Jacket impeller with functional graded material and method

1. An impeller for use in a compressor, the impeller comprising:

a disk section which is made from a carbon steel;

a counter disk section which is made from the carbon steel;

a plurality of blades made from the carbon steel in contact with the disk section and the counter disk section;

an intermediate layer attached on surfaces which are in a process gas flow path of the disk section, the counter disk section and the plurality of blades, wherein the intermediate layer is attached via a hot isostatic pressing, resulting in a porosity of generally less than one percent and a coefficient of thermal conductivity between a coefficient of thermal conductivity for the carbon steel and an external layer; and

an external layer attached to the intermediate layer via a hot isostatic pressing, the external layer having a porosity less than once percent after hot isostatic pressing and being corrosion resistant.

2. A method for manufacturing an impeller to be used by a compressor, the method comprising:

attaching a first layer to an insert, wherein the first layer is corrosion resistant after hot isostatic pressing;

attaching a second layer to the first layer, wherein a coefficient of thermal expansion of the second layer is between a coefficient of thermal expansion for a base metal and the first layer;

attaching a combination of the insert, the first layer and the second layer to the base metal such that the second layer and the base metal are in contact;

processing the insert, the first layer, the second layer and the base metal via hot isostatic pressing such that the second layer is bonded to the base metal, the first layer and the second layer are bonded and both the first layer and the second layer have a porosity of generally less than one percent; and

removing the insert to form the impeller.

3. A method for manufacturing an impeller to be used in a compressor, the method comprising:

attaching an intermediate layer to a base metal by placing a first metal powder into a gap between a first insert and the base metal;

processing with hot isostatic pressing the base metal, the first metal powder and the first insert such that the intermediate layer is bonded to the base metal, the intermediate layer having a porosity of generally less than one percent, wherein a coefficient of thermal expansion of the intermediate layer is between a coefficient of thermal expansion for the base metal and an external layer;

removing the first insert;

attaching an external layer to the intermediate layer by placing a second powder into a gap between a second insert and the intermediate layer;

processing the base metal, the intermediate layer, the second metal powder and the second insert via hot isostatic pressing such that the external layer is bonded to the intermediate layer, the external layer having a porosity of generally less than one percent; and

removing the second insert to form the impeller, wherein the external layer is corrosion resistant after the hot isostatic pressing.

4. The method of claim 3 , wherein the intermediate layer and the external layer have a coefficient of thermal expansion which varies as a distance of the intermediate and the external layers from the base metal varies.

5. The method of claim 3 , further comprising:

forming the intermediate layer to include at least two layers, each of the two layers having a different coefficient of thermal expansion.

6. The method of claim 3 , wherein the impeller includes a disk section, a counter disk section and a plurality of blades, all of which are formed from a single integrated piece of the base metal.

7. The method of claim 3 , wherein the impeller includes a disk section, a counter disk section and a plurality of blades, each of which is separately manufactured from the base metal and joined together via a hot isostatic pressing such that the intermediate and external layers are formed there between.

8. The method of claim 3 , wherein the impeller includes a disk section, a counter disk section and a plurality of blades, the counter disk section and the plurality of blades are a single integrated piece and the disk section is a single piece which are joined together via a hot isostatic pressing such that the intermediate and external layers are formed there between.

9. The method of claim 3 , wherein the impeller includes a disk section, a counter disk section and a plurality of blades, the disk section is formed integrally with a portion of the plurality of blades and the counter disk section is formed integrally with another portion of the plurality of blades which are joined together via a hot isostatic pressing such that the intermediate and external layers are formed there between.

10. The method of claim 3 , wherein the impeller includes a disk section, a counter disk section and a plurality of blades, the plurality of blades include a surface covering both an exterior surface of the disk section and an interior section of the counter disk section, are made from a corrosion resistant material and attached to the disk section and the counter disk section via a hot isostatic pressing.