Method for making a high temperature erosion resistant coating and material containing compacted hollow geometric shapes
View Patent ↗A method for making a material system includes the steps of: providing a chamber, placing hollow geometric shapes in the chamber, closing the chamber, evacuating air from the chamber, feeding a binder for the shapes into the evacuated chamber to impregnate the geometric shapes, drying the binder permeated geometric shapes, and heating the hollow shapes and binder to provide a unitary, sintered material system.
1. A method of making a material system for use at a predetermined use temperature in a high temperature environment, the method comprising:
forming a plurality of geometric shapes at a manufacturing temperature in excess of the use temperature to render the geometric shapes dimensionally stable at the use temperature;
filling at least a portion of a chamber with the plurality of geometric shapes such that the geometric shapes define void spaces therebetween and at least a portion of the geometric shapes are not bound to each other when placed into the chamber;
introducing a slurry comprising a carrier medium and a binder material into the chamber;
impregnating binder material into the void spaces and removing carrier medium from the chamber by vacuum impregnation to form a green body;
heating the green body to a processing temperature at which the geometric shapes do not sinter and that is less than the manufacturing temperature to form the material system adapted for use at the use temperature, wherein the forming includes stabilizing the geometric shapes so that the geometric shapes do not sinter to one another at a temperature at which the geometric shapes would sinter together prior to stabilization.
2. The method of claim 1 , wherein the geometric shapes are hollow, achieve dimensionally stability by being manufactured at a temperature in excess of 1600° C. and comprise an oxide based composition.
3. The method of claim 1 , wherein the binder material comprises an aluminum phosphate based composition.
4. The method of claim 1 , wherein the binder material is adhered to the geometric shapes by sintering the binder material to the geometric shapes at a temperature between 400° C. and 1600° C.
5. The method of claim 1 , wherein the material system is adapted for use in a combustion turbine engine by utilizing a chamber having a three dimensional shape that forms the material system to be near net shape for one of an airfoil and a combustor liner.
6. The method of claim 1 , further comprising introducing the slurry into the chamber through a first opening and applying a vacuum to the chamber through a filter to remove the carrier medium while retaining the binder material within the chamber.
7. The method of claim 1 , further comprising applying a first vacuum level to the chamber during a first period of time and applying a second vacuum level greater than the first vacuum level to the chamber during a second period of time.
8. The method of claim 1 , further comprising forming the slurry to comprise the carrier medium, the binder material and a filler material.
9. The method of claim 1 , further comprising infiltrating aluminum hydroxyl chloride into the green body.
10. The method of claim 1 , further comprising forming the geometric shapes to be hollow spheres with sphere walls of 70–100% of theoretical density.
11. The method of claim 1 , wherein a majority of the geometric shapes are not bound to each other when placed in the chamber.
12. The method of claim 1 , wherein all of the geometric shapes are not bound to each other when placed in the chamber.
13. The method of claim 1 , wherein the geometric shapes are spheres.