Kyocera Corporation

Takehiro Oda

Yoshihiro Okawa

Shoji Kohsaka

Kenichi Tajima

Kazuhiro Ishikawa

Masahito Nakanishi

Sentaro Yamamoto

Koichi Tanaka

Hideki Uchimura

Nobuyuki Horiuchi

Mizuho Oota

Teppei Kayama

Tomohiro Iwaida

Yuji Higashi

Yoshinori Hirano

Mizuho Ohta

A silicon nitride sintered body comprising &#x3b2;-sialon expressed by a composition formula of SiAlON, wherein z value being the dissolved amount is 0.1 to 1, as a main phase, a grain boundary phase and Fe silicide particles. The grain boundary phase contains RE (Group III elements in the periodic table)-Al&#x2014;Si&#x2014;O, and component ratios of Al, Si and RE in terms of AlO, SiO, REO, respectively is 5 to 50 mass % of AlO, 5 to 20 mass % of SiO, and the balanced amount of REO, the grain boundary phase is contained in a range of 20 volume % or less to 100 volume % of the sintered body, and the Fe silicide particles is contained in 0.02 to 3 mass % in terms of Fe to 100 mass % of the sintered body. Its high thermal shock resistance provides suitable applications to members for molten metal, hot working, and digging.

Silicon nitride sintered body and manufacturing method thereof, member for molten metal, member for hot working, and member for digging

A boron carbide sintered body having a plurality of pores, comprises a boron carbide as a main component and a plurality of graphite particles dispersed in the sinter. The graphite particles is exposed to the pores or is in the vicinity of the pores.

Boron carbide sintered body and method of manufacturing the same and protective body

A silicon nitride sintered material includes a silicon nitride crystal and a grain boundary layer that contains at least two of a first metal silicide (a metal silicide having, as a first metal element, at least one selected from the group consisting of Fe, Cr, Mn and Cu), a second metal silicide (a metal silicide having, as a second metal element, at least one of W or Mo) and a third metal silicide (a metal silicide having a plurality of metal elements including the first metal element and the second metal element), wherein the grain boundary layer has neighboring phase where at least two of the first through third metal silicides exist in contact with each other.

Silicon nitride sintered material and method for manufacturing

The compressive strength of a boron carbide sintered compact is improved by controlling crystals of the boron carbide to a polycrystalline structure having a grain size distribution in which coarse crystals with a grain size of 20 &#x3bc;m or more and fine crystals with a grain size of 10 &#x3bc;m or less are mixed in an appropriate ratio. Furthermore, a protective member having an improved compressive strength can be provided using the boron carbide sintered compact having a polycrystalline structure in which coarse crystals and fine crystals are mixed in an appropriate ratio or a boron carbide sintered compact containing graphite and silicon carbide.

Boron carbide sintered body and protective member

Ceramic granules for producing sintered products of silicon nitride that can be favorably used as structural materials for various heat engines such as automotive parts, gas turbines and the like, and as abrasion resistant materials and corrosion resistant materials. A process for preparing the ceramic granules and a process for preparing sintered products of silicon nitride by using the ceramic granules. Ceramic granules comprise a mixture of a silicon nitride powder, a silicon powder and an assistant, as well as an organic binder, said ceramic granules having an average particle diameter of from 50 to 300 .mu.m and a relative density of from 18 to 30%.

Ceramic granules, process for preparing the same, and process for

A sintered product of silicon nitride containing not smaller than 70 mol % of a .beta.-silicon nitride as well as an element of the Group 3a at least including Lu of periodic table and impurity oxygen, wherein when the content of the element of the Group 3a of periodic table and the content of the impurity oxygen are, respectively, expressed being reckoned as the amount of an oxide of the element of the Group 3a of periodic table (RE.sub.2 O.sub.3) and as the amount of SiO.sub.2 of impurity oxygen, their total amount is from 2 to 30 mol %, the molar ratio (SiO.sub.2 /RE.sub.2 O.sub.3) of the amount of the element of the Group 3a of periodic table reckoned as the oxide (RE.sub.2 O.sub.3) thereof to the amount of impurity oxygen reckoned as SiO.sub.2 is from 1.6 to 10, and the intergranular phase of the sintered product chiefly comprises a crystal phase consisting of the element of the Group 3a of periodic table, silicon and oxygen and a process for producing the same. The sintered product has a large strength from room temperature through up to high temperatures and maintains excellent resistance against oxidation even at high temperatures, and exhibits excellent resistance against creeping and excellent breaking toughness.

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Kirishima, Japan

Takehiro Oda