彩涂生产中刮涂料小样试验应注意的几个问题

检验涂料性能、涂敷工艺的合理性及涂敷过程中质量控制是保证涂层钢板性能达到高标准的重要环节,在上线投料生产前必须检验涂料性能和基板性能。这些都可以先在实验室中刮涂料小样做试验,根据试验结果得出结论,作出判断。

Effect of reagent films on coupling relationship between glass surface and particles

The experiments were conducted to investigate the behavior of airborne particles adhering to the glass slides which were coated by several reagent films. The results showed that the adhesion level could be significantly changed by the reagent films. There were no evident rules between the average size of particles and sampling time interval, the placing angle and reagent concentration. The average particle size on the surface coated by composite reagent （2-3 μm） was smaller than that on the single reagent coated surface, while the largest particle size （4-5 μm） was observed on the surface coated with the Tween 60. The experiment also demonstrated that the best adhesive performance was obtained on the surface which was coated with 0.5% SDBS and 0.5% fluorocarbon composite reagents. The experiment results indicated that each reagent had a certain optimum adhesive range to the particle. The composite reagents with different proportion of single reagents exhibited some particular physical and chemical properties, which could effectively change the adhesive performance between the solid surface and the particles.

Experimental investigation on fatigue of blade specimen subjected to resonance and effect of a damping hard coating treatment

Failures due to high-cycle fatigue have led to a high cost in aerospace engineering over the past few decades.In this paper,the experimental results of the fatigue behavior of compressor blade specimen subjected to resonance and the effects of a damping hard coating on relieving the fatigue progress are presented.The crack initiation and propagation processes were observed under resonance of the first bending mode by using the resonant frequencies as the indicator.Significant nonlinear features were observed in the spectrum of the blade with a fatigue crack.The finite element model considering the breathing crack was established with nonlinear contact based on the crack localization and size,which was obtained by ultrasonic phased array technology.The simulation results of the vibration behavior of the cracked blade were obtained and consistent with the experimental results.A NiCrAlY coating was deposited on the blade,and increases in the fatigue life were observed under the same condition.The results of this paper can help to better understand the fatigue of a compressor blade subjected to resonance and provide a preference for the application of a damping hard coating on compressor blades.

Effects of supplemental coated or crystalline methionine in low-fishmeal diet on the growth performance and body composition of juvenile cobia Rachycentron canadum(Linnaeus)

We evaluated the effects of supplemental coated and crystalline methionine （Met） on the growth performance and feed utilization of juvenile cobia （Rachycentron canadum Linnaeus） in a 60-d feeding trial. Fish groups were fed one of six isonitrogenous and isolipidic diets： 1） fishmeal control; 2） un- supplemented experimental （low-fish-meal diet deficient in Met）; or 3） one of four Met diets supplemented with crystalline L-Met, cellulose-acetate-phthalate coated L-Met, acrylic-resin coated L-Met, or tripalmitin- polyvinyl alcohol coated L-Met. The test diets were fed to triplicate groups of cobia （initial body weight 5.40-4-0.07 g） twice a day. The weight gain and specific growth rate of the fish fed the RES diet were highest among the Met-supplemented groups and were 23.64% and 7.99%, respectively, higher than those of the fish fed with the un-supplemented experimental diet （P〈0.05）. The protein efficiency ratio of the fish fed the MET diet was significantly higher than that of the fish fed the un-supplemented experimental diet and the fish in the other methionine supplementation groups （P〈0.05）. Our results suggest that supplementation of crystalline Met in low-fish-meal diets promotes the growth performance of juvenile cobia.

Influence of pH values on electroless Ni-P-SiC plating on AZ91D magnesium alloy

A novel Ni-P-SiC composite coating was prepared by electroless plating in order to improve the corrosion capacity and wear resistance of AZ91D magnesium alloy.The influence of pH values on deposition rates and properties of the coatings was studied.The microstructure and phase structure of the Ni-P-SiC coatings were analyzed by scanning electron microscopy(SEM)and X-ray diffractometry(XRD).The corrosion and wear resistance performances of the coatings were also investigated through electrochemical technique and pin-on-disk tribometer,respectively.The results indicate that the composite coating is composed of Ni, P and SiC.It exhibits an amorphous structure and good adhesion to the substrate.The coatings have higher open circuit potential than that of the substrate.The composite coating obtained at pH value of 5.2 possesses optimal integrated properties,which shows similar corrosion resistance and ascendant wear resistance properties to the substrate.

Deterioration of Water Ballast Tank Coating Systems by Active Substances in Ballast Water Management Systems

Sodium hypochlorite and ozone are the principal active substances and usually employed in ballast water management systems. In the present study, the authors focus on the effect of these active substances to the maaix polymer of coating. In order to obtain such information, the authors investigated the penetration of active substances to the polymer from cross section of specimens introduced by SAICAS （surface and interracial cutting analysis system）, followed by FT-IR-ATR （Fourier transform infrared and attenuated total reflectance） spectroscopy analysis from Z direction of cross section. The corrosion test of coating panels by these active substances （control as artificial seawater） has been conducted for 120 days. The results show that the depth profile of each active substance is around few dozens of micrometers from coating surface. The criteria of corrosion test cannot be determined by these results due to lacking in actual corrosion data immersed for 15 years under active substances. However, the authors evaluated the effect on ballast tank coating systems by active substances using analytical methods of SAICAS and FT-IR-ATR spectroscopy.

In vitro corrosion behavior and cytotoxicity property of magnesium matrix composite with chitosan coating

Mg-6%Zn-10%β-Ca3(PO4)2 composite was prepared through powder metallurgy methods with different chitosan coatings on its surface. The properties of the chitosan coatings on the surface of Mg-6%Zn-10%β-Ca3(PO4)2 composite, such as the adhesion ability, the corrosion behavior and the cytotoxicity properties, were investigated, and the microstructure of the chitosan coating was observed by scanning electron microscope(SEM). The results show that chitosan coating improves the corrosion resistance of the magnesium composite specimens significantly. Mg-6%Zn-10%β-Ca3(PO4)2 composite specimens exhibit good corrosion resistance and low p H values in simulated body fluid(SBF) at 37 °C in the immersion test with 7-layer chitosan coating whose relative molecular mass is 30×104 Da. The cytotoxicity tests indicate that Mg-6%Zn-10%β-Ca3(PO4)2 with chitosan coating is nontoxic with a cytotoxicity grade of zero against L-929 cells, which is better than that of uncoated composites.

A method for predicting critical load evaluating adhesion of coatings in scratch testing

In this paper based on the experiment principle of evaluating adhesion property by scratch testing, the peeling mechanism of thin films is discussed by applying contact theory and surface physics theory. A mathematical model predicting the critical load is proposed for calculating critical load as determined byscratch testing. The factors for correctly evaluating adhesion of coatings according to the experimental data arediscussed.

Preparation and Research of a Bionic Woven Tracheal Stent with Horizontal Pipeline

The paper designed a bionic woven tracheal stent and the stent was a multi-layer tubular structure with a transverse pipeline.Polydioxanone( PDO) monofilament and β-hydroxybutyrate and β-hydroxyvalerate copolymers/polylactic( PHBV/PLA) multifilament were chosen as the tissue engineering tracheal stent materials,and chitosan was chosen as the coating material. This study selected appropriate basic fabric structures and prepared the tracheal stent by setting reasonable weaving parameters,then treated the sample with coating and heat setting. Radical compression performances of the horizontal pipeline and longitudinal pipeline of this tracheal stent were investigated,and the experimental results showed that the stent had good performance on radial supporting force and elastic recovery,which meant it could supply adequate supports for cell growth and tissue regeneration of tracheal lesions; the horizontal pipeline could provide a good experimental foundation for reconstruction of the cartilage ring.

Improved properties of carbon fiber paper as electrode for fuel cell by coating pyrocarbon via CVD method

The fabrication of a pyrocarbon coated carbon paper and its application to the gas diffusion lay(GDL) of proton exchange membrane(PEM) fuel cell were described.This carbon paper was fabricated by using conventional carbon paper as the precursor,and coating it with pyrocarbon by pyrolyzing propylene via the chemical vapor deposition(CVD) method.For comparison,conventional carbon paper composites were also prepared by using PAN-based carbon fiber felt as the precursor followed by impregnation with resin,molding and heat-treatment.SEM characterization indicates that pyrocarbon is uniformly deposited on the surface of the fiber in the pyrocarbon coated carbon paper and made the fibers of carbon felt bind more tightly.In contrast,there are cracks in matrix and debonding of fibers due to carbonization shrinkage in the conventional carbon paper.Property measurements show that the former has much better conductivity and gas permeability than the latter.In addition,current density-voltage performance tests also reveal that the pyrocarbon coating can improve the properties of carbon paper used for electrode materials of fuel cell.

Application of drug-coated balloon in coronary artery intervention： challenges and opportunities

In recent decades, the outcomes of coronary heart disease （CHD） have markedly improved, which can be partly attributed to the use of novel drugs （especially statins and antiplatelet drugs） and partly to the evolution ofpercutaneous coronary intervention （PCI）. From percutaneous transluminal coronary angioplasty to bare-metal stent and then to drug-eluting stent, every step of PCI is attractive to interventional cardiologist, great progress has been made for patients with CHD. In the past few years, some successor devices for treating CHD have cmerged. Undoubtedly, drug-coated balloon （DCB）, which was recommended by 2014 ESC Guidelines on myocardial revascularization, is a ＂shining star＂ among them. DCB involves a semi-compliant angioplasty balloon coated with an anti-proliferative agent that can exert antirestenotic efficacy by permeating into the vessel wall during balloon contact. This review discusses the conception and merits, preclinical data, emerging clinical indications, and results from clinical trials of this novel interventional technology. Although DCB has shown authentic efficacy in the treatment ofin-stent restenosis, its use in de novo coronary lesions is still in dispute. Hence, concerns and the future direction of DCB are also covered in this paper.

Behaviour of Rendering Mortar for Rehabilitation of Buildings Subjected to Rising Damp

This paper presents an experimental study on the behaviour of rendering mortars used to rehabilitate buildings subjected to rising damp and consequently affected by efflorescence. This study was initiated by the characterization, ＂in situ＂ and in laboratory, of rendering mortar used as walls coating of an old building affected by efflorescence. Temperature, superficial humidity, mortar water content and salts content were used as characterization tests. Taking into account the reconstitution of old building rendering mortar composition, four different proportions were proposed to simulate different mortars skeletons and porosities. The mortars binders were composed by cement and three additions, such as hydrated lime, artificial hydraulic lime and quicklime paste. The results of capillary water absorption, soluble salts content and permeability test on masonry panels allowed analyzing the performance of mortars compared to the susceptibility of water rise and formation of salts. From this analysis, it was possible to draw some practical recommendations for design coating repair mortar in buildings subject to the problem of rising damp.

Computer Aided Thermal Stress Analysis of TBC Coated Specimen

Thermal barrier coatings （TBC） have been improved for the engine applications. During working process of the engine, components were subjected to thermal stresses. For simulating thermally stressed engine parts, disc specimen was objected to airflow at the temperatures about 1,000℃. In this study, finite element structural and thermal analyses were carried out on both uncoated （without coating） and ceramic-coated disc specimen using ANSYS code. A 150 micron super alloy bond coating （NiCrAIY） was first applied to the specimen. Then, the disc specimen was covered by 350 micron thickness of Mullit （3Al2O3.2SiO2） as a top coating. These analysis were performed for detecting the possible thermally problem areas. The disc＇s thermal stressed problematic areas were determined by the finite element analysis was helpful for improving the geometry and TBC.

Finite element and experimental analysis of Vickers indentation testing on Al_2O_3 with diamond-like carbon coating

Numerical simulation and experimental study of the Vickers indentation testing of the Al2O3 ceramic coated by diamond-like carbon(DLC) layer were conducted.The numerical analysis was implemented by a two-dimensional finite element(FE) axis symmetry model.FE analysis results gave insight into the fracture mechanism of DLC films coated on brittle ceramic(Al2O3) substrates.The maximum principal stress field was used to locate the most expected area for crack formation and propagation during the Vickers indentation testing.The results show that the median crack initiates in the interface under indenter,before ring crack occurs as the indenter presses down.Finally,the plastic deformation appears when the indenter penetrates into the substrate.The thicker DLC coating increases the Vickers hardness and fracture toughness.

Hydrogen Detection With FBG Sensor Technology for Disaster Prevention

Three fiber Bragg grating （FBG） sensors systems for hydrogen detection are presented using the classic Pd （palladium） coating technique （500nm） as the hydrogen sensitive film and titanium （Ti） as the adhesive layer with the etched cladding. These systems are compared and used for disaster environment prevention in hydrogen leakage environment where higher values than the normal are presented which increase the risk of explosion. With these systems, 0. 1% - 4% of the hydrogen volume concentration range in the volume ratio was detected and monitored experimentally in the test room with the very sensitive and stable value which reached 60pm/1% HE. In addition, a fast response time, about 6 s, was obtained with an advanced sensor.

Nanoindentation analysis of TiN,TiAlN,and TiAlSiN coatings prepared by cathode ion plating

The TiN, TiA1N and TiA1SiN coatings were deposited on H13 hot-worked mold steel by cathodic arc ion plating （CAIP）. The morphologies, phase compositions, and nanoindcntation parameters, such as creep hardness, elastic modulus and plastic de- formation energy of the coatings were analyzed with field emission scanning electron microscopy （FESEM）, X-ray diffraction （XRD） and nanoindentation testing, respectively, and the test results were compared with equation describing the indentation model. The results show that the TiN, TiA1N and TiAISiN coating surfaces were dense and composed of TiN, TiN ＋ TiA1N, TiN ＋ Si3N4 ＋ TiAIN phases, respectively. There was no spalling or cracking on the indentation surface. The creep hardness of the TiN, TiA1N and TiAISiN coatings was 7.33, 13.5, and 15.2 GPa, respectively; the corresponding hardness measured by nanoindentation was 7.09, 15.6, and 21.7 GPa, respectively; and the corresponding elastic modulus was 201.93, 172.79, and 162.77 GPa, respectively. The contact depth and elastic modulus calculated by the indentation model were close to those of the test results, but the remaining indentation parameters showed discrepancies. The sequence of plastic deformation energy was TiN 〉 TiA1N〉TiAISiN.

Technology for the next gravitational wave detectors

This paper reviews some of the key enabling technologies for advanced and future laser interferometer gravitational wave detectors, which must combine test masses with the lowest possible optical and acoustic losses, with high stability lasers and various techniques for suppressing noise. Sect. 1 of this paper presents a review of the acoustic properties of test masses. Sect. 2 reviews the technology of the amorphous dielectric coatings which are currently universally used for the mirrors in advanced laser interferometers, but for which lower acoustic loss would be very advantageous. In sect. 3 a new generation of crystalline optical coatings that offer a substantial reduction in thermal noise is reviewed. The optical properties of test masses are reviewed in sect. 4, with special focus on the properties of silicon, an important candidate material for future detectors. Sect. 5 of this paper presents the very low noise, high stability laser technology that underpins all advanced and next generation laser interferometers.

Tribological performance of TiAlSiN and TiAlCrN/TiAlN coating blades

A new laboratory evaluation method for the coating blade was developed, and the tribological properties of coating blades with different Ti-based coatings were studied by UMT-2 tribometer. Comparison between the areas of scratches before and after the cutting experiment was used to evaluate the cutting performance of the blades. Results showed that friction coefficient of TiA1CrN/TiA1N coating was significantly lower than that of TiA1SiN coating. Analysis of the worn surface revealed that the TiA1SiN and TiAICrN/TiA1N coatings in the dry turning process exhibited sign of inhornogeneous adhesive wear and abrasive wear. TiA1CrN/TiA1N coating has a longer working life and better anti-wear property because of its duplex coating.