Agency for Defense Development

Yong Kee Baek

Hyoun-Ee Kim

Eul Son Kang

June Ho Park

Seung Su Baek

Sung Min Lee

Ki Min Lee

Won Ho Lee

Suk-Joong L Kang

Jong Uk Yoon

Sang Ju Kwak

Young Hak Ko

Hak Sung Park

Eul-Son Kang

The present invention relates to a titanium diboride sintered body and a method for manufacturing thereof wherein silicon nitride is added to a titanium diboride as a sintering aid. The sintered body according to the present invention has a fine structure and excellent physical characteristics such as a strength, hardness, etc. Therefore, the sintered body according to the present invention may be applicable to certain materials which requires high strength and hardness.

Titanium diboride sintered body with silicon nitride as a sintering aid

The present invention relates to a high strength light-weight ceramic insulator and a method for manufacture thereof wherein the light-weight ceramic insulator may be used at a high temperature by using a heat-resisting ceramic fiber. A colloidal silica or colloidal alumina which is an inorganic binder, and a methyl cellulose or a liquid-phase organic polymer which is an organic binder are added to an alumina-silica-based fiber containing zirconia, a concentration thereof is adjusted, a slurry is vacuum-molded, and drying and heating are carried out, thereby fabricating the ceramic insulator. Here, it is possible to fabricate the high strength light-weight ceramic insulator by artificially selectively positioning the inorganic binder to a contact point of the fibers.

High strength light-weight ceramic insulator

Titanium diboride sintered body with silicon nitride as a sintering aid and a method for manufacture thereof

A silicon nitride sintered body is obtained by mixing 2.about.16 wt % of Yb.sub.2 O.sub.3 as a sintering additive with Si.sub.3 N.sub.4 powders including unavoidable impuirities, pressing the mixed powder into a desired form, and gas-pressure sintering the thusly pressed form, whereby an inner region of the sintered body has a fine microstructure, and an outer region thereof has a mixed microstructure in which elongated grains and fine grains co-exist and a method for manufacturing a silicon nitride sintered body, includes the steps of: adding and mixing 2.about.16 wt % of Yb.sub.2 O.sub.3 powder as a sintering additive into a silicon nitride (Si.sub.3 N.sub.4) powder; ball-milling the mixed powder to obtain a slurry; drying and classifying the slurry; press-forming the resultant powder in a die uniaxially and isostatically; and gas-pressure sintering the resultant compact body at a temperature in the range of 1800.about.2000.degree. C., whereby an inner region of the resultant sintered body has a fine microstructure, and an outer region of the resultant sintered body has a mixed microstructure in which elongated grains and fine grains co-exist.

Silicon nitride sintered body with region varying microstructure and

A method for strengthening and aging-prevention of a TZP ceramics includes the steps of: introducing TZP ceramic and Si-based ceramic powders into a furnace in which a water vapor pressure is controlled; and exposing the TZP ceramic next to Si-based ceramic in a flowing H.sub.2 atmosphere containing H.sub.2 O of no more than 0.1%, to form a silica/zircon layer on the surface of the TZP ceramic.

Method for strengthening and aging-prevention of TZP by formation of

A sialon composite and fabrication method thereof in which the phase of a surface layer thereof is modified differently from that of the bulk. The surface layer is modified to .alpha.-sialon or .alpha.-.beta. sialon composite but the bulk is .beta.-sialon. Also, the surface layer is modified to .beta.-sialon or .alpha.-.beta. sialon composite but the bulk is .alpha.-sialon.

Method of producing a surface modified sialon composite

Growing community of inventors

Taejon, South Korea

Yong Kee Baek