Preparation and application method of high-performance boron-free prefabricated slab

The invention discloses a preparation and application method of a high-performance boron-free prefabricated slab. According to the method, a boron-free Ni-Co-Ta-W-Cr-Ti-Al-Nb-Mo-Zr high-temperature alloy boron-free activating agent is involved, and the liquidus of the activating agent ranges from 1140 DEG C to 1170 DEG C. The invention further introduces a use method of the boron-free activating agent, the use method comprises two methods of direct sintering and preparation of a preset plate, the boron-free activating agent is fully mixed with mother alloy powder in a liquid phase form and then directly sintered or prepared into a prefabricated plate, the prefabricated plate is placed or attached to a to-be-repaired part, and the prefabricated plate can be melted and welded again below the solid solution temperature of a base material. During solidification, shrinkage deformation basically does not exist, a repaired area is uniform in structure and free of segregation, holes and other defects, the bonding str