Gte Laboratories Incorporated

Gte Valenite Corporation

Valenite, Inc.

Helmut Lingertat

Steven F Wayne

Sergej T Buljan

J Thomas Smith

Carr L Quackenbush

Anthony P Moschetti

Vinod K Sarin

Frank C Palilla

J Gary Baldoni, Ii

Vincent W Nehring

Gary G Gaudet

Sergei-Tomislav V Buljan

Sergej-Tomislav V Buljan

A dense cermet article including about 44-93% of a granular first hard phase, about 4-44% of a granular second hard phase, and about 2-20% of a metal phase, all expressed in % by volume. The first hard phase consists essentially of alumina and from 0% to less than 5% of one or more oxides selected from magnesia, zirconia, yttria, hafnia, and silica. The second hard phase consists essentially of a hard refractory carbide, nitride, or boride, or mixture or solid solution thereof. Preferred materials for inclusion in the second hard phase are titanium carbide, hafnium carbide, tantalum carbide, tantalum nitride, tungsten carbide, titanium diboride, and boron carbide. The metal phase consists essentially of a combination of nickel and aluminum having a ratio of nickel to aluminum of from about 85:15 to about 88:12, and 0-5% of an additive selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, cobalt, boron, and/or carbon. The preferred metal phase is substantially of the Ni.sub.3 Al ordered crystal structure.

Alumina ceramic-metal articles

A method for machining a high temperature nickel based alloy workpiece or other difficult-to-work material. The method involves machining the workpiece at an effective cutting speed of up to about 1500 sfm per minute, moving a ceramic-metal cutting tool across the face of the workpiece at a rate of up to about 0.04 in/rev, and cutting the workpiece with the ceramic-metal cutting tool to effect a depth of cut of up to about 0.15 inches per pass. The ceramic-metal cutting tool has a density of at least about 95% of theoretical, and includes about 80-98%, preferably 88-96%, by volume of granular hard phases and about 2-20%, preferably 4-12%, by volume of a metal phase. The granular hard phases are (a) a major hard phase portion of alumina and (b) a minor hard phase portion of hard refractory metal carbides, nitrides, carbonitrides, and borides. The metal phase is combination of nickel and aluminum having a ratio of nickel to aluminum of from about 80:20 to about 90:10, preferably 85:15 to 88:12 by weight with optional additives. Preferably, the metal phase is non-continuous and dispersed, and at least a major portion of the metal phase is segregated at hard phase triple points.

Method of machining nickel based superalloys

A dense cermet article including about 80-95% by volume of a granular hard phase and about 5-20% by volume of a metal phase. The granular hard phase consists essentially of a ceramic material selected from the hard refractory carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carboxynitrides, and borides of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, boron, and mixtures thereof. The metal phase consists essentially of a combination of nickel and aluminum having a weight ratio of nickel to aluminum of from about 90:10 to about 70:30 and 0-5% by weight of an additive selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, boron, or carbon, or combinations thereof. In the preferred metal phase, an amount of about 15-80% by volume of the metal phase component exhibits a Ni.sub.3 Al ordered crystal structure. The article may be produced by presintering the hard phase - metal phase component mixture in a vacuum or inert atmosphere at about 1475.degree.-1675.degree. C., then densifying by hot isostatic pressing at a temperature of about 1575.degree.-1675.degree. C., in an inert atmosphere, and at about 34-207 MPa pressure. Limiting the presintering temperature to 1475.degree.-1575.degree. C. and keeping the presintering temperature at least 50.degree. C. below the not pressing temperature produces an article of gradated hardness, harder at the surface than at the core.

Ceramic-metal articles and methods of manufacture

A dense cermet article including about 80-90% by volume of a granular hard phase and about 5-20% by volume of a metal phase. The hard phase is a carbide, nitride, carbonitride, oxycarbide, oxynitride, or carboxynitride of a cubic solid solution selected from W-Ti, W-Hf, W-Nb, W-Ta, Zr-Ti, Hf-Ti, Hf-Zr, V-Ti, Nb-Ti, Ta-Ti, or Mo-Ti. The metal phase consists essentially of a combination of nickel and aluminum having a ratio of nickel to aluminum of from about 90:10 to about 70:30 by weight, and 0-5% by weight of an additive selected from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, boron, and/or carbon. The preferred hard phase is a cubic solid solution of tungsten and titanium. In the preferred metal phase, an amount of about 15-80% by volume of the metal phase component exhibits a Ni.sub.3 Al ordered crystal structure. The article may be produced by presintering the hard phase - metal phase component mixture in a vacuum or inert atmosphere at about 1475.degree.-1675.degree. C., then densifying by hot isostatic pressing at a temperature of about 1575.degree.-1675.degree. C., in an inert atmosphere, and at about 34-207 MPa pressure. Limiting the presintering temperature to 1475.degree.-1575.degree. C. and keeping the presintering temperature at least 50.degree. C. below the hot pressing temperature produces an article of gradated hardness, harder at the surface than at the core.

Ceramic-metal articles

A method for manufacturing a dense cermet article including about 80-95% by volume of a granular hard phase and about 5-20% by volume of a metal binder phase. The hard phase is (a) the hard refractory carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carboxynitrides, borides, and mixtures thereof of the elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and B, or (b) the hard refractory carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, and carboxynitrides, and mixtures thereof of a cubic solid solution of Zr--Ti, Hf--Ti, Hf--Zr, V--Ti, Nb--Ti, Ta--Ti, Mo--Ti, W--Ti, W--Hf, W--Nb, or W--Ta. The binder phase is a combination of Ni and Al having a Ni:Al weight ratio of from about 85:15 to about 88:12, and 0-5% by weight of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Co, B, and/or C. The method involves presintering the hard phase/binder phase mixture in a vacuum or inert atmosphere at about 1475.degree.-1675.degree. C., then HIPing at about 1575.degree.-1675.degree. C., in an inert atmosphere, and at about 34-207 MPa pressure. Limiting the presintering temperature to 1475.degree.-1575.degree. C. and keeping the presintering temperature at least 50.degree. C. below the hot pressing temperature, produces an article of gradated hardness, harder at the surface than at the core.

Method for manufacturing ceramic-metal articles

A steel roughing grade coated cemented carbide cutting tool comprises WC grains equal to or less than 70 w/o of the tool substrate, from about 5 to about 10 w/o of a cobalt bonding phase and the remainder being metal carbide grains selected from the group TiC, TaC, NbC, HfC and combinations thereof. The average WC grain size is from about 0.9 to about 1.3 microns and less than 10% of the WC grains have a size less than 0.5 microns. The coated cemented carbide tool is coated with an adherent refractory coating layer. The coated cemented carbide cutting tool can be used to machine steel at rough and heavy rough cutting conditions.

Coated cemented carbide tool for steel roughing applications and methods

A method of preparing fully dense silicon nitride based ceramic articles comprises the steps of blending a metal oxide component and silicon nitride, wherein a portion of the silicon nitride comprises acicular crystals; comminuting the powder mixture to reduce the aspect ratio of the acicular crystals to an average of less than about 3; pressing the comminuted powder to form a compact; and pressureless sintering the compact to a fully dense ceramic body. Powder mixtures and powder compacts for forming fully dense silicon nitride based ceramic bodies are also disclosed.

Silicon nitride based ceramics and method

Sintered silicon nitride-silica-yttria ceramic articles having silica-rich or yttria-rich casing layers are disclosed. The surface layers are formed by sintering pre-compacted bodies in a powder setter bed to produce unitary sintered bodies having surface layers in which the atom ratio of yttrium to silicon has a smooth gradient from the surface of the article to the interior body of the article.

Sintered silicon nitride ceramic articles having surface layers of

Dense, composite, polycrystalline ceramic articles comprising silicon nitride, silicon dioxide, and yttrium oxide and having thin surface layers of controlled composition are formed by sintering pre-pressed compacts embedded in setter bed powder mixtures having compositions of silicon nitride, silicon dioxide, and yttrium oxide which differ from that of the pressed compact. Employing the method of this invention, articles are produced which have surface layers in which the minor phase of the article is enriched with either yttrium or silicon.

Method of producing dense silicon nitride ceramic articles having

This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, in a reactor charged with a material represented by the formula Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd. In a further aspect of this invention, a gas stream containing hydrogen sulfide or carbonyl sulfide and sulfur dioxide is passed through a reaction chamber charged with Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd, to catalytically produce at a sufficiently elevated temperature elemental sulfur with concomitant reduction of the concentrations of the undesired hydrogen sulfide or carbonyl sulfide and sulfur dioxide.

Catalytic process for removing sulfur dioxide from gas streams

This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, and a catalyst of the formula Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd.

Growing community of inventors

Dorchester, MA, United States of America

Helmut Lingertat