Carbon/Carbon (C/C) composites are widely used in thermo-structural components, especially in the aerospace sector. However, carbon has low resistance in ablative environments, limiting its application in thermal protection systems. This problem can be overcome by protecting the composite with passivation layers based on ceramic materials with low catalytic efficiency in reactions with oxygen and nitrogen at high temperatures. In this context, the main objective of this work is the synthesis of thick coatings with a compositional gradient between SiO2/SiC deposited on C/C composites using a new process called High Velocity Solution Plasma Spray (HVSPS). These coatings are formed from reactions between the C/C composite and the Si(OH)4 colloidal solution sprayed by a supersonic plasma jet generated by a direct current torch. The plasma torch has a different design from conventional torches, increasing the interaction time with plasma regions at high temperatures.