A turbine nozzle apparatus includes: a vane extending between inner and outer bands, the interior of the vane being open and communicating with an aperture in the outer band, wherein the vane and the bands are part of a monolithic whole of low-ductility material; a metallic baffle inside the vane, the baffle having upper and lower ends and a peripheral wall including a plurality of impingement holes defining an interior space, closed off by an end wall at the lower end; and a metallic retainer having a body with a shape generally matching the shape of the aperture, the body bearing against the upper end of the impingement baffle and being connected to the outer band by a plurality of mechanical fasteners.