FAN BLADE WITH ANODE AND METHOD FOR GALVANIC CORROSION MITIGATION
A blade for a gas turbine engine. The blade having: an airfoil formed from a first material; a protective sheath disposed on a leading edge of the airfoil, the protective sheath being formed from a second material, the first material being galvanically incompatible with the second material and the first material being less noble than the second material; a non-conductive material disposed between the protective sheath and the airfoil so that they are electrically isolated from each other; a sacrificial anode in contact with the blade, wherein the sacrificial anode is formed from a third material that is less noble than the first material such that it will corrode before the first material if the non-conductive material disposed between the protective sheath and the airfoil is compromised and the first material and the second material are no longer electrically isolated from each other.
1 . A blade for a gas turbine engine, comprising:
an airfoil formed from a first material;
a protective sheath disposed on a leading edge of the airfoil, the protective sheath being formed from a second material, the first material being galvanically incompatible with the second material and the first material being less noble than the second material;
a non-conductive material disposed between the protective sheath and the airfoil so that they are electrically isolated from each other;
a sacrificial anode in contact with the blade, wherein the sacrificial anode is formed from a third material that is less noble than the first material such that it will corrode before the first material if the non-conductive material disposed between the protective sheath and the airfoil is compromised and the first material and the second material are no longer electrically isolated from each other.
2 . The blade as in claim 1 , wherein the first material is aluminum.
3 . The blade as in claim 1 , wherein the second material is titanium.
4 . The blade as in claim 1 , wherein the third material is zinc or magnesium.
5 . The blade as in claim 1 , wherein the first material is aluminum, the second material is titanium and the third material is zinc.
6 . The blade as in claim 1 , wherein the first material is aluminum, the second material is titanium and the third material is magnesium and wherein the non-conductive material is an epoxy adhesive.
7 . The blade as in claim 1 , wherein the sacrificial anode is secured to a root of the blade.
8 . The blade as in claim 7 , wherein the first material is aluminum, the second material is titanium and the third material is zinc.
9 . The blade as in claim 7 , wherein the first material is aluminum, the second material is titanium and the third material is magnesium.
10 . The blade as in claim 9 , wherein the sacrificial anode is secured to an end portion of the root of the blade.
11 . The blade as in claim 8 , wherein the sacrificial anode is secured to a side portion of the root of the blade.
12 . A gas turbine engine, comprising:
a disk;
a plurality of blades secured to the disk, each of the blades having:
a root, and an airfoil formed from a first material;
a protective sheath disposed on a leading edge of the airfoil, the protective sheath being formed from a second material, the first material being galvanically incompatible with the second material and the first material being less noble than the second material;
a non-conductive material disposed between the protective sheath and the airfoil so that they are electrically isolated from each other; and
a sacrificial anode in contact with the blade, wherein the sacrificial anode is formed from a third material that is less noble than the first material such that it will corrode before the first material if the non-conductive material disposed between the protective sheath and the airfoil is compromised and the first material and the second material are no longer electrically isolated from each other.
13 . The gas turbine engine as in claim 12 , wherein the first material is aluminum, the second material is titanium and the third material is zinc and wherein the non-conductive material is an epoxy adhesive.
14 . The gas turbine engine as in claim 12 , wherein the first material is aluminum, the second material is titanium and the third material is magnesium.
15 . The gas turbine engine as in claim 12 , wherein the sacrificial anode is secured to a root of the blade.
16 . The gas turbine engine as in claim 15 , wherein the first material is aluminum, the second material is titanium and the third material is zinc.
17 . The gas turbine engine as in claim 15 , wherein the first material is aluminum, the second material is titanium and the third material is magnesium.
18 . The gas turbine engine as in claim 15 , wherein the sacrificial anode is secured to an end portion of the root of the blade.
19 . The gas turbine engine as in claim 15 , wherein the sacrificial anode is secured to a side portion of the root of the blade.
20 . A method of protecting a fan blade of a gas turbine engine from corrosion, comprising:
forming an airfoil formed from a first material;
locating a protective sheath disposed on a leading edge of the airfoil, the protective sheath being formed from a second material, the first material being galvanically incompatible with the second material and the first material being less noble than the second material;
electrically isolating the protective sheath from the airfoil with a non-conductive material disposed between the protective sheath and the airfoil; and
placing a sacrificial anode in contact with the blade, wherein the sacrificial anode is formed from a third material that is less noble than the first material such that it will corrode before the first material if the non-conductive material disposed between the protective sheath and the airfoil is compromised and the first material and the second material are no longer electrically isolated from each other.