Phosphate Films Research Articles

Fabrication and bioresorbability of Ag- and Ta-containing amorphous calcium phosphate films formed on titanium substrates by RF magnetron sputtering

Silver (Ag)- and tantalum (Ta)-containing amorphous calcium phosphate (ACP) coating films were fabricated on titanium substrates by radiofrequency magnetron sputtering for biomedical applications. The sputtering targets were hot-pressed into 10 mol% Ag-containing ß-tricalcium phosphate sintered compacts with and without 8 mol% Ta. The fabricated ACP coating films were dense and smooth, with all elements distributed homogeneously along the depth direction. In addition, Ag existed as ions in the ACP regardless of the presence of Ta. The resorbability of the Ag-containing ACP coating films in simulated body fluids was suppressed by the addition of Ta. The concentration of detected Ag ions was higher in diluted nutrient broth solution than in Tris-HCl solution.

Cell Adhesion Ability of α-Tricalcium Phosphate Films Formed on Titanium Substrates by an Er:YAG Laser Deposition Method: Imprecations for Management of Peri-Implant Inflammation

Dental implants have been widely used to restore missing or damaged teeth. Peri-implantitis is one of the main causes of the implant loss. However, a consensus concerning clinically successful peri-implantitis treatment has not been reached at present. We have newly proposed a treatment method for the peri-implantitis by applying the intraoral laser ablation technique to induce a surface modification of dental implants. In the present study, we investigated the cell adhesion ability of α-tricalcium phosphate (α-TCP) films formed on titanium substrates by an Erbium-Doped:Yttrium, Aluminum, and Garnet (Er:YAG) laser deposition method. Cell adhesion was enhanced by the α-TCP films attached firmly to the substrates using the Er:YAG laser deposition method. This intraoral laser deposition technique can be used to recover the osteointegration ability which was lost by the treatment procedures for peri-implantitis.

Effect of lubrication technique in tube drawing

Cold drawing process is widely used in steel tube manufacturing industry as it offers advantages like close dimensional tolerances, superior surface finish, flexibility in achieving different sizes and manipulated mechanical properties. This process needs to control friction parameters and lubrication extensively in order to obtain acceptable quality tubes and generally a phosphate and stearate coating has been the conventional approach to achieve this objective. Off late, some alternatives have emerged and a recently developed alternative lubrication system based on micro-porous lubricant carrierlayer generated on steel tube substrate by electroplating an alloy and selectively etching out one component of the alloy has been specifically taken up for detailed study. The porous layer is to trap the lubricant and act as lubricant reservoir in the metal deformation zone under the extreme pressures of cold drawing process. The attempt has been made to practically investigate the effectiveness of this alternative lubrication system for cold drawing process in tube manufacturing from an industrial perspective. Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope (SEM) has been used in the analysis to verify that the aimed chemical composition and uniform distribution and to visualize the generated porous layer. Experimental investigations were carried out by subjecting the tube specimens (with lubricated porous layer) to the cold drawing process carried through a special drawing die attachment mounted on Universal Testing Machine (UTM). Comparison of the results with the conventional phosphate and stearate film based lubrication method has been made. The results show 10% of reduction in draw load and about 40% of improvement in surface roughness.

Ni–Fe Phosphate/Ni Foam Electrode: Facile Hydrothermal Synthesis and Ultralong Oxygen Evolution Reaction Durability

Nickel–iron phosphate film with a porous surface formed by ultrathin nanotubes was successfully grown on Ni foam (NF) through a simple hydrothermal route at 150 °C for 90 min in the presence of HCl...

Chemical Phosphatizing of Carbon Steel

Kinetics of formation of phosphate coatings (PCs) on St3 carbon steel in zinc nitrate–phosphate solution (0.65 М Zn2+ + 0.3 М $${\text{PO}}_{{\text{4}}}^{{{\text{3}} - }}$$ + 1.0 М $${\text{NO}}_{{\text{3}}}^{ - },$$ рН 1.95) with various additives has been studied at 25°С. It has been shown that introduction of effective silicon-containing additive to phosphatizing solution and further treatment of phosphate films in aqueous solution containing silicon compounds has provided corrosion-stable PCs on St3. Using mathematical planning of Box–Wilson extreme experiment, preparation of PCs with increased protective ability has been optimized under these conditions.

Effect of Growing Conditions and Post Treatments on Calcium Phosphate Films Obtained by Electrode Position

The effect of growing conditions and post treatments in electrodeposited calcium phosphate films on 316 L stainless steel is presented. The concentration and pH of electrolyte solution and the potential values for the electrodeposition process were determined based on a study of cyclic voltammetry curves. The electrolyte concentration was fixed at 0.025 M ((NH4) H2PO4) and 0.042 M (Ca(NO3)2.4H2O), choosing a pH = 5 as the better condition for the films deposition. In addition, the electrolyte temperature was varied between room temperature and 60°C to determine the influence of this parameter on the deposited films. Films were characterized using Fourier Transform Infrared Spectroscopy, X-ray diffraction and Scanning electron microscopy equipped with energy dispersive spectroscopy. The as deposited films at -1.2 V and -1.7 V exhibit the dicalcium phosphate dihydrate phase (Brushite) while thermal post treatment favor the formation of octacalcium phosphate in amorphous phase, and basic treatment tend to produce the Hydroxyapatite phase. The suggested mechanism for the HAp phase formation, after the basic treatment, consists in providing the necessary OH- groups to complete the synthesis process.

Preferred orientations and microstructures of lanthanum phosphate films prepared via laser chemical vapor deposition

In this study, the vapor-phase growth of lanthanum phosphate (LaPO4 monazite) films having preferred orientations on polycrystalline alumina substrates was demonstrated via laser chemical vapor deposition using metal-organic precursors. The effects of the laser power densities and oxygen (O2) partial pressure on the crystal orientations, microstructures, and textures of the LaPO4 films were investigated. Monoclinic LaPO4 monazite was grown at laser power densities of 62–96 W cm−2 (deposition temperatures of 1075–1120 K) and an O2 partial pressure of 257 Pa. The (111¯)-oriented LaPO4 films with small pyramidal facets of less than 1 μm in sizes and large platelets were grown at laser power densities lower than 85 W cm−2. The preferred orientation of the monoclinic LaPO4 changed from (111¯) to (101¯) as the laser power density was increased to 95 W cm−2, at which large platelets inclined from the substrate surface were formed. Deposition with a reduced O2 partial pressure of 200 Pa induced the growth of highly (111¯)-oriented LaPO4 films with small pyramidal facets, which comprised (001), (100), and (010) faceted planes. At a low O2 partial pressure of 133 Pa, (100)-oriented LaPO4 films with platelet grains vertically grown from the substrate were formed. The deposition rates of the LaPO4 films were as high as 58.6 μm h−1.

A novel disposable self-adhesive inked paper device for electrochemical sensing of dopamine and serotonin neurotransmitters and biosensing of glucose

In this work, we detail the progress of a novel electrochemical disposable device, which has a relatively low cost and easy production, with a novel conductive ink, that consists of graphite and automotive varnish mixture, deposited over a self-adhesive paper, granting an easy production with relatively low cost. The electrode surface was characterized by scanning electron microscopy, X-ray powder diffraction and Fourier transforms infrared and Raman, cyclic voltammetry and electrochemical impedance spectroscopies. In addition, the proposed electrode was applied for individual electrochemical determination of dopamine and serotonin. The device achieved a linear response between 30 and 800 μmol L−1 and a limit of detection (LOD) of 0.13 μmol L−1, by square wave voltammetry for dopamine and a linear range from 6.0 to 100 μmol L−1, with a LOD of 0.39 μmol L−1, by differential pulse voltammetry for serotonin. Later, the working electrode was modified with glucose oxidase and dihexadecyl phosphate film in order to obtain a biosensor. At this stage, CV was applied to detect glucose in the range of 1.0–10 μmol L−1 and LOD of 0.21 μmol L−1. By three different techniques and analytes, the sensoring and biosensoring processes presented high reproducibility. The proposed adhesive electrode is easy to prepare, disposable, within non-restrictive nature, which allows an approach of a new device for electrochemical sensing and biosensing.

Phosphate coatings as a way to protect steel reinforcement from corrosion

Phosphate coatings are successfully applied as a method of protecting steel products and structures from corrosion. Phosphate coatings mechanically prevent the entry of aggressive particles, such as chloride ions, to the surface of steel reinforcement. The parameters of corrosion rate of reinforcing steel in aggressive environment are determined by graphical method. The analysis of corrosion diagrams allows us to judge the effect of protective phosphate coatings on the kinetics of the corrosion process of steel reinforcement in environments of varying degrees of aggressiveness. The tests of the protective properties of phosphate coatings by contact corrosion method show that films with a finer crystal structure, as in modified phosphate coatings, are more resistant to anodic dissolution of steel. In parallel to determination of iron ions content in solutions the potential of steel reinforcement samples was measured. In samples protected by phosphate films, the potential change is not as sharp as in samples without coating, and the “dilution” of steel is slower. The study of anodic behavior of steel reinforcement of reinforced concrete, experimental study of the mass transfer mechanism of electrolyte supply to the surface of reinforced steel allow to develop practical recommendations to improve corrosion resistance and ensure the durability of reinforced concrete building materials.

Optical spectroscopy of zinc phosphate films activated with Ce3+, Tb3+ and Mn2+ ions for white LED applications

Zinc phosphate films doped with Ce3+, Tb3+, Mn2+, Ce3+/Tb3+ and Ce3+/Tb3+/Mn2+ were deposited at 500 °C by the ultrasonic spray pyrolysis technique. Blue emission with color purity of 89.8% is generated from the Ce3+-singly doped film upon 280 nm excitation. The Mn2+-singly doped film emits neutral white light of 4896 K upon 410 nm excitation. The Tb3+-singly doped film excited at 377 nm emits in the green region. Yellowish-green emission is achieved by codoping with Ce3+ and Tb3+ upon Ce3+ excitation at 280 nm, such that Tb3+ is sensitized by Ce3+ through a non-radiative energy transfer with an efficiency of up to 25%. Yellow white emission of 2810 K can be generated from the film triply doped with Ce3+, Tb3+ and Mn2+ upon 280 nm excitation. Tb3+ and Mn2+ being sensitized by Ce3+ through a non-radiative energy transfer with an efficiency of 29%. The energy transfer from Ce3+ to Tb3+ and Mn2+, resulting in yellow white emission, as well the neutral white emission from the Mn2+-singly doped film, make the Mn2+ and Ce3+/Tb3+/Mn2+-doped zinc phosphate films versatile materials that could contribute to the design of efficient UV-blue LED pumped white phosphors.

Effects of Organic Modification of Montmorillonite on the Properties of Hydroxypropyl Di-Starch Phosphate Films Prepared by Extrusion Blowing.

The knowledge gained from starch-nanocomposite-film research has not been fully applied commercially because of the lack of appropriate industrial processing techniques for nanofillers and starch films. Three organically modified montmorillonites (OMMTs) were prepared using a semidry kneading method. The effects of the OMMTs on the structures and properties of starch nanocomposite films, prepared by extrusion blowing, were investigated. The X-ray diffraction (XRD) analysis results revealed that the OMMTs with various quaternary ammonium salts possessed differing layer structures and d-space values. The results of the XRD and Fourier-transform infrared spectroscopy (FT-IR) showed that the starch–OMMT interaction resulted in a structural change, namely the starch–OMMT films possessed a balanced exfoliated and intercalated nanostructure, while the starch–MMT film possessed an exfoliated nanostructure with non-intercalated montmorillonite (MMT). The results of the solid-state nuclear magnetic resonance (NMR) analysis suggested that the starch-OMMT nanocomposite possessed comparatively large quantities of single-helix structures and micro-ordered amorphous regions. The starch–OMMT films exhibited good tensile strength (TS) (maximum of 6.09 MPa) and water barrier properties (minimum of 3.48 × 10−10 g·m·m−2·s−1·Pa−1). This study indicates that the addition of OMMTs is a promising strategy to improve the properties of starch films.

Mechanical and moisture barrier properties of corn distarch phosphate film influenced by modified microcry stalline corn straw cellulose.

In this paper, a novel modified microcrystalline corn straw cellulose (MMCSC) was prepared by ultrasonic/microwave-assisted treatment. Effective incorporation of MMCSC into corn distarch phosphate (CDP)-based composite films was investigated. As the proportion of MMCSC was increased, tensile strength increased initially before decreasing, and the elongation at break always decreased. The composite film of MMCSC20 showed the lowest water vapor permeability (2.917 × 10-7 g m-1 h-1 Pa-1 ). The measurement of surface color showed that by the increasing of the MMCSC proportion in composite films, the L* and b* values and the total color difference (ΔE* ) increased, while a* values decreased. Fourier transform infrared spectroscopy and X-ray diffraction analysis indicated that, with the incorporation of MMCSC, the stable structure of the films was enhanced through cross-linking and the crystallinity was increased. A scanning electron microscopy study revealed the surface microstructure of films (MMCSC0-MMCSC30) was smooth and homogeneous, and there was no distinct separation in the matrix of composite films. The incorporation of suitable MMCSC could improve the properties of composite films. The CDP-MMCSC films, which are completely biodegradable and environmental friendly, have a high potential to be used for food packaging. © 2018 Society of Chemical Industry.

Osteoblast-like Cell Growth and Differentiation Behaviors on the Phospholipid Vesicle-Interacted Calcium Phosphate Films

Osteoblast-like Cell Growth and Differentiation Behaviors on the Phospholipid Vesicle-Interacted Calcium Phosphate Films

The Formation Mechanism and Corrosion Resistance of a Composite Phosphate Conversion Film on AM60 Alloy.

Magnesium alloy AM60 has high duc and toughness, which is expected to increase in demand for automotive applications. However, it is too active, and coatings have been extensively studied to prevent corrosion. In this work, a Ba-containing composite phosphate film has been prepared on the surface of AM60. The composition and formation mechanism of the film have been investigated using a scanning electronic microscope equipped with energy dispersive X-ray spectroscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, and X-ray diffractometry tests. The corrosion resistance of the film has been measured by electrochemical and immersion tests. The results show that the deposition film has fully covered the substrate but there are some micro-cracks. The structure of the film is complex, and consists of MgHPO4·3H2O, MnHPO4·2.25H2O, BaHPO4·3H2O, BaMg2(PO4)2, Mg3(PO4)2·22H2O, Ca3(PO4)2·xH2O, and some amorphous phases. The composite phosphate film has better anticorrosion performance than the AM60 and can protect the bare alloy from corrosion for more than 12 h in 0.6 M NaCl.

Electroanalytical determination of eugenol in clove oil by voltammetry of immobilized microdroplets

The determination of eugenol employing voltammetry of immobilized microdroplets (VIM) is reported in this work. The construction of the electrode was based on a glassy carbon substrate modified with carbon black nanoparticles and eugenol standard or clove oil sample within a dihexadecyl hydrogen phosphate (DHP) film. The different experimental parameters related to this proposed procedure, i.e., supporting electrolyte composition, pH, ionic strength, and square-wave voltammetry (SWV) parameters (amplitude, frequency, and step potential) were optimized. By doing that, the SWV measurements were performed on the following optimum experimental conditions: 0.2 mol L−1 phosphate buffer solution (pH 2.0), amplitude 90 mV, frequency 30 Hz, and step potential 5 mV. The analytical curve for eugenol was linear in the wide range from 0.03 to 26 μg (r = 0.999) with limits of detection (LOD) and quantification (LOQ) of 0.13 and 0.42 ng, respectively. Three commercial clove oil samples were successfully immobilized and analyzed using the proposed VIM procedure showing eugenol concentrations ranging from 14.0 to 68.3%. Comparing the results obtained by the proposed and comparative procedure (spectrophotometric), relative standard deviations (RSDs) lower than 5.0% were verified, demonstrating the concordance of the results obtained by both methods.

Fabrication and characterization of a dense Cr2O3-Al phosphate double coating as tritium permeation barrier

A dense Cr2O3-Al phosphate double coating was fabricated by electrodeposition and dip-coating. Cr layer was firstly electrodeposited on 321 steel substrates and subsequently was thermal oxidized in air to transform into Cr2O3 layer. Then an Al phosphate film was prepared by dip-coating to seal open pores of the Cr2O3 layer. By controlling the process parameters (current density, heat-treated temperature and dip-coating times) it is possible to obtain crack-free and homogeneous double coating. The thickness of Cr2O3 layer and Al phosphate layer is 5μm and 0.6μm, respectively, when electroplating current density is 0.3A/cm2 and dip coating Al phosphate for one time. The Al phosphate layer can effectively close the open pores and decrease the porosity to 0% of Cr2O3 layer. The Cr2O3-Al phosphate double coating sample exhibits a good resistance to corrosion and improved tritium resistant performance because the Al phosphate coating successfully fills pores and defects allowing passage of gas of Cr2O3 coating. And this double coating shows good thermal cycling performance. No obvious cracks can be observed on the surface of the Cr2O3-AlPlO4 coating even after 190 cycles.

Characteristics of RF-Sputtered Thin Films of Calcium Phosphate on Titanium Dental Implants

Hydroxyapatite (HA) coatings on titanium have been investigated for many years, and have demonstrated advantageous biocompatibility in dental implants. Animal experiments have demonstrated that the biological response to plasma-sprayed HA-coated implants shows disadvantages in terms of adherence, thickness uniformity, and long-term osseointegration effects. Determining how to resolve the degradation problem of HA in the body by improving osseointegration and stability in alveolar bones has become an increasingly researched topic. The present study investigated the film characteristics and dissolution properties of calcium phosphate (CaP) coatings obtained by radio-frequency (RF) sputtering of a self-developed atmospheric plasma spray (APS) HA target. The experimental parameters varied, including RF power (60–250 W), sputtering time (15–120 min), and substrate roughness (0.4–4 μm). Analyses were conducted using synchrotron X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), white light interferometry, and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (EDS). EDS analysis showed that the Ca/P ratio increased as the discharge power was increased. The analysis results also showed that a lower surface roughness resulted in higher crystallinity, because a larger surface-free energy was attained during sputtering. In-plane texturing has been proven when HA films are sputtered onto substrates of varying roughness, within appropriate deposition parameters. FTIR analysis revealed the presence of the principal PO43- bonds in the deposited calcium phosphate films. The CaP films induced calcium phosphate precipitation when immersed in simulated body fluid (SBF), suggesting that, based on in vitro bioactive behavior, the proposed combined surface modification can be used in dental implants.

Fabrication of Phospholipid Vesicle-Interacted Calcium Phosphate Films with Sterilization Stability

The development of a calcium phosphate (CP) coating technique on tissue culture poly(styrene) (TCPS) is important in biomedical fields. In this study, the CP hybridized with l-α-phosphatidylcholine phospholipid vesicle (PV) was formed on TCPS as the film state for suggesting the unique CP/PV hybrid films. The film formation was conducted by the following two different processes: (i) the CP deposited on PV was prepared in a simulated body fluid (SBF) and subsequently casted on TCPS to form the films, and (ii) the CP was precipitated in SBF on the pre-prepared PV films on TCPS. These films were denoted as “CP/PV-Bef” and “CP/PV-Aft” films. The stability of the CP/PV hybrid films against the sterilization processes (ethanol, UV/ozone, and autoclave treatments) and subsequent immersion process in a phosphate buffer saline (PBS) was also demonstrated. As a result, the CP/PV hybrid films were successfully coated on TCPS through the mediation by PV with preserving the vesicle structure. The morphologies and phys...

Effect of loading on the friction and interface microstructure of lubricated steel tribopairs

In this study, the tribological behavior and interfacial evolution of GCr15/Mild steel tribopairs lubricated by inorganic sodium metaphosphate was investigated under different applied loads at 800 °C. The results show that sodium metaphosphate lubricates the contact effectively at the load ranging from 5 to 30 N, with higher loads causing increased friction and wear. A layer of glassy phosphate film formed between the contacts is responsible for the improved tribological performance. FIB/TEM and XRD analysis reveals that the phosphate film was mainly composed of amorphous Na-Fe orthophosphate matrix filled up with fine oxide wear debris.

Plasma-enhanced atomic layer deposition of vanadium phosphate as a lithium-ion battery electrode material

Vanadium phosphate films were deposited by a new process consisting of sequential exposures to trimethyl phosphate (TMP) plasma, O2 plasma, and either vanadium oxytriisopropoxide [VTIP, OV(O-i-Pr)3] or tetrakisethylmethylamido vanadium [TEMAV, V(NEtMe)4] as the vanadium precursor. At a substrate temperature of 300 °C, the decomposition behavior of these precursors could not be neglected; while VTIP decomposed and thus yielded a plasma-enhanced chemical vapor deposition process, the author found that the decomposition of the TEMAV precursor was inhibited by the preceding TMP plasma/O2 plasma exposures. The TEMAV process showed linear growth, saturating behavior, and yielded uniform and smooth films; as such, it was regarded as a plasma-enhanced atomic layer deposition process. The resulting films had an elastic recoil detection-measured stoichiometry of V1.1PO4.3 with 3% hydrogen and no detectable carbon contamination. They could be electrochemically lithiated and showed desirable properties as lithium-ion battery electrodes in the potential region between 1.4 and 3.6 V versus Li+/Li, including low capacity fading and an excellent rate capability. In a wider potential region, they showed a remarkably high capacity (equivalent to three lithium ions per vanadium atom), at the expense of reduced cyclability.