Showing papers on "Ceramic published in 1968"

Lightweight ballistic armor

Abstract: A lightweight composite armor plate is disclosed wherein successive layers of small discrete ceramic blocks are encapsulated within a metallic matrix by solid-state diffusion bonding. Residual stress effects from the bonding step prestress the blocks in compression, whereby a greater amount of energy from an impacting projectile is required to shatter the ceramic.

Ceramic articles and method of fabrication

Abstract: Method of forming gas tight seals between polycrystalline ceramic bodies without a sealant material. Method, which is useful for joining sections of ceramic tubing in gastight relationship and for providing gastight seals for tubular bodies, depends on differing degrees of firing shrinkage of the components being joined, their ability to sinter together, and on the fact that the components, when fired, have substantially the same coefficient of thermal expansion. Various means of providing for differential firing shrinkages, such as a polycrystalline ceramic tube fired to near theoretical density is inserted in closely fitted relationship into a green tubular body of the same composition and the assembly is fired until both components are of maximum density. Sintering and shrinkage of the outer tubular body onto the inner body produces a monolithic structure with a completely continuous crystal structure across and replacing the former physical contact boundary. Ceramic articles, such as gas discharge lamp structures, embodying tubular ceramic bodies having end closures made by described method.

Structural and Electrical Properties of Vanadium Dioxide Thin Films

Abstract: Reactively sputtered vanadium dioxide films have been analyzed to determine the relation between their electrical and structural properties. The structure of the thin films was determined by x-ray diffraction, reflection electron diffraction, and electron microscopy of carbon replicas of the film surfaces. The various substrates which were evaluated for thin film VO2 deposition were amorphous glass, glazed ceramic, and single-crystal sapphire and rutile. Electrical conductivity measurements were made to correlate film perfection with the conductivity ratio between the semiconducting and metallic states. Films deposited on amorphous substrates such as glass and glazed ceramic are polycrystalline in structure with small grain size. Conductivity ratios of approximately 102 were observed with a very broad transition region centered at 68 °C. These films, in addition to VO2, exhibit an extra x-ray line at d = 2.25, tentatively identified as VO1.87. On sapphire substrates, highly textured films were obtained wh...

The Adhesion of Metal/Alumina Interfaces

Abstract: Cylinders of copper and nickel have been melted under various conditions to form sessile drops on alumina plaques. The resultant metal/ceramic adhesion at room temperature has been measured using the commonly adopted test in which the drops are pushed off the ceramic plaques. The stress system involved in the test has been analysed and it has been shown that the standard interpretation of the test, as a measure of interfacial shear strength, is not valid; the revised interpretation makes it a measure of adhesion in tension. Results for the Cu/Al2O3 and Ni/Al2O3 systems show that non-wetted interfaces can be strong and have strengths that are independent of contact-angle changes caused by wetting-temperature variations.

Current‐Voltage Characteristics of Semiconducting Barium Titanate Ceramic

Abstract: The current‐voltage characteristics of semiconducting BaTiO3 ceramic have been investigated with electric fields up to 2×104 V/cm. The results obtained are in agreement with Heywang's model for conduction in this material (other published models being unsatisfactory) provided that allowance is made for the Ohmic drop in the bulk material. It is found that most of the current is channeled through small pores (0.1–0.5 μ diam) in the intergranular boundaries.

Method of propping fractures with ceramic particles

Abstract: A method of propping fractures in a subterranean formation employs hard, ceramic particles having oppositely disposed surface elements which are linear and paralled. The composition of the particles may be glass or other ceramic material having a resistance to impact abrasion at least as great as soda-lime-silica glass. The particles may have the configuration of cylinders, rods, parallelepipeds, prisms, cubes, plates or other configuration which will have linear elements on its surface which are oppositely disposed and parallel. (9 claims)

Research and development of refractory oxidation resistant diborides

Abstract: : The oxidation, mechanical and physical properties of zirconium diboride and hafnium diboride and composites prepared from these diborides with appropriate additives, have been determined as a function of composition, microstructure and test temperature. The composites were designed to enhance oxidation resistance, strength and thermal stress resistance without sacrificing high temperature stability; the principal additives were silicon carbide or graphite. Several hundred diboride billets, in sizes from two inches diameter to six inches square, were fabricated by conventional hot pressing. A unique role for ceramic additives has evolved in enhancing the fabricability of diboride materials and producing fine grained crack free billets. All power materials and hot pressed microstructures subjected to properties evaluations have undergone extensive characterization through qualitative and quantitative chemical analyses, phase analyses and grain size and density measurements. An exploratory fabrication effort was initiated to develop alternate means to hot pressing for producing dense diboride materials; hot forging, plasma spraying and sintering are being studied. In addition, the hot pressing of diboride compositions containing additives such as SiC whiskers, carbon filaments or tungsten filaments is being studied.

A Solid‐State Electrochemical Cell Based on Ion Conductive Ceramics

Abstract: A solid‐state electrochemical cell has been devised using a ceramic ion conducting electrolyte and ceramic electrodes which are simultaneously ion and electron conducting. Charge/discharge of the cell occurs without chemical phase change and the reaction of the cell to an electric current is therefore capacitive. The origin of the capacitance is discussed in terms of the crystal structure of the ceramic used and the transient electrical characteristics described in terms of diffusion theory. Possible applications are suggested.

Ceramic to metal seal

Abstract: This disclosure is directed to metal to refractory seals wherein a ductile 50 atomic percent alloy of a group IVb metal with a group VIII metal of the same period is used to braze ceramic to metal. A preferred example is sealing Tantalum or Niobium to alumina with a 50 a/o Ti-Ni alloy braze.

Thermally insulated extrusion die and method of making

Abstract: A heated die plate for a plastic pelletizer, construction and method for applying alternate layers of metal and ceramic thermal insulating material that fills the space between a plurality of extrusion nozzles, the final layer of ceramic material being sealed against penetration by cooling fluids and also having uniform wear resistant qualities to reduce uneven abrasion of the cutting face and of the cooperating cutting edge of a rotary knife passing over the cutting face.

Composite ceramic armor

Abstract: PRESENTLY KNOWN COMPOSITE CERAMIC ARMOR PANELS DESIGNED FOR PROTECTION AGAINST SMALL ARMS FIRE CONSIST OF DENSE CERAMIC PLATES ADHERED TO A BACKING. ACCORDING TO THE PRESENT INVENTION, THE PREFERRED BACKING IS ALUMINUM ALLOY. IN ORDER TO INCREASE THE BEAM STRENGTH OF A FREE EDGE, TO MINIMIZED DEFLECTION UNDER IMPACT AND TO INCREASE THE OVERALL EFFECTIVENESS OF THE ARMOR, THE METAL BACKING PLATE IS FORMED NEAR THE FREE EDGE INTO AN ENCLOSING FLANGE OR LIP WHICH EXTENDS FROM THE BACKING PLATE AT AN ANGLE OF SUBSTANTIALLY 90* ADJOINING THE FACE PLATE AND MATERIALLY STIFFENING AND STRENGTHENING THE FREE EDGE. D R A W I N G

Method for metallizing a ceramic body

Abstract: A method for metallizing a ceramic body comprising coating a surface of the ceramic body with a metallizing composition consisting essentially of 10 to 90 weight parts uncoated molybdenum or tungsten metal particles, 4 to 80 weight parts molybdenum or tungsten metal particles which have an adherent coating of nickel, iron, and/or cobalt metal, and 2 to 27 weight parts ceramic sinter powder. The coated ceramic body is then heated in the range of about 1,100* to 1,500* C. in a reducing atmosphere to produce a sintered metal coating on the ceramic body. Then, the metal coating on the ceramic body may be brazed or soldered to a metal body or to another metallized body.

Electrically heatable elements

Abstract: AN ELECTRICALLY HEATABLE ELEMENT WITH A FILAMENT EMBEDDED IN A FUSED CERMIC MATERIAL HAVING A SOFTENING POINT NOT GREATER THAN 1500*C. HAS A CATALYTIC MATERIAL DEPOSITED ON THE OUTER SURFACE OF THE FUSED CERAMIC. AN ELECTRICALLY HEATABLE ELEMENT WITH A FILAMENT EMBEDDED IN A FUSED CERAMIC MATERIAL HAVING A SOFTENING POINT NOT GREATER THAN 1500*C. HAS A CATALYTIC MATERIAL DEPOSITED ON THE OUTER SURFACE OF THE FUSED CERAMIC. D R A W I N G

Spray process for creating electrical circuits

Abstract: Electrically conductive pathways are applied to a metallic base by means of the plasma flame spray process, which process is also employed to apply an intermediate layer of ceramic insulation. The conductor pattern is formed into a kaolin template through which the powdered copper conductor material is sprayed.

GLASS CONVERTIBLE TO TRANSPARENT GLASS CERAMICS CONTAINING AlPO{11

Abstract: Glass ceramics made from an initial glass composition, in weight percent, of SiO2 : 35-70 Al2O3 : 17-32 P2O5 : 5-17 Li2O : 2-5 MgO : 0-4 ZnO : 0-5 TiO2 : 1.5-6 ZrO2 : 0.5-3 Na2O : traces-0.6 As2O3 : 0.5-1.0, where the P2O5 to TiO2 ratio is up to about 4, and where the sum of ZrO2 and TiO2 is at least about 3 weight percent.

Ceramic fillers and covers for packed beds

Abstract: CERAMIC HONEYCOMB PLACED WITHIN OR ON TOP OF A PACKED BED, AND PARTICULARLY A CATALYTIC BED, IMPROVES THE EFFECTIVENESS OF THE BED. D R A W I N G

Silicon carbide semi-conductor igniter structure

Abstract: Igniter for jet and other internal combustion engines with a hot pressed, ceramic, electrically semiconducting button disposed between a center electrode and a ground electrode to provide a path along which spark discharge occurs. The button consists essentially of particles of silicon carbide bonded together by a ceramic matrix which can be alumina, mullite, forsterite, a glass frit spinel (MgO.A1203), a mixture of magnesium oxide and cobalt oxide, zirconium silicate, silica or the like. An igniter according to the invention is peculiarly adapted for service under severe conditions in an engine having a relatively low voltage (e.g., 3,000 volts All voltages reported herein are in volts DC unless otherwise indicated. or less), high-energy (e.g. 1 to 20 joules) ignition system.

Organic resin ceramic composite and method for making same

Abstract: A composite of organic resin, preferably an elastomer, and ceramic useful for wear-resistant linings for ball mills, conveyors or chutes for abrasive materials, truck bed linings and the like comprising ceramic pieces with metallized surfaces and with the organic resin bonded to the metallized surfaces of the ceramic, the metallized surfaces being applied to the ceramic by contacting the ceramic with metal, preferably titanium or zirconium with sufficient force and relative motion to cause the metal to be bonded to the ceramic.

Drilling device with coolant supply

Abstract: A drilling device adapted to be connected to a source of pressurized gaseous coolant and to a rotary tubular abrasive drill bit adapted to be connected to a source of power for portable use in the drilling of holes in vitreous or ceramic material, such as glass, tile, porcelain, cement, stone, and the like.

Fine grain ceramic ferrites

Abstract: THE INCORPORATION OF CRITICAL AMOUNTS OF MAGNESIUM SULFATE AS A STARTING INGREDIENT RESULTS IN CONTROLLED UNIFORM FINE GRAIN SIZE IN A VARIETY OF CERAMIC MATERIALS PRODUCED BY OTHERWISE CONVENTIONAL CALCINING AND FIRING. CONCERNED COMPOSITIONS INCLUDED MAGNETIC FERRITES OF A TYPE NOT ORDINARILY CONTAINING MAGNESIUM.

Substituting Sites of Rare Earth Ions in BaTiO3

Abstract: The electron spin resonance experiment has been performed in reduced ceramic samples of BaTiO3 containing La3+ ions. A characteristic F-center signal was observed for the Ba/Ti ration of 1.02. This observation of F-center signal indicates strongly that some of doped La3+ ions substitute Ti4+ ions and act as acceptors. The effect of some monovalent and trivalent ions on the substituting sites of Gd3+ ions has been also investigated. It was found that for a low concentration of monovalent ions they formed "pairs" with Gd3+ ions at Ba2+ sites.

The Electrical Conduction of Metal-to-Reduced BaTiO3 Single Crystal Contacts

Abstract: To study the PTC anomaly in semiconductive barium titanate ceramic specimens, some experiments are made with BaTiO 3- x single crystals and a model to explain the results together with the PTC anomaly of ceramic specimens,is proposed The barrier height of a metal-to-BaTiO 3- x contact is hardly influenced by the surface states The resistance through the barrier layer on a c -plate crystal, abruptly increases at the Curie point, while that through the barrier layer on a a -plate crystal decreases The resistivity vs temperature relations of some ceramic specimens show a gradual rise-up at the Curie point It can be explained by the fact that the Curie points are distributed on a wide temperature range owing to the non-uniformity of the grain boundary layers

Metal bonded non-skid coating and method of making same

Abstract: A metal panel suitable for use as an aircraft landing mat. The panel has a rough non-skid coating of ceramic particles prebonded to each other and to the panel by aluminum droplets and bonded with an aluminum coating. The method of making a panel as described, comprising cleaning the surface of a metal panel, spreading ceramic grit thereon, bonding the grit particles to each other and to the metal panel by the impact of a relatively low velocity plurality of heat softened aluminum particles. The final coating is provided by the relatively high velocity electric arc aluminum spray, with other bonding metals and nonskid grit.