A repetitive combustion coating apparatus for applying coatings of particulate materials such as powdered tungsten carbide and other metal alloys by discharging discrete quantities of material encapsulated in an elongated tape into a combustion chamber and igniting a fuel-air mixture therein to deliver the charge of combustion gases and entrained particulate material through a nozzle to impact the article to be coated. The apparatus includes a rotary indexing wheel over which the encapsulated tape is trained with the spaced apart capsules nested in circumferentially spaced supporting receptacles. The indexing wheel is mounted on support arms which permit limited linear reciprocation so that a ratchet mechanism incrementally indexes the wheel and permits linear movement of the wheel to successively clamp the tape capsules against a clamping die. High pressure gas is introduced through a support spindle for the indexing wheel and internal passages in the wheel to burst a capsule and deliver a charge of particulate material into a combustion chamber. The indexing of the wheel is controlled by a detent mechanism to compensate for dimensional variations in the various structural parts of the apparatus. A control system provides a timed sequence of events to deliver a charge of fuel-air mixture to the combustion chamber as well as a charge of particulate material and ignition of the mixture.