Tosoh Corporation

Kohei Imai

Koji Tsukuma

Hiroyuki Fujisaki

Isao Yamashita

Kiyotaka Kawamura

Shoichi Yamauchi

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

A subject of the invention relates to providing a powder for a translucent zirconia sintered body which is necessary for the production of a zirconia sintered body having a high sintered-body density and high strength and giving an excellent sense of translucency, without conducting any special sintering, such as HIP sintering. The invention relates to a technique for obtaining, through normal-pressure sintering, a translucent zirconia sintered body characterized by comprising zirconia which contains 2-4 mol % yttria as a stabilizer and has an alumina content of 0.2 wt % or lower, and by having a relative density of 99.8% or higher and a total light transmittance, as measured at a thickness of 1.0 mm, of 35% or higher. It is preferred that a powder containing 0-0.2 wt % alumina with a particle diameter of 0.01-0.5 &#x3bc;m, having a BET specific surface area of 5-16 m/g and an average particle diameter of 0.3-0.7 &#x3bc;m, and having a rate of sintering shrinkage in normal-pressure sintering (&#x394;&#x3c1;/&#x394;T; g/cm&#xb7;&#xb0; C.) of 0.0125 or higher but 0.0160 or lower should be subjected to normal-pressure sintering in the atmosphere.

Translucent zirconia sintered body, process for producing the same, and use of the same

A zirconia sintered body having not only high strength but also excellent aesthetic properties. A colored translucent zirconia sintered body, characterized by containing an iron compound and from 2 to 4 mol % of yttria, showing a lightness L* of from 51 to 80 in L*a*b* color system, and having a relative density of at least 99.80%. The colored zirconia sintered body preferably has a total light transmittance of at least 20% as measured at a sample thickness of 1 mm and with a D65 light source. The colored translucent zirconia sintered body has aesthetic properties equivalent to those of natural teeth and is particularly suitable for a zirconia sintered body to be used for dental applications, and further, suitable for a mill blank such as an artificial tooth material or the like, and an orthodontic bracket.

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Ayase, Japan

Kohei Imai