Abstract: Calcium phosphates useful as bone substitute material or for the manufacture of prosthetic devices have been prepared from calcium hydroxyapatite material which has a uniformly permeable microporous structure characterized by a substantially uniform pore volume in the range from about 10 to about 90% and by a pronounced three-dimensional fenestrate structure corresponding to the microstructure of the porous carbonate echinoderm or scleractinian coral skeletal material of marine life by reacting said calcium hydroxyapatite material which has a calcium to phosphorus atomic ratio of about 1.

Abstract: A manganite type composition of the formulaMn.sub.3-x-y-z Ni.sub.x Co.sub.y M.sub.z O.sub.4 (I)wherein M is at least one metal selected from Cu, Zn and Cd, y and z range from 0 to 1, and (x+y+z) is lower than 2. This composition can also contain a doping agent. The composition is either a particulate composition wherein at least 90% of the particles have a regular form and a size lower than 5 .mu.M or a ceramic material having a density greater than 94% of the theoretical density. The composition is useful in the production of thermistors.

Abstract: Greenware having improved green strength is prepared using poly(ethyloxazoline) as a binder.

Abstract: A fiber glass is provided for filling in a defect or hollow portion of bone. The fiber glass comprises calcium phosphate as a main ingredient and has a negative zeta potential. The calcium phosphate has a molar ratio of Ca/P of not less than 0.2 and less than 0.6 and the total content of CaO plus P.sub.2 O.sub.5 in the fiber glass is less than 80 wt %. The fiber glass is of long filament form or staple fiber form. The fiber glass of long filament form may be woven to form a woven filler.

Abstract: Suspensions of ceramic or metallic colloidal particles having a high volume fraction (greater than about 55 vol. %) solid particles are provided in a pourable form. The pourable suspension includes at least about 55 vol. % ceramic or metallic colloidal particles, an aqueous vehicle, and an acrylic acid-based polymeric polyelectrolytic dispersant. Such suspensions can be prepared by mixing the colloidal particles in a staged order of addition and under a high shear rate with the other components. The suspensions are suitable for making ceramic or metallic articles, and can exhibit a low viscosity.

Abstract: An investment for dental casting comprises a mixture of at least one refractory selected from alumina, zirconia, magnesia clinker, quartz, cristobalite and fused quartz with either a mixture of a soluble phosphate with magnesium oxide or hemi-hydrate gypsum, which act as a binder. The investment of the invention further contains 0.5 to 5 parts by weight of raw starch (original starch) and 0.1 to 50 parts by weight of at least one selected from the group consisting of carbides, nitrides, borides, silicides and sulfides of transition metals of Groups IV, V and VI in the periodic table, which are added as expanding agents to 100 parts by weight of the aforesaid mixture. The investment of the invention may still further contain 0.1 to 1 part by weight of soluble starch.

Abstract: A metal alcoholate is treated with a quantity of water such that the molar ratio of the quantity of water to the quantity of metal alcoholate is lower than the valency of the metal in the alcoholate.

Abstract: A method and product for coupling the ends of a pair of superconducting cored wires are provided, the core of the wires consisting essentially of a substantially unitary structure of a sintered powered superconducting compound material confined within a tubular element of a metal having an electrical conductivity of at least about 20% of that for pure copper taken as unity which metal forms a clad around the core material. The method comprises providing a pair of superconducting cored wires with the cladding material removed from an end of each of the wires to be coupled together to expose a finite length of said core material. A coupling device comprised of a tubular segment of the same metal as the cladding material is used to join the wires together, the tubular segment having disposed therein a green pellet of the superconducting material. The pellet is positioned inwardly from both ends of the tubular segment to allow for entry of the exposed end of the superconducting cored wires.

Abstract: Disclosed herein are a highly strong implant material having continuous passages in the two-dimensional direction, which is a ceramic material of hydroxyapatite and is useful as the substitutive material for bones in the fields of surgery and orthopedics or the filling material in the cavities of bones in the fields of dentistry and oral surgery, and a process for producing the implant material.

Abstract: A calcium-phosphate type hydroxyapatite which belongs to a series of hexagonal systems has unit lattice constants of 9.58.+-.0.08 .ANG. for the a axis and 7.00.+-.0.05 .ANG. for the c axis. Its Ca/P ratio is in the range of 1.50 to 1.90. It is for use as a column packing material for chromatographic separation of biopolymers. The hydroxyapatite is produced by firing it in the form of a gel or powder at a temperature of 400.degree. to 700.degree. C. As a gel the hydroxyapatite takes the form of a suspension or slurry. A powder is prepared by removing moisture from the hydroxyapatite in the gel form and then drying. Either gel or powder is fired by heating in the presence of oxygen or air at 500.degree. to 600.degree.0 C.

Abstract: The present invention replaces the aluminum oxide in ALCAP ceramics with zinc oxide or zinc sulfate or mixtures thereof to provide a resorbable high strength ceramic. Specifically, a zinc bioceramic is provided comprising about 10 to 50 wt. % zinc oxide or zinc sulfate or mixtures thereof, about 30 to 40 wt. % calcium oxide and about 10 to 40 wt. % phosphorus pentoxide.The zinc based ceramics of the present invention can be used in many of the same applications as hydroxyapatites, tricalcium phosphates and ALCAP ceramics. When mixed with a setting agent, the zinc based ceramics of the present invention are useful as surgical cements or grouts. The zinc based ceramics are also useful as hard tissue substitutes in orthopedic, dental and maxillofacial surgeries and as drug delivery devices.

Abstract: A fluoride-containing bioactive glass composition suitable for bulk implant prosthetic devices and coatings for prosthetic devices, the bioactive glass compositions selected from glass formulations containing, by mole 46.1% SiO.sub.2, 2.6% P.sub.2 O.sub.5, 26.9% CaO and 24.4% Na.sub.2 O and glass formulations containing, by mole, 52.1% SiO.sub.2, 23.8% CaO, 21.5% Na.sub.2 O, 2.6% P.sub.2 O.sub.5 wherein, respectively, 30 to 50 molar percent and 40 to 60 molar percent of the CaO is substituted with CaF.sub.2. These fluoride-containing bioactive glass materials demonstrate high resistance to demineralization in physiological fluids as well as extensive apatite formation which shows a predominance of crystalline apatite of mixed phase character.

Abstract: In a process for forming elements from a slurry that includes particulate ceramic and/or glass, an organic binder resin, and a solvent for the resin, where the element is shaped from the slurry, and the element heated to remove the organic materials of the slurry and subsequently fuse the ceramic and/or glass particles, the improvement comprised of coating the ceramic and/or glass particles prior to forming the slurry with a surface modification compound selected from the group consisting of organo silanes, organo silazanes, titanium chelates, titanium esters, and mixtures thereof.

Abstract: Sintered article suitable for artificial bones, for example, containing a calcium phosphate compound as a main component and additionally containing spinel or magnesium oxide formed by sintering magnesium oxalate dihydrate. This sintered article is produced by adding alumina and silica or magnesium oxalate dihydrate to a calcium phosphate compound and firing the resultant mixture.

Abstract: Toughening agents are produced by the application of high pressure, sufficient to transform a powder material into a denser high pressure polymorph. When the pressure is released, the high pressure phase is retrieved metastably at ambient conditions of pressure and temperature. The amount of high pressure phase retained at ambient conditions depends on the relative hydrostaticity of the pressurized environment and particle size of the powder. The high pressure phase is almost completely retained in a hydrostatic environment. One embodiment of the process of the present invention produces pressure transformation toughened zirconia comprising a high pressure phase having a symmetry no greater than tetragonal (defined as tetragonal II) dispersed within a matrix of a less dense monoclinic phase.

Abstract: A voltage-dependent ceramic resistance (varistor) based on ZnO and other addition elements, mostly in the form of oxides, is prepared, in that the addition elements are added to a suspension of ZnO powder in H.sub.2 O as chemical substances in the form of aqueous, mutually compatible, non-separating solutions of organic salts, acids, complex compounds and/or colloids, the suspension/aqueous solution formed in this manner is dried in the presence of air in a spray dryer, the free-flowing powder/granules prepared in this manner are pressed to a body and the pressed body is subjected to heat treatment, in order to decompose the organic substances, convert them into oxides, remove the decomposition products, and is finally sintered by successive heating to 650.degree. C., 900.degree. C. and 1100.degree. to 1300.degree. C. The water-soluble chemical substances to be used are preferably organic salts such as formates, acetates, lactates, tartrates, citrates, ammonium citrates and ammonium tartrates.

Abstract: A finely divided metal oxide powdery composition, preferably with a narrow particle size distribution, is produced from a particulate, sol-gel derived composition containing agglomerates by heating the particulate composition in the presence of an effective amount of a composition which decomposes upon heating and forms a gas to break at least a portion of the agglomerates so as to yield the desired finely divided ceramic particle composition. Examples of suitable gas-forming agents for use in the present invention include the ammonium salts or amides of organic and inorganic acids, volatile acids, and gases dissolved in a suitable solvent, such as water, alcohol or ammonia.

Abstract: Water soluble precursors of ceramic compounds are emulsified in an organic fluid containing an organic surfactant. The emulsion is subsequently mildly heated at a pressure of about 0.05 atmospheres to remove the free water from the emulsion droplets. The resulting sludge consists of particles deriving from the dehydrated emulsion droplets. These particles may only be bound by the surfactant, all or most of the original organic fluid having been boiling off under low pressure. This sludge is then heated in a standard air atmosphere to char the surfactant, which char is to maintain the separation between the dried droplet-derived particles to prevent forming sintered or fused agglomerates thereof. With continued heating the transient char is subsequently burned off and the particles are calcined to controllably and simply produce a fine ceramic powder of spherical particles having a narrow size distribution and an average size in the particularly useful range of 0.1 micron to 1.0 micron.

Abstract: The invention concerns a therapeutic dressing comprising an elongated flexible permeable support and a mixture of mineral components comprising 16 to 24% by mass of South African bentonite, 16 to 29% by mass of Kaolinite and 47 to 68% total by mass of South African illite and/or attapulgite, which mixture has been rendered into paste-form by the addition of at least an equal part by weight of a liquid mixture comprising 6 to 10 parts by mass of water and 6 to 2 parts by mass of glycerine.

Abstract: This invention relates to a process for reproducibly forming monodisperse titania spheres by the hydrolysis of titanium alkoxides in the presence of an amine containing additive in such a way as to constrain the particle size within a narrow range.

Abstract: This invention provides a novel apatite composite ceramic useful for implants such as artificial dental root, artificial bone or the like. The apatite composite ceramic comprises an interconnected structure of fluorapatite phase and an at least partially crystallized biologically active glass phase, which ceramic is obtained by reaction-sintering at a sintering temperature of 700.degree.-1100.degree. C. at a pressure of at least atmospheric pressure a powder mixture of a synthetic hydroxyapatite (A) and a biologically active glass (B) containing fluoride ions and having a crystallization temperature below the sintering temperature in a weight ratio of A/B ranging from 60/40 to 30/70. The reaction-sintered material has excellent biological affinity and high mechanical strength.

Abstract: A sliding-contact type ceramics article having a high density portion for increasing the mechanical strength of its slide-contact portion with an associated article. A method for manufacturing such a sliding-contact type ceramics article which is characterized in that, at first a compact body having a configuration which is approximate to a final article is molded in such a manner that a slide-contact portion with an associated article is intensively compressed, and then the compact body is grinded to obtain a compact body of a final configuration.

Abstract: The invention disclosed by this application relates to a novel method of processing sinterable powders into sintered ceramic products. This application also relates to novel forms of aluminum oxide, hydroxylapatite, and tricalcium phosphate ceramic products prepared in accordance with the method of this invention, as well as novel intermediate products useful to prepare the novel ceramic products of this invention.

Abstract: A homogeneous composition comprising(1) at least one particulate ceramic material, and(2) a liquid medium, in which the composition comprises at least 50% by volume of particulate ceramic material, in which the particulate ceramic material and liquid medium are selected such that a test composition has a friction coefficient of less than 0.2, and in which the particulate ceramic material has a mean aspect ratio of less than 1.70, a shaped article produced from the composition, a shaped article from which the liquid medium has been removed, and a product in which the particles of ceramic material have been sintered.

Abstract: A printwheel for an impact printer includes a sheet metal core having a central disk portion and a plurality of radially extending arms. Sintered ceramic or metal character slugs are affixed to retaining regions at the ends of the respective character arms. A polymer film jackets the disk portion and adjacent regions of the character arms.

Abstract: The present invention provides a fibrous product of apatite comprising one or more apatites selected from a group of apatites represented by the general formula:M.sub.10 (ZO.sub.4).sub.6 X.sub.2wherein M represents Ca, Ba, Mg, Sr, Pb, Cd, Fe and the like, ZO.sub.4 represents PO.sub.4, AsO.sub.4, VO.sub.4, CO.sub.3 and the like, and X represents F, Cl, OH and the like. This fibrous product of apatite has many applications such as uses for medical treatment, large scale microorganism cultivating media and others, and particularly it is useful as apatite implant materials having a good compatibility with living organism and superior workability.A fibrous apatite product of this invention may be produced by a method comprising the steps of:(a) preparing a dispersion of apatite by dispersing fine apatite particles uniformly in a solution of binder in water, said apatite being one or more apatites selected from a group of apatites represented by the general formula:M.sub.10 (ZO.sub.4).sub.6 X.sub.

Abstract: A porous ceramic material composed of a sintered porous body of a calcium phosphate compound is described. A multiplicity of capillary void paths having a diameter of 1 to 30 .mu.m and a multiplicity of pores having a diameter of 1 to 600 .mu.m are formed in the sintered porous body. At least part of the pores are connected to the exterior space of the sintered porous body through at least a part of the capillary voids. The porous ceramic material is valuable as a medical material, e.g., a substitute or prosthesis for bone or dental root, and also an electronic material and a genetic engineering material.When the porous ceramic material is embedded in a bone defect of human or animals, osteolytic cells, osteoblasts, erythrocytes and body fluid are selectively allowed to intrude through the porous ceramic material while almost no intrusion of osteoclasts and collagen fibers is allowed.

Abstract: An improved process and apparatus for producing sintered material such as dead burned clay, dolomite, magnesite or periclase with the highest particle specific gravity capable from each material. A grinding mill produces raw material which is 100% minus 20 mesh. The ground raw material is supplied to a suspension type preheater and then to a stationary flash calcining system where the material is soft burned at temperatures in the range of 1000.degree. to 1200.degree. C. From the calcining system, the calcined material is immediately supplied to hot briquetting machine where briquettes or nodules are formed. The hot nodules at a temperature of approximately 800.degree. C. are then immediately supplied to a rotary kiln which serves as a sintering furnace where the soft burned material is dead burnt at a temperature in the range of 1650.degree. to 1850.degree. C. Hot spent combustion gas from the sintering furnace is supplied to the calcining furnace to serve as preheated secondary air for combustion.

Abstract: A process for producing a ceramic body suitable for surgical implantation that has high strength and toughness and good compatibility with bone material. A porous material is provided by semi-sintering a ceramic compact. The pores in the surface of the porous material are filled with a first powder of either tricalcium phosphate or apatite or both, or with a material of the fine powder and a powder of a material substantially the same as the material of the ceramic compact. The porous material is then fired at the sintering temperature of the ceramic compact. Following sintering, the surface of the porous material is coated with a fine apatite powder or a finally pulverized mixture of apatite and a calcium phosphate base frit. The resulting assembly is then fired at a temperature up to about 1,350.degree. C.

Abstract: A ceramic is fabricated by dispersing ceramic particles in a liquid, sedimenting the dispersion to remove large particles, and then changing its pH to flocculate the dispersed particles. The size distribution of the particles in each individual floc is similar to the size distribution of particles throughout the dispersion. The supernate is removed and the flocs are cast by centrifuging them into a mold. The cast flocs are dried and sintered to form the ceramic. To provide a multiphase ceramic, particles of two or more ceramics can be mixed together and flocced prior to centrifuging.

Abstract: An implanting article which includes a base body composed of a mother material and a surface portion containing dispersed apatite particles. The base body and surface portion are formed in a mold by solidifying the mother material containing apatite particles under centrifugal force. The resulting implanting article has good mechanical properties because the base body scarcely includes apatite particles in addition the article has a good affinity with a live body because the surface portion contains apatite particles densely distributed thereat.

Abstract: An aqueous solution of precursors for biologically active glass, support particles coated with the solution, support particles coated with the glass, spheroidal particles of biologically active glass, processes for making the solution, coating the support, and for making the coated support and the spheroidal glass particles. The materials that comprise the biologically active glass are useful in prosthetic devices and implants for the human body.

Abstract: Sub-micron sized powders of the ceramic metal oxides such as zirconia, alumina, titania, etc. are produced by precipitation upon mixing aqueous or aqueous/organic solutions of salts of the corresponding metal(s) with substantially 95% solutions of ammonia donors such as hexamethylenetetramine which are capable of reacting with water to give ammonia. The precipitates are treated with an alkali metal hydroxide to remove adsorbed organic matter, neutralized after completion of this treatment with acid, then washed with ammoniated water to remove any residual soluble salt and/or organic matter, dried, and calcined. The powders thus produced are readily sintered to high density ceramic bodies after conventional pressing or casting into a desired shape.The process is especially suited to the production of zirconia powders, either pure or doped with conventional stabilizing oxides such as yttria, magnesia, or lime.

Abstract: The disclosure relates to a feedstock of particulate material for use in formation of articles therefrom, the feedstock including a homogeneous combination of large particles, small particles and a binder. The large particles comprise less than about 60% by volume of the feedstock and are defined as particles having a diameter greater than their diffusion length. The fine particles and binder combined comprise more than about 40% by volume of the feedstock, the fine particles being defined as particles having a diameter less than their diffusion length.

Abstract: A method of manufacturing ceramic sintered bodies. A basic starting material corresponding to the sintered body is mixed with compounds which form a melting phase with the starting material during sintering. Prior to the sintering, presintered starting material nuclei having an average crystallite size which corresponds at least three times the average crystallite size of the basic starting material are added to the basic material and melt-forming compounds. The nuclei are added in a quantity of at least 0.1% by weight of the starting material to be sintered. By this addition the grain size and grain distribution in the ceramic sintered body of materials with discontinuous grain growth can be effectively checked and controlled.

Abstract: A process for preparing a porous ceramic thin film which comprises applying an anhydrous solution containing an organometallic compound and a multifunctional organic compound to a substrate, and thermally decomposing the compounds. The porous ceramic thin film prepared by the process has pores of not more than 10 .mu.m in pore size, and is useable as for materials of various sensors.

Abstract: A method for preparing reversible-photochromic magnesium oxide (MgO) crystals. Single crystals of MgO doped with both lithium (Li) and nickel (Ni) are grown by a conventional arc fusion method. The as-grown crystals are characterized by an amber coloration. The crystals lose the amber coloration and become photochromic when they are thermochemically reduced by heating at temperatures greater than 1000.degree. K. in a hydrogen atmosphere. Alternate irradiation with UV and visible light result in rejuvenation and bleaching of the amber coloration, respectively.

Abstract: UO.sub.2 particles are brought into contact with liquid water of low pH in an oxidizing environment to dissolve uranyl hydroxide from the particle surfaces and cause more uranyl hydroxide to form and be dissolved. When sufficient uranyl hydroxide has entered the solution, the pH is raised to cause uranyl hydroxide to leave the solution and deposit on the UO.sub.2 particles. The particles are then ready for contact with an appropriate reactant to form a fugitive binder.

Abstract: Novel aqueous inorganic particle slurries, wherein some of the particles have had their charge potential altered to a sufficient extent to prevent segregation or settling of the particles, are described, along with a method for their preparation. The method of forming slurries of negatively charged particles comprises treating some of the particles with a cationic agent to reduce their charge and mixing these treated particles with the remainder of the particles to form a thick, cream-like flowable composition of a thixotropic nature. When slurries of positively charged particles are to be formed, an anionic agent is used instead of a cationic agent.

Abstract: A method of reoxidizing a partially-reduced ceramic. The partially reduced eramic is heated in a chamber having a non-oxidizing atmosphere. An oxidizing gas is then introduced into the chamber at a rate which is sufficiently slow that cracking will not occur.

Abstract: A process for sintering or reaction sintering ceramic or refractory materials with hot plasma gases. The hot plasma gases are produced by injecting a combined primary plasma arc with a secondary gas stream directly into a reaction furnace. The secondary gas stream is tangentially injected into the primary plasma arc gas stream to mix the gases for the required sintering temperature at the highest energy efficiency. The plasma torches are positioned in the furnace ports so that the plasma gas flow is perpendicular to the furnace process gas flow. This process is inexpensive and efficient and results in a superior quality sintered product. It may be adapted to continuous or periodic kilns to achieve a high furnace productivity.

Abstract: This invention relates to hydroxyapatite, ceramic material, implant material and a process for preparing thereof. The ceramic material is hydroxyapatite ceramic having an excellent thermal stability.

Abstract: Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

Abstract: A thin film magnetic material assembly for a magnetic head which has a non-magnetic substrate material and a magnetic metallic film vapor deposited thereon. The substrate material has a thermal coefficient of expansion approximating that of the magnetic metallic film. The substrate has a NaCl lattice structure and a composition represented by the formula Ni.sub.x Mn.sub.2-x O.sub.2 where 0.25.ltoreq.x<1. The substrate can optionally contain not more than 10% by weight of at least one of the group Al, Cr, Si, Sn, Ba as a secondary component. The magnetic metallic film most suitable in connection with the present invention is Fe-Ni, Fe-Al-Si or similar based alloys.

Abstract: A method of making a silicon metal containing article is characterized in the following steps. A water vehicle first slurry is formed which contains silicon metal particles, this first slurry being substantially free of ions which would cause a flocculation of the silicon metal particles. An organic vehicle based second slurry is formed which contains a compound which has an ion which would cause flocculation of silicon metal particles contained in a water vehicle slurry. The organic vehicle of said second slurry, however, is effective to suppress formation of ions by the ion forming compound. The first and the second slurries are added to form a castable silicon metal particle containing slurry in which the compound contained in the organic vehicle can form ions when in contact with the water vehicle. The castable silicon metal particle containing slurry is introduced into a casting mold.

Abstract: There are provided a novel sintered apatite body and a novel sintered apatite-mineral fiber material composite. The crystals of the sintered apatite have fine dense crystalline structures comprising needle-like fine crystals and are entangled together, whereby the mechanical properties of the sintered apatite body or composite are markedly enhanced. The sintered body and composite wherein the apatite is hydroxyapatite are useful for bioceramic uses. The sintered apatite body or composite is produced by baking an apatite material alone or in contact with a reinforcing mineral fiber material in the presence of water under pressure at a temperature lower than 1000.degree. C., and further at a temperature lower than the temperature causing deterioration of the fiber material in the case of the composite.

Abstract: Sub-micron sized powders of the ceramic metal oxides such as zirconia, alumina, titania, etc. are produced by precipitation from substantially anhydrous solutions of salts of the corresponding metal(s) with substantially anhydrous solutions of alkali metal hydroxides. The precipitates are subsequently washed with water to remove any residual soluble salt and/or solvent, then are dried and usually calcined. The powders thus produced are readily sintered to high density ceramic bodies after conventional pressing into the desired shape.The process is especially suited to the production of zirconia powders, either pure or doped with conventional stabilizing oxides such as yttria. In a typical example, a zirconia powder doped with 5.4% by weight of yttria is prepared by adding a solution of zirconium tetrachloride and yttrium chloride in anhydrous ethanol to a solution of sodium hydroxide in anhydrous ethanol. After washing, drying at 105.degree. C., and calcining at 500.degree. C.

Abstract: A filler for filling in defects or hollow portions of bones to coalesce with the bone tissues is provided which comprises powders of a calcium phosphate compound having the apatite crystalline structure of each crystallite size of 400 .ANG. or larger and of each crystal grain size of 3 .mu.m or smaller, said calcium phosphate compound being represented by the following general formula of Ca.sub.m (PO.sub.4).sub.n OH (1.33.ltoreq.m/n.ltoreq.1.95), and said powders being fluidized or plasticized.

Abstract: Coating for carbon electrodes used as anodes in the electrolysis of alumina to produce aluminum are disclosed. The coatings are aqueous and contain zinc chloride and powdered alumina.

Abstract: What is disclosed is a method of preparing carbon-containing monolithic glassy ceramics from organosilsesquioxanes, metal oxides and metal alkoxides through pyrolysis of their gels. Also disclosed are certain gel compositions used in the method and the glassy ceramics.