WO2018188871A1 - Ceramic layer constituted of partially and fully stabilized zirconium oxide - Google Patents

Abstract

The use of a physical mixture of partially stabilized and fully stabilized zirconium oxide powder for producing a thermal barrier coating results in good thermal barrier properties and good mechanical properties.

Description

 Partially and fully stabilized zirconium oxide powder as a ceramic

 layer

The invention relates to a ceramic layer system, is sprayed in the partially stabilized and fully stabilized powder as physika ^¬ metallic mixture or has been.

For high-temperature applications, such as gas turbines, metallic substrates are often protected by ceramic thermal barrier coatings.

Typical thermal barrier coatings (TBCs) have zirconia partially stabilized, such as 8 weight percent yttria-stabilized zirconia. Likewise known is fully stabilized zirconium oxide, which then has mostly as a bonding layer teilstabili ^¬ catalyzed zircon layer on the substrate. However, double-layered systems always have the problem of the difference in coefficients of thermal expansion. It is therefore an object of the invention to solve the above-mentioned problem.

The object is achieved by a ceramic layer system according to claim 1.

In the dependent claims further advantageous measures are listed, which are combined with each other Kings ^¬ nen to obtain further advantages. FIGS. 1 to 4 show ceramic thermal barrier coating systems.

It is proposed to use a physical mixture of part ^¬ stabilized and fully stabilized zirconia. Preferably, 8 wt% yttrium partially stabilized zirconia (PSZ) and 22% to 48% yttria fully stabilized zirconia (FSZ) are used. The area specifications for the Sta ^¬ bilisierung may vary, as can the type of sta- be changed bilisatoren, such. As ytterbium, europium, etc. or mixtures can be used.

Figure 1 shows an inventive ceramic layer system 1 ^λ with a substrate 4 of a preferably existing metal ^¬ metallic bonding layer 7, and in particular MCrAlY-Ba-sis, and an outer ceramic thermal barrier coating 10 having a physical mixture of partially stabilized and (fully stabilized zirconia ZrO > 2). M is preferably nickel (Ni) and / or cobalt (Co).

For the production of the ceramic thermal barrier coating 10 either powder FSZ and PSZ are pre-mixed together and sprayed comparable or powder of FSZ and PSZ are merged in ^¬ nerhalb a spray nozzle and sprayed together ^¬.

 Other approaches are possible. The proportion of FSZ in the mixture or in the TBC is preferably between 10% by weight and 90% by weight.

Figure 2 shows a similar embodiment of a layer system 1 ^{λ λ} , in which, as indicated by the arrow, in the Kerami ^¬ rule layer 10 ^λ a concentration gradient C is present, so that the proportion of the fully stabilized phase FSZ, for example, outwardly to the outermost surface 19 increases.

The concentration gradient C can vary over the entire

Layer thickness of the ceramic layer 10 ^λ extend or only partially.

3 shows from Figure 1 or 2, the possibility that the substrate 4, 4 ^λ and / or the adhesive layer 7 an edited structured surface 13 (Engineered surfaces), in order to achieve a better adhesion of the ceramic thermal barrier coating 10, 10 10 ^{λ λ} to the substrate 4 ^λ or adhesive layer 7 ^λ .

The structured surface 13 of the substrate 4 ^λ or the adhesion promoter layer 7 produces an at least 50% greater roughness compared to unprocessed substrates 4 or unprocessed adhesion promoter layers.

Figure 4 shows an embodiment starting from Figure 1, 2 or 3, in which starting from the outermost surface 19 of the ceramic thermal barrier coating 10, 10 10 ^{λ λ} depressions or longitudinal cracks 16 16 ^{λ λ} are present, which were preferably introduced later, for. B. by a laser (laser engravings) or by appropriate coating process or subsequent heat treatment process or which were preferably generated during the coating (Dense Vertical Cracks, DVC). The features of the cracks 16 16 ^{λ λ} , ... or depressions 16

16 ^{λ λ} , ... (Figure 4) and / or the machined adhesive surface 13 (Figure 3) may be combined (Figures 2, 3, 4). The substrate 4, 4 ^λ (Fig. 1, 2, 3, 4) may also be of CMC, in which case the adhesive layer 7 also is preferably ke ^¬ Ramisch.

Claims

claims

1. Ceramic thermal barrier coating system (1 ^λ , 1 ^{λ λ} , 1 ^{λ λ λ} , 1 ^IV ), which comprises at least:

a substrate (4, 4 ^λ ),

 especially

either a metallic substrate (4, 4 ^λ ),

 especially nickel or cobalt superalloy base,

 or

a substrate (4, 4 ^λ ) of CMC;

 in particular a bonding agent layer (7),

 the

 either

 in the case of a metallic substrate (4, 4) is metallic,

 in particular has an MCrAlY alloy,

 where M stands for nickel and / or cobalt,

 preferably nickel and cobalt,

 or

in the case of a substrate (4, 4 ^λ ) of CMC a ceramic bonding layer;

and an outer ceramic thermal barrier coating (10, 10 10 ^{λ λ} ),

having (10, 10 10 ^{λ λ} ) grains of partially stabilized (PSZ) as well as fully stabilized (FSZ) zirconia.

2. Ceramic thermal barrier coating system according to claim 1, wherein the stabilization of the zirconia is carried out by yttria,

in particular 8% for partial stabilization and / or 22% to 48% for full stabilization.

3. Ceramic thermal barrier coating system according to one or both of claims 1 or 2,

 in which the concentration (c) of the fully stabilized

Zirconia (FSZ) to the outermost surface (19) of the ceramic see thermal barrier coating (10 10 ^{λ λ} ) increases.

4. Ceramic thermal barrier coating system (1) according to one or both of claims 1 or 2,

in which the mixing ratio of PSZ and FSZ over the entire thickness of the ceramic layer (10, 10 ^{λ λ} ) is constant.

5. Ceramic thermal barrier coating system (1) according to one or more of claims 1, 2, 3 or 4,

in which starting from the outermost surface (19) of the ceramic layer (10, 10 10 ^{λ λ} )

Depressions (16 16 ^{λ λ} , ...) or

longer vertical cracks (16 16 ^{λ λ} , ...) are present, which were introduced in particular by laser or

 during the coating process or

 by a post-treatment method

 were generated.

6. Ceramic thermal barrier coating system according to one or more of the preceding claims,

wherein the surface of the substrate (4 ^λ ) or the adhesion promoter layer (7) on the substrate (4 ^λ ),

on which the ceramic layer (10) or the Haftvermitt ^¬ Lersch layer (7) is applied,

was edited.

7. Ceramic thermal barrier coating system according to one or more of the preceding claims,

 in which the proportion of FSZ is at least 10% by weight and at most 90% by weight.