1. A repaired gas turbine blade comprising
a turbine blade having a monocrystalline airfoil made of a first nickel-base superalloy; and
a repair squealer tip welded to a tip of the airfoil, wherein the repair squealer tip is made of a second nickel-base superalloy different from the first nickel-base superalloy and having less than about 0.15 weight percent total of carbon, boron, silicon, zirconium, and hafnium.
2. The repaired gas turbine blade of claim 1, wherein the total of carbon, boron, silicon, zirconium, and hafnium in the second nickel-base superalloy is less than about 0.10 weight percent.
3. The repaired gas turbine blade of claim 1, wherein the total of carbon, boron, silicon, zirconium, and hafnium in the second nickel-base superalloy is less than about 0.05 weight percent.
4. The repaired gas turbine blade of claim 1, wherein the second nickel-base superalloy has a nominal composition in weight percent of about 12.0 percent cobalt, about 6.8 percent chromium, about 1.5 percent molybdenum, about 4.9 percent tungsten, about 2.8 percent rhenium, about 6.35 percent tantalum, about 6.15 percent aluminum, balance nickel, carbon, boron, silicon, zirconium, hafnium, and impurity elements.
5. The repaired gas turbine blade of claim 1, wherein the second nickel-base superalloy has a nominal composition in weight percent of about 14.0 percent chromium, about 9.5 percent cobalt, about 4.0 percent molybdenum, about 4.0 percent tungsten, about 3.0 percent aluminum, about 5.0 percent titanium, balance nickel, carbon, boron, silicon, zirconium, hafnium, and impurity elements.
6. The repaired gas turbine blade of claim 1, wherein the second nickel-base superalloy has a nominal composition in weight percent of from about 7.4 to about 7.8 percent chromium, from about 5.3 to about 5.6 percent tantalum, from about 2.9 to about 3.3 percent cobalt, from about 7.6 to about 8.0 percent aluminum, from about from about 3.7 to about 4.0 percent tungsten, from about 1.5 to about 1.8 percent rhenium, balance nickel, carbon, boron, silicon, zirconium, hafnium, and impurity elements.
7. The repaired gas turbine blade of claim 1, wherein the first nickel-base superalloy has a nominal composition in weight percent of about 7.5 percent cobalt, about 7.0 percent chromium, about 1.5 percent molybdenum, about 5 percent tungsten, about 3 percent rhenium, about 6.5 percent tantalum, about 6.2 percent aluminum, about 0.15 percent hafnium, about 0.05 percent carbon, about 0.004 percent boron, about 0.01 percent yttrium, balance nickel and minor elements or a nominal composition in weight percent of about 12.5 percent cobalt, about 4.2 percent chromium, about 1.4 percent molybdenum, about 5.75 percent tungsten, about 5.4 percent rhenium, about 7.2 percent tantalum, about 5.75 percent aluminum, about 0.15 percent hafnium, about 0.05 percent carbon, about 0.004 percent boron, about 0.01 percent yttrium, balance nickel and incidental impurities.
8. A method for repairing a gas turbine blade, comprising the steps of
furnishing a turbine blade that has been in service, wherein the turbine blade has a monocrystalline airfoil with an airfoil tip, and wherein the airfoil is made of a first nickel-base superalloy;
removing damaged material from the airfoil tip; and
welding a repair squealer tip to the airfoil tip, wherein the repair squealer tip is made of a second nickel-base superalloy different from the first nickel-base superalloy and having less than about 0.15 weight percent total of carbon, boron, silicon, zirconium, and hafnium.
9. The method of claim 8, wherein the step of welding includes the step of providing the second nickel-base superalloy having a total of carbon, boron, silicon, zirconium, and hafnium of less than about 0.10 weight percent.
10. The method of claim 8, wherein the step of welding includes the step of providing the second nickel-base superalloy having a total of carbon, boron, silicon, zirconium, and hafnium of less than about 0.5 weight percent.
11. The method of claim 8, wherein the step of welding includes the step of providing the second nickel-base superalloy having a nominal composition in weight percent of about 12.0 percent cobalt, about 6.8 percent chromium, about 1.5 percent molybdenum, about 4.9 percent tungsten, about 2.8 percent rhenium, about 6.35 percent tantalum, about 6.15 percent aluminum, balance nickel, carbon, boron, silicon, zirconium, hafnium, and impurity elements.
12. The method of claim 8, wherein the step of welding includes the step of providing the second nickel-base superalloy having a nominal composition in weight percent of about 14.0 percent chromium, about 9.5 percent cobalt, about 4.0 percent molybdenum, about 4.0 percent tungsten, about 3.0 percent aluminum, about 5.0 percent titanium, balance nickel, carbon, boron, silicon, zirconium, hafnium, and impurity elements.
13. The method of claim 8, wherein the step of welding includes the step of providing the second nickel-base superalloy having a nominal composition in weight percent of from about 7.4 to about 7.8 percent chromium, from about 5.3 to about 5.6 percent tantalum, from about 2.9 to about 3.3 percent cobalt, from about 7.6 to about 8.0 percent aluminum, from about from about 3.7 to about 4.0 percent tungsten, from about 1.5 to about 1.8 percent rhenium, balance nickel, carbon, boron, silicon, zirconium, hafnium, and impurity elements.
14. The method of claim 8, wherein the step of welding includes the step of furnishing the first nickel-base superalloy having a nominal composition in weight percent of about 7.5 percent cobalt, about 7.0 percent chromium, about 1.5 percent molybdenum, about 5 percent tungsten, about 3 percent rhenium, about 6.5 percent tantalum, about 6.2 percent aluminum, about 0.15 percent hafnium, about 0.05 percent carbon, about 0.004 percent boron, about 0.01 percent yttrium, balance nickel and minor elements or a nominal composition in weight percent of about 12.5 percent cobalt, about 4.2 percent chromium, about 1.4 percent molybdenum, about 5.75 percent tungsten, about 5.4 percent rhenium, about 7.2 percent tantalum, about 5.75 percent aluminum, about 0.15 percent hafnium, about 0.05 percent carbon, about 0.004 percent boron, about 0.01 percent yttrium, balance nickel and incidental impurities.
15. A method for repairing a gas turbine blade, comprising the steps of
furnishing a turbine blade that has been in service, wherein the turbine blade has a monocrystalline airfoil with an airfoil tip, and wherein the airfoil is made of a first nickel-base superalloy;
removing damaged material from the airfoil tip;
identifying a candidate nickel-base superalloy different from the first nickel-base superalloy, wherein the candidate nickel-base superalloy has more than about 0.15 weight percent total of carbon, boron, silicon, zirconium, and hafnium;
preparing a second nickel-base superalloy having a composition of the candidate nickel-base superalloy, except that the second nickel-base superalloy has less than about 0.15 weight percent total of carbon, boron, silicon, zirconium, and hafnium; and
applying a repair squealer tip to the airfoil tip by welding, wherein the repair squealer tip is made of the second nickel-base superalloy.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A charge detecting device comprising a charge accumulating portion that includes a first region of a first conductivity formed on a semiconductor substrate, including one principal surface, a second region of a second conductivity formed in the first region, and a third region of the second conductivity formed between the second region and the principal surface,
wherein the third region is connected to an input terminal of an output circuit, and the entire second region is depleted after a reset voltage for discharging an accumulated charge accumulated in the charge accumulating portion is applied to the third region.
2. The charge detecting device according to claim 1, wherein an impurity concentration of the second region is lower than that of the third region.
3. The charge detecting device according to claim 1, wherein the second region includes a plurality of regions of the same conductivity, and an impurity concentration of a region on a surface side is lower than that of a region placed in a deeper portion with respect to the region on the surface side.
4. The charge detecting device according to claim 1, wherein an area of the third region on the principal surface is equal to or larger than an area of a portion where the second region contacts the third region.
5. The charge detecting device according to claim 1, wherein an impurity concentration of the second region is 2.01016 cm3 or less.
6. A charge detecting device comprising a charge accumulating portion that includes a first region of a first conductivity formed on a semiconductor substrate, including one principal surface, a second region of a second conductivity formed in the first region, and a third region of the second conductivity formed between the second region and the principal surface,
wherein the third region is connected to an input terminal of an output circuit, and the entire second region is depleted immediately after a reset voltage for discharging an accumulated charge accumulated in the charge accumulating portion is applied to the third region.
7. The charge detecting device according to claim 6, wherein the second region is depleted in a period from a time immediately after the reset voltage is applied at least to a time when a saturated charge is accumulated.
8. The charge detecting device according to claim 6, wherein an impurity concentration of the second region is lower than that of the third region.
9. The charge detecting device according to claim 6, wherein an area of the third region on the principal surface is equal to or larger than an area of a portion where the second region contacts the third region.
10. The charge detecting device according to claim 6, wherein an impurity concentration of the second region is equal to or less than 2.01016 cm3.