Novel hard compositions and methods of preparation

A precursor mixture useful for producing a very hard composition without requiring cobalt, said precursor mixture consisting essentially of:

• (a) a minor amount of a boron carbide component selected from the group consisting of
• (i) boron carbide and
• (ii) boron and carbon, both present in amounts effective to form boron carbide in situ, wherein said boron carbide is B.sub.4 C;
• and
• (b) a major amount of a second mixture consisting of
• (i) a first amount of a first component which is tungsten,
• (ii) a second amount of a second component which nickel, and
• (iii) a third amount of a third component which is iron,
• wherein said minor amount is an amount corresponding to a weight percent of said precursor mixture within the range from about 2.5 to about 3.0, wherein said major amount is a weight percent of about 100 minus said minor amount, wherein the sizes of particles of tungsten, nickel, iron, and B.sub.4 are on the order of microns, and wherein said tungsten, said nickel, and said iron are present in said second mixture in a weight ratio of 90-95 W:3.5-7 Ni:1.5-3 Fe.

A method of increasing the hardness of an alloy having a rounded grain shape and being formed from a first component selected from the group consisting of molbdenum, tungsten, mixtures thereof, and alloys thereof, a second component which is nickel, and a third component selected from the group consisting of iron, copper, and mixtures thereof, said method comprising:

• (a) combining a minor amount of a powdered boron carbide component selected from the group consisting of
• (i) boron carbide and
• (ii) boron and carbon with a major amount of a powder of said alloy, so as to obtain a combined mixture;
• and
• (b) then subjecting said combined mixture to heat and pressure effective to form a hard, densified composition, wherein said minor amount is a weight percent of said combined mixture within the range from about 1.5 to about 6.3 and wherein said major amount is a weight percent of said combined mixture within the range from about 93.7 to about 98.5.

A method of producing a hard composition, said method comprising:

• (a) mixing powders so as to obtain a first mixture consisting essentially of (1) a first component selected from the group consisting of tungsten, molybdenum, mixtures thereof and alloys thereof, (2) a second component consisting of nickel, and (3) a third component selected from the group consisting of iron, copper, and mixtures thereof, wherein said first component is an amount within the range from about 90 to about 97 weight percent of said first mixture when said first component is tungsten, wherein the sum of the amounts of said second component and of said third component is within the range from about 3 to about 10 weight percent of said first mixture, and wherein molybdenum can be substituted for tungsten on a mole-for-mole basis;
• (b) combining about 1.5 to about 6.3 weight percent of powdered boron carbide with about 93.7 to about 98.5 weight percent of said first mixture, so as to obtain a combined mixture;
• and then
• (c) applying both heat and pressure to said combined mixture effective to form said hard composition.

A method of producing a hard composition, said method comprising:

• (a) mixing powders so as to obtain a first mixture consisting essentially of (1) tungsten, (2) nickel, and (3) iron, wherein said tungsten, said nickel, and said iron are elemental powders;
• (b) combining about 1.5 to about 4.0 weight percent of powdered B.sub.4 C with about 96 to about 98.5 weight percent of said first mixture, so as to obtain a combined mixture;
• and then
• (c) applying both heat and pressure to said combined mixture effective to form said hard composition, wherein said first mixture consists of about 90 to about 97 weight percent tungsten and about 10 to about 3 weight percent of a mixture of nickel and iron having a weight ratio of nickel:iron within the range from about 3.5 to about 1.5.