Method for applying a low residual stress damping coating

Abstract

A method for applying a low residual stress damping coating to a surface of a substrate is provided. The method includes heating a ferromagnetic damping material in powder form such that the ferromagnetic damping material is at least partially molten. Next, the at least partially molten ferromagnetic damping material is directed at a surface of the substrate at an application velocity so that it adheres to the surface of the substrate to create a ferromagnetic damping coating on the surface of the substrate, resulting in a coated substrate. The ferromagnetic damping coating has a balanced coating residual stress, including a tensile quenching stress component and a compressive peening stress component. The balanced coating residual stress is within a range of ±50 MPa without having to subject the coated substrate to a high temperature annealing process. The resulting coated substrate exhibits a high damping capacity.

1 . A method to increase the damping of a substrate ( 20 ) having a substrate thickness ( 22 ), comprising:
 a) heating a ferromagnetic damping material in powder form such that the ferromagnetic damping material is at least partially molten;   b) directing the at least partially molten ferromagnetic damping material at a surface ( 24 ) of the substrate ( 20 ) at an application velocity such that the at least partially molten ferromagnetic damping material adheres to the surface ( 24 ) of the substrate ( 20 ) and cools to solidification within a solidification period to create a ferromagnetic damping coating ( 10 ) on the surface ( 24 ) of the substrate ( 20 ), resulting in a coated substrate ( 100 );   c) wherein the ferromagnetic damping coating ( 10 ) has a balanced coating residual stress and the balanced coating residual stress includes at least a tensile quenching stress component and a compressive peening stress component such that the balanced coating residual stress is within a range of ±50 MPa without the coated substrate ever being subjected to an annealing temperature of above 700° C. for an annealing period of longer than 30 minutes; and   d) wherein the ferromagnetic damping coating ( 10 ) has a coating thickness ( 12 ) of about 2% to about 20% of the substrate thickness ( 22 ), and the coated substrate ( 100 ) has a damping loss factor of at least 3.6×10 −3  at a strain amplitude of 0.0466×10 −4  to 7.77×10 −4 .   
     
     
         2 . The method according to  claim 1 , wherein the at least partially molten ferromagnetic damping material is directed at the substrate ( 20 ) at an application temperature of at least 800° C. and the application velocity is at least 450 m/s. 
     
     
         3 . The method according to  claim 2 , wherein the at least partially molten ferromagnetic damping material is directed at the substrate ( 20 ) at a damping material deposition rate of at least 30 g/min. 
     
     
         4 . The method according to  claim 3 , wherein the at least partially molten ferromagnetic damping material is directed at the substrate ( 20 ) at a damping material deposition rate of less than 80 g/min. 
     
     
         5 . The method according to  claim 1 , wherein the ferromagnetic damping material is selected from the group consisting of, by weight percent: about 16 percent chromium (Cr), about 1 percent to about 6 percent aluminum (Al), and the balance substantially iron (Fe); and about 16 percent chromium (Cr), about 1 percent to about 4 percent molybdenum (Mo), and the balance substantially iron (Fe). 
     
     
         6 . The method according to  claim 1 , wherein the ferromagnetic damping material comprises, by weight percent, about 22 percent to about 38 percent nickel (Ni), and the balance substantially cobalt (Co). 
     
     
         7 . The method according to  claim 1 , wherein the substrate ( 20 ) comprises a component of a turbine. 
     
     
         8 . The method according to  claim 7 , wherein the component of the turbine comprises at least one of titanium, titanium-based alloy, steel alloy, nickel, nickel-based alloy, aluminum, and aluminum-based alloy. 
     
     
         9 . A method to increase the damping of a substrate ( 20 ) having a substrate thickness ( 22 ), comprising:
 a) heating a ferromagnetic damping material in powder form such that the ferromagnetic damping material is at least partially molten;   b) directing the at least partially molten ferromagnetic damping material at a surface ( 24 ) of the substrate ( 20 ) at an application velocity of at least 450 m/s such that the at least partially molten ferromagnetic damping material adheres to the surface ( 24 ) of the substrate ( 20 ) and cools to solidification within a solidification period to create a ferromagnetic damping coating ( 10 ) on the surface ( 24 ) of the substrate ( 20 ), resulting in a coated substrate ( 100 );   c) wherein the ferromagnetic damping coating ( 10 ) has a balanced coating residual stress and the balanced coating residual stress includes at least a tensile quenching stress component and a compressive peening stress component such that the balanced coating residual stress is within a range of about ±50 MPa without the coated substrate ( 100 ) ever being subjected to an annealing temperature of above 700° C. for an annealing period of longer than 30 minutes; and   d) wherein the ferromagnetic damping coating ( 10 ) has a coating thickness ( 12 ) of about 2% to about 20% of the substrate thickness ( 22 ), and the coated substrate ( 100 ) has a damping loss factor of at least 3.6×10 −3  at a strain amplitude of 0.0466×10 −4  to 7.77×10 −4 .   
     
     
         10 . The method according to  claim 9 , wherein the at least partially molten ferromagnetic damping material is directed at the substrate ( 20 ) at a damping material deposition rate of at least 30 g/min. 
     
     
         11 . The method according to  claim 10 , wherein the at least partially molten ferromagnetic damping material is directed at the substrate ( 20 ) at a damping material deposition rate of less than 80 g/min. 
     
     
         12 . The method according to  claim 9 , wherein the ferromagnetic damping material is selected from the group consisting of, by weight percent: about 16 percent chromium (Cr), about 1 percent to about 6 percent aluminum (Al), and the balance substantially iron (Fe); and about 16 percent chromium (Cr), about 1 percent to about 4 percent molybdenum (Mo), and the balance substantially iron (Fe). 
     
     
         13 . The method according to  claim 9 , wherein the ferromagnetic damping material comprises, by weight percent, about 22 percent to about 38 percent nickel (Ni), and the balance substantially cobalt (Co). 
     
     
         14 . The method according to  claim 9 , wherein the substrate ( 20 ) comprises a component of a turbine. 
     
     
         15 . The method according to  claim 14 , wherein the component of the turbine comprises at least one of titanium, titanium-based alloy, steel alloy, nickel, nickel-based alloy, aluminum, and aluminum-based alloy. 
     
     
         16 . A turbine component, comprising:
 a) a titanium based substrate ( 20 ) having a substrate thickness ( 22 ), a surface ( 24 ), and a bulk hardness; and   b) a ferromagnetic damping coating ( 10 ) layer affixed to at least a portion of the surface ( 24 ) of the titanium based substrate ( 20 ), thereby providing a coated substrate ( 100 ) and defining a coating-substrate interface, and wherein:
 i) the ferromagnetic damping coating ( 10 ) has a balanced coating residual stress and the balanced coating residual stress includes at least a tensile quenching stress component and a compressive peening stress component such that the balanced coating residual stress is within a range of about ±50 MPa; 
 ii) the ferromagnetic damping coating ( 10 ) has a coating thickness ( 12 ) of about 2% to about 20% of the substrate thickness ( 22 ); 
 iii) the coated substrate ( 100 ) has a damping loss factor of at least 3.6×10 −3  at a strain amplitude of 0.0466×10 −4  to 7.77×10 −4 ; and 
 iv) a hardness of the titanium based substrate ( 20 ) at the coating-substrate interface is within 25% of the bulk hardness. 
   
     
     
         17 . The turbine component of  claim 16 , wherein the ferromagnetic damping coating ( 10 ) comprises a material selected from the group consisting of, by weight percent: about 16 percent chromium (Cr), about 1 percent to about 6 percent aluminum (Al), and the balance substantially iron (Fe); and about 16 percent chromium (Cr), about 1 percent to about 4 percent molybdenum (Mo), and the balance substantially iron (Fe). 
     
     
         18 . The turbine component of  claim 16 , wherein the ferromagnetic damping coating ( 10 ) comprises, by weight percent, about 22 percent to about 38 percent nickel (Ni), and the balance substantially cobalt (Co). 
     
     
         19 . The turbine component of  claim 16 , wherein the titanium based substrate ( 20 ) comprises Ti-6Al-4V alloy. 
     
     
         20 . The turbine component of  claim 16 , wherein the hardness of the titanium based substrate ( 20 ) at the coating-substrate interface is within 5% of the bulk hardness.