Hitachi Metals, Ltd.

Hitachi Carbide Tools, Inc.

Hitachi, Ltd.

Hitachi Taga Engineering Co., Ltd.

Yusuke Iyori

Hisaaki Ida

Nobuhiko Shima

Yasunobu Ogata

Hideko Fukushima

Tsutomu Iimura

Norio Takahashi

Kenzi Maruta

Toshiyuki Kasakoshi

A cermet alloy having a structure including a hard phase and a bonding phase which is composed of at least one ferrous metal, said bonding phase containing fine hard grains of a mean grain size not greater than 2000 .ANG. dispersed therein. The structure has a composition consisting of 10 to 70 wt % of TiCN, 5 to 30 wt % of WC, 5 to 30 wt % of NbC, 1 to 10 wt % of Mo.sub.2 C, 0.5 to 5 wt% of VC, 0.05 to 3 wt % of ZrC, 5 to 25 wt % of (Ni, Co), and not smaller than 2.5 wt% of total nitrogen and incidental impurities.

Cermet alloy

Aluminum nitride sintered body and semiconductor substrate thereof

This invention provides a method for producing an oxide superconductor which has a uniform texture and is markedly high in sintered density and current density. The method involves the formation of intermediate products from the starting materials. The intermediate products are then used to form the final product. Specifically, to form an oxide superconducting material having a compositional formula

Method for producing ceramic superconducting material using intermediate

This invention provides a cermet alloy improved in toughness high-temperature strength and chipping resistance. This cermet alloy consists essentially of 50-95% by weight of a hard phase of a composite carbo-nitride of at least both of W and Ti and, optionally, one or more elements selected from the group consisting of Groups 4a, 5a and 6a elements of the periodic table, the balance being a binding phase, of an Fe family element or elements and inevitable impurities, said composite carbo-nitride has a rim-and-core structure which comprises a core portion of a composite carbo-nitride poor in Ti and nitrogen, surrounded thereon by a rim portion of a composite carbo-nitride rich in Ti and nitrogen. It is preferred that the hard phase consists of 50% by volume or less of TiN or TiCN particles having N.gtoreq.C and forming no rim-and-core structure and the composite carbo-nitride having the rim-and-core structure.

A tough cermet made from 20-92 weight % of TiC and/or TiCN, 5-50 weight % of WC and 3-30 weight % of an iron-gorup metal. This tough cermet has a three phase grain microstructure and is made is mixing titanium carbonitride powder and up to 70 weight % of the total amount of the tungsten carbide fine powder. The resulting mixture is melted to form a solid solution, pulverized, mixed with the remaining amount of tungsten carbide fine powder, and sintered at temperatures of 1325.degree.-1650.degree. C.

Process for producing a tough cermet

A tough cermet made from 20-92 weight % of TiC and/or TiCN, 5-50 weight % of WC and 3-30 weight % of an iron-group metal. This tough cermet has a three phase grain microstructure consisting of a core phase rich in TiC and/or TiCN, an intermediate phase rich in WC and surrounding the core phase, and an outer phase made of (Ti,W)C and/or (Ti,W)CN and surrounding the intermediate phase. Because of this three-phase microstructure, the cermet has high toughness without sacrificing hardness. It is prepared by using WC powder of as fine as less than 3 .mu.m, without taking the course of forming a solid solution of TiC and/or TiCN and WC and pulverizing it.

Tough cermet and process for producing the same

A ceramic material for cutting tools is provided. The ceramic material has a high thermal conductivity and an excellent resistance to chipping failure and comprises a total of 10 to 40% by weight of titanium boride and titanium carbide, and 0.5 to 10% by weight of zirconia, the balance being alumina and incidental impurities.

Growing community of inventors

Fukaya, Japan

Yusuke Iyori