Methods of forming earth-boring tools

A method of forming an earth-boring tool, comprising:

• forming a plurality of composite particles, forming the plurality of composite particles comprising:
• coating a plurality of nucleation cores having an average particle size between about 2 nm and about 100 nm with a source material comprising at least one of graphite and amorphous carbon;
• and
• coating the at least one of graphite and amorphous carbon with a catalyst material;
• combining the plurality of composite particles with a plurality of grains of hard material and directly contacting surfaces of the plurality of grains of hard material with the catalyst material of the plurality of composite particles;
• after forming the plurality of composite particles, catalyzing the formation of inter-granular bonds between the plurality of composite particles and the plurality of grains of hard material to form a polycrystalline material comprising the plurality of grains of hard material and a plurality of in situ nucleated grains of hard material formed by nucleation of material onto the plurality of composite particles, the plurality of in situ nucleated grains of hard material and the plurality of grains of hard material being interspersed and inter-bonded, the plurality of grains of hard material having an average grain size at least about 150 times greater than an average grain size of the in situ nucleated grains of hard material;
• securing the polycrystalline material to a substrate;
• and
• securing the substrate to a body of an earth-boring tool.