Abrasive diamond composite and method of making thereof

A coated diamond particle for forming an abrasive diamond composite, said abrasive carbon composite comprising a plurality of coated diamond particles, a matrix material with the matrix material forming a skeleton structure containing a plurality of voids and open pores, a braze infiltrated through said matrix material and occupying a plurality of voids and open pores in said skeleton structure, and said braze includes at least 5 weight percent of at least one metal selected from the group consisting of cobalt, nickel, manganese, and iron, or said matrix material includes at least 5 weight percent of at least one metal selected from the group consisting of iron and manganese, said coated diamond particle comprising:

• a diamond crystal having an outer surface;
• and
• a protective coating disposed on said outer surface, said protective coating comprising a refractory material having a formula MCxNy, wherein M is a metal, C is carbon having a first stoichiometric coefficient x, and N is nitrogen having a second stoichiometric coefficient y, and wherein 0≦x, y≦2, and
• wherein said protective coating has a sufficient thickness and is of sufficient quality to provide said diamond crystal resistance from corrosive chemical attack by said matrix material.

An abrasive diamond composite, said abrasive diamond composite comprising a plurality of coated diamond particles, each of said coated diamond particles comprising:

• a diamond having an outer surface and a protective coating disposed on said outer surface, said protective coating being formed from a refractory material having the formula MCxNy, wherein M is a metal, C is carbon having a first stoichiometric coefficient x, and N is nitrogen having a second stoichiometric coefficient y, and wherein 0≦x, y≦2;
• and
• a matrix material disposed on said protective coating of each of said coated diamond particles, said matrix material interconnecting said coated diamond particles and forming a skeleton structure containing a plurality of voids and open pores, said matrix material comprising at least one of a metal carbide and a metal, and
• a braze infiltrated through said matrix material and occupying said voids and open pores;
• and
• wherein said protective coating has a sufficient thickness and is of sufficient quality to provide said diamond crystal resistance from corrosive chemical attack by said matrix material and/or said infiltrated braze and
• wherein said braze includes at least 5 weight percent of at least one metal from the group consisting of cobalt, nickel, manganese, and iron, or said matrix material includes at least 5 weight percent of at least one metal selected from the group consisting of iron and manganese.

An abrasive diamond composite, said abrasive diamond composite comprising:

• a plurality of coated diamond particles, each of said coated diamond particles comprising
• a diamond crystal having an outer surface and a protective coating disposed on said outer surface, said protective coating comprising a refractory material having a formula MCxNy, wherein M is a metal, C is carbon having a first stoichiometric coefficient x, and N is nitrogen having a second stoichiometric coefficient y, and wherein 0≦x, y≦2;
• and
• a braze infiltrating and filling interstitial spaces between said coated diamond particles and contacting said protective layer on each of said coated diamond particles, wherein said braze interconnects said coated diamond particles, said braze includes at least 5 weight percent of at least one metal from the group consisting of cobalt, nickel, manganese, and iron, and
• wherein said protective coating has a sufficient thickness and is of sufficient quality to provide said diamond crystal resistance from corrosive chemical attack by said matrix material and/or said infiltrated braze.

An abrasive diamond composite, said abrasive diamond composite comprising:

• a plurality of coated diamond particles, each of said coated diamond particles comprising
• a diamond crystal having an outer surface and a protective coating disposed on said outer surface, said protective coating comprising a refractory material having a formula MCxNy, wherein M is a metal, C is carbon having a first stoichiometric coefficient x, and N is nitrogen having a second stoichiometric coefficient y, and wherein 0≦x, y≦2;
• and
• a matrix material disposed on said protective coating of each of said coated diamond particles, said matrix material interconnecting said coated diamond particles and forming a skeleton structure containing a plurality of voids and open pores, said matrix material containing at least 5 weight percent of at least one metal selected from the group consisting of iron and manganese, and
• wherein said protective coating has a sufficient thickness and is of sufficient quality to provide said diamond crystal resistance from corrosive chemical attack by said matrix material.

A method for making an infiltrated abrasive diamond composite for use in an abrasive tool, the method comprising the steps of:

• applying a protective coating to an outer surface of a plurality of diamond crystals, thereby forming a plurality of coated diamond particles, wherein the protective coating has a sufficient thickness and is of sufficient quality to provide said diamond crystal resistance from corrosive chemical attack;
• combining a matrix material with the plurality of coated diamond particles to form a pre-form;
• heating the pre-form to a first temperature;
• combining a braze alloy with the pre-form;
• and
• heating the braze alloy and the pre-form to a second temperature, the second temperature being greater than a melting temperature of the braze alloy, wherein the braze infiltrates into the preform, thereby forming the infiltrated abrasive diamond composite and
• wherein said braze alloy includes at least 5 weight percent of at least one metal from the group consisting of cobalt, nickel, manganese, and iron, or said matrix material includes at least 5 weight percent of at least one metal selected from the group consisting of iron and manganese.

A method for making a liquid-infiltrated abrasive diamond composite for use in an abrasive tool, the method comprising the steps of:

• applying a protective coating to an outer surface of each of a plurality of diamonds crystals, thereby forming a plurality of coated diamond particles having a sufficient thickness and of a sufficient quality to provide said diamond crystal resistance from corrosive chemical attack;
• combining a matrix material with the plurality of coated diamond particles to form a pre-form in which the matrix material forms a skeleton structure containing a plurality of voids and open pores;
• placing a braze alloy in contact with the pre-form;
• heating the braze alloy and the pre-form to a first temperature above a melting temperature of the braze alloy, thereby creating a molten braze alloy;
• and
• infiltrating the molten braze alloy through the matrix material and occupying the plurality of voids and open pores with the molten braze alloy, thereby forming the liquid-infiltrated abrasive diamond composite and
• wherein said braze alloy includes at least 5 weight percent of at least one metal from the group consisting of cobalt, nickel, manganese, and iron, or said matrix material includes at least 5 weight percent of at least one metal selected from the group consisting of iron and manganese.