bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of biodiesel from waste cooking oil using heterogeneous catalyst
Authors: Jaya Danang , Wahyu Widayati Tunjung , Salsabiela Hanum , Abdul Majid Muhammad Fathan
Published: November 2022

The world's oil reserves are running low, which makes the government also implement a mandatory B30 policy starting in early 2020. With this policy, it is necessary to develop energy by utilizing renewable energy such as vegetable oil that can be converted into biodiesel. Waste cooking oil is one of the vegetable oils that has the potential to be processed into biodiesel because the use of waste cooking oil in Indonesia is still not developed. In this study, we report the yield of biodiesel from waste cooking oil with variations in the ratio of the number of moles and weight of heterogeneous catalysts. Biodiesel is made by esterification and transesterification with a heterogeneous catalyst (CaO), then a separation process is carried out to separate the biodiesel produced from the by-product in the form of glycerol. The separated biodiesel is then analyzed for density, viscosity, flash point, and pour point. The results showed that the best biodiesel was at a mole ratio of 1:24 with 3% CaO catalyst. Based on the analysis data, this biodiesel has the largest yield of 72.49% with a viscosity value of 4.9806 cSt, a flash point value of 72.5 oC, a pour point value of 0 oC, and a density value of 0.8662 g/ml and calorific value. 8837,302 cal/gram. With the results of the analysis, that are in accordance with the quality standards of SNI 7182:2015.
Renewable Energy from Pyrolysis of Pine Wood with Zeolite Catalyst
Authors: Achmad Zubaidi , Arsa Abdullah Kunta , Alfitamara Bety , Virgiandini Alfia
Published: November 2022

Renewable energy becomes a hot issue on the decrease of fossil energy reserves that can not be renewed. To answer the challenge of the availability of these energy a study was performed in a high-temperature cracking process from pine wood to obtain fuel oil or so-called pyrolysis. The purpose of this study was to determine the yield, physical properties, and the calorific value of the pyrolysis results. Pyrolysis process is done by varying the percentage of mordenite-type zeolite catalyst as much as  0% b/b, 2% b/b, and 4% b/b, with a mass of 100 grams of pine wood that passes sieving each sample to 50 mesh. Before use, the catalysts physically activated by heating at a temperature of 500°C and chemically activated using HCl to enhance the activity of the zeolite. Pyrolysis carried out at 400°C, 450°C, 500°C, and 550°C. After the analysis, bio-oil obtained optimum yield of 43.77142% by mass of the catalyst 4% b/b and a temperature of 500 °C. Physical properties obtained in the form of density 1.094723 g/ml, 2.96 cP viscosity, and 58°C flash point. While the highest calorific value on the condition of the catalyst 4% and the reaction temperature 550°C is 26045.50 kJ/kg.
Mathematical Model of Water Absorption in Arrowroot Starch-Chitosan Based Bioplastic
Authors: Yusuf Yusmardhany , Irfandy Fauzan , Istiani Alit
Published: November 2022

Expansion of the size of the weight of bioplastics often occurs in daily use. This phenomenon happens because the material from bioplastics can absorb significant amounts of water. This process can lead to accumulation of swelling degree. Therefore, a mathematical model is needed to quantify this mechanism to predict the dynamics of changes in the weight of bioplastics with respet to time while contact with water to help practitioners during application design for the use of bioplastics. This study aims to build a mathematical model derived from the mass sense validated by experimental data through curve fitting. The experiment was conducted by observing the rate of change in the mass of bioplastic made from starch and chitosan by measuring the change in mass concerning time immersed in water under atmospheric conditions. The immersion time was varied between 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40,50, and 60 minutes. As a result, it can be concluded that starch-chitosan-based biofilms can absorb water up to ±10.9174 gr-water/gr-bioplastic, and also this phenomenon can be quantified by a mathematical equation that derived from mass balance with an average percent error of 1.13% and R-squared coefficient of 0.9981.
Pengaruh Variasi Konsentrasi NaNO3 pada Medium Raoof terhadap Kultivasi Spirulina Platensis
Authors: Syaichurrozi Iqbal , Wardalia Wardalia , Dwicahyanto Sharfan , Toron Yustinus Selis
Published: November 2022

Nutrition is one of the factors that affect the growth of Spirulina platensis. The cultivation medium proposed by Raoof is a modified version of Zarrouk medium. Raoof medium requires less nutrients than Zarrouk medium but the biomass produced is almost the same. This study was conducted to vary the concentration of NaNO3 of 0.5; 1.5; 2.5; 3.5 g/L in Raoof medium to study its effect on growth and biomass composition of S. platensis. At each concentration of NaNO3 of 0.5; 1.5; 2.5; 3.5 g/L obtained the highest biomass concentration of 0.6425; 0.6455; 0.6745; 0,5193 g/L on days 12, 12, 12, 10. Concentration of NaNO3 of 2.5 g/L resulted in the highest specific growth rate of 0.1371/day and the lowest double time of 5.0566 days. In general, increasing the concentration of NaNO3 from 0.5 to 2.5 g/L increased the protein content from 33.30 to 36.98%. The addition of higher NaNO3 (3.5 g/L) actually decreased the protein content to 35.52%.
Acid Tar Waste Beneficiation Through Blending with Coal
Authors: Musademba Downmore , Simbi David Jambgwa , Kuipa Pardon Kusaziwa
Published: November 2022

The possibility of blending acid tar waste with coal as a beneficiation method was explored in this work. It was essential to first establish the material properties of the acid tar and coal samples together with that of the blends in terms of proximate analyses. The acid tar waste to coal blending ratios of 3:1, 1:1 and 1:3 were used. It was observed that acid tar waste exhibited high volatile and moisture content with low ash and carbon content when compared with coal. When compared with coal; a 3:1 blending ratio exhibited 56.9 % and 7.6 % reduction in ash and fixed carbon respectively and on the contrary a 38.1 % increase in volatile matter was observed. An opposite trend was obtained with 1:3 blend ratio. The 1:1 blend ratio was found to decrease the volatile and ash content by 8.3 % and 52.7 % respectively whilst fixed carbon boosted by 4.2 %. The choice for the blending ratio to apply is a trade-off between fixed carbon and volatile matter. If volatile matter is of any significance then a 3:1 mixture would be ideal; such a mixture will aid in easier ignition of coal.  On the other hand a 1:3 binary mixture yields a higher fixed carbon fraction, whose effect is to boost the calorific value of the fuel, an excellent factor for combustion. Overall however, it makes economic sense to blend coal with acid tar waste for enhancing sustainability.
Mass Transfer Coefficient Extraction of Oleoresin from Zodia Leaf (Evodia suaveolens) with Ethanol Solvent Using Ultrasonic Cleaner
Authors: Siswanti Siswanti , Saviatri Ratri , Adi Pratama Jeremy
Published: November 2022

The Aedes sp mosquito is a vector of Dengue Hemorrhagic Fever (DHF) and chikungunya which are still commonly found in Indonesia. To control DHF, natural insecticides from plants can be used. Zodia plants (Evodia suaveolens) can be used as natural insecticides because they contain essential oils that mosquitoes do not like. To obtain oleoresin with optimal quality and quantity, extraction can be carried out using ultrasonic waves. To design an efficient extractor, mass transfer coefficient data is needed. Until now, the data is still difficult to obtain. The experiment was carried out using an ultrasonic cleaner, by observing the concentration of oleoresin for various leaf mass ratios of 4, 6, 8, 10, and 12 grams, extracted with 300 mL ethanol for 900 seconds. Concentration observations were also carried out for a time variation of 90 - 900 seconds, with 90 seconds intervals. The best extraction results were tested using GC-MS, to determine the components in the oleoresin. To determine the mass transfer coefficient (Kc) is to make a relationship between concentration and time for the best ratio of leaf weight and ethanol volume.Based on research that has been done with 300 mL of ethanol and extraction time of 900 seconds, the highest concentration was 0.0120 gr/mL, for the experiment using a leaf weight of 12 gr. The largest percentage (%) of oleoresin that could be extracted was 88.5%, for the experiment the leaf weight was 2 g. The optimum mass transfer coefficient (Kc) is 0.161088 1/minute. These data were obtained for the experiment of the relationship between concentration and time. Oleoresin from Zodia leaves contains 20.61% nerolidol. This compound has effectiveness as a mosquito repellent.
Influence of Powder Particle Oxidation on Properties of Cold-Sprayed Tantalum
Authors: Descurninges L. L. , Mingault L. T. , Jeandin M. , Nifa A. , Berthe L. , Boustie M. , Laguionie T. , Bianchi L. , Ogawa K.
Published: November 2022

The adhesion mechanisms involved in the cold spray coatings are not still well elucidated. The quality of the deposit does depend mainly on particles and dynamic characteristics (which result from nozzle type, nozzle-substrate distance, etc.). The present work is based on the study of particle-substrate and particle-particle interfaces in the tantalum-copper coating-substrate system. The content focuses on the influence of the oxygen content in the starting powder on interface features, consequently on coating properties. Tantalum powders with different oxygen levels were studied using SEM (Scanning Electron Microscopy) and EPMA (Electron Probe Microanalysis). Laser shock spallation of cold-sprayed Ta coatings was developed as a reliable and flexible process to achieve Ta spalls to be deposited at a high-velocity onto Cu targets. The velocity due to the laser shock could be controlled to be similar to that of particles in conventional cold spray. This results in Ta-Cu interfaces, the study of which was carried out to go into interface phenomena involved in cold spray, using TEM (Transmission Electron Microscopy) in particular. Results were compared to those obtained from laser shock spallation of Ta bulk specimens (i.e. made of a conventional Ta sheet). The role of powder oxidation on interface soundness was exhibited. Adhesion was shown to be all the lower as powder oxygen content was higher, using LASAT (“ Laser Shock Adhesion Test”) in addition to direct observation of interfaces. Results were exploited to discuss properties of the corresponding Ta coatings onto Cu, i.e. which were cold sprayed using powders with different oxygen contents.
Investigation on the Effect of Helium-to-Nitrogen Ratio as Propellant Gas Mixture on the Processing of Titanium Coating using Cold Gas Dynamic Spray
Authors: Irissou E. , Ilinca F. , Wong W. , Legoux J.-G. , Yue S.
Published: November 2022

This paper reports on the influence of the He to N2 ratio on the properties of low pressure cold sprayed titanium coatings and on the characteristics of the generated supersonic two-phase flow. Experiments were carried out varying the He to N2 concentration ranging from pure He to pure N2. Samples were characterized by their microstructural properties (i.e. microhardness and porosity). Deposition rate was evaluated and particle velocities were measured for all conditions. Deposition efficiency, coating density, and microhardness were found to be a function of particle impact velocity. Velocity data were used to validate a computational fluid dynamic model. The numerical solution of the flow inside the nozzle was obtained from the Euler equations for the various He to N2 concentrations. Particle tracking was carried out by using the computed distribution of density, Mach number, temperature, viscosity, and a second order Runge-Kutta scheme. In addition, mean particle velocities at the exit of the nozzle were determined. Computed velocities were found to be in good agreement with measured ones. The model was then used to calculate nozzle dimensions that would maximize particle velocity. Optimized dimensions are proposed.
A Method for Residual Stress Estimation of AZ31 under Cold Spray Coating
Authors: Ghelichi R. , Guagliano M. , Jahed H. , Villafuerte J.
Published: November 2022

Surface treatment has become an effective method to improve corrosion resistance of magnesium alloys which are the lightest commercial structural alloys with superior specific strength and stiffness. Low pressure cold spraying is used to locally deposit aluminium on AZ31 in order to enhance general and galvanic corrosion of magnesium. This study is aimed at numerical estimation of the residual stress profile due to cold spray coating using FEM. The impact of particles on the substrate is modelled in Abaqus Explicit. The challenge of AZ31 simulations is the intrinsic yield asymmetry and anisotropy which results different behaviour of the material along different direction both in tension and compression. On the other hand, there is no precise material model capable of considering the yield asymmetry and anisotropy experienced by AZ31 in Abaqus. This paper studies the effect of anisotropy of the AZ31 on residual stress induced by cold spray. The results are compared with experimental X-Ray diffraction measurements. It is suggested that an isotropic analysis in the dominant stress direction of AZ31 may result in good estimation of the residual stress profile.
Investigation of Mechanical Properties of Coatings and Bulk Components of Various Grain Sized Tungsten-Carbide-Cobalt Based Materials
Authors: Melnyk C. , Gansert R. , Lajun D. , Weinstein B. , Grant D. , Watson M.
Published: November 2022

Thermal sprayed coatings produced from ultrafine, near-nano and nano grained powders provide improved properties as compared to conventional (micron size) powders. These ultrafine, near-nano and nano grained materials show significant potential for applications in the aerospace, energy, oil & gas and a great many other industries. A study was conducted to investigate the influence of grain size on the microstructures formed and mechanical properties of conventional, ultrafine, near-nano and nano size WC materials. Powders and coatings as well as consolidated forms of tungsten-carbide-10% cobalt- 4% chromium (WC-10Co-4Cr) and tungsten-carbide- 12% cobalt (WC-12Co) materials are examined. Thermal spray coatings are produced of carbides of several different grain sizes using high velocity oxygen-fuel (HVOF) thermal spray processing. Spark Plasma Sintering (SPS) is performed to provide consolidated forms of WC-10Co-4Cr materials. An examination of the thermal sprayed coatings is conducted using microstructural analysis and mechanical property testing. A brief examination of the wear and bend performance of a near-nano, and nano-enhanced material will be compared to a conventional material (micron sized).
The Proper Use of Gases in Thermal Spray Processes
Authors: Krömmer W. , Heinrich P. , Lang F.
Published: November 2022

The trend in thermal spraying is increasingly towards a globally uniform level of high-grade spray coatings. It is therefore extremely important that auxiliaries such as spray materials or industrial gases undergo precise examination in order to exactly define their influence. This is not only made possible by selecting the right system, but also by choosing the right gas and gas mixture. In order to broaden the range of thermal spray applications, we have endeavoured to investigate the issue of the right gas mix for arc spraying. In doing so, it was concluded that, by using wire as the spray material, this cost-effective process can often be used as an equally viable alternative to other methods. The optimization of costs, extended lifetime of systems and tailoring of coating properties to suit specific applications are just some of these influencing variables
Consideration of Adhesion Mechanisms for Aluminum Cold Spray Coatings on Various Glass Substrates
Authors: Sakaki K. , Idemoto T. , Takada K. , Hosono T.
Published: November 2022

Aluminum powder of 99.85 wt.% purity has been sprayed onto three kinds of glass substrates by cold spray. An interface between Aluminum coating and all glass substrates were smooth, and the single aluminum particle adhered without a gap. It is not observed erosion damage of glass substrate by aluminum with lower impact velocity than critical velocity. In Aluminum coating and the neighborhood of interface of Soda-lime glass substrate, sodium included in glass substrate was distributed in high density. There might be the stratum that the element which constituted an aluminum coating and glass substrate scattered, and it was suggested that the solid-phase joining by a chemical reaction were initiated.
Adhesive Strength Evaluation of the Interface between Thermal Sprayed Coating and Substrate by Tensile Pin Test
Authors: Sonoya K. , Nakamura M. , Ishida K. , Yen J. Y. K.
Published: November 2022

The pin test and stress analysis by FEM were performed for erosion-resistant thermal sprayed coatings, and characteristic of interfacial strength between sprayed coating and substrate was assessed. As a result, the (Kcr) was not affected with specimen size and uniformly converges in spite of the eccentricity of pin.
Electrochemical Impedance Measurement of Thermally Sprayed Aluminum Zinc Alloys in Sodium Chloride Solution
Authors: Takatani Y. , Tani K. , Masugata T.
Published: November 2022

The corrosion behavior of thermally sprayed Al-Zn alloy coatings immersed in NaCl aqueous solution was determined by using electrochemical impedance spectroscopy. Ohmic resistance and capacitance of the corrosion product film formed on the sprayed coating surface, and the corrosion resistance and electric double layer capacitance at the interface between the sprayed coating and the solution were evaluated. As immersion time in NaCl solution increased, the corrosion rate of the Al-2mass%Zn coating increased, but the corrosion rate for Al-6mass%Zn and Al-15mass%Zn coatings decreased due to the influence of the corrosion product.
High Temperature Aging Behavior and Order-Disorder Transformation of Plasma Sprayed Sm2Zr2O7 Coatings
Authors: Tao S. , Yu J. , Zhao H. , Zhou X. , Ding C.
Published: November 2022

Rare-earth zirconates with a pyrochlore structure have attracted great attention for potential application in thermal barrier coatings to further improve the performance and durability of gas turbines. In present work, the Sm2Zr2O7 coating was deposited by air plasma spraying technology, and its microstructure and phase composition were examined. The as-sprayed Sm2Zr2O7 coating exhibited anion-disordered while cation-ordered fluorite-type structure. Degree of ordering was considerable enhanced after high temperature aging, and transformed to ordered pyrochlore-type structure after thermal aging at temperatures above 1200 ºC. The typical lamellar structure for the as-sprayed Sm2Zr2O7 coating gradually decreased with increasing thermal aging temperature, which was caused by microcrack healing at high temperatures.
Thermal Shock Resistance of Gadolinium Zirconate Coating with Addition of Nanostructured Yttria Partially-Stabilized Zirconia
Authors: Zhong X. , Zhao H. , Zhou X. , Tao S. , Ding C.
Published: November 2022

Gadolinium zirconate (Gd2Zr2O7, GZ) as one of the promising thermal barrier coating materials for high-temperature application in gas turbine was toughened by nanostructured 3mol% yttria partially-stabilized zirconia (3YSZ) incorporation. The fracture toughness of the composite of 90mol%GZ-10mol% 3YSZ (GZ-YSZ) was increased by about 60% relative to the monolithic GZ. Both the GZ and GZ-YSZ composite coatings were deposited by atmospheric plasma spraying on Ni-base superalloys and then thermal-shock tested under the same conditions. The thermal-shock resistance of GZ-YSZ composite coating was improved significantly, which is believed to be mainly attributed to the enhancement of fracture toughness by the addition of nanostructured 3YSZ. In addition, the failure mechanisms of the thermal-shock tested GZ and GZ-YSZ composite coatings were also discussed.
HVOF K2 vs. Cold Gas Spraying
Authors: Wank A. , Schwenk A.
Published: November 2022

A conventional GTV K2 kerosene fuel HVOF spraying system has been modified with the aim to achieve process conditions comparable to cold gas spraying concerning the average particle velocities and surface temperatures in the spray distance. The employed measurements include the use of expansion nozzles that have been optimized for supersonic conditions up to a Mach number of 2.5 and the use of combustion chambers with reduced critical diameters that provide increased combustion chamber pressures up to 1600 kPa. Copper powders with different size fractions and oxygen content are sprayed with the novel HVOF technology. Coatings are analysed concerning their microstructure, oxygen content and electrical conductivity. In-flight particle velocities and surface temperatures are determined by the GTV NIR Sensor. Results are compared with those obtained for cold gas spraying using identical powders. The new HVOF technology permits the production of copper coatings that show similar levels of porosity, oxygen content and electrical conductivity like cold gas sprayed coatings. Also aluminium powder has been sprayed successfully with the novel technology. In-flight particle velocities can be almost as high as in modern cold gas spraying systems. Coatings are analysed and show a microstructure comparable to cold gas sprayed coatings.
Cost Effective Manufacturing of Molds for CFRP Component Production
Authors: Seeger M. , Reese E. D. , Jonke D. P. , Englhart M. , Drechsler K.
Published: November 2022

A cost effective manufacturing process for molds which are used to produce components of carbon fiber reinforced plastics (CFRP) is proposed. A wire arc spray process has been employed to reinforce a thin electroformed nickel shell by a several millimeter thick layer of thermally sprayed deposit, forming a vacuum tight mold system in a time saving and cost effective way. To achieve a low thermal expansion equivalent to CFRP, Fe64Ni36 is used as spray material. Here, the main challenge is the successful control of distortion which occurs due to residual stresses. In this paper, the influence of process parameters on shell temperature and distortion distribution is discussed. Key parameters influencing the heat flow into the substrate leading to distortion like continuous cooling, atomizing gas and spray distance are addressed. Temperature measurements were performed using infrared pyrometry as well as by use of thermocouples. Distortion measurements were carried out by use of optical measurement devices recording 3D surface coordinates before and after the thermal spray process. Further, mechanical and thermophysical properties of the as-sprayed composite are part of the investigations to evaluate how the Fe64Ni36 bulk material properties can be achieved. Differences between air atomized and inert gas atomized coatings are presented in detail.
Development of Arc Thermally Sprayed Fe-Mn-Cr-Si Coatings Against Cavitation Erosion
Authors: Pukasiewicz A. G. M. , Capra A. R. , Paredes R. S. C.
Published: November 2022

Cavitation erosion frequently occurs in hydraulic components such as turbines, valves, pumps, and ship propellers. Arc thermal spray processing has the possibility to be used for maintenance recovering of hydraulic blade runners. Fe-Cr-Mn-Si is a cavitation-resistant class of steel with a high concentration of oxidation elements—which can be important for arc thermally sprayed coatings—and a strain-induced phase transformation. The influence of chemical composition on oxide formation, microstructure, and cavitation resistance of Fe- Mn-Cr-Si thermally sprayed coatings was studied, and its field performance in a Francis type runner was evaluated. Microstructures and properties were investigated by XPS, XRD, optical microscopy, and ultrasonic cavitation testing. The best cavitation resistance was obtained in Fe-Mn-Cr-Si alloy with a nickel addition; this composition has lower oxide and splash droplets content and exhibits better splat wetting than Fe-Mn-Cr-Si without nickel. Strain-induced phase transformation occurred in arc thermally sprayed coatings during cavitation tests. Better performances for Fe-Mn-Cr-Si alloys, without nickel, were obtained in alloys with higher strain induced martensite contents after cavitation tests. In field tests, after 2000 operation hours, it was verified that the recovered areas presented only a small number of eroded areas, and cavitation erosion was reduced compared with uncoated areas.
Influence of the Powder Morphology and Alumina Content in Cold-Sprayed Ni-Al2O3 Coatings
Authors: Sevillano F. , Poza P. , Múnez C. J. , Vezzù S. , Rech S. , Trentin A.
Published: November 2022

Coldspray is becoming a consolidated technology in deposition of several metallic coatings such as aluminium, titanium, nickel, copper and their alloys. However, increasing attention is paid to the capabilities of coldspray to deposit composite Cer-Met coatings starting from powders blends. High ceramic content coatings are difficult to get by Cold-Spray technique due to the low ductility of the ceramic phase, but as for metal coatings the low deposition temperature reduce the residual stresses, coating porosity and oxidation. Furthermore, using powder blends, obtained by quickly mixing the pure components, leads to a great versatility on materials usable for deposition. In present work, the influence of alumina content on coldspray deposition of Ni-Al2O3 coatings was studied. Five different powder blends were prepared, the ceramic content was set as 10, 25, 50, 75 and 90 weight percent of alumina. Ni-pure coatings have been prepared and compared with composites coatings. Characterization techniques were employed in order to determine the coating morphology and microstructure , with special attention to determine the real alumina content in the coating with respect to initial powder feedstock. The final coating porosity and the matrix hardness were also evaluated. Finally, the performance of the coatings in terms of oxidation resistance was determined and discussed.
Effects of Particle Strength of Feedstock Powders on Properties of Warm-Sprayed WC-Co Coatings
Authors: Chivavibul P. , Watanabe M. , Kuroda S. , Kawakita J. , Komatsu M. , Sato K. , Kitamura J.
Published: November 2022

Warm Spray (WS) process, which can control the temperature of a combustion gas jet used to propel powder, has been successfully applied to deposit WC-Co coatings. Detrimental reactions resulting from dissolution of WC into Co binder and decarburization were suppressed effectively by keeping the WC-Co particles’ temperature below the m.p. of the binder phase. In this study, three nano-structured WC-12Co powders with different particle strength were prepared by changing the sintering conditions of spray-dried powder and were deposited by WS. The deposition efficiency and porosity of the coatings decreased with increasing the particle strength. The coating deposited from the powder with very low particle strength showed significant phase changes, while those deposited from the higher particle strengths showed almost no change. Particle Image Velocimetry revealed significant disintegration of the weakest powder, which explains the changes observed. The hardness and wear properties of the former coating, therefore, were inferior to the other two.
Microplasma Wire Spraying of Biomedical Ti-Coatings
Authors: Borisov Yu. , Kyslytsya O. , Voinarovych S. , Kuzmyc-Ianchuk Ie. , Pidgaetskyi V.
Published: November 2022

Biomedical Ti-coatings were deposited on Ti-substrates by the microplasma wire spraying method. The influence of different factors of the wire spraying process on sizes of the particles produced as a result of atomisation of the wire melt by the microplasma jet, as well as the deposition efficiency were determined by using multifactorial experimental design. Linear regression models were developed, showing the effect of the most significant process parameters (current, plasma gas flow rate, wire feed speed) on formation of a jet of the spraying Ti-particles, structure and properties of the Ti-coatings. Establishing the possibility of controlling macroporosity of the Ti-coatings in microplasma wire spraying and correspondence of the Ti-coatings bond strength in tensile and shear tests to the ISO 13779-2 and ASTM C633 requirements, as well as data of the Ti-coatings “in-vivo” tests proved the efficiency of using them for manufacture of various-purpose endoprostheses (hip joint, dental, etc.).
Development of Optical Monitoring for Thermal Spray Processing
Authors: Chivel Yu. , Smurov I.
Published: November 2022

A new approach has been developed for monitoring thermal spray processing that involves visualization of the movement of particles using a high speed video camera and wide-band intensive illumination to measure particle temperature, velocity, size, and distribution. Synchronously with the capture of the particle parameters, the surface temperature of the coating is measured with a two-channel pyrometer that has high spatial and a temporal resolution. This paper presents the results of investigations of cold spraying and D-gun spraying using these techniques.
Investigation and Comparison of Particle Parameters Determined with SprayWatch and LDA (Laser Doppler Anemometry) During the Cold Gas Spraying Process
Authors: Tewes J. , Hertter M. , Voggenreiter H. , Biermordt T. , Heinrich M. , Zimmermann S. , Landes K. , Schein J.
Published: November 2022

Properties and performance of coatings deposited by the Cold Gas Spraying process are affected by particle properties, which can be changed by using various spraying parameters. Different diagnostic systems can be applied to investigate these parameters. By means of the commercial SprayWatch system, particle properties (velocity, temperature, size, number density) can be measured and evaluated. In comparison the Laser Doppler Anemometry (LDA) system determines velocity and number density. Using both systems the velocity has been measured for a range of parameters, including different materials, different gas properties and nozzles thus offering the possibility to compare the two different diagnostic systems. In the present paper only the results of different gas properties will be shown.
Intelligent Gun Technology: Reducing Costs with EvoLink in R&D and Operations
Authors: Koller M. , Kilchenmann A. , Barth A.
Published: November 2022

A new technology has been introduced to measure process variables as well as to store gun-relevant data directly inside a thermal spray gun. This paper describes how this technology helps to reduce cost on the areas of process quality, maintenance and coating development. Test series have been carried out proofing reduced failure costs by detecting erroneous spray system configuration and functionality. Another section describes a cost decrease of maintenance prevention by intelligently using gun data. Additional test series show a cost reduction in parameter development in case of parameter transport to different thermal spray systems.
Nanostructured Metal Matrix Composite Coating Production by Pulsed Gas Dynamic Spraying
Authors: Yandouzi M. , Brochu M. , Jodoin B.
Published: November 2022

The objective of this work is to demonstrate the ability of the Pulsed Gas Dynamic Spraying process (also known as Shockwave Induced Spraying) to produce nanostructured metal matrix composite. Nanocrystalline and microcrystalline (conventional) Al5356+20%B4C composite feedstock powders were used. The influence of the coating process as well as the nature of the feedstock material on the microstructure and mechanical properties of the coatings were studied. The new spraying process provides an opportunity to produce hard and dense coatings with good cohesion between deformed particles and good adhesion to the substrate. No phase degradation, low compressive residual stresses and high dry sliding wear resistance were observed which seem to be an advantage compared to the traditional thermal spray coatings.
Modeling a Formation of Fe-Cr-Al Coating Produced By Arc Spraying
Authors: Korobov Yu. , Filippov M. , Nevezhin S. , Shallimov M.
Published: November 2022

Simulation of oxygen intake into Fe-Cr-Al coating at arc spraying was done. Based on the study of structure and properties of these coatings, the reliability of the model was evaluated.
An Efficient Numerical Method for Calculating the Shape of Structures Produced by Thermal Spraying
Authors: Ilin A. , Logvinov R. , Prihodovsky A. , Ploshikhin V. , Jonke D.
Published: November 2022

An advanced method for the efficient numerical prediction of the shape of the structure produced by thermal spray is presented. This method is based on the combination of a local non-linear thermo-mechanical FEM calculation of the inherent strain distribution after the process of thermal spraying in a representative sample and a global linear FEM calculation of the shape of the whole structure. One of the advantages of this method is the significant reduction of the computation time compared to a traditional transient FEM simulation. An application example shows the results of shape prediction of a large and complex structure generated by thermal spraying. The application of this method to the prediction of the shape of large structures opens the way for the optimization of the thermal spray technology towards the near net shape production process.
Understanding the Adhesion Mechanism of Cold Sprayed TiO2 Coatings
Authors: Tjitra Salim N. , Yamada M. , Isago H. , Shima K. , Nakano H. , Fukumoto M.
Published: November 2022

We have shown the fabrication of ceramics titanium dioxide (TiO2) coating via cold spray process. Cold spraying of any hard ceramics coating is considered to be difficult, including TiO2. However, we could obtain a coating with thickness greater than 100 µm. The adhesion mechanism of this cold sprayed TiO2 coating needs to be clarified. The effects of process gas parameters and substrate materials on coating's adhesion strength were studied. It was found that adhesion strength did not vary significantly with the change of process gas parameters, indicating that mechanical embedment is not the sole factor of coating¡¦s adhesion. The study of changing substrate materials reveals the degradation of adhesion strength due to surface oxide layer and that TiO2 shows better adhesion on bare metal surface. Hence, by altering the surface chemistry, the adhesion of TiO2 is varied, indicating the possibility of physical or chemical bonding between cold sprayed TiO2 and substrate.
Testing of the Electric Conductivity of Non-Ferrous Metallic Coatings
Authors: Trenkle F. , Vollmar H.-P. , Hartmann S.
Published: November 2022

For the development and quality control of highly electrically conductive coatings, a device is required by which the electric conductivity can be measured. For this purpose a handheld device for measuring the electric conductivity of nonferrous metals in a nondestructive manner was tested. The measurement principle is based on an eddy current sensor which allows determining the electric conductivity within seconds. The method fulfills the demands for using it in the environment of a job shop for thermal spraying. Coatings applied with different thermal spraying methods like cold gas, HVOF, electric arc or flame spraying have been examined. Thus, it will be presented a comparison of the electric conductivity dependent on different spraying methods. Additionally, important edge conditions for spraying and measuring the conductivity of highly electrically conductive coatings like the influence of the oxygen content of the powder, the minimal coating thickness measurable with the device and the influence of the surface roughness onto the measurement were analyzed.
Microtomographic Analysis of Splat Formation and Layer Build-Up of a Thermally Sprayed Coating
Authors: Tillmann W. , Nellesen J. , Abdulgader M.
Published: November 2022

Thermal spraying is a material processing technique, which is based on the combination of thermal and kinetic energy. The used feedstock is melted in a hot flame and the melt is atomized and accelerated by means of atomization or process gases. The formed particles are rapidly solidified and consolidate to form splats as they hit a pre-treated substrate. The splats pile one-on-top-of-other forming lamellas and creating the final coating. In the work presented here a combination of cored wire (WC as filling powder) and massive wire (copper) were simultaneously sprayed using the twin wire arc spraying (TWAS) process. 3D micro tomography was used in order to gain knowledge about splat formation and layer build-up. Due to the high attenuation coefficient of tungsten in comparison with copper and carbon tungsten-rich particles and splats can easily be spotted in the tomogram of the coating layer. It turns out that besides irregular formed flat splats also ball-shaped particles exist in the coating layer which suggests that the spherical particles impacted on the substrate in an un-molten state. By 3D data processing tungsten-rich particles were visualized to analyze their spatial distributions as well as their geometric parameters were quantified. This work aims at contributing to the understanding of spraying processes.
Oxidation Behavior of Bond Coats with and Without Y Addition
Authors: Izumi T. , Arikawa H. , Kojima Y. , Okada M. , Hisamatsu T.
Published: November 2022

In this study, the effects of bond coat compositions with and without 0.5 mass.% Y on oxidation behaviour were investigated. Oxidation behaviour was accessed in terms of The TGO structure and growth kinetics. After isothermal oxidation tests, the TGO formed on Y-free CoNiCrAl coatings was composed mainly of alumina without the presence of Y-rich oxide and showed lower growth kinetics than that formed on conventional CoNiCrAlY coating. This result indicates that potential improvements to the bond coat oxidation behaviour can be achieved using Y-free bond coat compositions.
Improving Atmospheric Plasma Spraying of Zirconate Thermal Barrier Coatings based on Particle Diagnostics
Authors: Mauer G. , Sebold D. , Vaßen R. , Stöver D.
Published: November 2022

Lanthanum zirconate (La2Zr2O7) was proposed as a promising material for thermal barrier coatings. At atmospheric plasma spraying (APS) of La2Zr2O7 a considerable amount of La2O3 can evaporate in the plasma flame, resulting in a non-stoichiometric coating. As indicated in the phase diagram of the La2O3-ZrO2 system, in the composition range of pyrochlore structure, the stoichiometric La2Zr2O7 has the highest melting point and other compositions are eutectic. APS experiments were performed with a TriplexPro-200 plasma torch at different power levels to achieve different degrees of evaporation and thus stoichiometry. For comparison, some investigations on Gd2Zr2O7 were included which is less prone to evaporation and formation of non-stoichiometry. Particle temperature distributions were measured by the DPV-2000 diagnostic system. In these distributions, characteristic peaks were detected at specific torch input powers indicating evaporation and solidification processes. Based on this, process parameters can be defined to provide stoichiometric coatings intended to show good thermal cycling performance.
Characterisation of HVOF-Sprayed Fe-Based Alloy Coatings
Authors: Bolelli G. , Bonferroni B. , Lusvarghi L. , Milanti A. , Niemi K. , Laurila J. , Vuoristo P.
Published: November 2022

The dry sliding wear behaviour of two HVOF-sprayed Fe-Cr-Ni-Si-B-C (Colferoloy) alloy coatings was studied by ball-on-disk tests performed at room temperature (against alumina and 100Cr6 steel balls), at 400 °C and at 700 °C (against alumina balls only). HVOF-sprayed Ni-Cr-Fe-B-Si-C and Cr3C2-NiCr layers were also tested for comparison. Under all test conditions, the wear rate of the Colferoloy coatings is lower than that of the Ni-Cr-Fe-B-Si-C coating but larger than that of the Cr3C2-NiCr cermet. Specifically, at room temperature, the Colferoloy coatings exhibit a combination of mild abrasion, delamination and tribo-oxidative wear against alumina, whereas, against steel, they undergo very limited delamination with negligible wear loss. By contrast, the Ni-Cr-Fe-B-Si-C coating suffers larger wear against steel and undergoes more severe abrasive grooving against alumina. Although the Colferoloy and Ni- Cr-Fe-B-Si-C coatings possess similar microstructure and micro-hardness, their scratch behaviours, which depend on cracking resistance and plastic deformability, differ, thus explaining the micromechanical reason for the different wear mechanisms. At 400°C and 700°C, all of the metal alloy coatings are softened and suffer more severe abrasive grooving; by contrast, the behaviour of the Cr3C2-NiCr layer at 700 °C is controlled by the formation and delamination of an oxidised layer.
Influence of Computational Grid Spacing on Gas/Particle Flow of Cold Spray
Authors: Katanoda H.
Published: November 2022

The grid-spacing dependency of the numerical solutions of the supersonic gas/particle impinging flow of the cold spray is investigated. The control parameters of the grid spacing in the nozzle are the radial grid spacing normal to the nozzle wall, the axial grid spacing at the nozzle exit, and the radial number of grids in the nozzle. The working gas is nitrogen with a pressure and a temperature of 2MPa and 600K at the stagnant chamber. The solid particle to be accelerated by the supersonic gas flow is spherical copper 5µm in diameter. The numerical results reveal that the computational result with coarsest grid poorly captures the supersonic gas flow in the nozzle. However, the impinging velocity of the particle onto the substrate differs less than 3.5% between those results obtained from the finest and coarsest grids.
Helium-Free Parameter Development for TriplexPro-210 Plasma Gun
Authors: Chen D. , Colmenares-Angulo J. , Molz R. , Dambra C. , Hawley D.
Published: November 2022

This paper focuses on the use of hydrogen and nitrogen as secondary gases for atmospheric plasma spray using the TriplexPro-210 gun platform. The paper includes process mapping of particle state in addition to measurements of actual stress states within the coating during coating application. The feedstock powders used for this investigation include yttria stabilized zirconia, chromium oxide, nickel chromium aluminum and nickel aluminum. In addition, the paper discusses differences in application costs.
Deposition of La-Sr-Fe-Co Perovskite Coatings with Different Microstructures by Low Pressure Plasma Spraying
Authors: Zotov N. , Hospach A. , Mauer G. , Sebold D. , Vaßen R.
Published: November 2022

Preparation of La1-xSrxFe1-yCoyO3-δ (LSFC) coatings by plasma spraying at low pressure (200 Pa) using different plasma spray parameters is reported and discussed. Deposition with Ar-He plasma leads always to formation of coatings containing a mixture of LSFC perovskite, SrLaFeO4, FeCo and metal oxides. Coatings deposited at higher oxygen partial pressures by addition of oxygen into the vacuum chamber contain more than 85% perovskite and only few percent Fe3O4 and/or CoO. The microstructures of the investigated LSFC coatings depend sensitively on the oxygen partial pressure, the substrate temperature and the deposition rate.
The Characteristic of Plasma Torch Designed for the Very Low-Pressure Plasma Spraying
Authors: Gao Y. , Yang D.-M. , Tian B.-H.
Published: November 2022

In contrast with the atmosphere plasma spraying (APS), the very low pressure plasma spraying (VLPPS) shows lower ability for heating spray materials at the plasma free region exit of nozzle. Most very low pressure plasma spraying at the present usually use a high power plasma gun which operated at great arc currents up to 2500A to meet lower ability for heating materials, thus result in a series of problems not only for the plasma torch but also for associated facility. According to the plasma spray characteristic in the low pressure environment we designed a plasma torch with separating anode and nozzle, and the powder injected to the plasma jets is from inside nozzle intake. In this study, the pressures in the plasma gases intake, nozzle intake and out of the plasma torch were measured respectively. For the practice, SUS 316 stainless steel coatings were prepared at plasma currents of 500-600A and arc voltage of 50V and the chamber pressure of 1000 Pa, the results indicated that the coatings with the equiaxed microstructure could deposited in the appropriate conditions.
Reconstitution of Yttria-Stabilised Zirconia Nanopowders to Obtain Coatings by Atmospheric Plasma Spraying
Authors: Sánchez E. , Felíu C. , Carpio P. , Bannier E. , Moreno R. , Alcázar M. C. , Salvador M. D. , Benavente R. , Bonache V.
Published: November 2022

Yttria-stabilised zirconia (YSZ) coatings were deposited on austenitic stainless steel coupons from nanostructured powders using atmospheric plasma spraying (APS). Two suspensions of YSZ nanoparticles were used as starting material: a diluted commercial suspension and a highly concentrated in-house prepared suspension (obtained by adding an YSZ submicronic powder to the diluted suspension). Both suspensions were reconstituted into sprayable micrometric granules. The reconstitution process was performed by spray drying, followed by a thermal treatment in order to reduce porosity and enhance agglomerate sinterability. The reconstituted powders were characterised by XRD, SEM, granule and pore sizing techniques, and a flowability evaluation. The effect of suspension characteristics on granule morphology and porosity was examined. The reconstituted powders were successfully deposited, yielding well-bonded coatings. The coating microstructure was characterised by XRD and SEM. Mechanical properties and erosion resistance were also determined. Coating microstructure consisted of semi-molten feedstock agglomerates surrounded by fully molten areas that acted as binders. The influence of feed powder characteristics on coating microstructure and properties was also studied.
Comparison of Isolated Indentation and Grid Indentation Methods for HVOF Sprayed Cermets
Authors: Nohava J. , Houdková Š. , Plzeň CZ , Haušild P. , Enžl R.
Published: November 2022

This paper compares the results of two approaches of instrumented indentation for characterization of mechanical properties of HVOF coatings. Three types of industrially used HVOF sprayed coatings (Cr3C2-NiCr, WC-Co, (Ti, Mo)(C,N)-NiCo) were selected. The indentation methods applied were: isolated nanoindentation in metallic matrix and carbides with 2 mN peak load and grid indentation with 2 mN peak loads, comprising 400 indentations. The results of the isolated indentation revealed hardness and elastic modulus of the individual phases with surprisingly low standard deviation and in good agreement with the corresponding bulk equivalent. The grid indentation method, based on statistical evaluation of a large number of indentations, was influenced by the carbide-matrix interface, which gave rise to a strong third peak apart from the two peaks corresponding to the hard carbides and softer metallic matrix. This makes the statistical analysis much more complex than using simple bimodal Gaussian fit for separation of matrix and carbide properties. Nevertheless, the results of both grid indentation and isolated nanoindentation compared with microindentation values obtained at higher loads gave important information about the cohesion of the coatings.