Abstract: A straight, thin, monolithic abrasive wheel formed of hard and rigid abrasive grains and a sintered bond including a metal component and an active metal component exhibits superior stiffness. The metal component can be selected from among many sinterable metal compositions. The active metal is a metal capable of reacting to form a bond with the abrasive grains at sintering conditions and is present in an amount effective to integrate the grains and sintered bond into a grain-reinforced composite. A diamond abrasive, copper/tin/titanium sintered bond abrasive wheel is preferred. Such a wheel is useful for abrading operations in the electronics industry, such as cutting silicon wafers and alumina-titanium carbide pucks. The stiffness of the novel abrasive wheels is higher than conventional straight monolithic wheels and therefore improved cutting precision and less chipping can be attained without increase of wheel thickness and concomitant increased kerf loss.

Abstract: Abrasive tools suitable for precision grinding of hard brittle materials, such as ceramics and composites comprising ceramics, at peripheral wheel speeds up to 160 meters/second are provided. The abrasive tools comprise a wheel core attached to an abrasive rim of dense, metal bonded superabrasive segments by means of a thermally stable bond.

Abstract: A wire saw has a small diameter metal wire and a layer of abrasive grains firmly affixed to the wire surface by a brazed active metal bond. Preferably, the grains are present in a single layer. The grains are disposed on the surface of the wire in a preselected surface distribution. The wire saw can be made by a completely continuous process involving coating the wire with a paste of metal bond powder components combined with a fugitive liquid binder composition. Abrasive grains are deposited into a layer of the paste. Thereafter, the bond composition is fused at elevated temperature to braze the grains to the wire. The abrasive grains can include superabrasive materials, such as diamond and cubic boron nitride. Accordingly, the novel wire saw is suitable for cutting ultra thin wafers ceramic wafers with minimum waste of the work piece.

Abstract: Abrasive tools suitable for precision grinding of hard brittle materials, such as ceramics and composites comprising ceramics, at peripheral wheel speeds up to 160 meters/second are provided. The abrasive tools comprise a wheel core attached to an abrasive rim of dense, metal bonded superabrasive segments by means of a thermally stable bond. A preferred tool for backgrinding ceramic wafers contains graphite filler and a relatively low concentration of abrasive grain.

Abstract: A method for precision cylindrical grinding of hard brittle materials, such as ceramics or glass and composites comprising ceramics or glass, provides material removal rates as high as 19-380 cm.sup.3 /min/cm. The abrasive tools used in the method comprise a strong, light weight wheel core bonded to a continuous rim of abrasive segments containing superabrasive grain in a dense metal bond matrix.

Abstract: An abrasive grit for a metal bonded Single Layer abrasive tool includes abrasive grains coated with a first active component. The active component is mechanically-bound to the surface of the superabrasive grains. Preferably the abrasive is a superabrasive, especially diamond, and the first active component is titanium, either in the form of elemental Ti or TiH.sub.2. The novel grit is made by mixing the first active powder component in a liquid binder to form an adhesive paste; mixing the paste with the abrasive grains to wet the grains, and drying the mixture to adhere active component to the grains. The coated abrasive can be brazed onto a core to form a Single Layer tool, especially with a brazing composition that includes a bronze alloy and small concentrations of a second active component. During brazing the novel abrasive grains provide excellent surface contact with the brazing composition and the braze strongly bind the grains to the tool core.

Abstract: A bond material for a metal single layer abrasive tool, and especially for a tool with diamond abrasive, provides an excellent combination of mechanical properties including structural strength and impact resistance. The bond material is sufficiently compatible with both metal and diamond to effectively wet the abrasive grains and the core of the tool during brazing. The bond material can braze at a temperature range low enough that the core will not distort and diamond grains will not graphitize during brazing. The novel bond material composition contains a copper/tin bronze alloy; elemental titanium; zirconium; hard granular wear resistant particles; and elemental carbon. The wear resistant particles are preferably titanium carbide. Importantly, the bond produced from the material has superior wear resistance while remaining very adhesive to diamond.

Abstract: A composite, polymer bonded abrasive wheel is disclosed for grinding operations and especially for use with multiple station, glass beveling machines. The abrasive wheel breaks in quickly and delivers consistent performance with little or no dressing needed over the entire life of the wheel. In one aspect, the novel abrasive wheel includes a concentrically mounted, annular abrasive rim on a cup shaped hub. The rim can contain an abrasive such as diamond or cubic boron nitride which is embedded in a bonding composition that includes amino aldehyde and phenolic thermoset polymers, a plasticizer, and optionally filler. The hub includes a crosslinkable, strong and rigid, engineering polymer, preferably melamine phenolic thermoset polymer, mixed with spodumene in amount effective to make the coefficient of thermal expansion of the hub match that of the rim. The wheel can be made by simultaneously hot pressing rim and hub preforms and without an additional baking step.

Abstract: A fully dense ceramic-metal body including 40-88 v/o of an oxide hard phase of, in v/o of the body, 4-88 v/o M-aluminum binary oxides, where the binary oxide has a C-type rare earth, garnet, .beta.-MAl.sub.11 O.sub.18, or perovskite crystal structure, and M is a lanthanide or indium, and 0-79 v/o .alpha.-alumina; about 10-50 v/o of a hard refractory carbide, nitride, or boride as a reinforcing phase; and about 2-10 v/o of a dispersed metal phase combining Ni and Al mostly segregated at triple points of the microstructure. The preferred metal phase contains a substantial amount of the Ni.sub.3 Al ordered crystal structure. In the preferred body, the reinforcing phase is silicon carbide partially incorporated into the oxide grains, and bridges the grain boundaries. The body including a segregated metal phase is produced by densifying a mixture of the hard phase components and the metal component, with the metal component being present in the starting formulation as Ni powder and Al powder.

Abstract: Composite materials, articles and cutting tools are prepared by densification to form a body comprising whiskers of hard refractory transition metal carbides, nitrides or carbonitrides uniformly distributed in a two-phase silicon nitride matrix. A first phase comprises silicon nitride grains and the second phase is an intergranular phase formed from one or more suitable densification aids. Optionally, dispersoid particles and/or polycrystalline fibers may also be incorporated. The preferred composite article or cutting tool has a fracture toughness equal to or greater than about 3.5 MPa.m.sup.1/2.

Abstract: 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.

Abstract: A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength. The powder mixture includes 9a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon mitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12m.sup.2 g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified articel an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid.

Abstract: A process for producing a silicon nitride-based article of improved fracture toughness and strength. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12 m.sup.2 /g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid.

Abstract: Single crystal whiskers of carbides, nitrides and carbonitrides of Ti, Zr, Hf, V, Nb, Ta, and W coated with one or more layers of different carbides, nitrides, or carbonitrides of Ti, Zr, Hf, Nb, Ta, or W or oxides of Al, Zr, or Hf. A process for the whisker production is also disclosed.

Abstract: A reactor for producing single crystal metal carbide, nitride, or carbonitride whiskers, where the metal is one or more of Ti, Zr, Hf, Nb, Ta or W. The reactor walls and inner fixtures provide the substrate surfaces, greatly increasing the surface area available for whisker growth. Preferred substrate materials are nickel or high nickel alloy coated with TiC or TiN, or, for carbide or carbonitride whiskers, nickel impregnated graphite. An alternate embodiment provides a collecting chamber and vibrating means to mechanically detach whiskers, allowing for more efficient batch, or continuous operation.

Abstract: A method for coating single crystal whiskers of carbides, nitrides or carbonitrides of Ti, Zr, Hf, V, Nb, Ta, or W with one or more layers of a carbide, nitride or carbonitride of Ti, Zr, Hf, Nb, Ta, or W, or oxides of Al, Zr, or Hf. The method involves flowing past the whiskers at about 1025.degree.-1125.degree. C. a mixture of hydrogen and one of the following gaseous mixtures: Group I comprises one or more of Ti, Zr, Hf, Nb, Ta, or W hhalides mixed with one or more of N.sub.2, NH.sub.3, or suitable free carbon forming aliphatic hydrocarbons. The atomic ratio of carbon and/or nitrogen to metal is about 5:1-16:1, and the volume ratio of hydrocarbon and/or N.sub.2 and/or NH.sub.3 to H.sub.2 is about 1:5 to 1:20. Group II comprises one or more Al, Zr, or Hf halides mixed with one or more suitable oxygen donor gases, in proportions selected to form the desired metal oxide.

Abstract: A cutter bit holder which can be used as a point attack mine tool and a road milling tool is described. The cutter bit holder has a replaceable cutter tip which can be replaced in the field when the cutter tip is worn by unscrewing the flange from the shank of the holder and replacing the worn cutter tip with a new one.

Abstract: A chemical vapor deposition process for producing single crystal whiskers of metal carbides, nitrides, or carbonitrides involving flushing a reaction chamber including a suitable substrate surface heated to 1025.degree.-1125.degree. C., and flowing reactant gases past the substrate to form whiskers. The reactants comprise a halide of Ti, Zr, Hf, Nb, Ta or W and one or more of nitrogen, ammonia and suitable aliphatic hydrocarbons. The atomic ratio of carbon and/or nitrogen to metal is about 5:1 to 16:1; the volume ratio of hydrocarbon and/or nitrogen and/or ammonia to hydrogen is about 1:50-1:20. The preferred substrate materials are nickel or a high nickel alloy coated with TiC or TiN, or, for carbide whiskers, nickel impregnated graphite. The reactor walls and internal fixtures preferably provide the substrate surfaces. A more efficient batch process and a continuous process for whisker growth are disclosed.

Abstract: This invention relates to abrasion resistant materials and to articles of manufacture made therefrom. More particularly, it is concerned with abrasion resistant materials comprising boron doped TiC or boron doped VC distributed in a matrix containing silicon nitride and with articles made therefrom.

Abstract: A coated insert for such drilling tool bits as mine tool roof bits or masonry drill bits. A hard, fracture resistant substrate is coated with one or more thin adherent layers of refractory coating material. The material of each layer is a carbide, nitride, or carbonitride of titanium, hafnium, vanadium, tantalum, or niobium, or an oxide of aluminum or zirconium or a mixture or solid solution of these compounds. Methods for drilling holes in a mine roof or other hard materials are also disclosed.