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.

In vitro Behaviour of Alumina-Hydroxiapatite Composites Coatings

2018 ◽  
Vol 69 (6) ◽  
pp. 1416-1418
Author(s):  
Alexandru Szabo ◽  
Ilare Bordeasu ◽  
Ion Dragos Utu ◽  
Ion Mitelea
Keyword(s):  
Pure Titanium ◽  
Titanium Substrate ◽  
High Strength ◽  
Biological Properties ◽  
Commercially Pure Titanium ◽  
Hvof Spraying ◽  
Before And After ◽  
Sbf Solution ◽  
Oxygen Fuel

Hydroxyapatite (HA) is a very common material used for biomedical applications. Usually, in order to improve its poor mechanical properties is combined or coated with other high-strength materials.The present paper reports the manufacturing and the biocompatibility behaviour of two different biocomposite coatings consisting of alumina (Al2O3) and hydroxyapatite (HA) using the high velocity oxygen fuel (HVOF) spraying method which were deposited onto the surface of a commercially pure titanium substrate. The biological properties of the Al2O3-HA materials were evaluated by in vitro studies. The morphology of the coatings before and after their immersing in the simulated body fluid (SBF) solution was characterized by scanning electron microscopy (SEM). The results showed an important germination of the biologic hydroxyapatite crystallite on the surface of both coatings.

scholarly journals Tribological Behavior of Laser Textured Hot Stamping Dies

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Andre Shihomatsu ◽  
Sergio Tonini Button ◽  
Iris Bento da Silva
Keyword(s):  
Surface Topography ◽  
High Pressures ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Tests ◽  
Textured Surface ◽  
Laser Texturing ◽  
Stamping Dies ◽  
Before And After

Hot stamping of high strength steels has been continuously developed in the automotive industry to improve mechanical properties and surface quality of stamped components. One of the main challenges faced by researchers and technicians is to improve stamping dies lifetime by reducing the wear caused by high pressures and temperatures present during the process. This paper analyzes the laser texturing of hot stamping dies and discusses how different surfaces textures influence the lubrication and wear mechanisms. To this purpose, experimental tests and numerical simulation were carried out to define the die region to be texturized and to characterize the textured surface topography before and after hot stamping tests with a 3D surface profilometer and scanning electron microscopy. Results showed that laser texturing influences the lubrication at the interface die-hot sheet and improves die lifetime. In this work, the best texture presented dimples with the highest diameter, depth, and spacing, with the surface topography and dimples morphology practically preserved after the hot stamping tests.

scholarly journals Fluoride Treatment and In Vitro Corrosion Behavior of Mg-Nd-Y-Zn-Zr Alloys Type

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 566
Author(s):  
Pham Hong Quan ◽  
Iulian Antoniac ◽  
Florin Miculescu ◽  
Aurora Antoniac ◽  
Veronica Manescu (Păltânea) ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Orthopedic Implants ◽  
Immersion Test ◽  
Nacl Solution ◽  
Fluoride Ions ◽  
Fluoride Treatment ◽  
Cardiovascular Stents ◽  
Before And After

Fluoride conversion coatings on Mg present many advantages, among which one can find the reduction of the corrosion rate under “in vivo” or “in vitro” conditions and the promotion of the calcium phosphate deposition. Moreover, the fluoride ions released from MgF2 do not present cytotoxic effects and inhibit the biofilm formation, and thus these treated alloys are very suitable for cardiovascular stents and biodegradable orthopedic implants. In this paper, the biodegradation behavior of four new magnesium biodegradable alloys that have been developed in the laboratory conditions, before and after surface modifications by fluoride conversion (and sandblasting) coatings, are analyzed. We performed structural and surface analysis (XRD, SEM, contact angle) before and after applying different surface treatments. Furthermore, we studied the electrochemical behavior and biodegradation of all experimental samples after immersion test performed in NaCl solution. For a better evaluation, we also used LM and SEM for evaluation of the corroded samples after immersion test. The results showed an improved corrosion resistance for HF treated alloy in the NaCl solution. The chemical composition, uniformity, thickness and stability of the layers generated on the surface of the alloys significantly influence their corrosion behavior. Our study reveals that HF treatment is a beneficial way to improve the biofunctional properties required for the studied magnesium alloys to be used as biomaterials for manufacturing the orthopedic implants.

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.

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

INFLUENCE OF CARBON NANOTUBES REINFORCEMENT ON CHARACTERISTICS OF THERMALLY SPRAYED CERAMIC COATINGS

2020 ◽  
pp. 2050052
Author(s):  
G. MOHAMMED THALIB BASHA ◽  
B. VENKATESHWARLU
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Ceramic Coatings ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Hvof Spraying ◽  
Titania Coatings ◽  
Thermally Sprayed ◽  
Spraying Process ◽  
Reduced Surface

The influence of reinforcement of carbon nanotubes (CNTs) on microstructural features and mechanical properties of thermally sprayed Al2O3–3[Formula: see text]wt.%TiO2 and WC–20[Formula: see text]wt.%Co coatings was investigated. Alumina–Titania coatings were deposited by Air Plasma Spraying (APS) and Tungsten Carbide–Cobalt coatings were deposited by High-Velocity Oxy-Fuel (HVOF) spraying process. The coatings obtained with reinforcement of CNTs were characterized to interpret the microstructural changes and also to evaluate the variation in their mechanical properties. The percentage composition of CNTs in both APS and HVOF coatings systems were varied in the order of 2, 4, and 6[Formula: see text]wt.%. It has been found that homogenous dispersion of carbon nanotubes in the coating systems results in increased microhardness and reduced surface roughness. Also, the microstructural features of the coating systems clearly showed that the coatings are denser with fewer pores due to the presence of CNTs.

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