We have investigated the phase equilibria in (RE)BaCuO/Ag systems, the influence of Ag on the processing of (RE)BaCuO/Ag composites and the resulting properties. YBaCuO/Ag composites have been grown by the modified melt crystallization process with YBa2Cu3O7, Y2O3, Pt and Ag2O in the precursor. The improved strength of the YBaCuO/Ag composites compared with the conventional YBaCuO bulk material permitted us to magnetize these materials to achieve trapped fields up to 16 T (at 24 K) in the gap of a mini-magnet. The investigation of the microstructure revealed a remarkable increase of the spacing between micro-cracks especially of those perpendicular to a/b-planes when 12wt%Ag was added. In the case of SmBaCuO/Ag composites, Ag has a strong influence on processing and causes interactions between RE123 seeds and the sample. We show the growth of single-grain SmBaCuO/Ag composites in air and discuss the influence of post-annealing on increasing Tc and Jc. Furthermore, YBaCuO/Ag composites have been shown to The have the same equilibria in (RE) BaCuO / Ag systems, the influence of Ag on the processing of (RE) BaCuO / Ag composites and the resulting properties. YBaCuO / Ag composites have been grown by the modified melt crystallization process with YBa2Cu3O7 Y2O3, Pt and Ag2O in the precursor. The improved strength of the YBaCuO / Ag composites compared with the conventional YBaCuO bulk material permitted us to magnetize these materials to achieve trapped fields up to 16 T (at 24 K) in the gap of a mini-magnet. The investigation of the microstructure revealed a remarkable increase of of spacing between micro-cracks especially of those perpendicular to a / b-shells when 12 wt% of silver was added. In the case of SmBaCuO / Ag composites, Ag has a strong influence on processing and causes interactions between RE123 seeds and the sample. We show the growth of single-grain SmBaCuO / Ag composites in air and discuss the influence of post-annealing on increasing Tc and Jc. Further, YBaCuO / Ag composites have been shown to