Diamond transition layer construction with improved thickness ratio

An insert for a drill bit comprising:

• a metallic carbide body;
• an outer layer of polycrystalline diamond material on the outermost end of the insert, the polycrystalline diamond material comprising a plurality of interconnected first diamond grains and a first binder material and first metal carbide or carbonitride particles in interstitial regions between the interconnected first diamond grains;
• and
• at least one transition layer between the metallic carbide body and the outer layer, the at least one transition layer comprising a composite of second diamond grains, first metal carbide or carbonitride particles, and a second binder material,
• wherein a thickness of the outer layer is greater than a thickness of the at least one transition layer.

An insert for a drill bit comprising:

• a metallic carbide body;
• an outer layer of polycrystalline diamond material on the outermost end of the insert, the polycrystalline diamond material comprising a plurality of interconnected first diamond grains and a first binder material in interstitial regions between the interconnected first diamond grains, the plurality of first diamond grains occupying more than 91.5 volume percent of the outer layer;
• and
• at least one transition layers between the metallic carbide body and the outer layer, the at least one transition layers comprising a composite of second diamond grains, first metal carbide or carbonitride particles, and a second binder material;
• and
• wherein a thickness of the outer layer is lesser than that of the at least one transition layer.