Flame Sprayed Plastic Coatings^★

The history of flame spraying is briefly reviewed. Both guns and powder containers used for applying flame sprayed coatings of plastic powders are described in some detail. Necessary criteria for organic materials both thermoplastic and thermosetting are indicated. Problems involved in producing suitable powders of tough non-friable resins are discussed and indications given of several promising solutions, Properties of flame sprayed Thiokol (a polysulphide synthetic rubber) coatings are reviewed in some detail. Recent work on improvements in flame spraying technique are illustrated by a discussion of the advances in the flame spraying of various polyethylene compounds. This includes comments on current theory, various fuel gas combinations and polyethylene compounding for obtaining specific properties in flame sprayed coatings. Some data is presented on the effect of after-treatments of flame sprayed plastic coatings. Experimental work being done on producing flame sprayed coatings of fluorinated hydro-carbons is described, and a preliminary report given on the properties of these coatings. Recent developments in the technique for producing smooth non-porous coatings of hot melt compositions is discussed in some detail. Procedures developed for producing sprayable powders of hot melt composition and for stabilizing them for storage are described. An indication is given of results obtained to date and probable effect of future developments in this field. In an attempt to indicate how the corrosion engineer can evaluate the suitability of flame sprayed plastic coatings for a particular corrosion problem, the history of several successful applications is reviewed.