Effect of the Spray Parameters on the Particle Behavior and the Coating Properties During ID Warm Spraying of Fine WC-12Co Powders (-10 + 2 μm)

2021 ◽  
Author(s):  
W. Tillmann ◽  
I. Baumann ◽  
A. Brinkhoff ◽  
S. Kuhnt ◽  
E.-C. Becker-Emden ◽  
...  
Keyword(s):  
Thermal Spraying ◽  
Statistical Design ◽  
Internal Diameter ◽  
Outer Diameter ◽  
Spray Parameters ◽  
Coating Properties ◽  
Statistical Design Of Experiments ◽  
Particle Behavior ◽  
Warm Spraying ◽  
Compact Design

Abstract Internal diameter (ID) coating by means of thermal spraying for the wear and corrosion protection of components is currently experiencing growing interest in science and industry. While high-kinetic spray processes (such as HVOF, HVAF or warm spraying) in combination with cermet materials (e.g. WC-Co or Cr3C2-NiCr) are well established for this purpose in traditional coating of external OD (outer diameter) surfaces, they have hardly been used in the ID (internal diameter) area so far. Even though a few special ID spray guns with compact design and low combustion energy are by now available on the market, only little is known about the effects and interactions of the spray parameters on the particle behavior and the coating properties. Due to the mentioned gun specifications and the usually required short spray distances for ID coating, fine spray powders < 15 μm must be used to ensure sufficient melting and acceleration of the particles. In this study warm spraying of fine WC-12Co powders (-10 + 2 μm) using a novel spray gun “ID RED” (Thermico, Germany) was investigated. Statistical design of experiments (DoE) was employed to analyze and to model the influence of varying spray parameter settings on the in-flight particle behavior and the corresponding coating properties.

scholarly journals Internal Diameter Coating by Warm Spraying of Fine WC-12Co Powders (− 10 + 2 µm) with Very Short Spray Distances up to 10 mm

2021 ◽  
Author(s):  
I. Baumann ◽  
W. Tillmann ◽  
C. Schaak ◽  
K. Schmidt ◽  
L. Hagen ◽  
...  
Keyword(s):  
Thermal Spraying ◽  
Volume Ratio ◽  
Phase Evolution ◽  
Flight Behavior ◽  
Internal Diameter ◽  
Interest In Science ◽  
Warm Spraying ◽  
Fine Powders ◽  
Compact Design ◽  
Heat And Momentum Transfer

AbstractThe internal diameter (ID) coating by means of thermal spraying is currently experiencing growing interest in science and industry. In contrast to the well-established plasma- and arc-based spray techniques, there is a lack of knowledge concerning kinetic processes such as HVOF, HVAF and warm spray (WS). A major challenge represents the necessity of short spray distances and the compact design of novel ID spray guns with reduced combustion power. Conventional WC-Co powders (− 45 + 15 µm) are not able to achieve a sufficient heat and momentum transfer. The use of fine powders < 15 µm offers an approach to overcome this drawback as they feature a larger surface-to-volume ratio and a lower mass. However, the processing of fine powders requires suitable spray equipment and a sensitive parameter adjustment. In this study, warm spraying of fine WC-12Co powders (− 10 + 2 µm) with a novel ID spray gun (HVOF + N2) “ID RED” (Thermico Engineering GmbH, Germany) was investigated. First, the flame profile as well as the in-flight behavior of the particles along the spray jet (spray distances SD = 10-80 mm) was analyzed at different nitrogen flows NF = 15-115 L/min to find suitable spray parameter intervals. Subsequently, planar steel samples were coated with SD = 10-50 mm and constant NF = 90 L/min. Analyses regarding the microstructure, the mechanical properties and the phase evolution of the coatings were performed. The aim was to study spraying with the novel ID gun and to scrutinize shortest feasible spray distances. Finally, steel tubes (internal diameter of 81.6 mm and a wall thickness of 10.0 mm) were coated with SD = 20 mm and NF = 90 L/min to investigate in how far the results can be transferred to ID parts. Correlations between the particle behavior, the microstructure and the coating properties were made.

Statistical Optimization of HVAF Sprayed Cr3C2-NiCr Coatings for Minimizing Decarburization

2000 ◽  
Author(s):  
S.J. Matthews ◽  
M.M. Hyland
Keyword(s):  
Factorial Design ◽  
Statistical Design ◽  
Process Variable ◽  
Traverse Speed ◽  
Deposition Efficiency ◽  
Spray Parameters ◽  
Statistical Design Of Experiments ◽  
Spray Coatings ◽  
Wide Range ◽  
Statistical Designs

Abstract High-velocity air fuel (HVAF) spraying was selected for spray trials of a Cr3C2-NiCr powder. To determine the effect of spray parameters on coating characteristics, particularly porosity and phase degradation, a statistical design of experiments was implemented. A wide range of statistical designs have been applied to the optimization of thermal spray coatings with a great deal of success. In this instance, a lack of prior knowledge and the need to assess many process-variable interactions efficiently led to the selection of a two-level full factorial design. High and low settings for each variable, including spray distance, traverse speed, and powder feedrate, were chosen based on the ranges typically used to spray similar materials. The resulting coatings were assessed for microhardness, porosity, residual stress, deposition efficiency, and phase transformation, after which several follow-up runs were conducted to explore trends brought to light by the initial factorial design.

STATISTICAL DESIGN OF EXPERIMENTS FOR THE Cr(VI) ADSORPTION ON WEED Salvinia cucullata

2013 ◽  
Vol 12 (3) ◽  
pp. 465-474 ◽  
Author(s):  
Saroj Sundar Baral ◽  
Ganesan Surendran ◽  
Namrata Das ◽  
Polisetty Venkateswara Rao
Keyword(s):  
Design Of Experiments ◽  
Statistical Design ◽  
Statistical Design Of Experiments

scholarly journals Synthesis of an Addition-Crosslinkable, Silicon-Modified Polyolefin via Reactive Extrusion Monitored by In-Line Raman Spectroscopy

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1246
Author(s):  
Steffen Ulitzsch ◽  
Tim Bäuerle ◽  
Mona Stefanakis ◽  
Marc Brecht ◽  
Thomas Chassé ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Performance ◽  
Process Analytical Technology ◽  
Statistical Design ◽  
Reactive Extrusion ◽  
Statistical Design Of Experiments ◽  
Grafting Efficiency ◽  
Grafting Reaction ◽  
Central Composite Experimental Design ◽  
Process Factors

We present the modification of ethylene-propylene rubber (EPM) with vinyltetra-methydisiloxane (VTMDS) via reactive extrusion to create a new silicone-based material with the potential for high-performance applications in the automotive, industrial and biomedical sectors. The radical-initiated modification is achieved with a peroxide catalyst starting the grafting reaction. The preparation process of the VTMDS-grafted EPM was systematically investigated using process analytical technology (in-line Raman spectroscopy) and the statistical design of experiments (DoE). By applying an orthogonal factorial array based on a face-centered central composite experimental design, the identification, quantification and mathematical modeling of the effects of the process factors on the grafting result were undertaken. Based on response surface models, process windows were defined that yield high grafting degrees and good grafting efficiency in terms of grafting agent utilization. To control the grafting process in terms of grafting degree and grafting efficiency, the chemical changes taking place during the modification procedure in the extruder were observed in real-time using a spectroscopic in-line Raman probe which was directly inserted into the extruder. Successful grafting of the EPM was validated in the final product by 1H-NMR and FTIR spectroscopy.

scholarly journals Evaluation of Cutting-Tool Coating on the Surface Roughness and Hole Dimensional Tolerances during Drilling of Al6061-T651 Alloy

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1783
Author(s):  
Hamza A. Al-Tameemi ◽  
Thamir Al-Dulaimi ◽  
Michael Oluwatobiloba Awe ◽  
Shubham Sharma ◽  
Danil Yurievich Pimenov ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Cutting Tool ◽  
Good Practice ◽  
Cutting Tools ◽  
Statistical Design ◽  
Cutting Parameters ◽  
Statistical Design Of Experiments ◽  
Hole Quality ◽  
Coated Tools ◽  
Tool Coating

Aluminum alloys are soft and have low melting temperatures; therefore, machining them often results in cut material fusing to the cutting tool due to heat and friction, and thus lowering the hole quality. A good practice is to use coated cutting tools to overcome such issues and maintain good hole quality. Therefore, the current study investigates the effect of cutting parameters (spindle speed and feed rate) and three types of cutting-tool coating (TiN/TiAlN, TiAlN, and TiN) on the surface finish, form, and dimensional tolerances of holes drilled in Al6061-T651 alloy. The study employed statistical design of experiments and ANOVA (analysis of variance) to evaluate the contribution of each of the input parameters on the measured hole-quality outputs (surface-roughness metrics Ra and Rz, hole size, circularity, perpendicularity, and cylindricity). The highest surface roughness occurred when using TiN-coated tools. All holes in this study were oversized regardless of the tool coating or cutting parameters used. TiN tools, which have a lower coating hardness, gave lower hole circularity at the entry and higher cylindricity, while TiN/TiAlN and TiAlN seemed to be more effective in reducing hole particularity when drilling at higher spindle speeds. Finally, optical microscopes revealed that a built-up edge and adhesions were most likely to form on TiN-coated tools due to TiN’s chemical affinity and low oxidation temperature compared to the TiN/TiAlN and TiAlN coatings.

Study of surface modification of recycled ultrafiltration membranes using statistical design of experiments

2021 ◽  
Vol 23 ◽  
pp. 100978
Author(s):  
L. Rodríguez-Sáez ◽  
J. Landaburu-Aguirre ◽  
S. Molina ◽  
M.C. García-Payo ◽  
E. García-Calvo
Keyword(s):  
Surface Modification ◽  
Design Of Experiments ◽  
Statistical Design ◽  
Statistical Design Of Experiments ◽  
Ultrafiltration Membranes

Role of Magnesium Salts in Coal De-Ashing by Flotation

2021 ◽  
Vol 58 (1) ◽  
pp. 51-58
Author(s):  
Rawya Gamal ◽  
Nader A.A. Edress ◽  
Khaled A. Abuhasel ◽  
Ayman A. El-Midany ◽  
Salah E. El-Mofty
Keyword(s):  
Particle Size ◽  
Strong Interaction ◽  
Statistical Design ◽  
Ash Content ◽  
The Other ◽  
Pulp Density ◽  
Statistical Design Of Experiments ◽  
Coal Flotation ◽  
Magnesium Salts

Abstract The most frequently investigated salts in coal flotation are chlorides. However, seawater contains additional salts such as sulfates. In coal flotation, magnesium chlorides showed the best results in terms of higher yield and lower ash content compared to the other magnesium salts studied. Therefore, two magnesium salts were tested in this investigation, namely magnesium chloride and magnesium sulfate. The effect of the magnesium salts as well as the optimization of coal flotation were investigated by statistical design of experiments in terms of pulp density, particle size, conditioning time and different dosages of MgCl2 and MgSO4. The flotation results obtained by statistical design show that the ash content was lowest at 8.2% when a mixture of 2 kg/t MgSO4 and 2 kg/t MgCl2 has been used, with pulp density 20%, particle size 400 lm and conditioning time 15 min. The particle size plays an important role in reducing the ash content when the conditioning time has been extended and pulp density has been reduced. The strong interaction between the salts hinders the reduction of the ash content to less than 8.2%.

Porosity Control of Thermally Sprayed Ceramic Deposits

1998 ◽  
Author(s):  
P. Chraska ◽  
V. Brozek ◽  
B.J. Kolman ◽  
J. Ilavsky ◽  
K. Neufuss ◽  
...  
Keyword(s):  
Gas Permeability ◽  
Water Immersion ◽  
Thermal Spraying ◽  
Spray Parameters ◽  
Post Processing ◽  
Free Standing ◽  
Spray Process ◽  
Wide Range ◽  
Controlled Porosity ◽  
Selection Of

Abstract Porosity regulates the deposit's properties and therefore methods for its control are of a vital industrial importance. Thermal spraying can produce deposits in a wide range of porosities by selection of a spray process itself, by selection of spray parameters, feedstock size and chemistry, etc. Manufacturing of deposits with controlled porosity may be difficult if the selection of spray processes and materials is limited. Special methods of deposition or/and subsequent post processing may be therefore necessary. These methods are studied in the presented work. All spraying was done with the water-stabilized plasma (WSP®) system PAL 160. Thick deposits and free-standing parts were sprayed from alumina, zircon, metal Al and Ni powders and their combinations. Porosity was characterized by number of techniques such as gas permeability, water immersion, MIP, SEM and SANS. Mechanical properties were characterized by the Young's modulus. Special methods of deposition, such as spraying of mixtures of ceramics and metals were successfully used. Either sandwiched-structures with alternating layers of ceramics and metals were sprayed (for the sealing purpose) or mechanical mixtures of ceramic and metallic feedstock were sprayed. Several post-processing methods were used to change porosity volumes or other materials characteristics. To increase the porosity the metallic phases were subsequently removed by leaching or by annealing at temperatures above the melting point of metal. A number of sealing materials (organic and inorganic) were used to seal the pores by infiltration at ambient or higher pressures. The results show, that significant changes of porosity volume and, especially, of the gas permeability are possible. Another tested method was annealing/calcination of deposits, which resulted in an increase or decrease of porosity, depending on deposit's chemistry and annealing conditions. Results show that all used post processings are capable of significant changes of deposit microstructure and that they may be successfully applied in practice.

Sign in / Sign up

Export Citation Format

Share Document