Showing papers on "Coating published in 1987"

Scanning electron microscopy and x-ray microanalysis

Abstract: SEM-Instrumentation: Introduction Principles of Operation Specimen/Electron Interactions Detectors Operating Conditions and Limitations Specimen Preparation: Specimen Characteristics Drying Techniques Coating Cryo-SEM SEM X-Ray Microanalysis-Instrumentation: Introduction X-Ray Production in the SEM Wavelength Dispersive Systems (WDS) Energy Dispersive Systems (EDX) Operating Conditions and Limitations Data Handling Other Surface Analytical Techniques.

Plasma sprayed coatings of hydroxylapatite

Abstract: The technique of plasma spraying has been applied to deposit a thin, dense layer of hydroxylapatite onto a titanium substrate. Bond strength of such apatite coatings with the substrate have been measured, as well as the (absence of) influence of the coating process on fatigue properties of the substrate. Animal studies showed similar histological reactions to apatite coatings as to (well documented) apatite bulk materials.

Current status of thermal barrier coatings — An overview

Abstract: The science and technology of thermal barrier coatings has advanced considerably since reports of the first test on turbine blades in a research engine in 1976. Today thermal barrier coatings are flying in revenue service in a low risk location within the turbine section of certain gas turbine engines. The state-of-the-art coating system for gas turbine applications is currently a plasma-sprayed ZrO 2 -(6%–8%) Y 2 O 3 ceramic layer over an MCrAlY (M ≡ Ni, Co or NiCo) bond coat layer plasma sprayed at low pressure. Although the potential for meeting current and short-term goals is high, longer-range goals may not be attainable with current coating concepts. These longer-range goals will involve high risk designs where coating loss could lead directly to component loss. Several steps must be taken to help meet these goals. Improved understanding of coating failure mechanisms is required. Models are needed to predict lifetimes. Process automation and quality control procedures must be instituted. Finally, new concepts in plasma-sprayed coatings must be developed and alternatives to the plasma- spraying process may be required. The current status of thermal barrier coatings and prospects for future progress in the above areas are summarized.

The effect of surface macrotexture and hydroxylapatite coating on the mechanical strengths and histologic profiles of titanium implant materials.

Abstract: A mechanical and histological evaluation of uncoated and hydroxylapatite-coated titanium implant materials was performed. Cylindrical implants of uncoated commercially pure (CP) titanium and hydroxylapatite-coated Ti-6Al-4V alloy were studied using a transcortical model, with implants evaluated after periods of 3, 5, 10, and 32 weeks. All implants had a surface macrotexture consisting of a series of semicircular annular grooves, approximately 750 micron in maximum depth. The attachment characteristics of interface shear stiffness and interface shear strength were determined by mechanical push-out testing. Nondecalcified histologic and microradiographic techniques, with implants in situ, were used to evaluate the response to the implant materials and the presence of the surface macrotexture. Mechanical testing results indicated that the hydroxylapatite-coated implants exhibited significantly greater values of maximum interface shear strength than the uncoated implants after all time periods. Interface shear stiffness was also significantly greater at all time periods for the hydroxylapatite-coated implants as compared to the uncoated implants. Histological evaluation after 3 weeks revealed an osteoid layer covering on all areas coated with the hydroxylapatite material; mineralization of this layer appeared to be complete after 10 weeks. In all cases, longer-term implants demonstrated mineralization of interface bone directly onto the hydroxylapatite coating, and in no case was a fibrous layer observed between the hydroxylapatite coating and the interface bone. Sections from the uncoated CP titanium implants revealed a thin fibrous layer present in nearly all areas. Only isolated regions of direct bone-implant apposition were observed for the uncoated implants. The presence of this fibrous tissue layer, however, apparently did not adversely affect the development of considerable attachment strength. The results from this study indicate that the hydroxylapatite coating can significantly increase the attachment strength of implants which rely upon bone apposition for fixation. In addition, the hydroxylapatite coating provides an osteophilic surface for bone deposition, and allows for a more rapid development of implant-bone attachment.

Industrial deposition of binary, ternary, and quaternary nitrides of titanium, zirconium, and aluminum

Abstract: Improved wear behavior compared to chemically vapor deposited (CVD) and physically vapor deposited (PVD) TiN coatings have been found with (Ti,Al)N, (Ti,Zr)N, and (Ti,Al,V)N coatings using high‐speed steel and cemented carbide substrates. High‐speed drills coated by (Ti,Al)N films, produced from Ti:Al 50:50 at. % targets revealed in certain cases up to three times better performance than conventionally TiN ion plated tools. In the case of cemented carbides the flank and crater wear could be improved considerably also up to three times compared to CVD TiN/TiC depending on cutting conditions. Basic correlations between process and film characteristics of new multicomponent hard coating have been established. Planar magnetron sources and powder metallurgically prepared targets in an industrially useful ion plating deposition process have been developed and proved under production conditions. The first part of the paper describes the basic research and development of new coating materials. The second part inv...

Chemical implant fixation using hydroxyl-apatite coatings. The development of a human total hip prosthesis for chemical fixation to bone using hydroxyl-apatite coatings on titanium substrates.

Abstract: Sintered hydroxyl-apatite implants form very tight bonds with living bone but are susceptible to fatigue failure. Plasma-sprayed apatite coatings on titanium substrates overcome the fatigue problem. The static tensile substrate bond strength of the apatite coating is in excess of 85 megapascals (MPa) (12,000 psi). In a plug implant study designed to discount mechanical retention, a bone bonding shear strength of 64 MPa (9280 psi) was achieved, comparable to the strength of cortical bone. Histologic sections confirm the close bonding between apatite coating and living bone. In a canine total hip arthroplasty study, the apatite-coated implants proved far superior to the uncoated controls. Uncoated prostheses were surrounded by fibrous tissue and were easily extracted from the femur at any postoperative time. The apatite-coated implants were rigidly fixed within three weeks with demonstrable bone formation up to the implant surface. Bony defects up to 2 mm in depth were filled with bone within six weeks. The hypothetical mechanism of bone bonding is chemical. Hydroxyl-apatite coatings permit an implant fixation far superior to current methods using either cemented or cementless techniques. The plan is to study a human total hip prosthesis with hydroxyl-apatite coating for chemical fixation to bone.

Multilayer ceramics from hydrogen silsesquioxane

Abstract: This invention related to materials produced by diluting in a solvent a hydrogen silsesquioxane resin solvent solution which is applied to a substrate and ceramified by heating. One or more ceramic coatings containing silicon carbon, silicon nitrogen, or silicon carbon nitrogen can be applied over the ceramified SiO₂ coating. A CVD or PECVD top coating can be applied for further protection. The invention is particularly useful for coating electronic devices.

Multilayer wiring substrate

Abstract: A multilayer wiring substrate wherein a substrate of ceramic material (11) contains a plurality of power supply wiring layers (1) and is formed with first and second through-holes (20,20a) Each of the first through-holes (20) contains a first metal layer (32,33) which is connected to at least one of the power supply wiring layers (12,13) Each of the second through-holes (20a) has a wall surface coated with a layer of a fluoride resin dielectric (21) with a second metal layer (22) formed on the coating A circuit is supplied with power via the first metal layers and with signals via the second metal layers The circuit comprises thin film wiring layers (25) formed on the substrate, insulating layers (24) made of an organic material, and electronic circuit elements (not shown) The substrate is made by coating upper and lower surfaces and through-holes of a substrate with a layer of the fluid resin dielectric, removing the coating from the upper and lower surfaces, forming a metal layer in the upper and lower surfaces and on the coating and removing the metal layer except for portions at each end of and within the through-holes

Coated synthetic resin lens

Abstract: Coated synthetic resin lenses having a primer layer of a copolymer of an acrylic and/or methacrylic monomer and an aromatic vinyl compound between the base material and a cured abrasion resistant layer of colloidal silica and an inorganic anti-reflection coating are provided. The cured coat of colloidal silica has a particle diameter between about 1 and 100 millimicrons and is dispersed in a hydrolyzed silane compound. The organic primer coating improves adhesion properties between the base material and the cured abrasion-resistant layer resulting in coated lenses of improved impact resistance.

Credit card and method of making the same

Abstract: An improved credit card having a clear, unbroken metallized surface with printed graphics thereon which is scratch resistant and a method of making the same are disclosed. The method involves heat transferring a metallized foil to a first surface of a plastic substrate, silk-screen printing over the metallized foil with ultraviolet curable ink, drying the ink with ultraviolet light and overlaminating the printed foil with a clear polyester film coated with a heat-activated adhesive or coating it with an ultraviolet curable varnish which is cured by applying ultraviolet light to the coating. The plastic substrate is in the form of a large sheet from which a plurality of cards are die cut after the printing and application of the transparent film. A magnetic tape is then applied to the back of each card.

Method of forming a metal coating on a substrate

Abstract: A method for producing a uniform metal coating on a substrate consisting of (1) selecting one or more metals to be coated onto the substrate wherein the metals are soluble in a molten salt when heated, (2) preparing a bath consisting of the dissolved metal-molten salt, (3) inserting a substrate into the bath, and (4) decreasing the temperature at the substrate to a level at which the metal will precipitate out of solution onto the substrate. Multiple coatings can be made by repeating the method using the same or different metal-molten salt systems. Deposition can be enhanced by adding more salt to the bath to increase precipitation of the metal onto the substrate or by introducing additional metal into the bath by electrolysis, either by electrowinning or electrorefining. The metal coating can be patterned by localized heating of the metal coating in the metal-molten salt bath to reverse deposition or by masking areas on the substrate prior to deposition. The method can also be used to purify the metal or compound being precipitated by controlling the composition and processing parameters of the metal-molten salt bath. Alternatively, these same parameters can be controlled to deposit metals or compounds containing desired levels of specific impurities such as in the case of doped GaAs.

Open-cell, low-density ceramics fabricated from reticulated polymer substrates

Abstract: Processing procedures and resulting mechanical properties of open-cell, low-density (relative density < 0.1) ceramic macrostructures were investigated. These macrostructures were fabricated by slurry coating reticulated polymer substrates. Cracks in the struts powder coating, which were produced during the pyrolysis of the substrate, remained after powder densification at high temperatures and were the major cause of suboptimum properties. Additionally, lack of slurry drainage during the coating process could fill cells with powder which would differentially shrink during densification, leaving large regions within the macrostructure void of cell struts. This problem became increasingly produced with decreasing cell size. Mechanical properties were measured for a commercial transformation-toughened Al{sub 2}O{sub 3}/ZrO{sub 2} open-celled material fabricated using reticulated polymer substrates with cell sizes of 12, 26, and 39 pores/cm. Approximately half of the specimens were treated by the manufacturer in an attempt to heal the partially cracked struts. The relative density of all materials ranged from 7 to 12% of theoretical. Mechanical properties appeared to be independent of cell size. The elastic modulus, which ranged from 1 to 5 GPa, increased with density and was higher for the healed materials.

Process for the production of a display means by cathodoluminescence excited by field emission

Abstract: A process of producing a display operating by cathodoluminescence excited by field emission, including forming parallel cathodes on a glass substrate, depositing a silica coating on the cathodes, then a conductive coating and then producing a matrix of holes in the conductive coating and silica coating, depositing on the perforated conductive coating a fourth coating not covering the holes and then depositing on the complete structure a coating of an electron emitting material, eliminating the fourth coating so as to expose the microemitters, forming in the conductive coating grids crossing the cathodes and placing above the grids an anode covered by a cathodoluminescent coating.

Photoresist composition and printed circuit boards and packages made therewith

Abstract: A photocurable composition which is useful as a permanent resist in the manufacture of printed circuit boards and packages of such boards comprises a multifunctional epoxidized resin, a reactive diluent, a cationic photoinitiator and, optionally, an exposure indicator, a coating aid and a photosensitizer.

Multilayer ceramic coatings from silicate esters and metal oxides

Abstract: This invention relates to materials produced by diluting in a solvent a preceramic mixture of a partially hydrolyzed silicate ester and a metal oxide precursor selected from the group consisting of an aluminum alkoxide, a titanium alkoxide, and a zirconium alkoxide. The preceramic mixture solvent solution is applied to a substrate and ceramified by heating. One or more ceramic coatings containing silicon carbon, silicon nitrogen, or silicon carbon nitrogen can be applied over the ceramified SiO₂/metal oxide coating. A CVD or PECVD top coating can be applied for further protection. The invention is particularly useful for coating electronic devices.

Method for parallel fabrication of nanometer scale multi-device structures

Abstract: Articles exhibiting fabricated structures with nanometer size scale features (nanostructures), typically a device comprising nanostructures of a functional material on or in a substrate of dissimilar material, are produced by a method employing a substrate base or coating and a thin layer serving as a lithographic mask or template, consisting of a self-assembled ordered material array, typically a periodic array of molecules such as undenatured proteins, exhibiting holes, thickness or density variations. It is possible to produce complex structures containing large numbers of nanometers scale elements through a small number of simple steps.

Brazing of diamond

Abstract: A monolayer diamond tool is made by coating diamond abrasive particles with a carbide-forming metal and then brazing the coated diamond to a tool substrate.

Methods of forming synthetic diamond coatings on particles using microwaves

Abstract: An apparatus and method for applying hard surface coatings to articles of manufacture such as particles, filaments, sphereoids, rollers, bearings, tools, and assemblies. In one form, coating of hard surface film, such as synthetic diamond, is effected while the objects fall freely through space in a coating chamber. In another form, coating is effected while particles are fluidized by gas containing molecules which are formed of matter to be deposited by gas or chemical vapor deposition employing high energy radiation, such as microwave energy and/or other form of radiation. In other forms, an ion beam or beams containing hot carbon ions is directed through a fluidized bed of particles to be coated or through a chamber in which small objects are made to continuously fall freely through space to coat same with carbon in the form of synthetic diamond. In another method, such small objects are caused to continuously tumble through a coating region of a coating chamber into which is directed gas and/or vapor containing molecules of a hydrocarbon, such as methane, and hydrogen, while microwave energy is directed through such region. Other forms of the invention include the selective deposition and coating of synthetic diamond onto substrates to form or protect microminiature electronic circuits and circuit elements such as transistors and interconnects and to protect bonds such as welds, or to form bonds between components joined together thereby. In yet another form, hard synthetic diamond coatings are deposited per se or in combination with other materials, by a hybrid process including chemical vapor deposition, ion deposition by beam(s), sputtering and the like.

Long-life membrane electrode for non-ionic species

Abstract: An improved membrane electrode (11) for measuring the concentration of a non-ionic species in an essentially aqueous medium comprising: an electrically conductive substrate (17); a first coating (13) surrounding said substrate (17) composed of a mixture of polymeric material, an anion exchange material, and a water-insoluble alkaline earth metal salt of said non-ionic species, and a hydrogel coating (15) of material surrounding said first coating (13) having a positive charge of sufficient potential to prevent leaching of the substantial amounts of the alkaline earth metal component of said salt.

Micromechanical elements and methods for their fabrication

Abstract: A method and the product resulting from the method, for making a microminiature structure with two or more members measuring less than 1000 micrometers in any linear dimension and relatively movable to each other, comprising the steps of (a) providing a first sacrificial coating over a substrate having openings therethrough to expose a portion of the substrate, (b) depositing a first structural layer over the first sacrificial coating and the exposed portion of the substrate, with openings therethrough to expose a second portion of the substrate, (c) providing a second sacrificial coating over the second exposed portion of the substrate and said first structural layer, with openings through both the first and second sacrificial layers to expose a third portion of the substrate, (d) adding a second structural layer thereover and defining it, (e) possibly adding alternately other sacrificial coatings and other structural layers, and (f) etching the first and second and other sacrificial layers to remove them completely so that the two or more structural layers become movable relative to each other.

Antimicrobial wound dressings

Abstract: Antimicrobial wound dressings are provided comprised of a substrate coated with an antimicrobially effective film of a silver salt. These antimicrobial wound dressings are prepared by vapor coating or sputter coating certain silver salts onto a variety of wound dressing substrates. Preferred silver salts are silver chloride and silver sulfate.

Behavior of thermal barrier coatings for advanced gas turbine blades

Abstract: The work reported herein deals with a plasma-sprayed zirconia-yttria ceramic coating with a nickel-chromium-aluminum bond coat on a super- alloy substrate. This investigation has as its principal objective the quantitative determination of stress states in a model thermal barrier coating as it cools in air. The effects associated with an idealized rough ceramic-bond interface were investigated. The influence of bond coat oxidation was also determined, together with the impact of initial cracking within the coating. An improved understanding of these coating behaviors is expected to lead to the discovery of coating failure mechanisms which can greatly benefit the designer. In this investigation the powerful finite element method was employed to model the coating which is assumed to be elastic for this initial effort. To obtain the necessary accuracy a very fine finite element grid was developed, utilizing generalized plane-strain elements to model a cylindrical coated specimen. The model which is named TBCOC contains 1316 nodal points and 2140 elements. Using a generic code called MARC, numerical results were obtained from this model. The actual calculations were performed on a CRAY-1S supercomputer. Detailed stress distributions in the coating were obtained to reflect the effects of thermal expansion mismatch and the material properties. Results to date have pinpointed the existence (and location) of large radial tensile stresses in the ceramic layer adjacent to the rough ceramic- bond interface. The effects of oxidation on the stresses are shown together with the influence of initial cracking at specific locations near the ceramic-bond interface. A preliminary failure mechanism for thermal barrier coatings is proposed on the basis of these numerical results and published experimental work.