scholarly journals PDC Glass/Ceramic Coatings Applied to Differently Pretreated AISI441 Stainless Steel Substrates

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 629 ◽  
Author(s):  
Milan Parchovianský ◽  
Ivana Parchovianská ◽  
Peter Švančárek ◽  
Günter Motz ◽  
Dušan Galusek
Keyword(s):  
Stainless Steel ◽  
Bond Coat ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Spray Coating ◽  
Ceramic Coatings ◽  
Strong Adhesion ◽  
Cleaning Procedures ◽  
Small Cracks ◽  
Steel Substrates

In this work, the influence of different cleaning procedures on adhesion of composite coatings containing passive ceramic and commercial glasses was investigated. Two compositions (C2c, D2-PP) of double-layer polymer-derived ceramic (PDC) coating systems, composed from bond coat and a top coat, were developed. In order to obtain adherent coatings, stainless steel substrates were cleaned by four different cleaning procedures. The coatings were then deposited onto the steel substrate via spray coating. Pretreatment by subsequent ultrasonic cleaning in acetone, ethanol and deionised water (procedure U) was found to be the most effective, and the resultant C2c and D2-PP coatings, pyrolysed at 850 °C, indicated strong adhesion without delamination or cracks, propagating at the interface steel/bond coat. In the substrate treated by sandblasting and chemical etching, small cracks in the bond coat were observed under the same pyrolysis conditions. After oxidation tests, all coatings, except for those subjected to the U-treated substrates, showed significant cracking in the bond coat. The D2-PP coatings were denser than C2c, indicating better protection of the substrate.

scholarly journals Fabrication and Characterization of Zein/Hydroxyapatite Composite Coatings for Biomedical Applications

Surfaces ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 237-250 ◽  
Author(s):  
Yusra Ahmed ◽  
Muhammad Yasir ◽  
Muhammad Atiq Ur Rehman
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Biomedical Applications ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Sem Images ◽  
Taguchi Design Of Experiments ◽  
Hydrophilic Nature ◽  
Strong Adhesion ◽  
Steel Substrates

Stainless steel is renowned for its wide use as a biomaterial, but its relatively high corrosion rate in physiological environments restricts many of its clinical applications. To overcome the corrosion resistance of stainless steel bio-implants in physiological environments and to improve its osseointegration behavior, we have developed a unique zein/hydroxyapatite (HA) composite coating on a stainless steel substrate by Electrophoretic Deposition (EPD). The EPD parameters were optimized using the Taguchi Design of experiments (DoE) approach. The EPD parameters, such as the concentration of bio-ceramic particles in the polymer solution, applied voltage and deposition time were optimized on stainless steel substrates by applying a mixed design orthogonal Taguchi array. The coatings were characterized by using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and wettability studies. SEM images and EDX results indicated that the zein/HA coating was successfully deposited onto the stainless steel substrates. The wettability and roughness studies elucidated the mildly hydrophilic nature of the zein/HA coatings, which confirmed the suitability of the developed coatings for biomedical applications. Zein/HA coatings improved the corrosion resistance of bare 316L stainless steel. Moreover, zein/HA coatings showed strong adhesion with the 316L SS substrate for biomedical applications. Zein/HA developed dense HA crystals upon immersion in simulated body fluid, which confirmed the bone binding ability of the coatings. Thus the zein/HA coatings presented in this study have a strong potential to be considered for orthopedic applications.

Sintering of EPD Ceramic Coatings by Electron Beam

2006 ◽  
Vol 45 ◽  
pp. 1200-1205
Author(s):  
Maria Federica De Riccardis ◽  
Daniela Carbone ◽  
Emanuela Piscopiello ◽  
Antonella Rizzo ◽  
Marco Vittori Antisari
Keyword(s):  
Stainless Steel ◽  
Electron Beam ◽  
Ceramic Coating ◽  
Steel Substrate ◽  
Ceramic Coatings ◽  
Metallic Substrates ◽  
Transmission Electron ◽  
Novel Method ◽  
Pull Tests ◽  
Steel Substrates

In order to obtain wear resistant coating as well as thermal barrier on metallic substrates by EPD, the conventional high temperature treatments are inapplicable; so we used an alternative method to densify and make the electrophoretic deposit more adherent. In this work we described a novel method to obtain EPD deposits with good density and adherence to stainless steel substrate. At first, we achieved stabilized alumina and alumina-zirconia based suspensions; to improve the adhesion of ceramic coating on metal, some stainless steel substrates were sandblasted, others were coated with titanium bond layers. Then the substrates were coated by EPD; finally, we used the electron beam to treat the ceramic coating-metallic substrate system on the surface; in this way we obtained adherent and dense EPD coatings. In order to evaluate the quality and the microstructure of the coating sintering, the samples were observed by scanning and transmission electron microscopy; pull tests showed the adhesion of treated EPD coating was about one hundred times higher than that of deposited EPD coating.

Laser Sintering of Nano-Al2O3 Powders on Plasma Sprayed Ceramic Based Coatings

2007 ◽  
Author(s):  
Lida Shen ◽  
Yinhui Huang ◽  
Zongjun Tian ◽  
Guoran Hua
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Plasma Spraying ◽  
Bond Coat ◽  
Continuous Wave ◽  
Ceramic Coatings ◽  
Laser Sintering ◽  
Al2o3 Ceramic ◽  
Plasma Sprayed ◽  
Steel Substrates

This paper describes an investigation of nano-Al2O3 powders reinforced ceramic coatings, which has included NiCrAl and Al2O3+13%wt.TiO2 coats pre-produced by atmosphere plasma spraying, implemented by laser sintering. Commercial NiCrAl powders were plasma sprayed onto 45 Steel substrates to give a bond coat with thickness of ∼100μm. The 600μm thick Al2O3+13%wt.TiO2 based coating was also plasma sprayed on top of the NiCrAl bond coat. With 2.5kw continuous wave CO2 laser, nano-Al2O3 ceramic powders were laser sintered on the based Coatings. The micro structure and chemical composition of the modified Al2O3+13%wt.TiO2 coatings were analyzed by such detection devices as scanning electronic microscope (SEM) and x-ray diffraction (XRD). Microhardness, wear resistance and corrosion resistance of the modified coatings were also tested and compared with that of the unmodified. The results show that the crystal grain size of Al2O3 had no obvious growth. In addition, due to the nanostructured Al2O3 ceramic phases, the coatings exhibited higher microhardness, better wear resistance and corrosion resistance than those unmodified counterparts. The complex process of plasma spraying with laser sintering as a potential effective way of the application of ceramic nano materials was also simply discussed and summarized in the end.

Interface Evaluation of MCrAlY Powder Bond Coat on 316 SS Processed with Laser Irradiation

2014 ◽  
Vol 802 ◽  
pp. 409-414 ◽  
Author(s):  
Viviane Teleginski ◽  
Daniele C. Chagas ◽  
Luis Gustavo de Oliveira ◽  
Getúlio de Vasconcelos
Keyword(s):  
Stainless Steel ◽  
Laser Beam ◽  
Optical Microscopy ◽  
Bond Coat ◽  
Surface Texturing ◽  
Ceramic Coatings ◽  
Metallic Substrate ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
First Case

As aircraft and thermoelectric turbine blades work in aggressive environments (high temperatures and pressures), they are exposed to oxidation reactions. Ceramic coatings are employed to increase the turbine work temperature (improving its performance) and a bond coat (BC), base of particulate material of Ni-Cr-Al powders, which assure a good adhesion, gradual decrease in thermal expansion coefficient between the metallic substrate and the ceramic top coat, avoiding the oxidation effect in the metallic substrate. This research aims the study and comparison of two different deposition process routes of particulate materials of BC (MCrAlY) on AISI 316 stainless steel substrate. In the first case, the BC powder was pre-deposited by segregation method and irradiated by a CO2laser beam. In the second case, laser surface texturing was done on the stainless steel surface by a Yb: fiber laser beam, the BC was deposited by the same method, and further, irradiated by a CO2laser beam. The main focus of this work was to evaluate the resulting interface for both mentioned cases. For this propose, characterizations were made using the techniques of optical microscopy and roughness measurements. In the first case, homogenous layers of bond coat were obtained. Optical microscopy suggest the formation of a metallurgic bonding between the substrate and the MCrAlY. For the laser surface texturing, the surface roughness can be adjusted by the laser beam parameters.

Flexible stainless steel foil as a substrate for superconducting Y-Ba-Cu-O films

1990 ◽  
Vol 5 (4) ◽  
pp. 717-720 ◽  
Author(s):  
S. Witanachchi ◽  
S. Patel ◽  
Y. Z. Zhu ◽  
H. S. Kwok ◽  
D. T. Shaw
Keyword(s):  
Stainless Steel ◽  
Critical Current ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Surface Condition ◽  
Heat Treating ◽  
Critical Currents ◽  
Buffer Layers ◽  
Critical Temperatures ◽  
Steel Substrates

As-deposited superconducting Y-Ba-Cu-O films have been grown on stainless steel substrates by the plasma assisted laser deposition technique. Low interfacial diffusion of iron at the 550°C growth temperature enables us to produce superconducting films with critical temperatures up to 83 K and critical currents up to ∼4 × 103 A/cm2 (40 K). Dependence of the superconducting properties of the Y-Ba-Cu-O films on the surface condition of the mirror finished stainless steel substrate has been studied. Critical temperature and critical current of the films have been improved by heat-treating the substrate and incorporating buffer layers. Variation of the critical current with the bend radii of the film is discussed.

Electrophoretic Deposition of PEEK-TiO2 Composite Coatings on Stainless Steel

2012 ◽  
Vol 507 ◽  
pp. 127-133 ◽  
Author(s):  
Sigrid Seuss ◽  
Tayyab Subhani ◽  
Min Yi Kang ◽  
Kenji Okudaira ◽  
Isaac E. Aguilar Ventura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Electrophoretic Deposition ◽  
Biomedical Applications ◽  
316L Stainless Steel ◽  
Treatment Process ◽  
Composite Coatings ◽  
Heat Treatment Process ◽  
Steel Substrates ◽  
Scanning Electron

Electrophoretic deposition (EPD) has been successfully used to deposit composite coatings composed of polyetheretherketone (PEEK) and titanium dioxide (TiO2) nanoparticles on 316L stainless steel substrates. The suspensions of TiO2 nanoparticles and PEEK microparticles for EPD were prepared in ethanol. PEEK-TiO2 composite coatings were optimized using suspensions containing 6wt% PEEK-TiO2 in ethanol with a 3:1 ratio of PEEK to TiO2 in weight and by applying a potential difference of 30 V for 1 minute. A heat-treatment process of the optimized PEEK-TiO2 composite coatings was performed at 335°C for 30 minutes with a heating rate of 10°Cminto densify the deposits. The EPD coatings were microstructurally evaluated by scanning electron microscopy (SEM). It was demonstrated that EPD is a convenient and rapid method to fabricate PEEK/TiO2 coatings on stainless steel which are interesting for biomedical applications.

scholarly journals Effects of WC Particle Types on the Microstructures and Properties of WC-Reinforced Ni60 Composite Coatings Produced by Laser Cladding

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 583 ◽  
Author(s):  
Pengxian Zhang ◽  
Yibin Pang ◽  
Mingwei Yu
Keyword(s):  
Stainless Steel ◽  
Uniform Distribution ◽  
Laser Cladding ◽  
Steel Surface ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Composite Coatings ◽  
304 Stainless Steel ◽  
Stainless Steel Surface ◽  
Different Types

WC-reinforced Ni60 composite coatings with different types of WC particles were prepared on 304 stainless steel surface by laser cladding. The influences of spherical WC, shaped WC, and flocculent WC on the microstructures and properties of composite coatings were investigated. The results showed that three types of WC particles distribute differently in the cladding coatings, with spherical WC particles stacking at the bottom, shaped WC aggregating at middle and lower parts, with flocculent WC particles dispersing homogeneously. The hardnesses, wear resistances, corrosion resistances, and thermal shock resistances of the coatings are significantly improved compared with the stainless steel substrate, regardless of the type of WC that is added, and especially with regard to the microhardness of the cladding coating; the addition of spherical or shaped WC particles can be up to 2000 HV0.05 in some areas. Flocculent WC, shaped WC, and spherical WC demonstrate large to small improvements in that order. From the results mentioned above, the addition of flocculent WC can produce a cladding coating with a uniform distribution of WC that is of higher quality compared with those from spherical WC and shaped WC.

Tantalum Based High-Pressure Cold Spray Coatings on Stainless Steel Substrate

2019 ◽  
Vol 813 ◽  
pp. 429-434
Author(s):  
Jagannadh V.S.N. Sripada ◽  
Megil F. Gallant ◽  
Gobinda C. Saha ◽  
Reeti Singh ◽  
Jan Kondas
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Cold Spray ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Transition Element ◽  
Spray Coating ◽  
Deposition Efficiency ◽  
High Heat ◽  
Inlet Temperature

Tantalum as a transition element possesses good corrosion resistant properties, along with ductility and hardness. It is also one of the best heat-resistant material (melting point 2996°C) and is known for its high heat and electrical conductivity. In this research, Tantalum is deposited on stainless steel substrate using high-pressure cold spray (HPCS) method. Cold spray coating technology enables the deposition of powder feedstock without melting. Feedstock particles are propelled through a nozzle at supersonic velocities and they deform plastically on impact, resulting in good bonding strength to the substrate. The low temperature and solid-state deposition associated with cold spray allows refractory materials such as Ta, Mo, and W to be deposited without high temperature requirements. The objective of this work is to achieve a dense and nonporous coating microstructure with a high deposition efficiency. The hardness of as-received tantalum particles is found to be 279 HV0.3 and the microstructure is very dense. Tensile testing carried on the sample coated at a stagnation gas pressure of 50 bar and gas inlet temperature of 900°C exhibited an ultimate tensile strength of 442 MPa and adhesion strength of 77 MPa. Further mechanical properties of the coating in terms of hardness is carried out by nanoindentation. These results will be correlated with microstructural imaging and elemental analysis including morphology and composition using scanning electron microscopy and X-ray diffraction techniques.

scholarly journals Electrochemical Polymerization of PEDOT–Graphene Oxide–Heparin Composite Coating for Anti-fouling and Anti-clotting of Cardiovascular Stents

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1520 ◽  
Author(s):  
Yang ◽  
Tsou ◽  
Hsiao ◽  
Cheng ◽  
Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Graphene Oxide ◽  
Blood Clotting ◽  
Electrochemical Polymerization ◽  
Composite Coatings ◽  
3T3 Cells ◽  
Clotting Time ◽  
Cardiovascular Stents ◽  
Electrochemical Copolymerization ◽  
Steel Substrates

ABSTRACT: In this study, a novel hemocompatible coating on stainless steel substrates was prepared by electrochemically copolymerizing 3,4-ethylenedioxythiophene (EDOT) with graphene oxide (GO), polystyrene sulfonate (PSS), or heparin (HEP) on SUS316L stainless steel, producing an anti-fouling (anti-protein adsorption and anti-platelet adhesion) surface to avoid the restenosis of blood vessels. The negative charges of GO, PSS, and HEP repel negatively charged proteins and platelets to achieve anti-fouling and anti-clotting. The results show that the anti-fouling capability of the poly(3,4-ethylenedioxythiophene) (PEDOT)/PSS coating is similar to that of the PEDOT/HEP coating. The anti-fouling capability of PEDOT/GO is higher than those of PEDOT/HEP and PEDOT/PSS. The reason for this is that GO exhibits negatively charged functional groups (COO−). The highest anti-fouling capability was found with the PEDOT/GO/HEP coating, indicating that electrochemical copolymerization of PEDOT with GO and HEP enhances the anti-fouling capability. Furthermore, the biocompatibility of the PEDOT coatings was tested with 3T3 cells for 1–5 days. The results show that all PEDOT composite coatings exhibited biocompatibility. The blood clotting time (APTT) of PEDOT/GO/HEP was prolonged to 225 s, much longer than the 40 s of pristine SUS316L stainless steel (the control), thus greatly improving the anti-blood-clotting capability of cardiovascular stents.

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