Showing papers on "Coating published in 1989"

High-temperature-resistant, corrosion-resistant coating, in particular for components of gas turbines.

Abstract: A high-temperature-resistant, corrosion-resistant coating, in particular for components of gas turbines, which possesses good corrosion-resistant properties at temperatures between 600 and approximately 1150 °C, contains the following elements (in weight percent): 25-40 % nickel, 28-32 % chromium, 7-9 % aluminium, 1-2 % silicon, 0.3-1 % yttrium, the remainder cobalt, at least 5 %, and unavoidable impurities. Various optional constituents may also be present. The properties of the corrosion-resistant coating can be further enhanced by the addition of rhenium even in minute quantities. The preferred range is 4-10 % rhenium. The corrosion-resistant coating is particularly suitable for components in the inlet region of gas turbines with high inlet temperature, which must also operate occasionally at partial load.

A review of microstructure and properties of plasma sprayed ceramic coatings

Abstract: The present understanding of the plasma-sprayed coating formation process is reviewed. The development of porosity, and the very fine voids formed by incomplete inter-splat contact is discussed. The strong relation between porosity and mechanical and thermal properties of ceramic coatings is reviewed. Some of the controlling factors for the grain size and crystal structure within the deposited splats are discussed, particularly in reference to zirconia coatings.

Medical apparatus having protective, lubricious coating

Abstract: A method for providing a medical apparatus with a protective, lubricious coating is described. The method comprises providing a coating solution which contains a protective compound such as a urethane, a slip additive such as a siloxane, and optionally, a crosslinking agent for the protective compound such as a polyfunctional aziridine, coating the solution onto a surface of a medical apparatus and allowing the coating to set. The resulting surface coating is lubricious, tough and flexible. The coating is well suited for use with materials used as components of balloon catheters.

Hydrophilic lubricious coatings

Abstract: A new method is provided to impart a hydrophilic lubriciious coating onto articles such as medical devices. A device, for example a catheter, is first contacted with a polyisocyanate solution, to provide coupling, then contacted with a poly(carboxylic acid) solution to give a coating, and is then finally oven dried. These coatings have lubricity that only becomes manifest upon exposure to water ro body fluids, and moreover, are also long lasting and have good abrasion resistance. This combination of properties is not available from other currently used or proposed coatings.

The reactive element effect in high-temperature corrosion

Abstract: When small quantities (typically 1 wt.% or less) of a number of reactive elements are added to high-temperature alloys containing chromium or aluminum, a number of beneficial effects result. This is called the “reactive element effect” (REE). Some or all aspects of the REE can be developed when the reactive element is added as an alloy addition, when it is present as a dispersion of oxide particles in the alloy, when it is ion implanted into the surface, or when a coating of the reactive element oxide is applied to the surface of the alloy. In this paper, the experimental evidence is briefly summarized, and different models that have been proposed to account for one or more aspects of the REE are assessed in terms of this evidence.

Functionalized polypyrroles. New molecular materials for electrocatalysis and related applications

Abstract: The concept of altering the chemical structure of an electrode surface with a view to controlling the course of an electrochemical reaction was pioneered some 15 years ago by Lane and Hubbard. This promising new areas of electrochemistry rapidly attracted interest, the major objective being to tailor spectifically the electrode material in such a way as to promote the desired electrochemical reaction. The possibility of making electrodes with specific chemical, electrochemical, or optical surface properties gave rise to numerous possible applications of these modified electrodes in the fields of electro- and photocatalysis, electrosynthesis, electroanalysis, molecular devices, and electrochromism. Among the numerous chemical functions that could undergo electrochemical polymerization, the pyrrole group is exceptionally convenient for carrying out the coating of electrode surfaces by nonpassifying polymer films containing catalytic and/or redox active centers. Furthermore, polypyrrolic films are characterized by a long-term chemical stability, which allows their productive use in various applications. An account of this topic, mainly devoted to electrocatalytic applications, will be given here. A few typical extra examples, including bio- and electroanalysis, microelectronics, and electroreleasing devices, are also presented to emphasize the versatility of this type of polymeric coating.

Spin coating: One‐dimensional model

Abstract: The model of the spin‐coating process presented here accounts for variations of concentration, viscosity, and diffusivity across the thickness of the spin‐coated film. The flow of the liquid is governed by a balance between centrifugal driving force and viscous resisting force. Radial variations in film thickness and concentration are neglected. The Galerkin/finite‐element method is employed to solve the equation set. Film thinning slows initially due to decreasing film thickness and ceases finally due to dramatically increasing viscosity of the coating liquid as solvents evaporate. The formation of a region of extremely low solvent concentration and correspondingly high viscosity and low binary diffusivity at the free surface, i.e., a solid ‘‘skin,’’ is predicted. Coating defects can occur if convective flow has not completely ceased when this skin forms. Skin formation can be eliminated or delayed by partially saturating the overlying gas with solvent or by using mixed solvents (having both high and low...

Cemented and cemented/sintered superabrasive polycrystalline bodies and methods of manufacture thereof

Abstract: Superabrasive cutting elements, backed compacts and methods for their manufacture are disclosed wherein metal coated superabrasive particles are cemented under HPHT conditions. The superabrasives bond to the metal of the coating and the metal coatings of adjacent particles bond to each other forming a matrix. A binding aid with thermal expansion characteristics close to that of the superabrasive particle can be infiltrated through or otherwise mixed with the particles to assist in the bonding between the metal coatings and to fill in voids. Catalyst and non-catalyst binding aids can also be used. Uncoated, smaller superabrasive particles can be interstitially dispersed among the coated particles to increase the superabrasive concentration and can self bond to form a cemented/sintered structure. Tungsten is a preferred metal coating and silicon is a preferred binding/sintering aid. The superabrasive can be diamond, cubic boron nitride, boron doped diamond or crushed sintered polycrystalline aggregates. The free-standing cutting element can have a brazeable layer and the compact can be backed with, for example, cemented tungsten carbide. Free-standing cutting elements can be thermally stable up to 1,200° C. Backed compacts can be thermally stable up to 1,100° C.

Lubricious antithrombogenic catheters, guidewires and coatings

Abstract: Method for rendering a preformed article lubricious and antithrombogenic and a device being the same. On the surface of the article a thin coating of a biologically compatible, lubricious, hydrophilic polymer including acid groups, is provided. On the coating, ammonium cation, and heparin are applied in the manner that heparin is bound by electrostatic attraction to the ammonium cation of the coating to permit time release of heparin. A buffer solution may be applied in a manner to act to enhance the lubriciousness of the coating.

Electrochemical Impedance of Organic‐Coated Steel: Correlation of Impedance Parameters with Long‐Term Coating Deterioration

Abstract: : Electrochemical impedance results are presented for 550 day exposures of organic coated carbon steel samples. Coatings consisted of translucent pigmented and unpigmented epoxy and conventional opaque epoxy polyamide systems. Coating thicknesses ranged from 20 to 185 microns. Specimens were exposed under freely corroding conditions and at two cathodic polarization levels (-805 mV and -1250 mV versus SCE) in ASTM artificial ocean water. The objective was to identify impedance parameters which measure subcritical coated-metal system property changes at early exposure times that are indicators of significant long term coating deterioration. Impedance data developed at early times, including coating resistance, coating capacitance, the increase in frequency associated with the coating's resistive-capacitive (RC) 45 degree phase angle, and low frequency impedance data, are compared to the coating system's performance evaluated after 550 days exposure. Keywords: Electrochemical impedance, Organic coating, Corrosion, Alternating current impedance, Anti-corrosion coating.

Thin film structure having magnetic and colour shifting properties

Abstract: The disclosure relates to a thin film structure having magnetic and optical variable properties comprising a substrate (12) and a multilayer interference coating (16) carried by the substrate producing an inherent colour shift with angle. The interference coating has a metal-dielectric design which includes a metal (17) which has reflective as well as magnetic properties.

Coated silicon carbide abrasive grain

Abstract: An abrasive grain on the basis of silicon carbide with a binder-free coating of highly dispersed silicon, aluminum or titanium oxide for preferred use in resin-bonded or ceramic-bonded abrasive wheels.

Conductive polymers and plastics

Abstract: Compounded conductive plastics - types of conductive fillers, applications plated conductive plastics - types of plated conductive plastics, applications intrinsically conductive polymers (ICPs) - state-of-the-art technology, potential uses, coating applications.

Light emitting panel assemblies and method of making same

Abstract: Light emitting panel assemblies and method of making same include one or more layers of woven fiber optic material having disruptions or bends at discrete locations along the length of the fibers to allow light to be emitted therefrom. Only selected areas of the disruptions or bends are coated with a suitable coating material that has a refractive index that changes the attenuation of the light emitted from the selected areas. The coating material may be applied to the selected areas using one or more carrier members which become part of the panel. Alternatively, a non-permanent carrier such as a roller may be used to coat selected areas of the optical fiber disruptions or bends with the coating material after the weaving process.

Zirconia Coating on Stainless Steel Sheets from Organozirconium Compounds

Abstract: The stability and the coating characteristics of a variety of organozirconium compounds have been investigated to coat ZrO/sub 2/ films on stainless steel sheets for the improvement of heat resistance against oxidation. Zirconium tetraoctylate and zirconium tetrakis(acetylacetonate). The authors discuss how the compounds were found to be more stable than zirconium alkoxides in an ambient atmosphere. The ZrO/sub 2/ films from zirconium alkoxides became white and discontinuous when the thickness of the films exceeded about 200 A (20nm). On the other hand, transparent ZrO/sub 2/ films were obtained from zirconium tetraoctylate and zirconium tetrakis(acetylacetonate). The IR spectra of the films showed that the heat treatment at 400{sup 0}C for 5 min produced organic-free ZrO/sub 2/ films. The heat resistance of stainless steel sheets against oxidation was improved by the ZrO/sub 2/ coating, depending on the film thickness.

Catheter and hydrophilic, friction-reducing coating thereon

Abstract: A friction-reducing coating may be applied to a base material, for example the outer surface of a catheter, to provide a significant reduction in catheter friction, particularly when the friction-reducing coating is hydrated. The coating comprises an intimate mixture of a structural plastic material, for example polyurethane, and high molecular weight poly(ethylene oxide).

X-ray diffraction studies of physically vapour-deposited coatings

Abstract: X-ray diffraction was used to analyse coatings that had been deposited onto various substrates by a physical vapour deposition process known as sputter ion plating. To gain an overall picture for the evolution of coating microstructure with deposition time and substrate material, several aspects of X-ray diffraction were utilized: lattice parameter determination, line broadening studies, texture (preferred orientation) analysis and residual stress measurements. The lattice distortions observed were resolved into three types: macrostrain, microstrain and pseudo-macrostrain, defined as Types I, II and III respectively. Type I distortions are due to internal stress present in a thin film and this varies with the substrate material and coating density. Based on a simple biaxial stress analysis, it was shown that for titanium nitride coatings this stress consists of two components, one thermal and the other structural in origin. Ananlysis of the residual stress distribution was extended to include the effects of shear stresses and stress gradients. Results are presented which illustrate the errors which may be introduced into the values of the principal stresses σ11 and σ22 by assuming a biaxial stress distribution. The paper then goes on to a description of the origins of Type II and Type III distortions and how these relate to coating microstructure.

High temperature coatings for gas turbine blades: A review

Abstract: High temperature coatings are formed to protect many engineering components from environmental degradation. The operating temperature and the nature of the corrodant dictate the choice of the coating. The coatings can be formed by different methods, but invariably the properties are dependent on the coating process. The life of the coating depends upon the mode of degradation in service. It is also influenced by the nature of the substrate. The need for coatings is well illustrated by their wide use in gas turbines. This review covers the development of the oxidation- and hot-corrosion-resistant coatings for turbine blades. The rationale behind such protection, starting from the nickel aluminide to future thermal barrier oxide coatings, is outlined. It is followed by a discussion of current trends in post-coating modifications to improve the properties of the coatings. The principles underlying the development of these coatings should serve as a useful guide in the choice of coatings for other high temperature applications.

Polysiloxane-grafted copolymer non-pressure sensitive topical binder composition and method of coating therewith

Abstract: This invention relates to non-pressure sensitive topical binder compositions comprising a copolymer having a vinyl polymerica backbone with grafted pendant siloxane polymeric moieties and to a method of topically coating animals therewith.

State of the art on high-temperature corrosion-resistant coatings

Abstract: A high-temperature protective coating must meet several criteria: provide adequate environmental resistance, be chemically and mechanically compatible with the substrate, be applicable. Comprehensive reviews on high-temperature coatings have appeared regularly since the early 1970s. Our purpose is not to recapitulate the material covered therein but rather to focus on recent trends, and point out some research perspectives. Historically the development of high-temperature protective coatings has been linked with the evolution of demanding applications such as super-alloy components in gas turbine engines; the searches for better performance (higher inlet temperatures, longer lifetimes, etc.) and for cost-saving solutions (use of contaminated low-grade fuels) have been the main incentives for developing the different coatings now available in production: simple and “modified” diffusion coatings, overlay coatings, thermal barriers. In recent years research and development activity has been concentrating on the following points. 1. (a) Degradation mechanisms in high-temperature corrosion of metallic coatings; basic studies on the growth mechanisms of oxide scales, for example are still required, in particular to understand the role of addition elements such as platnum and palladium. 2. (b) Alternative techniques for depositing MCrAlY coatings; electrolytic codeposition and electrophoresis, for example, have been developed at the laboratory stage and these permit the deposition of MCrAlY coatings with claimed economic and technical advantages over processes already in production. 3. (c) Thermal barrier coatings; ceramic coatings have been applied to sheet metal combustor components for about 15 years; only recently have they been used in the turbine section. Two challenges remain though to exploit these coatings on turbine blades: improve their reliability and, in the case of stationary gas turbines, their hot corrosion resistance. Both structural and mechanical approaches are required to determine, in particular, the role of microstructure, microcracking, porosity, residual stresses, oxidation of the bond layer in the degradation mechanisms of these coatings. 4. (d) Mechanical properties of coated systems; the intrinsic mechanical properties of coating materials are still poorly described and the lack of information hinders the adequate modelling of the behaviour of coating-substrate composite systems. In parallel, an increasing activity is noted concerning the design and development of high-temperature coatings for protecting materials other than superalloys, for instance ceramic composites and titanium-based alloys.

Conformable bandage and coating material

Abstract: The liquid, polymer-containing coating materials of this invention comprise a polymer of a polymerizable, nitrogen-containing, hydrophilic monomer, which may give thermoresponsive properties, and which is copolymerized with a hydrophobic, polymerizable siloxy-containing monomer, in a solvent system of a volatile hydrophobic (non-polar) liquid that is non-stinging to a user. The material forms a coating or bandage in the form of a film when applied to a surface or the skin of a user.

Method of toughening diamond coated tools

Abstract: of the Disclosure Method of toughening the structure of a diamond or diamond-like coated tool, by the steps of: (a) depositing, by low pressure CVD, a plurality of layers of separated diamond or diamond-like particles onto a nondiamond or nondiamond-like tool substrate (i.e., SiAlON, Si3N4, SiC, Si, Ti, Co cemented WC, TiC, Ni-Mo cemented TiCN), the substrate being selected to facilitate diamond or diamond-like deposition and to retain its strength-related properties after such CVD; and (b) interposing a mechanically adherent, planarized binding material (i.e. transition metals, silicon, boron) between and on said layers of particles and across the separated particles of each particle layer, said binding material being substantially devoid of diamond graphitizing or dissolution agents. A barrier layer is deposited onto said tool substrate prior to step (a) to prevent the egress of chemicals capable of graphitizing diamond or diamond-like particles. The total thickness of the coating structure is about 50-125 microns.

Inverse gas chromatography

Abstract: This book reports on inverse gas chromatography (IGC), a useful technique for characterizing synthetic and biological polymers, copolymers, polymer blends, glass and carbon fibers, coal, and solid foods The technique involves creating within a column a stationary phase of the solid material of interest The stationary phase may be a thin polymeric coating on an inert substrate, a finely divided solid, or a thin polymeric coating on the column wall A volatile probe of known characteristics is passed through the column via an inert mobile phase and the output is monitored The residence time of the probe and the shape of the chromatogram indicate the characteristics of the stationary phase and its interaction with the probe Thus, IGC is a variation of conventional gas chromatography

Bond Strength of Epoxy-Coated Reinforcing Bars

Abstract: Epoxy-coated bars are used in nearly all types of structures where corrosion may cause deterioration. Bridge decks and parking garages are especially susceptible to salt-induced damage. For satisfactory structural performance, bond between concrete and steel is essential, and the effect of coatings that might decrease bond should be considered in designs. In this study, 21 beams with lap splices in a constant moment region were tested in nine groups and the bond strength of epoxy-coated bars was compared to that of uncoated bars. Variables were bar size, concrete strength, casting position, and coating thickness. In each test group, the only variable was the coating thickness.

Pressure sensitive adhesive/release liner laminate

Abstract: Addition-curable silicone pressure sensitive adhesives can be covered with an addition-cured fluorosilicone release coating to provide a releasable laminate. The release force of the laminate is low to moderate and the subsequent adhesion and tack of the adhesive is high and all three values are stable with time. The laminate can be prepared by contacting the release coating with cured adhesive or by curing the adhesive in contact with the release coating.

Composite solar/safety film and laminated window assembly made therefrom

Abstract: A laminated window construction includes a solar control film formed by a flexible plastic substrate such as a PET sheet having on one surface a multilayer solar coating. This multilayer solor coating includes at least one thin layer of metal and at least one adjacent adherent layer of a dielectric material. An energy absorbing safety film of the type normally used in shatterproof glass laminates (e.g., plasticized PVB) is bonded to at least one side, and preferably both sides, of the solar control film to form a composite solar/safety film. This composite solar/safety film is specially designed to contribute, after incorporation into a glass laminate, no more than about two percent of visible reflection (based on total incident visible radiation) which has the effect of substantially masking the visible effects of wrinkles in the solar control film substrate (i.e., the wrinkles are made less visible). This low level of visible reflection contribution is achieved by careful control of the optical properties of the solar control film, the safety film or both. Outer layer transparent glass panes are laminated to one or both sides of the composite solar/safety film to provide a safety window which in one preferred embodiment is a windshield having at least seventy percent normal visible light transmissibility, and a total reflection of visible light of generally less than ten percent.