Composite thermal spray powder of oxides and non-oxides
Composite thermal spray powders are formed by manufacturing two or more powder feedstock components having different chemical compositions, particle size ranges and morphologies, these different features arising from different powder manufacturing processes. The resulting coatings typically serve as abradable seals, thermal barrier coatings or environmental barrier coatings, have improved temperature resistance, and maintain favorable properties over a longer time span compared to current coating materials. The thermal spray coating may be formed by using the described composite powders consisting of two or more powder components having at least one of different powder fractions in particle size, morphology and/or chemical composition or by co-spraying the described single components with at least different morphologies such as agglomerated, agglomerated-and-sintered, cladded, fused-and-crushed, or hollow oven spherical powder.
1 . A method of making a thermal spray powder, the method comprising:
combining two or more component powders to form a composite powder,
wherein each of the two or more component powders have different morphologies;
wherein each of the two or more component powders consist of
rare earth stabilized zirconia in an amount of from greater than 0 weight percent to 90 weight percent;
an oxide selected from the group consisting of aluminum oxide, barium strontium aluminosilicate, calcium oxide, hafnium oxide, high entropy oxide, magnesium oxide, mullite, and silicon oxide, and
a rare-earth oxide selected from the group consisting of Ce, Dy, Er, Eu, Gd, Hf, Ho, La, Nd, Lu, Pm, Pr, Sc, Sm, Tb, Tm, Y, Yb, and mixtures thereof;
wherein the high entropy oxide comprises a matrix having at least three principal elements each constituting between 5 weight percent and 35 weight percent of the matrix;
wherein at least one of the two or more component powders has a particle size range of from about 10 μm to about 180 μm; and
wherein at least two of the two or more component powders are produced via different manufacturing process selected from the group consisting of agglomeration, agglomeration-and-sintering, fused-and-crushed, chemical cladding, physical cladding, and hollow oxide spherical powder (HOSP).
2 . The method of claim 1 , wherein the composite powder comprises a material selected from the group consisting of at least one principal component and a combination of one or more secondary components.
3 . The method of claim 2 , wherein the primary component is a matrix former.
4 . The method of claim 2 , wherein one of the one or more secondary components is a porosity former.
5 . The method of claim 2 , wherein one of the one or more secondary components is a structure hardener.
6 . The method of claim 1 , wherein the thermal spray powder is suitable for use in a thermal spray process selected from the group consisting of air plasma spraying, high velocity oxyfuel or combustion spraying.
7 . The method of claim 6 , wherein the thermal spray powder is suitable for use in a thermal spray process that provides a thermal-sprayed coating having a thickness of from about 5 μm to about 8,000 μm.
8 . The method of claim 1 , wherein the composite powder excludes a polymeric binder.
9 . The method of claim 1 , wherein each of the two or more component powders have at least one of i) different compositional ratios; or ii) different particle size ranges relative to other component powders.
10 . The method of claim 1 , wherein the rare earth stabilized zirconia of at least one of the components is present in an amount of from 5 weight percent to 60 weight percent.
11 . The method of claim 10 , wherein the rare earth stabilized zirconia of at least one of the components is present in an amount of from 15 weight percent to 25 weight percent.
12 . The method of claim 10 , wherein the rare earth stabilized zirconia of at least one of the components is present in an amount of from 45 weight percent to 55 weight percent.
13 . The method of claim 10 , wherein the rare earth stabilized zirconia of at least one of the components is present in an amount of from 5 weight percent to 15 weight percent.
14 . The method of claim 1 , wherein the rare-earth oxide is selected from an oxide of yttrium or ytterbium.
15 . The method of claim 14 , wherein the rare-earth oxide is a yttrium-stabilized zirconia.
16 . A method of making a thermal spray powder, the method comprising:
combining two or more component powders to form a composite powder;
wherein each of the two or more component powders have different morphologies;
wherein each of the two or more component powders consist of
an oxide selected from the group consisting of aluminum oxide, barium strontium aluminosilicate, calcium oxide, hafnium oxide, high entropy oxide, magnesium oxide, mullite, silicon oxide, and zirconium oxide, and
a rare-earth oxide selected from the group consisting of Ce, Dy, Er, Eu, Gd, Hf, Ho, La, Nd, Lu, Pm, Pr, Sc, Sm, Tb, Tm, Y, Yb, and mixtures thereof;
wherein the high entropy oxide comprises a matrix having at least three principal elements each constituting between 5 weight percent and 35 weight percent of the matrix;
wherein at least one of the two or more component powders has a particle size range of from about 10 μm to about 180 μm; and
wherein at least two of the two or more component powders are produced via different manufacturing process selected from the group consisting of agglomeration, agglomeration-and-sintering, fused-and-crushed, chemical cladding, physical cladding, and hollow oxide spherical powder (HOSP).
17 . A method of forming an abradable coating layer, the method comprising:
thermal spraying or co-spraying the composite powder of claim 1 to form the abradable coating layer on a substrate, wherein the thermal spraying or co-spraying is done at a temperature sufficient to partially melt particles of the powder feedstock during spraying; and
cooling the abradable coating layer to room temperature wherein the abradable coating layer is substantially free of any cracks.
18 . The method of claim 17 , wherein the thermal spraying comprises at least one selected from the group consisting of air plasma spraying, high velocity oxyfuel and combustion spraying.
19 . The method of claim 17 , wherein the component powders have different particle size ranges or different chemical compositions.
20 . The method of claim 17 , wherein the abradable coating layer has a thickness of from about 5 μm to about 8,000 μm.
21 . The method of claim 20 , wherein the thermal-sprayed coating comprises a porosity of from about 1% to about 90% as determined by at least one of the following measurement techniques: apparent density measurement (ASTM B212 or ASTM B329), tap density measurement (ASTM B527), or BET surface area measurement (ASTM D3663 or ISO 9277).