A mold assembly for use in forming a component having an internal passage defined therein includes a mold defining a mold cavity therein, and a jacketed core positioned with respect to the mold. The jacketed core includes a hollow structure, and an inner core disposed within the hollow structure and positioned to define the internal passage within the component when a component material in a molten state is introduced into the mold cavity and cooled to form the component. The jacketed core also includes a first coating layer disposed between the hollow structure and the inner core.