Degradation and biocompatibility of one-step electrodeposited magnesium thioctic acid/magnesium hydroxide hybrid coatings on ZE21B alloys for cardiovascular stents

Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing composite coatings are usually complicated and time-consuming.Herein,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step electrodeposition.Scanning electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform structure.And the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch test.Electrochemical test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg substrates.Haemocompatibility experiment and cell culture trial detect that the composite coating is of fine biocompatibility.Finally,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and proposed.This coating shows a great potential application for cardiovascular stents.

Er,Cr∶YSGG激光联合Hybrid Coat脱敏剂治疗牙本质过敏症的疗效观察

目的:评价Er,Cr∶YSGG激光联合Hybrid Coat脱敏剂在牙本质过敏中的治疗效果。方法:纳入100名牙本质暴露患者(310颗牙齿),随机分为A、B、C 3组,A组Er,Cr∶YSGG激光治疗(n=106);B组Hybrid Coat治疗(n=100),C组Hybrid Coat联合Er,Cr∶YSGG激光治疗(n=104)。观察并记录治疗后的治疗效果。结果:在治疗后即刻、1个月疗效对比,3种方法的治疗效果没有显著差异(P>0.05);而在治疗后3个月、6个月,A和B没有显著差异,但C有效率高于A、B组(P<0.05);3种发病原因中楔缺和龈退在治疗前后无统计学差异(P>0.05),磨耗与楔缺、龈退有统计学差异(P<0.05);治疗前后VAS值有统计学差异(P<0.05),治疗后各时间点无统计学差异(P>0.05),C组治疗后各时间点的VAS值均低于A、B组(P<0.05)。结论:Er,Cr∶YSGG激光联合Hybrid Coat脱敏剂治疗牙本质过敏获得了较好的早期疗效及中远期效果。

Effect of cerium ion(Ⅲ) on corrosion resistance of organic-inorganic hybrid coating on surface of aluminum-tube used in refrigeration equipment

Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10?7 A/cm2 and?0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.

Investigation of anti-corrosion property of hybrid coatings fabricated by combining PEC with MAO on pure magnesium

Novel hybrid coatings on pure magnesium were prepared by combining plasma electrolytic carburizing(PEC)with micro-arc oxidation(MAO)to further enhance the anti-corrosion property in this paper.Scanning electron microscopy(SEM)was used to observe the microstructure of the coatings,meanwhile,energy dispersive spectrometry(EDS)and X-ray diffraction(XRD)were separately used to investigate the elemental as well as phase compositions of the coatings.The anti-corrosion property of the coatings was evaluated by potentiodynamic polarization curves as well as electrochemical impedance spectroscopy(EIS).The results show that PEC process is closely related with the effects of adsorption as well as diffusion of the activated carbon atoms,and it can provide a favorable pretreatment surface with predesigned chemical composition to obtain a new kind of phase,namely Si C with superior corrosion resistance and chemical stability,in the following PEC+MAO hybrid coatings.Meanwhile,PEC preprocessing also can afford an excellent micro-structure to increase the coating thickness as well as to improve the compactness of the PEC+MAO hybrid coatings.During the fabrication process of the PEC+MAO hybrid coatings,an overlapping phenomenon in regard to coating thickness can be observed instead of heaping up layer by layer.Compared with both single PEC surface modification layers as well as single MAO coatings,the PEC+MAO hybrid coatings exhibit more superior anti-corrosion property.Especially,the EIS data reveal that the PEC+MAO hybrid coatings can act as an effective protection system to provide relatively excellent long-range anti-corrosion protection.Note also that employing same MAO technique for both single MAO treatment as well as PEC+MAO combining procedure is the key to this research.

Effect of carbon on microstructure of CrAlC_xN_(1-x) coatings by hybrid coating system

A systematic investigation of the microstructure of CrA1CxN1-x coatings as a function of carbon contents was conducted. Quaternary CrA1CxN1-x coatings were deposited on Si wafers by a hybrid coating system combining an arc-ion plating technique and a DC reactive magnetron sputtering technique using Cr and AI targets in the Ar/N2/CH4 gaseous mixture. The effect of carbon content on microstructure of CrA1C^N~ x coatings was investigated with instrumental analyses of X-ray diffraction, X-ray photoelectron, and high-resolution transmission electron microscopy. The results show that the carbon content of CrA1CxN1-x coatings linearly increases with increasing CH4/（CH4/N2） gas flow rate ratio. The surface roughness of the CrA1CxN1-x coating layer decreases with the increase of carbon content.

Effects of Vacuum Ultraviolet Radiation on Atomic Oxygen Erosion of Polysiloxane/SiO_2 Hybrid Coatings

Polysiloxane/SiO2 hybrid coatings have been prepared on Kapton films by a sol-gel process. The erosion resistance of polysiloxane/Si02 （20 wt pct） coating was evaluated by exposure tests of vacuum ultraviolet radiation （VUV） and atomic oxygen beam （AO） in a ground-based simulation facility. The experimental results indicate that this coating exhibits better AO resistance than pure polysiloxane coating. The erosion yield （Ey） of the polysiloxane/Si02 （20 wt pct） hybrid coating is about 10-27 cm3/atom, being one or two orders of magnitude lower than that of polysiloxane. VUV radiation can affect the erosion process greatly. Under simultaneous AO and VUV exposure, the value of Ey of the polysiloxane/5iO2 （20 wt pct） hybrid coating increases by 3g% compared with that under single AO exposure.

Structural investigation of the zirconium-titanium based amino trimethylene phosphonate hybrid coating on aluminum alloy

A zirconium-titanium based amino trimethylene phosphonate hybrid coating on AA6061 aluminum alloys was formed by dipping in a fluorotitanate/zirconate acid and amino trimethylene phosphonic acid （ATMP） solution for improving the lacquer adhesion and corrosion resistance as a substitute of chromate coatings. The morphology and structure of the hybrid coating were studied by means of scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The surface composition and structure characteristics were also investigated by means of X-ray photoelectron spectroscopy （XPS） and Fourier transformation infra-red spectroscopy （FTIR）. The results of SEM and AFM show that the hybrid coating present piece particle distribution which is much denser than that of the zirconium-titanium coating. The results of XPS and FTIR indicate that the hybrid coating is a hybrid composite structure composed of both the zirconium-titanium and amino trimethylene phosphonate coatings.

Evaluation of corrosion resistance, mechanical integrity loss and biocompatibility of PCL/HA/TiO_(2) hybrid coated biodegradable ZM21 Mg alloy

A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in physiological media. The prepared hybrid coating was dip coated over ZM21 from HA/TiO_(2)and PCL solutions followed by creating a microporous PCL layer by utilizing Non-solvent Induced Phase Separation(NIPS) technique. The electrochemical measurement and in-vitro degradation study in SBF after 28 days showed that the PCL/HA/TiO_(2) hybrid coating reduced H2 evolution rate, weight loss, and corrosion rate by 64, 116 and 118 times respectively, as compared to uncoated ZM21 samples. The surface studies carried out using SEM-EDX, FTIR and XRD revealed formation of highly stable 3d flower-like HA crystals with Ca/P ratio of 1.60 in the PCL micropores. This dense apatite growth effectively protected the PCL/HA/TiO_(2)hybrid coated samples to maintain the good mechanical integrity even after 28 days of immersion as compared to HA/TiO_(2)composite coated, As-polished(A/P) and As-machined(A/M) samples. The failure analysis of samples under mechanical loading were performed using SEM-BSE-EBSD.The in-vitro cellular viability of L929 fibroblast cells on PCL/HA/TiO_(2)hybrid coating was found 50.47% higher with respect to control group,whereas bacterial viability was supressed by 57.15 and 62.35% against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial models. The comprehensive assessment indicates PCL/HA/TiO_(2)hybrid coating as a suitable candidate to delay early degradation and mechanical integrity loss of Mg-based alloys for devising biodegradable orthopaedic implant.

劲润(Hybrid Coat)治疗活髓牙全冠制备后牙本质过敏的临床研究

目的:探讨劲润(Hybrid Coat)对活髓牙全冠制备后牙本质过敏的临床治疗效果。方法:2009年12月—2010年3月进行活髓牙牙体全冠制备的患者152例(共201颗基牙),随机分为两组:劲润治疗组(105颗基牙)和对照组(96颗基牙)。在活髓牙牙体制备后,对两组基牙进行温度测试,采用可视分级评价法(visual analogue scale,VAS)评估基牙的敏感程度。然后对治疗组基牙涂布劲润,对照组涂布0.9%氯化钠液。再次对两组基牙进行温度测试并评分。2次评分差值代表各组治疗效果。结果:治疗前两组基牙敏感程度评分结果无显著差异(劲润组6.19±0.072比对照组6.22±0.084,P>0.05)。两组治疗前后的评分差值有显著性差异(劲润组3.10±0.077比对照组0.95±0.089,P<0.05)。结论:劲润能够有效地降低活髓牙全冠制备后牙本质的敏感度,保护牙髓组织。

Effect of manganese on the formation of hybrid zirconiumbased conversion coating on low carbon steel surface

This study revealed the effect of Mn on the formation of hybrid zirconium-based conversion coatings(HZCC)on low carbon steel.The XPS results indicated that the Mn compounds on the surface of low carbon steel were mainly MnO and Mn_(2)SiO_(4).Combined with the electrochemical measurements,the corrosion resistance of HZCC showed an increase followed by a decrease with increasing Mn concentration,which was related to the Mn_(2)SiO_(4) and SiO_(2) on the surface of low carbon steel.The excessive Mn concentration resulted in the loss of SiO_(2) and aggregation of Mn_(2)SiO_(4) on the low carbon steel surface,which caused the aggregation of Zr compounds on the surface and reduced the uniformity of the coating.Meanwhile,a moderate amount of Mn addition would be beneficial to increase the adhesion of organic coatings.

Hybrid-coat联合树脂充填治疗敏感型楔状缺损的临床疗效观察

目的 :研究Hybrid-coat联合树脂充填治疗敏感型楔状缺损的临床疗效。方法 :选择2016年7月—2016年12月在上海交通大学医学院附属第九人民医院口腔综合科就诊的敏感型楔状缺损患者70例,共159颗患牙,随机分为2组。联合组35例患者,81颗患牙采用Hybrid-coat脱敏后,复合树脂充填治疗楔状缺损。直接充填组35例患者,78颗患牙直接使用复合树脂充填。2组经过不同方式治疗后,采用SPSS 13.0软件包对各组患者在统一临床检查标准下的有效率(术后即刻,术后1、3、6个月复查)进行统计学分析。结果:2组在树脂充填后,Hybrid coat联合树脂充填组在术后3个月和术后6个月分别有1颗和2颗牙充填体脱落,直接充填组在术后6个月有2颗牙充填体脱落,2组差异无统计学意义。Hybrid coat联合树脂充填组术后即刻、术后1、3、6个月的脱敏有效率分别为91.36%、88.89%、79.01%和70.37%,均高于直接充填组分别为78.21%、76.92%、69.23%和61.54%;术后即刻和术后1个月,2组差异有统计学意义(P<0.05);术后3个月和6个月,2组差异无统计学意义。结论:Hybrid-coat联合复合树脂充填治疗敏感型楔状缺损有良好疗效,早期能明显改善牙敏感症状。

In-situ polymerized nanosilica/acrylic/epoxy hybrid coating:Preparation,microstructure and properties

An in-situ polymerization method was employed to synthesize the nanosilica/acrylic/epoxy (SAE) hybrid coating on AISI 430 stainless steel (430SS), as compared with a traditional blending method. Mi- crostructures of the blending SAE hybrid coating (BC) and in-situ SAE hybrid coating (ISC) were characterized by transmission electron microscopy (TEM). Corrosion resistance of BC and ISC on 430SS was evaluated by the neutral salt spray test and potentiodynamic polarization technique. Failure mechanism of the BC on 430SS was suggested by the microstructures and corrosion behaviors. Serious aggregation of nanosilica particles in the BC impairs its structural uniformity and induces the flaws formation. These flaws in the BC initiates the failures of pitting, filiform corrosion and peeling which are accelerated by the O2 concentration cell and H+ self-catalysis in chlorine-containing moist environments. The ISC-coated 430SS shows a more advantageous corrosion resistance than that of the BC-coated. The ISC-coated 430SS can suffer the salt spray over 1000 h. Besides, it exhibits a high corrosion potential beyond 0.925 V and good passivation characteristics during the potentiodynamic polarization.

Electrochemical Impedance Spectroscopy of Hybrid Epoxy Resin Emulsion Coatings

A hybrid epoxy resin one pack emulsion with acrylate was synthesized for application in the field of corrosion protec- tion. Electrochemical impedance tests were applied to steel specimens coated with hybrid epoxy and tested after im- mersion in 3.5% NaCl solution at room temperature. Results taken from Nyquist and Bode plots as were analyzed by means of software provided with the instrument. Specimens were examined under scanning electron microscope shows a clear rupture and degradation in hybrid epoxy coating after prolonged exposer to salt solution.

Effect of H_2 dilution on the structure and properties of nc-CrC/a-C:H coatings deposited by a hybrid beams system

Nanocomposite Cr C/hydrogenated amorphous carbon(nc-CrC/a-C:H) coatings were deposited by a hybrid beams system comprised of a hollow cathode ion source and a cathodic arc ion-plating unit with varying H_2 flow rates. The influences of H_2 flow rates on the morphologies, microstructures, and properties of the coatings were systematically studied. The morphologies and microstructures of the coatings were characterized by SEM, AFM, XPS, Raman spectroscopy, GIXRD, and HRTEM. The mechanical and tribological properties were measured by a nano-indenter, scratch tester, and ball-ondisk tribometer. The wear tracks were evaluated using 3D profilometer, optical microscope, and EDS analysis. It has been found that a moderate H_2 flow rate can effectively smooth the surface, enlarge the fraction of a sp^3 bond, and improve the properties. The coating exhibits the highest hardness and elastic modulus at the H_2 flow rate of 40 sccm. A superior combination of adhesion strength,friction coefficient, and wear resistance can be achieved at the H_2 flow rate of 80 sccm.

A hybrid algorithm for reengineering the refractive index profile of inhomogeneous coatings from optical in-situ broadband monitoring data

Reengineering the refractive index profile of inhomogeneous coatings is a troublesome task. Multiplicity of solutions may significantly reduced by providing additional information. For this reason an in-situ broadband monitoring system was developed to measure the transmittance of the growing film directly at the rotating substrate. For characterization of these coatings, a new model was developed, which significantly reduces the number of parameters. The refractive index profile may be described by a proper number of equally spaced volume fraction values using the Bruggeman effective media approach. A good initial approximation of the refractive index profile can be generated based on deposition rates for both materials recorded with quartz crystal monitor during manufacturing. During the optimization process, a second order minimization algorithm was used to vary the refractive index profile of the whole coating and film thickness of the intermediate stages. Finally, a significantly improved accuracy of the modelled transmittance was achieved.

Effect of Al_2O_3 and Y_2O_3 on the corrosion behavior of ZrO_2-benzotriazole nanostructured coatings applied on AA2024 via a sol–gel method

zirconia-based nanostructured coatings were deposited on AA2024 to improve the corrosion resistance properties. Three different nanostructured coatings, namely, zirconia–benzotriazole, zirconia–alumina–benzotriazole, and zirconia–yttria–benzotriazole, were applied on AA2024 via a sol–gel method using the dip-coating technique. Next, the coatings were annealed at 150°C after each dipping period. The phases and morphologies of the coatings were investigated using grazing incidence X-ray diffraction(GIXRD), Fourier transform infrared spectroscopy(FT-IR), field emission scanning electron microscopy(FESEM), and atomic force microscopy(AFM). The corrosion properties were evaluated using electrochemical methods, including polarization and electrochemical impedance techniques in 3.5 wt% NaCl solution. The obtained results confirm the formation of homogeneous and crack free zirconia-benzotriazole-based nanostructured coatings. The average roughness values for zirconia-benzotriazole, zirconia-alumina-benzotriazole, and zirconia-yttria-benzotriazole nanostructured coatings were 30, 8, and 6 nm, respectively. The presence of alumina as a stabilizer on zirconia coating was found to have a beneficial impact on the stability of the corrosion resistance for different immersion times. In fact, the addition of alumina resulted in the dominance of the healing behavior in competition with the corrosion process of zirconia-benzotriazole nanostructured coating.

Influence of Machining Parameter on Tool Life While Machining Hybrid Metal Matrix Composites

A metal matrix composite constitutes a continuous metallic matrix and a discontinuous phase known as reinforcement. The hybrid metal matrix composites (Hmmcs) have been used to manufacture drive shafts, disc brake rotors, brake drums, connecting rods pistons, engine block cylinder liners for automotive and rail vehicle applications. The Hmmcs castings of diameter 120 mm and length 300 mm were prepared through sand mould technique following stir casting methodology. The cast components further subjected to evaluation of physical properties and machining tests using two grades of coated inserts and PCD inserts. The experiments were carried out following ISO 3685 standards. The coating thickness of the TiN coated and TiAlN coated inserts were measured using Kalo testing method; the results of the test show that the interface of the substrate and coating was free from the porosity, and the coating thickness of TiN coating was 4.84 microns and TiAlN coating was measured 4.6 microns. The results of the experiments show that performance of the PCD insert was better than coated inserts at 0.1 mm/rev feed; however at 0.2 mm/revolution feed PCD insert failed by micro chipping of cutting edge while machining Hmmcs. When TiAlN coated inserts were used to machine Hmmcs the coated inserts failed by gradual wear and BUE formation.

Fabrication of TiB_2 composite powders coated with BN by high speed airflow impact

TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition was summarized. Scan electron microscope of JSM-5610LV and transmission electron microscope of H-600STEM/EDS were used to observe the microstructure of coated powders. Results show that treatment time, rotation speed, granularity ratio of TiB2 to BN, pretreatment of materials etc influence the coating results evidently. Mixing raw materials and coating with BN under the appropriate condition can get round TiB2/BN composite powder with smooth surface and compact coating layer.

Development of a Novel Hybrid Aluminum-Based Sol-Gel Materials: Application to the Protection of AA2024-T3 Alloys in Alkaline Environment

Extensive research on environmentally complaint sol-gel coatings is currently underway for a wide range of applications. Sol-gel technology combines the synergistic properties of inorganic and organic components to design nanostructured coating materials with advanced physical properties. Through a judicious choice of precursors and additives improved performances, such as chemical resistance or pH stability, it can be achieved. This is of particular interest for copper rich AA 2024-T3 aluminium alloys used on aircraft, where increase in local pH occurs at corrosion sites. This work focuses on improving the alkaline stability and anticorrosion properties of such a sol-gel coatings on AA2024-T3 by incorporating aluminium functionality into hybrid materials prepared from hydrolysis and condensation of 3-methacryloxypropyltrimethoxysilane, zirconium n-propoxide and zirconium/alkoxide precursors. Dynamic light scattering technique was used to study the particle size nature of the sol-gel materials in colloidal form. X-ray photoelectron spectroscopy was used to study the oxidation state of the aluminium and zirconium at the sol-gel coating surface. Field emission scanning electrochemical microscopy coupled with energy dispersive spectroscopy was used to assess the microstructural features. Electrochemical characterisations employing potentiodynamic scanning and electrochemical impedance spectroscopy were performed to investigate the anticorrosion performance of the hybrid sol-gel coatings. The best anti-corrosive protection of AA2024-T3 in an alkaline saline solution (pH = 10) was achieved with materials containing 10 mol% and 15 mol% aluminium doped sol-gel coatings. This study shows that presence of aluminium has a positive effect on alkaline stability of the coatings and is a potential green candidate for the protective coatings on aerospace alloys.