Advanced Damping Technologies for Small Turbine Engines

The Army’s new turbine engine airfoil designs have the potential of increased high cycle fatigue. The current Phase I SBIR program demonstrated the usefulness of plasma sprayed damping coatings to produce significant damping on Hastelloy X at temperatures between 1000 and 1500 °F. Concentrations of as little as 1% high temperature viscoelastic additives exhibited significant damping. The metal oxide powder blends were successfully plasma sprayed on Hastelloy X test specimens. The coating bond strength and microstructure were essentially unaffected by the incorporation of high temperature viscoelastic materials (VEM's) in the ceramic feed stock. The Phase II SBIR program will investigate in more detail the effect of plasma spray process variables on the plasma sprayed coating’s mechanical and damping properties. In particular, the effect of high “g” loads on the mechanical and damping properties of candidate ceramic/VEM blends will be investigated. The Phase II studies will also include damping, fatigue, erosion, and impact testing. Candidate VEM's will be selected to achieve maximum damping over a range of temperatures between 800 °F and 2000 °F. The plasma spray process is an accepted method of applying high temperature erosion, corrosion, and heat resistant coatings to jet engine components. The Phase II program will demonstrate the ability of plasma sprayed ceramic/VEM coatings to provide damping to military and commercial turbine engines at high temperature.