TaC coatings were plasma-sprayed in a controlled argon atmosphere. The microstructure of the coatings was determined by scanning electron microscopy and transmission electron microscopy. All the lamellae in the coating are formed by a mosaic of columnar grains normal to the interface, perfectly polygonized and jointed. This microstructure can be explained by a crystal growth mechanism in the solid phase (a grain growth mechanism) starting immediately after the solidification of the first lamella.