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

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.

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 629 ◽  
Author(s):  
Milan Parchovianský ◽  
Ivana Parchovianská ◽  
Peter Švančárek ◽  
Günter Motz ◽  
Dušan Galusek

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.


2012 ◽  
Vol 507 ◽  
pp. 127-133 ◽  
Author(s):  
Sigrid Seuss ◽  
Tayyab Subhani ◽  
Min Yi Kang ◽  
Kenji Okudaira ◽  
Isaac E. Aguilar Ventura ◽  
...  

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.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Udomdej Pakdee ◽  
Surasak Chiangga ◽  
Suchat Suwannatus ◽  
Pichet Limsuwan

Multiwalled carbon nanotubes (MWCNTs) were synthesized on austenitic stainless steel foils (Type 304) using a home-built thermal chemical vapor deposition (CVD) under atmospheric pressure of hydrogen (H2) and acetylene (C2H2). During the growth, the stainless steel substrates were heated at different temperatures of 600, 700, 800, and 900°C. It was found that MWCNTs were grown on the stainless steel substrates heated at 600, 700, and 800°C while amorphous carbon film was grown at 900°C. The diameters of MWCNTs, as identified by scanning electron microscope (SEM) images together with ImageJ software program, were found to be 67.7, 43.0, and 33.1 nm, respectively. The crystallinity of MWCNTs was investigated by an X-ray diffractometer. The number of graphitic walled layers and the inner diameter of MWCNTs were investigated using a transmission electron microscope (TEM). The occurrence of Fe3O4 nanoparticles associated with carbon element can be used to reveal the behavior of Fe in stainless steel as catalyst. Raman spectroscopy was used to confirm the growth and quality of MWCNTs. The results obtained in this work showed that the optimum heated stainless steel substrate temperature for the growth of effective MWCNTs is 700°C. Chemical states of MWCNTs were investigated by X-ray photoelectron spectroscopy (XPS) using synchrotron light.


2019 ◽  
Vol 86 (3) ◽  
pp. 30301 ◽  
Author(s):  
Zouina Amina Ait-Djafer ◽  
Nadia Saoula ◽  
Daniel Wamwangi ◽  
Noureddine Madaoui ◽  
Hamid Aknouche

In this study, a negative substrate bias voltage is used to tune the structural, morphological, mechanical and electrochemical properties of TiAlN coatings fundamental for protective coating applications. TiAlN thin films have been deposited on glass, (001)Si and stainless steel substrates by RF magnetron sputtering at a power density of 4.41 W/cm2. The deposition rate was determined from X-ray reflectivity measurements to 7.00 ± 0.05 nm/min. TiAlN films used in this work were deposited for 60 min to yield a film thickness of 420 nm. Structural analysis has shown that TiAlN coating forms a cubic (fcc) phase with orientations in (111), (200), (220) and (222) planes. The deposited coatings present maximum hardness (H = 37.9 GPa) at −75 V. The dependence of hardness and Young's modulus and corrosion resistance on microstructure has been established. Electrochemical studies by potentiodynamic polarization in aggressive environment (3.5 wt.% NaCl) have revealed that stainless steel substrate with TiAlN coating exhibits excellent corrosion resistance.


2011 ◽  
Vol 214 ◽  
pp. 291-295
Author(s):  
Wei Yu Ho ◽  
Chung Hsien Yang ◽  
Wei Che Huang ◽  
Woei Yun Ho

In this study, various multilayered TiN/CrN coatings were deposited on the SS316L stainless steel substrates by the cathodic arc deposition technique. By varying the turntable rotation speed, the multilayered coatings with different periodic layer thickness were obtained. The main target of this study is to enhance the corrosion resistance and electrical conductivity of the stainless steel for potential application of metallic bipolar plate of PEMFC. The results showed that all of the TiN/CrN coated samples presented a better corrosion resistance than the bare stainless steel substrate. The multi-layered coatings deposited at the 2 rpm provided the best corrosion resistance of the coated stainless steels when they were subjected to polarization test in 1M H2SO4 solution. The result of single fuel cell test shows that the TiN/CrN multi-layered coating with the best corrosion resistance is considered to be a candidate for PEMFC bipolar plate application in this study.


2013 ◽  
Vol 785-786 ◽  
pp. 872-876
Author(s):  
Yong Huang ◽  
Shu Guang Han ◽  
Ya Jing Yan ◽  
Xiao Feng Pang

This work elucidated corrosion resistance of the electrodeposited MgO/calcium phosphate (Ca-P/MgO) films on titanium (Ti). The microstructure, phase composition, and corrosion resistance of the films were studied. Results revealed that The Ca-P/MgO composite coatings were rough and inhomogeneous, the upper layer was floral-like crystals or flakes agglomerates morphology, and the lower layer was needle-like crystals which were mutually cross linked. The coating was very dense, and the content of Mg was about 0.3 wt%. Potentiodynamic polarization test manifested that the Ca-P/MgO-coated surface exhibited superior corrosion resistance than the bare titanium.


2011 ◽  
Vol 399-401 ◽  
pp. 2055-2060
Author(s):  
Ji Bo Jiang ◽  
Wei Dong Liu ◽  
Lei Zhang ◽  
Qing Dong Zhong ◽  
Yi Wang ◽  
...  

Ni–B4C composite coatings on carbon steel substrates with various contents of B4C nano-particulates were prepared by electrodeposition in Ni plating bath containing B4C nano-particulates. Microhardness, Scanning Electron Microscopy (SEM), Tafel polarization and Electrochemical Impedance Spectroscopy (EIS) measurements were used to compare pure nickel coatings and Ni–B4C composite coatings. Pure Ni coating microhardness is lower than that of Ni–B4C coatings and the microhardness of the composite coatings increases with the increase of the content of B4C nano-particulates. The effects of various contents of B4C nano-particulates on the corrosion resistance were investigated and it was found that the best anti–corrosion property of Ni–B4C composite coatings is at 6 g/L B4C in the bath formulation.


1990 ◽  
Vol 5 (4) ◽  
pp. 717-720 ◽  
Author(s):  
S. Witanachchi ◽  
S. Patel ◽  
Y. Z. Zhu ◽  
H. S. Kwok ◽  
D. T. Shaw

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.


2012 ◽  
Vol 05 ◽  
pp. 833-840
Author(s):  
S.R. Allahkaram ◽  
S. Salmi ◽  
E. Tohidlou

Electroless composite coatings have been vastly used in various industries during last decades due to their good properties, such as corrosion and wear resistance, hardness and uniform thickness. In this paper, co-deposition of TiO 2 nano-particles with Nickel-Phosphorus electroless coatings on API-5L-X65 steel substrates was investigated. Surface morphology and composition of coatings were studied via SEM and EDX, respectively. XRD analyses showed that these coatings had amorphous structure with TiO 2 crystalline particles. TiO 2 nano-particles increased microhardness of coatings. Corrosion resistance of these coatings was tested using linear polarization in 0.5M sulfuric acid electrolyte. Results showed that NiP - TiO 2 electroless composite coatings increased corrosion resistance of substrates.


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