Glass Coatings Research Articles

Stress State of a Glass Coating In Pipes

Stress State of a Glass Coating In Pipes

Enhance the Biological Properties of Commercial Pure Titanium with Bioactive Glass Coating by Pulsed Laser Deposition

Titanium is the most broadly employed implant material for the load bearing dental and the orthopedic uses due to its brilliant biological and mechanical characteristics. The aim of the present study is to assay the biological behavior of pure Titanium coated with a bioactive glass coating made by pulsed laser deposition. The coating characteristic and the biological behavior of coated specimens were assessed and compared with uncoated specimens. In vitro biological behavior including bioactivity, biocompatibility and antibacterial property was evaluated. The bioactivity of the specimens was assayed by immersion in a simulated body fluid for various times (7 and 14) days. Biocompatibility was assessed by MTT assay of L929 mouse fibroblast cells after 1, 3 and 5 days. Also, the antibacterial property was evaluated against S. aures by optical density method. The obtained results revealed that the pulsed laser deposited bioactive glass coating significantly improved the potential of Titanium for dental and orthopedic applications.

Morphological and mechanical characterization of chitosan/gelatin/silica-gentamicin/bioactive glass coatings on orthopaedic metallic implant materials

Metals are the most widely used materials for orthopedics and dentistry due to their high mechanical properties. However, for certain uses like fixation plates and screws, dental implants, and osseo-articular prosthesis, their surface characteristics such as non-toxic and non-corrosive behavior, good cell adhesion and proliferation, and resistance to bacterial biofilm formation should be accompanied with high mechanical performance. One way to improve metallic implant performance in vivo is to coat them with biopolymer or inorganic thin films. This work describes two multifunctional coating systems for orthopedic titanium and stainless steel implants. Titanium implants were coated with a system consisting of a base hybrid sol-gel layer with bioactive glass particles (applied via spraying) and a top chitosan/gelatin layer with silica-gentamicin nanoparticles (applied via electrophoretic deposition, EPD). Stainless steel implants, which are designed to be removable, were coated only with the top chitosan/gelatin/ silica-gentamicin nanoparticles layer with the aim of providing a temporal attachment to bone and to combat possible bacterial adhesion. The microstructural and mechanical characterization of the coatings was conducted by optical microscopy, transmission and scanning electron microscopy, digital image processing, as well as nanoindentation and nanoscratch tests to advance the understanding of their elastic-plastic, morphologic and adhesive behavior. The coatings were homogeneous, providing good coverage to both substrates. Their surface properties, such as roughness and wettability, indicate that they represent excellent substrates for cell attachment. Bioactive glass particles can be added to titanium implant systems as bioactive components without affecting adhesion or mechanical performance of the chitosan/gelatin/silica-gentamicin nanoparticle EPD coatings. The increase in both hardness and elastic modulus of the coated systems could be due to the presence of the silica-gentamicin nanoparticles and their compaction during the penetration of the indenter. When the samples are subjected to scratch tests, the critical load increases with the reinforcement of the coatings by the silica-gentamicin nanoparticles absorbing the applied load and maintaining the elastic properties of the coatings.

Corrosion behaviour of plasma sprayed Fe based metallic glass (Fe73Cr2Si11B11C3 (at%) coatings in 3.5% NaCl solution

In this study, Fe based amorphous/nanocrystalline composite coatings with different coating thicknesses were deposited on a mild steel substrate by atmospheric plasma spraying (APS) using a low Cr-containing gas atomised amorphous Fe73Cr2Si11B11C3 (at%) powder. The corrosion behaviour of the amorphous/nanocrystalline coatings of different thickness was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analysis in a freely aerated 3.5 wt% NaCl solution. The variation in microstructural characteristics of the coatings with various coating thicknesses and the effect of the surface morphology, porosity content, surface roughness and amorphous content in the coatings have been correlated with the corrosion behaviour of the coatings. The results demonstrate that the corrosion resistance of the plasma sprayed Fe based composite coatings is better than that of the steel substrate regardless of coating thickness. Moreover, the best corrosion resistance of the coating with a thickness level of 110 ± 12 μm is attributed to (i) its optimum presence of content of amorphous, porosity, and surface roughness, (ii) excellent film and charge transfer resistance, and (iii) higher protection ability of the rust as compared to the other coating thickness values.

Bioactive glass coatings obtained by thermal spray: Current status and future challenges

Several inorganic materials such as bioactive glasses, glass–ceramics and calcium phosphates have been shown to be bioactive and resorbable which make them suitable for coating bone implants. This study focuses only on bioactive glasses. These biomaterials are highly biocompatible and can form a strong chemical bond with the tissues. This review comprehensively covers bibliographic reports that have investigated bioactive glass deposition using different thermal spray techniques.The main drawback for the glass coating deposition is the low adherence with the substrate. Some strategies can favour a good bond such as using bond coats, blends, pre-heating the substrate or modifying the glass composition.The characteristics of the feedstock powders are determinant for the properties of the coatings obtained. Porosity and thickness of the coatings can be modulated by using different thermal spray techniques and varying parameters of the process.The degradation rate of some bioactive glasses can achieve kinetics similar to the new bone formation. Taking advantage of its dissolution capacity, glasses can be doped with functional elements.While several biological studies have been performed with bioactive glass materials, there has been relatively little research on the biological response of coated glasses by thermal spray techniques. Research studies have demonstrated the opportunities of this promising material to enhance the bioactivity of the implants.

Design, fabrication and assessment of an optomechanical sensor for pressure and vibration detection using flexible glass multilayers

We introduce an easily implementable optomechanical device for pressure and vibration sensing using a multilayer structure on a flexible substrate. We present the design, fabrication and evaluation steps for a proof-of-concept device as well as optical glass components. The design steps include optical, mechanical, and optomechanical correlation simulations using the transfer matrix method, finite element analysis, geometric optics and analytical calculations. The fabrication part focuses on the deposition of multilayers on polymeric flexible substrates using the radio frequency sputtering technique. To investigate the quality of the glass coatings on polymeric substrates, atomic force microscopy and optical microscopy are also performed. Optical measurements reveal that, even after bending, there are no differences between multilayer samples deposited on the polymeric and SiO 2 substrates. The performance assessment of the proof-of-concept device shows that the sensor resonance frequency is around 515 Hz and the sensor static response is capable of sensing from 50 Pa to 235 Pa. • A fabrication protocol for the deposition of SiO 2 /TiO 2 multilayers on flexible substrates using the RF-sputtering technique. • The film quality was characterized using optical microscopy, AFM, and spectrophotometer measurements. • An innovative sensing approach is demonstrated for force and vibration detection based on flexible photonic components. • A proof-of-concept optomechanical sensor has been designed, fabricated, and assessed. • Optical and mechanical modeling & simulation were also presented.

Evaluation of Glass Coatings with Various Silica Content Corrosion in a 0.5 M HCl Water Solution

Two enamel coatings with a high and a low silica content were prepared on 35CrMo steels via vacuum firing. Their corrosion behavior in a 0.5 M HCl solution including corrosion kinetics, microstructures and electrochemistry performance were studied in comparison with uncoated steels. The results show that catastrophic corrosion occurred for uncoated steels while enamel coatings significantly decreased the corrosion rate. Enamel coatings with a high silica content exhibited the best corrosion resistance against hydrochloric acid due to their highly connected silicate network, which inhibited the leaching process of alkali metals in the acid solution. The corrosion inhibition efficiency for enamel containing a high silica content reached a maximum of 94.3%.

Experimental investigation of the anti-soiling performances of different wettability of transparent coatings: Superhydrophilic, hydrophilic, hydrophobic and superhydrophobic coatings

Natural soiling of photovoltaic (PV) panel is an increasing problem especially in arid and desert areas. Finding a strategy that can reduce dust adhesion on PV panels is highly desirable but remains challenging. In this paper, different wettability of transparent coatings including superhydrophilic, hydrophilic, hydrophobic and superhydrophobic coatings were prepared to investigate the importance of surface roughness and surface energy. Their anti-soiling effects were investigated under different airflow velocity and different tilt angles. Dust deposition density, reduced transmittance, the ratio of reduced transmittance between bare glass surfaces and coatings, and PV efficiency reduction were used to characterize dust resistance performances. It is found that dust adhesion on superhydrophilic coatings was eminently governed by their respective high surface energy, with surface roughness rendering lesser contribution towards resisting/adhering effects. However, for other three coatings, further reducing the surface energy had little influence on the improvement of dust-proof ability. A large airflow velocity is beneficial to resist dust adhesion for all four types of coatings. However, a large airflow velocity has a limited ability to improve the anti-soiling effect of superhydrophilic coating under different tilt angles compared with other three coatings. The anti-soiling coatings can be referred to hydrophilic and hydrophobic coatings, not limited to superhydrophobic coating only. The study provides an invaluable guiding significance for preparation of dust-resistant coatings.

All-Nanoparticle Monolayer Broadband Antireflective and Self-Cleaning Transparent Glass Coatings.

The vast majority of light-emitting diode and liquid-crystal displays, solar panels, and windows in residential and industrial buildings use glass panels owing to their high mechanical stability, chemical resistance, and optical properties. Glass surfaces reflect about 4-5% of incident light if no antireflective coating is applied. In addition to energy losses in displays, surface reflections diminish picture quality. Engineering of antireflective coatings can be beneficial for all types of glass screens, specifically for large screens and touch-screen devices when scratch-resistance and self-cleaning properties of the glass surface are also desired. A scalable and robust approach to produce antireflective coatings for glass surfaces with desired optical and mechanical properties is introduced in this work. The developed coating mimics the structure of a moth-eye cornea. The coating is a subwavelength-microstructured thin layer on the glass surface made of a monolayer of hemispherical silica nanoparticles obtained by hydrothermal fusion of spherical particles to the glass substrate. The sequence of the particle deposition in the layer-by-layer process is adjusted to balance attractive-repulsive interactions among nanoparticles and between the nanoparticles and the glass surface to generate coatings with a high surface coverage of up to 70%, which exceeds the 54.7% limit of the random sequential addition model. This level of surface coverage allows for a combination of properties beneficial for the described applications: (i) an average reflectance of 0.5 ± 0.2% for a visible and near-infrared optical spectrum, (ii) an improved mechanical stability and scratch resistance, and (iii) non-wetting behavior.

Synthesis and Characterization of TiC-reinforced Metallic Glass Composite Coatings

In this paper, the Co-based metallic glass coatings deposited on soft metal substrates by pneumatic squeezing method were investigated. Also, the effects of TiC additions (%0-10) on the mechanical properties of the coatings were discussed in terms of hardness measurements. Microstructural observations have shown that the coatings with a thickness range of about 20-30 µm can be produced as non-porous layers in either entirely amorphous (0-6% TiC) or composite (8-10% TiC) structures. The glassy and TiC-reinforced glass composite coatings exhibit good adhesion characteristics and form a harder layer with the average hardness values between 1000 and 1600 Hv respectively. The hardness measurements evaluated together with XRD and EDX analyses showed that (Ti,Ta)C crystals precipitated in the amorphous matrix are responsible for further increase of the coatings hardness value up to 1600 Hv. The results also provide clues for mass manufacturing route in one step synthesis of the metallic glass and their composite coatings.

Design, synthesis, characterization, and aging properties of a new end‐capped three‐dimensional high‐refractive index hybrid organic–inorganic polysiloxane

AbstractThe actual need for hybrid organic–inorganic polysiloxanes is very high due to their importance in optoelectronic applications, especially for the preparation of anti‐ and low‐reflection layers, photopatterned overcoats, flexible hard coats, and glass and metal coatings. However, such three‐dimensional hybrid polysiloxanes have very often a limited shelf life and aged very rapidly. Consequently, this type of polymer may require to be stored at cold temperatures and needs to be dilute in organic solvent to a very low solid content, which are unprofitable conditions for commercialization purposes. Therefore, there is an urgent demand to prepare three‐dimensional polysiloxanes, which are more resistant toward aging processes. Herein, a new hybrid three‐dimensional polysiloxane has been designed and synthesized from three different silane precursors using the sol–gel technology, and characterized using gel permeation chromatography, 1H, 13C, and 29Si nuclear magnetic resonance and MS spectroscopies. One‐fourth of the silanol groups present in the polysiloxane have been protected with chlorotrimethylsilane. The refractive index of the silicon wafer coated with the new polysiloxane was found to be 1.53, which is higher compare to traditional values. Importantly, the new protected three‐dimensional polysiloxane did not age after being stored at T = 40°C for 3 weeks.

Color Tunable Emission of Y3Al5O12:Ce3+ and Sm3+‐Doped Zinc–Germanate–Tellurite Glass Nanocomposite Powders and Coatings for Light‐Emitting Diodes Applications

A series of nanocomposite (NC) powders and coatings of ZnO–GeO2–TeO2:xSm3+ glass and Y3Al5O12:Ce3+ nanoparticles (YAG:Ce) are fabricated. Samarium ions concentration of the glass phosphor is varied with x values of 0.3, 1.0, 3.0, and 5.0 mol%. The powder batches are prepared with a 95/5 mass ratio of glass/YAG:Ce and uniaxially pressed to obtain powder pellets that are heat‐treated at 350 °C. Morphology and structural characterization are conducted through X‐ray diffraction analysis, scanning electron microscopy, and Raman spectroscopy. The photoluminescence properties of NCs are investigated under different wavelengths of 340, 403, and 460 nm, showing a global emission tonality in the reddish‐orange and yellowish‐green region according to the estimated CIE 1931 chromaticity coordinates. Also, NC coatings soda–lime glass slides are fabricated, and their photoluminescence is characterized using an UV light‐emitting chip (≈365 nm) and a blue light‐emitting chip (≈460 nm). The global emission under UV and blue light from the light‐emitting diode (LED) chips of the NC coatings shows a color tunability in the warm white light and yellowish‐green region.

Corrosion protection of NiNb metallic glass coatings for 316SS by magnetron sputtering

Metallic glasses (MGs) appear as promising anti-corrosion coating materials due to their microstructural and physicochemical advantages. Herein, we proposed magnetron sputtered NiNb thin film MG coatings (MGCs) with different structures and compositions for corrosion protection of 316 stainless steel in an aggressive saline environment. The properties of monolayered Ni50Nb50 and Ni60Nb40, as well as the multilayered Ni50Nb50/Ni60Nb40 (at.%) MGCs, were characterized in terms of morphology and microstructural properties, as well as the anticorrosion behavior. All the NiNb MGCs presented compact structure and the monolayered coatings exhibited preferable adhesion properties in comparison with the multilayered coating. The electrochemical tests and XPS results imply that the monolayered Ni50Nb50 MGC with high Nb content resisted corrosion mainly due to the formation of stable passive film that contained abundant Nb2O5 species, whereas the Ni60Nb40 MGC with high Ni content showed week corrosion protection performance during long-term service due to the dissolution of Ni cations and the devastation of the coating structure. Though with bit worse adhesion and more vulnerable Ni60Nb40 layers, the multilayered Ni50Nb50/Ni60Nb40 MGC possessed comparable corrosion resistance with the monolayered Ni50Nb50 MG coating, which remained stable even after 32 days of exposure. Such performance should be ascribed to the combined eff ;ect of the repassivation property for the sub-layers, the hindrance of propagation paths of micro-defects, and the obstruction of corrosive species by interfaces in the multilayered coating.

In-vitro cell interaction and apatite forming ability in simulated body fluid of ICIE16 and 13-93 bioactive glass coatings deposited by an emerging suspension high velocity oxy fuel (SHVOF) thermal spray

ICIE16 and 13-93 bioactive glasses have been proposed as alternative chemically stable compositions in physiological fluid keeping bioactivity comparable to Bioglass®. ICIE16 and 13-93 bioactive glasses coatings were produced via an emerging suspension high-velocity oxy-fuel (SHVOF) thermal spraying technique. Suspensions of ICIE16 and 13-93 with 10 wt% solid loading in isopropanol (IPA) and water were used to produce coatings on AISI304 stainless steel using a flame power of 50 kW and 75 kW. For both glass formulations, the coatings deposited at a lower flame power were more porous, less hard, and less rough (~6% porous and 242 HV) than the coatings obtained at a higher flame power (~4% porosity and 300 HV). ICIE16 coatings showed more dissolution in SBF (simulated body fluid) than the 13-93 coatings. Moreover, the 13-93 glass coating sprayed at 75 kW showed the highest stability in SBF since only 2% of the coating was resorbed in SBF after 7 days of immersion and revealed apatite precipitation after 7 days. In-vitro cell tests, using MG63 cells, showed good cell attachment and proliferation on the surfaces of the coatings, revealing good cytocompatibility. The 13-93 coating sprayed at 75 kW revealed the highest cell proliferation after 7 days of incubation. This can be attributed to the higher surface roughness of the coating (Ra = 6.5 ± 0.6 μm).

Preparation and characterization of oxidation-resistant black glass (SiCO) coatings obtained by hydrosilylation of polysiloxanes

Two SiCO coatings deposited on AISI 301 type austenitic stainless steel have been prepared by pyrolysis (at 900 °C) from polysiloxane precursors. These precursors have been obtained by hydrosilylation of polymethylvinylsiloxane (V3) with 2,4,6,8-tetramethylcyclotetrasiloxane (D4H), and polymethylhydrosiloxane (PMHS) with 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D4Vi). Polymer coatings and coatings after pyrolysis have been studied using IR spectroscopy to determine the efficiency of the hydrosilylation process, as well as examine the degree of transformation to ceramic layers after pyrolysis. The presence of a free carbon phase in the layers after pyrolysis has been investigated by Raman spectroscopy. Oxidation-resistant properties of SiCO layers have been investigated in air atmosphere under isothermal conditions. In order to determine the physicochemical properties of SiCO layers (before and after corrosion tests), SEM, XRD, AFM and nanoindentation methods have been used.

Microstructures and corrosion properties of novel Fe46.8-Mo30.6-Cr16.6-C4.3-B1.7 metallic glass coatings manufactured by vacuum plasma spray process

Metallic glass coating layers were fabricated using new Fe46.8-Mo30.6-Cr16.6-C4.3-B1.7 metallic glass powders via vacuum plasma spray process (VPS). The microstructure and corrosion properties of the VPS Fe-based metallic glass coating layer were examined and compared with coating layer of same composition prepared through the conventional atmospheric plasma spray process (APS). Broad halo peaks were found in the metallic glass powder feedstock and two coating layers. Splat particles and minor un-melted powders were observed in the two metallic glass coating layers. For APS coating layer deposited under aerobic condition, Fe–Cr based oxides were detected at the particle boundaries and Cr element was found depleted in regions near the oxide. Meanwhile, all the alloying elements in the VPS material were evenly distributed throughout the coating layer. Corrosion tests showed that the corrosion properties of the APS coating layers were Ecorr: −0.347 V and Icorr: 1.38 × 10−5A/cm2, whereas for the VPS coating layer, Ecorr: −0.342 V and Icorr: 3.21 × 10−6A/cm2, signifying superior corrosion resistance in the VPS material to the APS material. The corrosion started from the pores and particle boundaries in both the coating layers and then advanced along the particle boundaries. It was apparent that the Cr depletion area inside the APS coating layer was susceptible to corrosion. Based on the above results, the corrosion mechanisms of the Fe-based metallic glass coating layers fabricated by the VPS and the APS processes were also discussed.

Synthesis and characteristics of aluminate spinel ceramic pigments based on spent aluminium-cobalt-molybdenum catalyst

PurposeThe purpose of this paper is to conduct the directed synthesis of blue-colour aluminate spinel pigments based on spent aluminium–cobalt–molybdenum (ACM) catalyst and to study peculiar features of mineral formation processes and changes in their colour indices depending on composition and firing temperature.Design/methodology/approachAluminate spinel ceramic pigments with specified colour indices were synthesised by directed formation of their mineral composition and identification of the most rational technological parameters of production. Mineral composition of synthesised pigments was evaluated by X-ray phase analysis. The colour indices of pigments and pigment-containing glaze coatings were studied on the comparator colour. The chemical resistance of pigments was determined by loss of their weight loss after boiling in 1 N hydrochloric acid solution and 1 N sodium hydroxide solution.FindingsPeculiar features of formation of the mineral composition of aluminate spinel pigments based on the ACM catalyst were studied. The expediency of using magnesium and zinc oxides in their composition has been proved. It is found that for the formation of stable pigments of intense blue colour, a concentration of cobalt (II) oxide in the amount of 0.5 mol is sufficient, which is 23.1 Wt.%. The colour of such pigments is determined by the ratios of cobalt, magnesium and zinc aluminates, which form a spinel solid solution.Practical implicationsThe use of developed aluminate spinel pigments provides obtaining of high-quality glass coatings of blue colour, in particular, for ceramics.Originality/valueAluminium oxide in the spent ACM catalyst is predominantly in the active form (of amorphous aluminium hydroxide and y-Al2O3). This is a prerequisite for the use of this waste material as a complete substitute for chemically pure Al2O3 in the technology of aluminate spinel pigments and reduction of their firing temperature. Besides, spent ACM catalyst already contains 5 Wt.% of expensive cobalt (II) oxide in the form of stable colour-bearing phase CoAl2O4.

Characterization of FeP-based metallic glass coatings prepared with laser cladding

Fe-based metallic glasses are distinguished by high mechanical strength, good corrosion resistance and reasonable price, but due to limited ductility cracks often appear during thermal processing like laser cladding. This problem is especially visible when several beads are deposited. Therefore, an alloy with increased ductility was selected for tests to check if it can facilitate cladding of defect-free coatings. The alloy was gas atomized and then sieved to desired fraction. The coatings were then deposited with laser cladding. The obtained coatings were fully crystallized with microstructure varied from dendritic to globular one and strong segregation of the phosphorous and molybdenum.

Effect of feedstock and plasma gun on the microstructure and bioactivity of plasma sprayed bioactive glass coatings

Plasma-sprayed 45S5 bioactive glass coatings were manufactured using two types of powder feedstocks (commercial and lab-made 45S5 glass) and two plasma torches (single and triple cathode) to analyse their influence on the microstructure and bioactivity of the coatings. Besides, the volatilisation of glass oxides such as Na2O and P2O5 during the deposition was studied. All coatings were microstructurally characterised by scanning electron microscopy, X-ray diffraction and X-ray dispersive energy analysis. Moreover, the bioactivity of the sprayed coatings was studied by immersing the coatings in Simulated Body Fluid until 14 days.The coatings obtained using the triple cathode torch showed similar thickness, less total porosity and greater microstructural homogeneity than the coating deposited with the single cathode torch. X-ray dispersive energy analysis revealed lower amounts of sodium and phosphorus at the surrounding of the lamellae, due to its volatilisation during the formation of the coatings. The volatilisation of these elements varied depending on the type of feedstock and plasma jet enthalpy. Concerning the bioactivity of the coatings, all of them have developed a hydroxycarbonate apatite layer on their surface.

Borate and Silicate Bioactive Glass Coatings Prepared by Nanosecond Pulsed Laser Deposition

Silicate (13-93) and borate (13-93-B3) bioactive glass coatings were successfully deposited on titanium using the nanosecond Pulsed Laser Deposition technique. The coatings’ microstructural characteristics, compositions and morphologies were examined by a number of physico-chemical techniques. The deposited coatings retain the same functional groups of the targets, are a few microns thick, amorphous, compact and crack free. Their surface is characterized by the presence of micrometric and nanometric particles. The surface topography, investigated by Atomic Force Microscopy, is characterized by spherical or ellipsoidal particles of the 0.2–3 μm size range for the 13-93 silicate bioactive glass film and of the 0.1–1 µm range for the 13-93-B3 borate bioactive glass coating. Equine adipose tissue-derived mesenchymal stem cells (ADMSCs) were applied for biological tests and the osteogenic differentiation activity of cells on the deposited coatings was studied after ADMSCs growth in osteogenic medium and staining with Alizarin Red. Cytocompatibility and osteogenic differentiation tests have shown that thin films retain the biocompatibility properties of the target silicate and borate glass, respectively. On the other hand, no antibacterial activity of the borate glass films was observed, suggesting that ion doping is advisable to inhibit bacterial growth on the surface of borate glass thin films.