Abstract: An impregnated diamond drill bit having a generally cylindrical, hollow crown structure with a lower portion containing diamond particles and a steel shank attached to the crown structure at its upper end. The diamond particles are dispersed within a metal matrix in the lower portion of the crown. Around both the outside circumferential wall and the inside circumferential wall of portions of the crown structure, there are layers of a highly wear resistant material. These layers are formed of a material that is more wear resistant than the material used for the metal matrix in which the diamond particles are dispersed.

Abstract: An impregnated diamond drill bit having a crown containing a plurality of diamond particles. The crown is formed from a fused powdered metallic matrix that includes titanium carbide and a nickel-manganese alloy. The diamond particles are dispersed within the metallic matrix which is then fused so as to hold the diamond particles in place. Although the mixture including the nickel-manganese solid solutions has a lower degree of hardness than that of prior impregnated diamond drill bits, the use of the nickel-manganese alloy improves the retention ability of the metallic matrix for securing the diamonds within the crown. A steel shank is attached to the crown.