DEPOSITION AND CHARACTERIZATION OF FLAME- SPRAYED ALUMINUM ON CURED GLASS AND BASALT FIBER-REINFORCED EPOXY TUBES

摘要

An oxy-acetylene flame spray torch was used to deposit thin layers of aluminum onto cured glass and basalt fiber-reinforced epoxy tubes. Surface coatings and layers embedded in composite laminates were produced. Composite specimens were fabricated by filament winding. Composite substrates were grit blasted to promote adhesion of the molten aluminum particles. The investigation showed that adhesion increased significantly when the composite substrate was lightly grit-blasted, as opposed to the adhesion on smooth composite surfaces. The number of passes of the flame spray torch was varied to change the coating thickness and uniformity over the substrate. The electrical resistance of the coatings was measured to assess the suitability of a coating as a conductor. It was found that uniform, electrically conductive coatings were produced with a minimum of two torch passes. Optical images were captured to characterize coating microstructure and thickness. This investigation did not reveal any visible evidence of damage to the composite substrate. To assess possible degradation effects from the blasting and flame spraying, tube specimens were subjected to mechanical testing applying internal pressurization. Tests indicated that the grit blasting and flame spray processes must be carefully executed to mitigate degradation of composite material strength.