The Functional TiO2-Biodegradable Plastic Composite Material Produced by HVOF Spraying Process

2007 ◽  
Vol 7 (11) ◽  
pp. 3830-3833 ◽  
Author(s):  
Hee-Seon Bang ◽  
Han-Sur Bang ◽  
Yoon-Ki Lee
Keyword(s):  
Photocatalytic Performance ◽  
Xrd Analysis ◽  
Gas Pressure ◽  
Photocatalytic Efficiency ◽  
Hvof Spraying ◽  
Photo Degradation ◽  
Fuel Gas ◽  
Plastic Composite ◽  
Polybutylene Succinate ◽  
Spraying Process

Photocatalytic TiO2 coatings on bio-degradable plastic(polybutylene succinate: PBS) were prepared by HVOF spraying using three kinds of agglomerated powders (P200: 200 nm, P30: 30 nm, P7: 7 nm). The microstructures of the coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of the coatings was evaluated by photo degradation of gaseous acetaldehyde. For both the HVOF sprayed P200 and P30 coatings, high anatase ratio of 100% was achieved, regardless of the fuel gas pressure. On the other hand, for the HVOF sprayed P7 coating, the anatase ratio decreased from 100% to 49.1% with increasing fuel gas pressure. This decrease may be attributed to the much higher susceptibility to heat of the 7 nm agglomerated powders than the 30 nm and 200 nm agglomerated powders. In terms of the photocatalytic efficiency, HVOF sprayed P200 and P30 coatings seemed to outperform the P7 coatings because of their higher anatase ratios. However, the HVOF sprayed P7 coatings did not show photocatalytic activity possibly because of the extremely small reaction surface area to the photo-catalytic activity and low anatase ratio. Therefore, the present study found that functional PBS plastic with photocatalytic performance could be produced by spraying of ceramics such as TiO2.

An Attempt to Improve the Deposition Efficiency of AI2O3 Coating by HVOF Spraying

2000 ◽  
Author(s):  
Y. Shimizu ◽  
K. Sugiura ◽  
K. Sakaki ◽  
A. Devasanapathi
Keyword(s):  
Hardness Test ◽  
Deposition Efficiency ◽  
Nozzle Geometry ◽  
Hvof Spraying ◽  
Fuel Gas ◽  
Dense Microstructure ◽  
Alumina Particles ◽  
Coating Characteristics ◽  
Nozzle Geometries ◽  
Spraying Process

Abstract High Velocity Oxy-Fuel (HVOF) method using propylene as a fuel gas was employed to spray alumina particles. In order to improve the coating characteristics such as the deposition efficiency and the hardness, three HVOF gun nozzles of varying geometry were designed and tested experimentally. The spraying process was also simulated numerically for each of the nozzle geometries to understand their effectiveness in influencing the velocity and temperature of the sprayed particles. The coating was characterized using optical and scanning electron microscopy (SEM), micro-vickers hardness test and X-ray diffractometry (XRD). Results showed that with the use of a convergent and divergent type gun nozzle, similar to that of a Laval nozzle, the extent of melting of the alumina particles could be increased. This was exhibited by an increase in the deposition efficiency to the extent of 45%. However, the sharp changes in the convergent and divergent nozzle geometry, resulted in fusion and agglomeration of alumina particles leading to spitting during the spraying process. The results clearly showed that alumina coatings of excellent hardness in the range of 920-1290 HV, with a relatively dense microstructure could be obtained in HVOF method irrespective of the gun nozzle geometry, provided the spraying parameters are properly controlled.

NiFe-LDH@ZnO@NF composite for photo-degradation of Rhodamine B dye

MRS Advances ◽  
2019 ◽  
Vol 4 (33-34) ◽  
pp. 1887-1893
Author(s):  
Jun Wu ◽  
Yonghui Gong ◽  
Qiang Fu ◽  
Chunxu Pan
Keyword(s):  
Rhodamine B ◽  
Photocatalytic Performance ◽  
Nickel Foam ◽  
Photogenerated Electron ◽  
Chemical Compositions ◽  
Photocatalytic Efficiency ◽  
Electron Hole ◽  
Photo Degradation ◽  
Potential Applications ◽  
Rhodamine B Dye

ABSTRACTIn this paper, a novel NiFe-LDH@ZnO composite was prepared by using a facile two-step process upon nickel foam (NF) substrate. The morphologies and chemical compositions of the samples were characterized by SEM, EDS, XRD and XPS. Photocatalytic degradation of Rhodamine B dye was tested with the samples NiFe-LDH@ZnO@NF, ZnO@NF and NiFe-LDH under the same conditions. The experimental results revealed that the NiFe-LDH@ZnO@NF composite exhibited excellent photocatalytic performance, i.e., 1.4 and 2.5 times higher than that of pure ZnO and NiFe-LDH, respectively. The reason was that the NiFe-LDH@ZnO@NF composite provided a possibility to effectively inhibit the recombination of the photogenerated electron-hole pairs, and therefore enhanced the photocatalytic efficiency. This composite is expected to have potential applications in wastewater treatment field.

Fabrication Porous Ag/BiVO4 Film for Efficient Degradation of Phenol under Visible Light

2012 ◽  
Vol 518-523 ◽  
pp. 732-735 ◽  
Author(s):  
Xi Qiang Li ◽  
Xiu Fang Zhang ◽  
Xiao Li Dong ◽  
Chun Ma ◽  
Xin Xin Zhang ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Xrd Analysis ◽  
Diffusion Resistance ◽  
Photocatalytic Efficiency ◽  
Photogenerated Electrons ◽  
Ag Particles ◽  
Carrier Separation ◽  
Rapid Transfer

Porous BiVO4 film was fabricated by templating procedure with polystyrene (PS) balls as the template. Ag particles were loaded on the porous BiVO4 film by photoreduction technique. SEM revealed there were many pores in the film and Ag particles were successfully loaded on the porous BiVO4 film. XRD analysis indicated that the chemical state of Ag particles was metallic Ag. The experiment of photocatalytic degradation of phenol showed that the degradation rate on porous Ag/BiVO4 film was 4.74 times as much as that on the BiVO4 film. The enhanced photocatalytic performance was firstly attributed to the rapid transfer of the photogenerated electrons from BiVO4 to Ag, which could increase the charge carrier separation, limit their recombination, and enhance the photocatalytic efficiency. Furthermore, porosity of the photocatalyst may enhance diffusion process and decrease diffusion resistance of the reactants throughout the channels in the photocatalyst, and thus improves the surface reactions.

scholarly journals Visible-enhanced photocatalytic performance of CuWO4/WO3 hetero-structures: incorporation of plasmonic Ag nanostructures

2018 ◽  
Vol 42 (13) ◽  
pp. 11109-11116 ◽  
Author(s):  
R. Salimi ◽  
A. A. Sabbagh Alvani ◽  
N. Naseri ◽  
S. F. Du ◽  
D. Poelman
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Light Irradiation ◽  
Photo Degradation ◽  
Gel Method ◽  
Sol Gel Method

A new plasmonic Ag hybridized CuWO4/WO3 heterostructured nanocomposite was successfully synthesized via a ligand-assisted sol gel method and the photocatalytic activity was evaluated by photo-degradation of methylene blue (MB) under visible light irradiation.

Production and Characterization of HVOF Sprayed NiCr-TiC Coatings Using SHS Powder Feedstock

2000 ◽  
Author(s):  
M.T. Blatchford ◽  
A.J. Horlock ◽  
D.G. McCartney ◽  
P.H. Shipway ◽  
J.V. Wood
Keyword(s):  
Thermal Spraying ◽  
Xrd Analysis ◽  
Powder Size ◽  
Coating Properties ◽  
X Ray Diffraction ◽  
Hvof Spraying ◽  
X Ray ◽  
Wear Rates ◽  
Powder Feedstock

Abstract In this paper, the production of NiCr-TiC powder by SHS, suitable for HVOF spraying, is discussed together with results on the microstructure and coating properties. Compacts for SHS were prepared by mixing elemental Ti and C with pre-alloyed Ni-20wt.% Cr powder to give an overall composition of 35wt.% NiCr and 65wt.% TiC. These were then ignited and a self-sustaining reaction proceeded to completion. Reacted compacts were crushed, sieved, and classified to give feedstock powders in size ranges of 10-45 µm and 45-75 µm. All powder was characterized prior to spraying based on particle size distribution, x-ray diffraction (XRD), and scanning electron microscopy (SEM/EDS). Thermal spraying was performed using both H2 and C3H6 as fuel gases in a UTP/Miller Thermal HVOF system. The resulting coatings were characterized by SEM and XRD analysis, and the microstructures correlated with powder size and spray conditions. Abrasive wear was determined by a modified 'dry sand rubber wheel' (DSRW) test and wear rates were measured. It has been found that wear rates comparable to those of HVOF sprayed WC-17wt% Co coatings can be achieved.

Properties of TiC-Ni Based Coatings Deposited by Different HVOF Spraying

2000 ◽  
Author(s):  
P. Vuoristo ◽  
M. Väisänen ◽  
T. Mäntylä ◽  
L.-M. Berger
Keyword(s):  
Wear Resistance ◽  
Flame Temperature ◽  
Oxygen Flow ◽  
Spray Parameters ◽  
Coating Properties ◽  
Hvof Spraying ◽  
Fuel Gas ◽  
Wear Rates ◽  
Operation Conditions ◽  
Satisfactory Coating

Abstract Hardmetal-like coatings of the TiC-Ni system are potential for use as wear, corrosion and heat resistant coatings in various operation conditions. Our previous works [1-12] have shown that these materials are well sprayable using different thermal spray processes such as plasma, D-Gun and HVOF spraying. Since HVOF spraying is today the most important process used to apply carbide based coatings, this study was carried out in order to evaluate more systematically the sprayability of these novel spray powders and the influence of HVOF spray parameters on some coating properties. Coating samples were prepared by using DJ Hybrid gun with propane as a fuel gas, and a CDS gun with hydrogen fuel gas. Oxygen flow rate was varied in both cases for changing the flame temperature. Microstructure, phase composition, hardness, and abrasion wear resistance of the coated samples were investigated. The results showed that both HVOF processes used give satisfactory coating properties and that the use of high oxygen flow rates is beneficial for improving the wear resistance of the coatings. Powders with fine particle size are beneficial in the DJ Hybrid process; the use of coarse powders results in coatings with somewhat higher wear rates. The optimum spray condition for the TiC-Ni system powders differs from that typically used for conventional WC-Co and Cr3C2-NiCr powders by a higher flame temperature.

High Temperature Erosion Properties of Thermal Barrier Coatings Produced by Acetylene Sprayed High Velocity Oxygen Fuel Process

2000 ◽  
Author(s):  
M.A. Cole ◽  
R. Walker
Keyword(s):  
High Temperature ◽  
Thermal Barrier Coatings ◽  
High Velocity ◽  
Thermal Barrier ◽  
High Velocity Oxygen Fuel ◽  
Hvof Spraying ◽  
Powder Morphology ◽  
Fuel Gas ◽  
Barrier Coatings ◽  
Oxygen Fuel

Abstract Over the past 30 years, there has been considerable interest in the development of thermally sprayed thermal barrier coatings (TBCs) for aerospace and land based turbine applications. The use of TBCs enables higher operating temperatures, resulting in significant fuel efficiency savings. This paper reports on the development of dense Yttria Stabilised Zirconia (YSZ) thermal barrier coatings produced by High Velocity Oxygen Fuel (HVOF) spraying using acetylene as the fuel gas. The use of a high temperature gas erosion rig allowed the controlled evaluation of erodent size, velocity, impact angle, and temperature on coating performance. The work also covers the optimization of process parameters, including powder morphology, stand-off distance, oxygen to fuel ratio, gas pressures, and flowrates, and their effect on coating characteristics such as deposition efficiency, microhardness, and surface roughness.

Novel Coatings of Cemented Carbides by an Improved HVOF Spraying Process

2009 ◽  
pp. 159-166
Author(s):  
Makoto Watanabe ◽  
Pornthep Chivavibul ◽  
Jin Kawakita ◽  
Seiji Kuroda
Keyword(s):  
Cemented Carbides ◽  
Hvof Spraying ◽  
Spraying Process

Investigations of Corrosion Behavior on Combined Fast Laser Texturing and HVOF TiO2 Powder Deposition Surface Engineering Treatment

2019 ◽  
Vol 1153 ◽  
pp. 119-125
Author(s):  
Aurel Valentin Bîrdeanu ◽  
Dubravka S. Milovanovic ◽  
Jovan Ciganovic ◽  
Sanja Petronić ◽  
Mirela Vaida ◽  
...  
Keyword(s):  
Surface Engineering ◽  
Classical Method ◽  
Nacl Solution ◽  
Laser Texturing ◽  
Hvof Spraying ◽  
Deposition Surface ◽  
Powder Deposition ◽  
Before And After ◽  
Duplex Surface Treatment ◽  
Spraying Process

The paper presents the characteristics of TiO2 coatings realized by HVOF spraying process by two different processing paths, i.e. using the classical method of preparing the substrate by sandblasting and by applying a fast laser texturing of the substrate (instead of sandblasting) before the actual HVOF spraying respectively (a duplex treatment). The obtained coatings’ morphology were characterized by SEM before and after electrochemical measurements in NaCl solution. The textured sample presented better resistance to corrosion compared with classical processing path. Keywords: coatings, fast laser texturing, HVOF spraying, duplex surface treatment, anticorrosive.

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