Fiber-reinforced polymer composites (CFRP) are increasingly used in aerospace for weight-sensitive applications. However, they are subjected to degradation from the erosive forces of solid particles and water droplets. This degradation results in a decreased service life of composite components and increased repair costs. A coating can protect the CFRP surface against wear and plasma spraying could be a candidate technique to achieve this coating. However, an issue is the thermal and mechanical damage to the composite surface by the plasma-sprayed particles. Another issue is the coating adhesion, because of the low wettability of polymer surface to liquid metal and ceramic and different atomistic properties between substrate and coating material. A possible solution to both issues is the use of a primary layer deposited by a “softer” technique than thermal spraying. This study deals with the deposition of this primary layer by three methods (magnetron sputtering, air gun spraying and sol-gel) and the deposition of topcoat layer by plasma spraying. The effectiveness of the protection of the CRFP by the primary layer during topcoat plasma spraying is investigated as well as the interfaces of the duplex coatings.