared by cold spraying of Ni/Al-Al2O3 composite powders followed by post-spraying annealing treatment. The phase transformation mechanism from Ni/Al mechanical alloy to intermetallics was explored to aim at controlling the microstructure of the composite coating. Results showed that, with the porous Ni/Al and Ni/Al-Al2O3 green compacts, self-propagating high-temperature synthesis (SHS) reaction was ignited at a temperature of 500-600°C. However, SHS reaction was not able to be ignited for the cold-sprayed dense Ni/Al alloy coating with or without substrate. SHS reaction was even not ignited for the Ni/Al-40vol.%Al2O3 composite coating, although the thermal conductivity of the coating was significantly decreased by the addition of Al2O3 ceramic particles. The phase transformation from Ni/Al mechanical alloy to NiAl intermetallics during post-spraying annealing can be evidently attributed to diffusion mechanism.
As Coated Compounding of Intermetallics from Feedstock of High and Low Melting Points by Cold Spraying
Authors: Ko K. H. , Choi J. O. , Lee H. 
Published: January 2023

Abstract
It is well known that the inlet temperature of the spray gas influences the impact velocity of particles which, in turn, affects the mechanical and chemical properties of the final coating. From cold spray of high- and-low-melting-point feedstock such as Cu-Sn, it was found that those effects can vary with changes in particle shape and size. Copper powder feedstocks with different shapes, such as and dendritic (under 25 μm), were selected for analysis. For spherical (under 10 μm) powders of Cu6Sn5, an intermetallic compound (IMC) of Cu-Sn was formed in the as-coated state at and above gas inlet temperatures of 100 °C. for A gas inlet temperature of at least 300 °C was needed for the dendritic Cu powders. As temperatures increase, another IMC, Cu3Sn, was also formed. The onset temperature for the formation of the additional IMC was 450 °C for both shapes. Below 300 °C, both Cu and Sn were in solid state and thermodynamic driving forces were drawn from impact energy. Therefore, the spherical particles had more stored energy (strains) than the dendritic particles to initiate IMC formation.
Corrosion Protection of Mg-Alloys with Cold Sprayed Composite Coatings
Authors: Maeva E. , Dzhurinskiy D. , Leshchynsky V. , Maev R.Gr. 
Published: January 2023

Abstract
Due to the demand for improved fuel economy as well as increased safety features, weight reduction is one of the major aims in the automotive industry. Future lightweight automotive components for the next car generation will probably use lots of magnesium alloy. These will form galvanic couples with other materials and may induce phenomena accelerating the corrosion rate of automotive components. The materials used were magnesium alloy AZ31B and several types of cold sprayed coating. The relative performance of each cold sprayed corrosion preventive compounds (CPC) was assessed in combination with the materials under several different electrochemical and accelerated corrosion tests. Baseline data for AZ31B with no CPC applied was also collected. CPC characteristics and properties are also included and discussed. The studies on bare Mg/Steel couples validated accelerated corrosion but found that CPC cold sprayed coatings mitigate corrosion rates. Thus Mg/Fe interfaces with defect-free cold sprayed coatings CPC can prevent buildup of corrosion products and reduce galvanic corrosion of automotive components.
Influence of Chemical Composition of WC Cermet Powders on Cold Spraying
Authors: Sato K. , Furukawa H. , Kitamura J. , Sato K. , Seo D. , Ogawa K. 
Published: January 2023

Abstract
From the appearance of high velocity oxygen fuel (HVOF) thermal spray system in the 1980s, WC cermet coatings have been used as anti-wear coatings in many industrial manufacturing applications. Recently, WC cermet spray materials were applied using new thermal spray methods such as warm spray and cold spray, which are still in the research phase. In HVOF spraying, WC-Co and WC-Ni powders are regularly used as coating materials. On the other hand, using cold spray, WC-Fe alloy series can be deposited as dense and thick coatings, better than WC-Co. In this study, WC-Fe alloy powders were sprayed by cold spray to investigate the influence of binder metal on the coating properties and compared with those of HVOF WC-CoCr coatings. It was observed that the lower metal ratio and FeCrNi chemical composition exhibited improved results.
Atmospheric Plasma Sprayed Forsterite (Mg2SiO4) Coatings: An Investigation of the Processing-Microstructure-Performance Relationship
Authors: Cojocaru C.V. , Lamarre J.-M. , Legoux J.-G. , Marple B.R. 
Published: January 2023

Abstract
Evaluating and understanding the relationship between processing, microstructure and performance of a dielectric coating is essential for its practical usage and reliable application. In this study, the role of the powder feedstock on the properties of atmospheric plasma sprayed forsterite (Mg2SiO4) dielectric coatings was investigated by using different forsterite powder cuts. The microstructural and porosity characteristics of the coatings associated with the spray conditions employed were assessed via scanning electron microscopy (SEM) and image analysis. The phase composition of the coatings was studied via X-ray diffraction and their crystallinity index determined. The electrical insulating characteristics were investigated using the dielectric breakdown test. The obtained electrical properties were correlated with the microstructural characteristics. Ultimately, a performance comparison between forsterite and other dielectric coatings tested in similar conditions is presented.
Influence of Thermal Spray Parameters on Two-Wire Arc Aluminum Semiconductor Equipment Coatings
Authors: Watson M. , Gansert R. 
Published: January 2023

Abstract
Thermal spray metallic coatings are used for a range of applications in the semiconductor equipment industry including applications from particle reduction to precious metal reclaim in chamber operations during thin film deposition. Thermal spray coatings assist in reducing part costs, increasing product performance and lifetimes, and reducing chamber maintenance. The processing parameters in two-wire arc spraying of aluminum are traditionally used to provide a range of coating properties in industry from dense coatings for corrosion control applications- to rough texture coatings for anti-slip applications. Thus, the two-wire arc processing parameters selected for use for semiconductor applications are critical for surviving the semiconductor processing environment and increasing product performance. Important two wire processing parameters include current, voltage, atomizing air pressure, and stand-off distance between the gun and target (sprayed part). Secondary processing parameters including robotic traverse rate, air cooling, part manipulation (turntable speed, etc.) and others. Further, the specifics of the two-wire arc gun design (make/model), nozzle diameter, air caps, and wire diameter are also important variables. Current and voltage are important parameters for generating the electric arc for melting the aluminum wire. An optimum processing window exists for the range of current and voltage used for producing the aluminum coatings. The atomizing air pressure also has an optimum range for atomizing the molten aluminum produced from the electric arc. A range of atomizing air pressures are used to produce a range of coatings from dense to rougher textured coatings. Higher operating current increases the quantity of molten producing the coatings, and the lower operating current reduces the spray rates of the aluminum to be atomized. This paper examines the two-wire arc parameters producing aluminum coatings. Two-wire arc parameters to be examined include current, voltage, atomizing air pressure and stand-off distance varied to produce coatings. The coating produced from these parameter changes will be investigated in terms of microstructure and mechanical properties. The microstructural investigation will involve porosity analysis. Mechanical property testing will include tensile-adhesion bond strength. The surface roughness will also be investigated
Instability of the Arc Spraying Using Cored Wires
Authors: Tillmann W. , Abdulgader M. 
Published: January 2023

Abstract
Owing to the arc ignition in twin wire arc spraying (TWAS) the wire tips are heated in three different zones. The outer part of the wire tips (contact zone) is heated directly by the arc ignition (zone I). The wires material in this zone becomes fully liquefied. The heat propagation phenomenon raises the temperature of the area immediately adjacent (towards the fed wires) generating a doughy material (zone II). Next to the doughy zone (towards the fed wires) the transferred heat softens the wire material causing a permanent deformation (zone III). The deformation is due to the exerted aerodynamic forces of the atomization gas pressure. A high speed imaging system was used to observe the melting behavior, metal break up, and particle formation under different operating conditions. The liquidus metal in zone I is directly atomized in the form of smaller droplets. Their size is a function of the specific properties of the molten metal and the exerting aerodynamic forces. The doughy area (zone II) is the origin of the extruded metal sheets at the anode and cathode side. The extruded metal sheets in case of cored wires are shorter than the ones observed by solid wires. The extruded metal sheets support the re-ignition of the arc and therefore enhance the process stability in twin wire arc spraying. In this study the effects of adjustable parameters and powder filling on melting behavior, particle formation and process instability were revealed and a comparison between solid and cored wires was made. The findings can improve the accuracy of TWAS process modeling and enhance the atomization of metal droplets through the adoption of specific nozzle geometry modifications.