A new concept of high energy recovery of dc plasma torch has been developed and applied to the deposition of polymer composites. The heat transferred to low cost fillers, such as alumina or silica injected into the high temperature zone of the plasma, is recovered in the applied polymer coating, which is injected downstream in a much cooler zone of the plasma. The result is a polymer/ceramic composite spraying process having the following benefits: Shrinkage phenomena due to polymer recrystallisation is eliminated, providing a good coating adhesion, a high spray material throughput rate is achieved and die risk of coating polymer combustion is greatly reduced. The polymer composite form decreases the overall costs of coatings and the type of filler employed influences the properties of the composite. Abrasion resistant composites have been produced with alumina and silica fillers (50 wt.%). Medium density polyethylene (MDPE), sprayed with 50 wt.% reinforcement, have shown abrasion resistance as high as UHMWPE. Polymer degradation, abrasion mechanisms and microstructures of these composite coatings are explained.

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