Andrews and Paule introduced a new class of directed graphs, called broken k-diamond partitions. Let Δ_k(n) denote the number of broken k-diamond partitions of n for a fixed positive integer k. In this paper, we establish new infinite families of congruences modulo 5, 7, 25 and 49 for Δ_k(n) via a standard q-series technique and modular forms.