Agency of Industrial Science and Technology

Japan As Represented by Director General of Agency of Industrial Science

Other

Tokyo Kokyu Rozai Co., Ltd.

Kazuhisa Shobu

Tadahiko Watanabe

Eiji Tani

Hideki Yamamoto

Yuji Enomoto

Osamu Yagishita

Yukio Kai

Junshiro Hayakawa

Eiichi Sudoh

Morito Akiyama

Hidetoshi Ueno

Akira Kitahara

Yuko Tsuya

Tsuyoshi Doutsu

Tatsuo Tabaru

Hisatoshi Hirai

High temperature oxidation resistant alloy materials and method of producing the same

The present invention provides a dense SiC-infiltrated composite material or a dense carbon-fiber-reinforced SiC-infiltrated composite material and a dense SiC-infiltrated composite material with granular carbon dispersed therein that are unlikely to bond to a carbon crucible and that have excellent heat and oxidation resistance. This composite material can be obtained by infiltrating molten carbon-silicide of Mo that is approximately expressed as Mo.sub.3 Si.sub.2 C or a eutectic mixture of carbon-silicide and silicon carbide into a silicon-carbide-based preform having 10 to 60 vol. % of continuous voids and then cooling and solidifying the melt.

High-temperature ceramics-based composite material and its manufacturing

Disclosed is a method for the preparation of a fiber-reinforced silicon carbide-based composite ceramic body having outstandingly high mechanical strengths even without using any sintering aids or without undertaking the hot-press sintering method. The method comprises impregnating carbon fibers or silicon carbide fibers with a slurry containing an elementary silicon powder, an organic resin, e.g., phenolic resins, and an organosilicon polymer, e.g., polysilastyrenes, according to a specified formulation and shaping the impregnated fibers into a green body which is subjected to a calcination treatment at 1300.degree.-1500.degree. C. in an inert atmosphere under normal pressure.

Method for the preparation of silicon carbide-based composite ceramic

The present invention provides a SiC-MoSi.sub.2 infiltration material with high heat-resistant property, which can be used at 1500.degree. C. under atmospheric condition, can be produced at lower manufacturing temperature, and can maintain high resistance to oxidation. This ceramic composite material with high heat-resistant property can be obtained by infiltrating aluminum silicide of molybdenum, which is expressed by a formula of Mo(Al.sub.x Si.sub.1-x).sub.2 (where 0.1&lt;x&lt;0.5) into a porous preform of silicon carbide having porosity of 10 to 50% in volume ratio.

Ceramic composite material with high heat-resistant property

A novel method is disclosed for the preparation of a silicon carbide-based composite ceramic body reinforced with carbon fibers having an outstandingly high mechanical strength. The method comprises impregnating carbon fibers with a mixture of fine silicon particles and a thermosetting resin such as a phenolic resin to give a carbon fiber compact body impregnated with the mixture, which is then subjected to a heat treatment at about 1400.degree. C. in an inert atmosphere so that the thermosetting resin is thermally decomposed to produce free carbon capable of reacting with the silicon particles without affecting the carbon fibers embedded in the matrix due to the preferential reactivity of the silicon particles with the free carbon produced from the resin thus not to decrease the recinforcing effect of the carbon fibers.

Method for the preparation of silicon carbide-carbon fiber composite

Metallic boride-based ceramics having mechanical properties suited for use in extensive applications as abrasion-resistant and cutting tools are prepared by sintering a mixture essentially consisting of 20 to 88% by weight of one or more metallic borides and 10 to 70% by weight of a powder of zirconium oxide, with 2 to 70% by weight of one or more cubic nitrogen carbides selected from the group of Ti(C, N) and Zr(C, N).

Boride-zirconium oxide-nitrogen carbide-based ceramics

A high density metal-boride based ceramic sintered body consists essentially of component (A) at least one of TiB.sub.2, ZrB.sub.2, CrB.sub.2, HfB.sub.2, VB.sub.2, TaB.sub.2, NbB.sub.2, MnB.sub.2, MoB.sub.2, YB.sub.2, AlB.sub.2, MgB.sub.2, CrB, VB, TaB, NbB, MoB, HfB, YB, ZrB, HfB, TiB, MnB, W.sub.2 B.sub.5 and Mo.sub.2 B.sub.5, componet (B) 0.1 wt. %-10 wt. % based on the total amount of a metal binder comprising at least one of cobalt boride, nickel boride and iron boride, and component (C) 0.1 wt. %-10 wt. % based on the total amount of at least one of a double carbide comprising Ti, Zr, W and C, ZrCN, HfCN, or a double carbo-nitride comprising Ti, Zr, Hf and C, N. The sintered body is not easily oxidized and has extremely few pores and high shock resistance even using a fine grain raw material powder because component (C) has an oxygen removing effect during sintering.

High density metal boride-based ceramic sintered body

A powder of at least one of TiB.sub.2, ZrB.sub.2 and HfB.sub.2 is mixed with at least one of Ti, Zr, Hf, TiB, ZrB and HfB, or with at least one of Ti, Zr, Hf, TiB, ZrB and HfB and a powder of boron, to prepare a mixed powder which can form a sintered product having a boron content of 65 to 67 atom %. Alternatively, a powder of at least one of Ti, Zr, Hf, TiB, ZrB and HfB is mixed with a powder of boron to prepare the mixed powder. The mixed powder may further contain up to a maximum of 30% by weight of a powder of AlN. Then, the mixed powder is sintered to make metal diboride ceramics. The lower-melting metal or compound which the mixed powder contains melts to form a liquid phase and enables the manufacture of a sintered product of high density by a customary sintering operation employing a low temperature. The sintered product having a boron content of 65 to 67 atom % consists solely of metal diboride crystals having a structure of the hexagonal system.

Method of manufacture metal diboride ceramics

The present invention is characterized by a ceramic sintered body consisting of (1) a primary mixed powder in which boride metal powder the MB.sub.2 type or M.sub.2 B.sub.5 type (M indicates the metal) is mixed with a titanium hafnium carbide powder; (2) a secondary mixed powder in which titanium carbonitride is mixed with the above-mentioned primary mixed powder; or (3) a tertiary mixed powder or a quaternary mixed powder in which carbide powder such as hafnium carbide or zirconium carbide is mixed with above-mentioned primary mixed powder or the secondary mixed powder. The resulting sintered bodies have high hardness and toughness.

Titanium hafnium carbide-boride metal based ceramic sintered body

Described herein is a chromium oxide-based ceramic material obtained by sintering a powder mixture consisting of chromium oxide powder and 0.1-90 wt % of chromium carbide powder based on the total amount of the powder mixture. The sintered product has not only a small coefficient of friction over a wide temperature range from normal to high temperature but also excellent deflection resistance and high density with less pores, which are suitable for application as a sliding material.

Chromium oxide-base ceramic material

The present invention is characterized by ceramic materials comprising ceramic sintered bodies consisting of (1) 1-90 wt % chromium carbide and the remainder carbonic titanium nitride; (2) 1-90 wt % chromium carbide, 0.1-5 wt % B.sub.4 C and the remainder titanium carbo-nitride; or (3) either of the above compositions plus less than 95 wt % of a metal boride such as Ti or Zr. Such ceramic sintered bodies are used for cutting tools or wear-resistant machine parts because of their high density, high hardness and high strength.

Sintered titanium carbo-nitride ceramics

Disclosed herein is a method for preparing a homogenized mixture of fine powders of heterogeneous substances or of fine powder and a fibrous component or whiskers, for use as a starting material in the production of a composite metallic material or a composite ceramic material. The invention utilizes chemical vapor deposition which ensures extremely high permeation into narrow spaces in producing whiskers or fine particles, the reaction product of the chemical vapor deposition, in the gaps between individual particles of fine powder or forming coated layers of the reaction product on the surfaces of powder particles to obtain a homogenized mixture of the fine powder and the reaction product.

Method for preparing mixture to be used for production of composite

This invention relates to a high-strength molybdenum silicide-based ceramic material and a process for producing such ceramic material. A powder mixture obtained by adding to titanium carbonitride 0-100% by weight of a specific metal boride compound is added to powder of molybdenum silicide used as base component, and the obtained mixed powder composition is sintered. Both strength and density of molybdenum silicide are increased while maintaining its low-temperature sinterability.

Growing community of inventors

Tosu, Japan

Kazuhisa Shobu