High temperature imaging media for digital image correlation
A thermal barrier coating is provided. The thermal barrier coating is configured to remain adherent to a substrate under high strains, thus allowing the use of non-contacting strain measurement systems, using digital image correlation for example. The thermal barrier coating may include a first layer of a partially metallic material configured to adhere to a metallic substrate, and a second layer of a partially ceramic material configured to adhere to the first layer. A successful configuration has a top layer thickness that is approximately two-thirds of the first layer thickness.
1. A method of measuring strain in a metallic substrate, the method comprising applying digital image correlation to a metallic substrate having a thermal barrier coating wherein the thermal barrier coating comprises a bond layer disposed on the metallic substrate and a top layer disposed on the bond layer,
wherein the thermal barrier coating further comprises a thermally grown oxide layer disposed between the bond layer and the top layer.
2. The method of claim 1 , wherein the bond layer has a thickness and the top layer has a thickness and the thickness of the top layer is two thirds of the bond layer thickness of the bond layer.
3. The method of claim 1 , wherein the bond layer has a thickness of 0.003 inches and the top layer has a thickness of 0.002 inches.
4. The method of claim 1 , wherein the top layer comprises yttria-stabilized zirconia.
5. The method of claim 1 , wherein the top layer comprises alumina.
6. The method of claim 1 , wherein digital image correlation is applied after the substrate and thermal barrier coating are subjected to a temperature of 1400° F. and a strain of 10-30%.
7. The method of claim 1 , wherein digital image correlation is applied after the substrate and thermal barrier coating are subjected to a temperature of 1400° F. to 1600° F. and a strain of 30-40%.
8. A method of measuring strain in a metallic substrate, the method comprising applying digital image correlation to a metallic substrate having a thermal barrier coating wherein the thermal barrier coating comprises a bond layer disposed on the metallic substrate and a top layer disposed on the bond layer and the top layer has a thickness that is two thirds of a thickness of the bond layer,
wherein the top layer comprises yttria-stabilized zirconia or alumina.
9. The method of claim 8 , wherein the bond layer has a thickness of 0.003 inches and the top layer has a thickness of 0.002 inches.
10. The method of claim 8 , wherein the top layer comprises yttria-stabilized zirconia.
11. The method of claim 8 , wherein the top layer comprises alumina.
12. The method of claim 8 , wherein digital image correlation is applied after the substrate and thermal barrier coating are subjected to a temperature of 1400° F. and a strain of 10-30%.
13. The method of claim 8 , wherein digital image correlation is applied after the substrate and thermal barrier coating are subjected to a temperature of 1400° F. to 1600° F. and a strain of 30-40%.