In a Ni-based, Co-based, or Ni—Co-based braze alloy (1) for high-temperature brazing of components (7) of modular structure and for repairing damaged components (7) which are formed of single crystal or directionally solidified superalloys using said braze alloy (1), the braze alloy has a first metallic powder component (2) having particle sizes in the nanometer range and a second metallic powder component (3) having particle sizes in the micrometer range. The surface of the particles of the second powder component (3) is thinly coated with particles of the first powder component (2). The braze alloy (1) additionally includes grain boundary stabilizing elements as alloying elements. In addition, melting point depressants can be present in the braze alloy (1) in a commercially common quantity or with a considerably increased proportion. Both the melting temperature of the braze alloy (1) and the probability of recrystallization are advantageously reduced.