Removal of Thermally Sprayed Coatings Using a Plain Water Jet

Abstract

A plain water jet is applied for the removal of plasma sprayed Al2O3 and ZrO2 coatings on stainless steel (JIS SUS304) substrates. The water jet impinges perpendicularly to the surface of the specimen with a constant traverse rate of VT = 150 or 300 mm/min. The jet pressure (Jp = 70-300 MPa) and the standoff distance (Ds = 5-30 mm) are systematically varied. The flow and erosive properties of the water jet are experimentally investigated to avoid unwanted erosion of the substrate. Particle image velocimetry (PIV) analysis is also applied, but only for lower jet pressure (less than 10 MPa) conditions. The results show that coating removal is significantly dependent on the material properties, especially the adhesion strength and porosity. Coating removal is successfully achieved within the present experimental conditions. The reported data suggest that the water jet process is a useful method for coating removal, although further verification and understanding of the fracture mechanisms are required.

Keywords

• plain water jet
• erosive properties
• thermally sprayed coatings
• coating removal