Tosoh Corporation

Toyo Soda Manufacturing Co., Ltd.

Nippon Silica Glass Co., Ltd.

Other

Koji Tsukuma

Isao Yamashita

Tomoyuki Akiyama

Takaaki Tsukidate

Hiroya Nagata

Shoichi Yamauchi

Yoshikazu Kikuchi

Masayuki Kudo

Toru Tsuyoshi

Hideaki Segawa

Shinichi Kondo

Hitoshi Nagayama

Kohei Imai

Nobusuke Yamada

Kuniyoshi Ueda

Masayuki Kudou

Keishi Honta

Takeshi Ito

Shinkichi Hashimoto

Seiji Oda

Satoshi Kondoh

Tetsuo Fujii

Yoshitaka Kubota

Naoki Shinozaki

Yoshihiro Matsumoto

Masahiro Watanabe

Hirotoshi Haga

Yushiharu Funakoshi

Emiko Abe

Kouichi Ono

Kenji Kamo

Koichi Orii

Yukinobu Hara

Minoru Kuniyoshi

A composite plate having a thickness of no more than 2 mm, and having laminated therein a zirconia sintered body, an adhesive layer, and a base material, the elasticity of the base material being no more than 100 GPa, and the apparent density of the composite plate being no more than 4.3 g/cm.

Composite plate and production method therefor

A composite plate has a thickness of 2 mm or less, which is obtained by laminating and closely fixing a zirconia sintered body and a fiber-reinforced plastic with each other, and the thickness ratio of the zirconia sintered body to the fiber-reinforced plastic is 0.01 to 1, and the apparent density of the composite plate is 4.3 g/cmor less. A composite plate has a thickness of 2 mm or less, which is obtained by laminating and closely fixing a zirconia sintered body and a fiber-reinforced plastic with each other, and the maximum roughness depth of the surface of the zirconia sintered body is 50 &#x3bc;m or less per 1 cm.

Composite plate and method for producing same

To provide a zirconia sintered body which has at least two different color tones such as white and black, and which has no color bleeding or no gap between sintered bodies. A zirconia sintered body comprising a first zirconia sintered body and a second zirconia sintered body, characterized in that the first zirconia sintered body is a zirconia sintered body containing aluminum oxide; the second zirconia sintered body is a zirconia sintered body containing a spinel oxide; a bonding plane is formed between the first zirconia sintered body and the second zirconia sintered body; and it has no gap or no color bleeding at the bonding plane.

Zirconia sintered body and use thereof

Translucent zirconia sintered bodies have had a problem that incorporation of titania improves translucency but lowers mechanical strength. The invention provides: a zirconia sintered body containing titanium oxide, the sintered body containing 6-15 mol % yttria and 3-20 mol % titania and having an in-line transmission of 50% or higher when examined at a sample thickness of 1 mm and a measuring wavelength of 600 nm; and a zirconia sintered body having especially high translucency which is a high-quality transparent zirconia sintered body that contains 3-20 mol % titania and 6-15 mol % yttria and has an in-line transmission, as measured at a wavelength of 600 nm, of 73% or higher and a haze value of 2.0% or less and that is highly translucent and is undimmed (cloudless). The invention further relates to a production process in which a powder having the composition is molded and thereafter subjected to ordinary-pressure primary sintering and hot isostatic pressing (HIP) under specific conditions.

High-strength transparent zirconia sintered body, process for producing the same, and uses thereof

An object of the present invention is to provide a colored translucent zirconia sintered body having red color and high translucency. The present invention relates to a zirconia sintered body, characterized by containing 6 to 30 mo % of yttria and 0.1 to 5 mol % of cerium oxide in terms of CeO, the cerium oxide containing an oxide of trivalent cerium. The zirconia sintered body of the present invention has, in addition of high hardness, diamond luster based on high refractive index inherent in zirconia, deep red color and transparency.

Red light transmitting zirconia sintered body, method for producing the same, member comprising the sintered body, and jewelry goods and exterior component using the member

A colored translucent zirconia sintered body contains a transition metal element as a coloring agent, having a clear color tone and high transparency, and being excellent in both design properties and esthetic properties, and its production process. A colored translucent zirconia sintered body includes yttria in an amount of at least 6 mol % and at most 15 mol % and at least one member selected from the group consisting of iron, nickel, manganese, cobalt, chromium, copper and vanadium in an amount of at least 0.02 mol % and at most 0.5 mol % as calculated as oxides, and having a porosity of at most 1,000 ppm. The average crystal grain size is preferably at most 60 &#x3bc;m.

Colored translucent zirconia sintered body, its production process and its use

The subject of the present invention relates to obtaining a zirconia sintered body having excellent in both properties of a translucency and a mechanical strength. The present invention relates to obtaining a high-strength zirconia sintered body having a translucency of an in-line transmission of 50% or more at a sample thickness of 1 mm for visible light at a wavelength of 600 nm and an average flexural strength of 300 MPa or more by subjecting a zirconia primary sintered body having an average grain size of 1 &#x3bc;m or less and a relative density of 92% or more and the crystal phase composed of cubic crystals only to HIP treatment at a temperature of 1,250&#xb0; C. to 1,600&#xb0; C. and a pressure of at least 50 MPa. The primary sintered body is obtained by maintaining a molded body of a zirconia powder containing 7 mol % to 30 mol % of yttria at 1,100&#xb0; C. to 1,300&#xb0; C. for at least 5 hrs or by heating the molded body at a high rate of temperature rise of 500&#xb0; C./hr or more.

Transparent zirconia sintered body, method for producing same, and use of same

The invention relates to the use of a sintered body obtained by subjecting a primary sintered body having a relative density of 95% or higher produced from a fine yttria-containing zirconia powder to HIP sintering at a temperature of 1,200-1,600&#xb0; C. and a pressure of 50 MPa or higher. This sintered body is either a sintered body which has a total light transmittance, as measured at a thickness of 0.5 mm, of 43% or higher and a three-point bending strength of 1,700 MPa or higher or a zirconia sintered body which has a total light transmittance, as measured at a thickness of 1 mm, of 40% or higher and a three-point bending strength of 500 MPa or higher and which combines high strength and total light transmission.

Zirconia sintered bodies with high total light transmission and high strength, uses of the same, and process for producing the same

Because fracture toughness and translucency of translucent colored alumina sintered body of the past were low, the alumina sintered body was not suitable for uses such as dental materials, which require high toughness. The present invention relates to providing a translucent colored alumina sintered body that contains transition metal oxides, and with which the fracture toughness is 4.5 MPa&#xb7;mor more and the maximum value of total forward transmittance (sample thickness 1 mm) to a wavelength of 300-800 nm is 60% or more. The present invention relates to obtaining a sintered body, at least 20% of which contains anisotropic grains with a long axis length of 10 &#x3bc;m or greater and an aspect ratio of 1.5 or more by subjecting an alumina sintered body containing transition metal oxides having a eutectic point with alumina or an alumina sintered body containing transitional metal oxides and at least one selected from the group consisting of Group 1A alkali metal oxides, Group 2A alkaline earth metal oxides, and SiO, BO, POand GeOto pressureless sintering and HIP treatment.

Colored alumina sintered body of high toughness and high translucency, and its production method and its uses

A method for producing an orthodontic bracket is comprised of sintering a molded body of highly-pure alumina fine powder at a temperature of 1,200&#xb0; C. to 1,300&#xb0; C. to obtain a sintered body composed of crystals having a relative density of 96% to 99.5% and an average crystal grain size of at most 1 &#x3bc;m, and thereafter subjecting the sintered body to an HIP treatment at a temperature of 1,200&#xb0; C. to 1,350&#xb0; C., under a pressure of at least 50 MPa. Such an orthodontic bracket has high strength and high translucency, can be processed into a complicated shape, similar to that of a metal bracket, and maintains excellent translucency.

Process for producing an orthodontic bracket

An orthodontic bracket is comprised of a translucent ceramic containing at least 99.5 wt % of alumina, and having an absorption/scattering coefficient of at most 2.8 mmfor visible light at a wavelength of 550 nm and a bending strength of, at least 700 MPa. This bracket is obtained, for example, by sintering a molded body of highly-pure alumina fine powder at a temperature of from 1,200&#xb0; C. to 1,300&#xb0; C. to obtain a sintered body composed of crystals having a relative density of from 96% to 99.5% and an average crystal grain size of at most 1 &#x3bc;m, and thereafter subjecting the sintered body to an HIP treatment at a temperature of from 1,200&#xb0; C. to 1,350&#xb0; C. and under a pressure of at least 50 MPa. Such an orthodontic bracket has high strength and high translucency, can be processed into a complicated shape, similar to that of a metal bracket, and maintains excellent translucency.

Orthodontic bracket and process for producing the same

In the conventional alumina sintered bodies, a sintered body having high flexural strength, high toughness and high translucency in combination is not obtained, and a translucent alumina sintered body suitable for a dental material requiring both strength and sensuousness was not obtained. A translucent alumina sintered body having fracture toughness of 4.5 MPa&#xb7;mor more, flexural strength of 350 MPa or more, and all light transmittance (sample thickness: 1 mm) to a visible light having a wavelength of 600 nm, of 60% or more is provided. The sintered body wherein sintered crystal grains are slender plate-like and/or columnar shape having an average aspect ratio of 1.5 or more and an average long axis length of 15 &#x3bc;m or less is preferred.

High toughness translucent alumina sintered body, method for producing the same, and its uses

A primary sintered body having a density of 95 % or more obtained by sintering a zirconia powder comprising an yttria main component as a stabilizer under ordinary pressure is set in a vessel of a semi-sealed state and subjected to HIP treatment (secondary sintering) at a temperature of from 1,600 to 1,900&#xb0; C. under a pressure of 50 MPa or higher, and according to need, heated treated in an oxidizing atmosphere, thereby producing a polycrystalline sintered body of zirconia having high transparency of an in-line transmission of 50% or higher.

Transparent zirconia sintered body

Granular secondary particles of a lithium-manganese composite oxide suitable for use in non-aqueous electrolyte secondary batteries showing high-output characteristics which are granular secondary particles made up of aggregated crystalline primary particles of a lithium-manganese composite oxide and have many micrometer-size open voids therein with a defined average diameter and total volume of open voids. A process for producing the granular secondary particles which includes spray-drying a slurry of at least a manganese oxide, a lithium source, and an agent for open-void formation to thereby granulate the slurry and then calcining the granules.

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Kanagawa, Japan

Koji Tsukuma