Novel Liquid Fuel HVOF Torches Fueled with Ethanol: Optimization and Erosion Wear Response of Cr3C2-NiCr Coatings

Author(s):  
Shaowu Liu ◽  
Michel Moliere ◽  
Hanlin Liao

Abstract In this work; a novel liquid fuel HVOF process fueled with ethanol was used to prepare 75wt%Cr3C2–25wt%NiCr coatings on AISI304 stainless steel substrate. Taguchi method was employed to optimize the spray parameters (ethanol flow rate; oxygen flow rate; powder feed rate and standoff distance) to achieve better erosion resistance at 90° impact angle. The results indicated that ethanol flow rate and oxygen flow rate were identified as the highly contributing parameters on the erosion wear loss. The important sequence of the spray parameter is ethanol flow rate > oxygen flow rate > standoff distance > powder feed rate. The optimal spray parameter (OSP) for minimum erosion wear loss was obtained under ethanol flow rate of 28slph; oxygen flow rate of 420slpm; powder feed rate of 76.7 g/min and standoff distance of 300mm. The phase composition; microstructure; hardness; porosities; and the erosion wear behaviors of the coatings have been studied in detail. Besides; erosion wear testing of the optimized coating was conducted at 30°; 60° and 90° impact angle using air jet erosion testing machine. The SEM images of the erodent samples were taken to analyze the erosion mechanism.

Author(s):  
Ratnesh Kumar Sharma ◽  
Randip Kumar Das ◽  
Shiv Ranjan Kumar

Fe-based coating (Fe50Mo5C15Si10Cr10Ti10) was deposited on 316L stainless steel substrate by high-velocity oxy-fuel spraying coating process. High-velocity oxy-fuel spraying process parameters such as oxygen flow rate and spray distance were varied to investigate their effect on mechanical, wear and thermal properties. The prepared coatings were characterized in terms of mechanical properties such as micro-hardness and fracture toughness, thermal properties and erosion wear properties. X-ray diffraction analysis showed presence of hardened phase Fe2Ti and Fe-Cr. Results of this study indicated that increase in oxygen flow rate from 200 to 250 slpm improved the fracture toughness and micro-hardness by 33% and 6.7%, respectively. On the other hand, increase in spray distance decreased the fracture toughness and micro-hardness by 27.2% and 6.7%, respectively. The wear rate was increased with the increase in oxygen flow rate and decreased with the increase in spray distance. The erosion wear rate was more dependent on fracture toughness as compared to micro-hardness.


Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 75
Author(s):  
Rong Gen Neo ◽  
Kaiqiang Wu ◽  
Sung Chyn Tan ◽  
Wei Zhou

Cold spray technology using micron-sized particles to produce coatings is increasingly used for reparative tasks in various industries. In a cold spray setup, the gun is usually connected to a robotic arm to deposit coatings on components with complex geometries. For these components, the standoff distance used in the cold spray process has to be large enough for easy maneuverability of the gun around a small radial feature. However, a small standoff distance is commonly found in most studies, which is thought to prevent a velocity drop of the particles over a larger distance. Here, a study was carried out by measuring the Inconel 625 particle velocity at different spray distances, ranging from 3 to 40 cm. The highest average velocity of 781 m/s was found at a spray distance of 8 cm. Furthermore, a study with varying powder feed rates was also conducted. An increase in the powder feed rate was found to have a minimal effect on the particle velocity. Inconel 625 coatings deposited at the optimum standoff distance (8 cm) were found to have low porosity and high hardness. The results in this study demonstrate that a larger standoff distance can be applied without a significant drop in velocity for cold spray applications requiring high maneuverability.


2012 ◽  
Vol 271-272 ◽  
pp. 86-91 ◽  
Author(s):  
Ming Liu ◽  
Hai Jun Wang ◽  
Yi Jiang ◽  
Yong Ming Guo ◽  
Ya Nan Song

In this paper, an optimization experiment was designed to get the optimal performance of supersonic sprayed coating. Response surface methodology based on Box-Behnken design has been used in this experimental design. Input factors were designed with four representative spraying parameters: powder feed rate, spraying power, argon flow rate and hydrogen flow rate. Porosity of NiCrBSi coating, as the only measured response, was applied to estimate the influence of spraying process on the coating performance. Results indicate that porosity is the most sensitive to change powder feed rate, followed by argon flow rate, hydrogen flow rate and spraying power. A minimum porosity of 1.8% was obtained under the optimization spraying parameters.


Author(s):  
Peter Kayode Farayibi

Laser deposition is an advanced manufacturing technology capable of enhancing service life of engineering components by hard-facing their functional surfaces. There are quite a number of parameters involved in the process and also desirable output characteristics. These output characteristics are often independently optimised and which may lead to poor outcome for other characteristics, hence the need for multi-objective optimisation of all the output characteristics. In this study, a laser deposition of Ti-6Al-4V wire and tungsten carbide powder was made on a Ti-6Al-4V substrate with a view to achieve a metallurgical bonded metal matrix composite on the substrate. Single clads were deposited with a desire to optimise the composite clad characteristics (height, width and reinforcement fraction) for the purpose of surface coating. Processing parameters (laser power, traverse speed, wire feed rate, powder feed rate) were varied, the experiment was planned using Taguchi method and output characteristics were analysed using principal component analysis approach. The results indicated that the parameters required for optimised clad height, width, and reinforcement fraction necessary for surface coating is laser power of 1800 W, traverse speed of 200 mm/min, wire feed rate 700 mm/min and powder feed rate of 30 g/min. The powder feed rate was found to most significantly contribute 43.99%, followed by traverse speed 39.77%, laser power 15.87% with wire feed rate having the least contribution towards the multi-objective optimisation. Confirmation results showed that clad width and reinforcement fraction were significantly improved by the optimised parameters. The multi-objective optimisation procedure is a useful tool necessary to identify the process factors required to enhance output characteristics in laser processing.


1997 ◽  
Vol 495 ◽  
Author(s):  
Karl F. Schoch ◽  
Theodore R. Vasilow

ABSTRACTFormation of ferrites from aqueous solution of metal salts is a well known process involving precipitation of metal hydroxides followed by oxidation of the resulting gel. The purpose of the present work was to determine the effects oxygen flow rate on the progress of the reaction and on the structure and properties of the resulting precipitate. The reaction was carried out at 70°C with pH of 10.5 and oxygen flow rate of 2,4, or 8 standard liters per hour. The progress of the reaction was monitored by following the oxidation-reduction potential of the solution, which changes dramatically after the Fe(II) is consumed. The reaction rate increased with increasing oxygen flow rate. The Mg content of the precipitate was lower than that of the reaction mixture, possibly because of the pH of the reaction mixture. X-ray diffraction and infrared spectroscopy confirmed formation of a ferrite under these conditions.


2021 ◽  
Vol 39 ◽  
pp. 43-53
Author(s):  
Divyeshkumar P. Dave ◽  
Akshay M. Patel ◽  
Kamlesh V. Chauhan ◽  
Sushant K. Rawal

The influence of oxygen flow rate is examined on structural, optical and tribological properties of molybdenum oxide films deposited by reactive magnetron sputtering. The films were characterized by X-ray diffraction, scanning electron microscope (SEM), and contact angle measurement system. The optical properties of the films were measured by UV-Vis-NIR spectrophotometer and transmittance of ∼73% in the visible region of the spectrum was achieved. The band gap increases with increases in oxygen gas flow rate. AFM figure illustrates that the roughness of surface increases as oxygen flow rate increases. As oxygen increases wear rate and COF decreases while at the 18 sccm the lowest wear rate found.


2022 ◽  
Vol 40 (1) ◽  
pp. 013405
Author(s):  
Nilton Francelosi A. Neto ◽  
Cristiane Stegemann ◽  
Lucas J. Affonço ◽  
Douglas M. G. Leite ◽  
José H. D. da Silva

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 517
Author(s):  
Pengfei Kong ◽  
Yunti Pu ◽  
Ping Ma ◽  
Jiliang Zhu

Scandium oxide (Sc2O3) thin films with different numbers of oxygen defects were prepared by ion-beam sputtering under different oxygen flow rates. The results showed that the oxygen defects heavily affected crystal phases, optical properties, laser-induced damage threshold (LIDT) and surface quality of Sc2O3 films. The thin film under 0 standard-state cubic centimeter per minute (sccm) oxygen flow rate had the largest number of oxygen defects, which resulted in the lowest transmittance, LIDT and the worst surface quality. In addition, the refractive index of 0 sccm Sc2O3 film could not be measured in the same way. When the oxygen flow rate was 15 sccm, the Sc2O3 film possessed the best transmittance, refractive index, LIDT and surface roughness due to the lowest number of oxygen defects. This work elucidated the relationship between oxygen defects and properties of Sc2O3 films. Controlling oxygen flow rate was an important step of limiting the number of oxygen defects, which is of great significance for industrial production.


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