Abstract: A composite article comprising a metal and an amorphous metal bonded thereto by the explosion, being free from residual stress and compression stress in the amorphous metal portion, and having excellent magnetic properties inherent to the amorphous metal can be obtained by heating a composite article produced by bonding an amorphous metal to a metal through the explosion pressure to remove the residual stress caused in the amorphous metal during the explosion bonding, and then subjecting the heat treated composite article to a plastic working so as to give a tensile stress in the amorphous metal in an amount sufficient to offset the compression stress caused in the amorphous metal due to the heat treatment.

Abstract: An amorphous metal-metal composite article comprising a metal and an amorphous metal thin sheet firmly bonded thereto and having high durability and reliability can be obtained by a method, wherein the surface roughness of a metal to be bonded with an amorphous metal thin sheet is adjusted to a certain surface roughness and an explosion shock is applied to an assembly of the metal and the amorphous metal thin sheet superposed thereon, under a condition that the moving velocity of the collision point of the amorphous metal thin sheet to the metal is higher than the sound velocity in the amorphous metal.

Abstract: A composite sintered compact consisting of a sintered body portion, which contains at least one of high density boron nitride and diamond, and a cermet or metal portion bonded to the sintered body portion through an amorphous metal interposed between the sintered body portion and the cermet or metal portion at their bonding area, has high hardness and strength, and further has excellent handleability, heat resistance and toughness during the whole processes ranging from its production to its consumption.

Abstract: A high-hardness sintered article having high-pressure phase boron nitride as its matrix is manufactured by preparing a mixture consisting of 65 to 95% by volume of a high-pressure phase boron nitride formed of boron nitride of cubic phase having a continuous grain size distribution ranging fom a maximum grain size of 10 to 50 .mu.m to a minumum grain size of less than 1 .mu.m and optionally admixed with wurtzite type boron nitride, 4 to 34% by volume of carbide, nitride or carbonitride of titanim alone or in conjunction with carbide, nitride, or carbonitride of tantalum, and the balance to make up 100% by volume of aluminum and sintering the mixture at a temperature of at least 1,200.degree. C. under pressure of at least 20,000 atmospheres. A high-hardness sintered article is obtained without entailing any loss of hardness during the course of sintering by additionally incorporating in the mixture as 100% 0.

Abstract: Amorphous alloy shaped articles having excellent magnetic properties, high hardness and strength, or high corrosion resistance can be obtained by a method, wherein amorphous alloy or atomized alloy raw material powder layer is laminately arranged adjacently to a metal powder layer having a shock impedance a little different from that of the raw material powder layer, and a shock pressure is applied to the raw material powder layer.

Abstract: A drill bit the point of which has two or more outer cutting edges and is formed with a V-shaped notch. The V-shaped notch has its center lying on the axis of rotation of the drill bit and opens in the direction of feed of the tool. The V-shaped notch defines inner cutting edges terminating in respective outer cutting edges.

Abstract: Diamond can be easily purified from a powdery mixture of diamond and graphite by heating the mixture together with ammonium nitrate and at least one metal oxide of lead monoxide, trilead tetroxide, magnesium oxide and zinc oxide, to oxidize the graphite powder, and removing the oxidized graphite.

Abstract: A high density boron nitride-containing sintered body consisting of 60-95% by volume of high density boron nitride and 40-5% by volume of metal alone or in admixture with a ceramic, which high density boron nitride consists of 60-95% by volume of cubic system boron nitride and 40-5% by volume of wurtzite-structured boron nitride, and which cubic system boron nitride has an average particle size of at least 5 times that of the wurtzite-structured boron nitride. The sintered body has a high cutting performance and is suitable as a cutting tool for chilled roll, ultra-heat resisting alloy, cast iron and the like.

Abstract: A cutting tool having a high wear resistance is disclosed. The cutting tool consists of a plate-shaped body comprising a sintered cermet layer and a sintered body layer containing high density boron nitride or diamond, said sintered cermet layer constituting the center portion of the plate-shaped body and being surrounded and adhered at the side surface or at the side surface and upper and lower surfaces with the sintered body layer.

Abstract: A composite sintered compact containing high density boron nitride, which consists of zincblende-type boron nitride, wurtzite-type boron nitride, ceramic material and metal in a specifically limited mixing ratio and has a high abrasion resistance, can be obtained under a relatively mild sintering condition and can be easily worked into a cutting tool.

Abstract: A sintered compact of boron nitride with high density form having high oxidation resistance, water resistance, compressive strength and hardness can be obtained by sintering wurtzite-structured boron nitride together with a boride of titanium, zirconium or hafnium, or with mixtures thereof under a condition of high temperature and high pressure.