U.S. patent application number 15/028949 was filed with the patent office on 2016-09-01 for two-ply ceramic layer with different microstructures.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. The applicant listed for this patent is SIEMENS AKTIENGESELLSCHAFT. Invention is credited to JENS BAY DUSTERHOFT, CLAUS HEUSER, MATTHIAS RICHTER, WERNER STAMM.
Application Number | 20160251971 15/028949 |
Document ID | / |
Family ID | 49484128 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160251971 |
Kind Code |
A1 |
DUSTERHOFT; JENS BAY ; et
al. |
September 1, 2016 |
TWO-PLY CERAMIC LAYER WITH DIFFERENT MICROSTRUCTURES
Abstract
A two-ply heat-insulating ceramic layer is provided with a
highly porous crackfree lower ply and an outermost heat-insulating
ply with vertical cracks in order to ensure both a high heat
insulation as well as a high erosion resistance. In one aspect is a
layer system having a two-ply, outermost ceramic layer, which has a
lower ceramic layer and an outermost ceramic layer. The lower
ceramic layer has a porosity of at least 5%, in particular at least
8%, very particularly preferably at least 10%, and barely any or no
vertical cracks, in particular no vertical cracks running right
through, and the outermost ceramic layer has a layer thickness of
not more than 40%, in particular not more than 20%, very
particularly preferably not more than 10% of the layer thickness of
the lower ceramic layer.
Inventors: |
DUSTERHOFT; JENS BAY;
(SCHLUCHTERN, DE) ; HEUSER; CLAUS; (ALZENAU,
DE) ; RICHTER; MATTHIAS; (SINNTAL, DE) ;
STAMM; WERNER; (Mulheim an der Ruhr, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SIEMENS AKTIENGESELLSCHAFT |
Munchen |
|
DE |
|
|
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
MUNCHEN
DE
|
Family ID: |
49484128 |
Appl. No.: |
15/028949 |
Filed: |
May 13, 2014 |
PCT Filed: |
May 13, 2014 |
PCT NO: |
PCT/EP2014/059738 |
371 Date: |
April 13, 2016 |
Current U.S.
Class: |
428/213 |
Current CPC
Class: |
C23C 4/11 20160101; F05D
2230/312 20130101; F05D 2300/611 20130101; Y02T 50/6765 20180501;
C23C 4/134 20160101; Y02T 50/60 20130101; C23C 28/042 20130101;
F05D 2300/5023 20130101; C23C 28/3215 20130101; F01D 5/288
20130101; F05D 2220/31 20130101; F01D 9/02 20130101; C23C 28/3455
20130101; F04D 29/542 20130101; F04D 29/324 20130101; F05D 2220/323
20130101 |
International
Class: |
F01D 5/28 20060101
F01D005/28; C23C 28/00 20060101 C23C028/00; F04D 29/54 20060101
F04D029/54; F01D 9/02 20060101 F01D009/02; F04D 29/32 20060101
F04D029/32; C23C 4/11 20060101 C23C004/11; C23C 28/04 20060101
C23C028/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 22, 2013 |
EP |
13189688.8 |
Claims
1. A layer system having a two-ply, outermost ceramic layer, which
has a lower ceramic layer and an outermost ceramic layer, wherein
the lower ceramic layer has a porosity of at least 5%, and is
substantially free of vertical cracks running therethrough, and the
outermost ceramic layer has a layer thickness of not more than 40%,
of the layer thickness of the lower ceramic layer.
2. The layer system as claimed in claim 1, wherein the outermost
ceramic layer has a minimum layer thickness of 30 .mu.m.
3. The layer system as claimed in claim 1, wherein the outermost
ceramic layer has a maximum layer thickness of 500 .mu.m.
4. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the two-ply ceramic layer has a porosity of 12+ or
-4% and in particular has a layer thickness of up to 1 mm.
5. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the two-ply ceramic layer has a porosity of 15+ or
-4% and in particular has a layer thickness of up to 1 mm.
6. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the two-ply ceramic layer has a porosity of 20+ or
-4% and has a layer thickness of up to 1.5 mm.
7. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the ceramic layer has a porosity of 25+ or -5% and
has a layer thickness of >1.5 mm.
8. The layer system as claimed in claim 1, wherein the lower
ceramic layer has a porosity of >15%.
9. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the thermal barrier layer has a ductile columnar
structure.
10. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the two-ply ceramic thermal barrier layer has been
produced by an APS process.
11. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the two-ply ceramic thermal barrier layer has been
produced by spraying of ceramic powders with polymers.
12. The layer system as claimed in claim 1, wherein the lower
ceramic layer of the two-ply, ceramic thermal barrier layer has
been produced by suspension plasma spraying.
13. The layer system as claimed in claim 1, wherein the materials
for the lower ceramic layer and of the outermost ceramic layer are
selected from among: zirconium oxide, partially stabilized or fully
stabilized, and pyrochlores.
14. The layer system as claimed in claim 1, wherein the two-ply
ceramic layer is the outermost layer.
15. The layer system as claimed in claim 1, wherein the lower
ceramic layer has a minimum thickness of at least 100 .mu.m.
16. The layer system as claimed in claim 1, wherein the outermost
ceramic layer is dense and has a porosity of less than 8%.
17. The layer system as claimed in claim 1, wherein the outermost
ceramic layer has cracks running vertically through it.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to PCT Application No.
PCT/EP2014/059738, having a filing date of May 13, 2014, based off
of EP Application No. 13189688.8 having a filing date of Oct. 22,
2013, the entire contents of which are hereby incorporated by
reference.
FIELD OF TECHNOLOGY
[0002] The following relates to a ceramic layer which has a two-ply
structure, with different microstructures being present in the
layers.
BACKGROUND
[0003] Ceramic layers are used, in particular, as thermal barrier
layers in turbine blades and have a porosity.
[0004] Vertically segmented thermal barrier layers in which cracks
are formed during coating by means of a subsequent treatment are
likewise known.
[0005] However, there is the problem that when the porosity is
increased to achieve greater thermal insulation, the erosion
resistance of a thermal barrier layer, which is generally
plasma-sprayed, is reduced.
SUMMARY
[0006] The advantages are good thermal insulation and good erosion
resistance.
BRIEF DESCRIPTION
[0007] Some of the embodiments will be described in detail, with
reference to the following figures, wherein like designations
denote like members, wherein:
[0008] FIG. 1 is a working example of a layer system in accordance
with embodiments of the invention;
[0009] FIG. 2 is a working example of a layer system in accordance
with embodiments of the invention;
[0010] FIG. 3 is a working example of a layer system in accordance
with embodiments of the invention;
[0011] FIG. 4 is a working example of a layer system in accordance
with embodiments of the invention;
[0012] FIG. 5 a list of superalloys in accordance with embodiments
of the invention; and
[0013] FIG. 6 a turbine blade in accordance with embodiments of the
invention.
DETAILED DESCRIPTION
[0014] The description and the figures represent only working
examples of embodiments of the invention.
[0015] FIG. 1 and FIGS. 2 to 4 in each case show a layer system 1',
1'', . . . which has at least one metallic substrate 4.
[0016] The metallic substrate 4 comprises, in particular, a cobalt-
or nickel-based superalloy, in particular as shown in FIG. 5.
[0017] A metallic bonding layer 7 has preferably been applied to
the substrate 4 (FIGS. 1-4), very particularly preferably directly
to the substrate 4.
[0018] This metallic bonding layer 7 preferably comprises an alloy
of the NiCoCrAl (X) type, on the surface of which a protective
aluminum oxide layer (not shown) is formed during further coating
or during operation (TGO).
[0019] A lower ceramic layer 10' (FIG. 1) of a two-ply, outermost
ceramic thermal barrier layer 15' is applied to the substrate 4 or
the metallic bonding layer 7.
[0020] The porosity is preferably reported in percent by
volume.
[0021] An APS process is preferably used for the lower ceramic
layer 10' as per FIG. 1 and the lower ceramic layer 10' of the
two-ply, outermost ceramic thermal barrier layer 15' preferably has
a porosity of (12+/-4) %.
[0022] The lower ceramic layer 10' preferably has a layer thickness
of up to 1 mm.
[0023] The minimum thickness of the lower ceramic layer 10' is at
least 100 .mu.m, very particularly preferably at least 150 .mu.m
(FIGS. 1-4).
[0024] The outermost, ceramic layer 13 in FIGS. 1 to 4 has a layer
which is dense compared to the lower layer 10', . . . , 10.sup.IV
of the two-ply ceramic thermal barrier layers 15', 15'', . . . and
through which cracks run vertically, i.e. the porosity is
preferably <8%.
[0025] The minimum layer thickness of the outermost ceramic layer
13 is 30 .mu.m, in particular at least 50 .mu.m (FIGS. 1-4).
[0026] The maximum layer thickness of the outermost ceramic layer
13 is not more than 500 .mu.m, in particular not more than 300
.mu.m (FIGS. 1-4).
[0027] The porosity of the segmented layers like that of the
outermost ceramic layer 13 here corresponds to that from the known
art.
[0028] FIG. 2 shows a further working example having a layer system
1''.
[0029] In contrast to FIG. 1, the lower layer 10'' of the ceramic
thermal barrier layer 15'' has a porosity of (15+/-4)%.
[0030] The lower ceramic layer 10'' in FIG. 2 can likewise
preferably have a layer thickness of up to 1.5 mm, in particular
from >1 mm to 1.5 mm, and then have a porosity of (20+/-5)%.
[0031] The minimum layer thickness of the outermost, ceramic layer
13 is 30 .mu.m, in particular at least 50 .mu.m.
[0032] The porosity of the lower ceramic layer 10'' in FIG. 2 can
likewise preferably be increased further to (25+/-5)% and layer
thicknesses of >1.5 mm are then preferably produced.
[0033] The minimum layer thickness of the outermost, ceramic layer
13 is 30 .mu.m, in particular at least 50 .mu.m.
[0034] FIG. 3 shows a further working example of a layer system
1''' according to embodiments of the invention.
[0035] The lower ceramic layer 10''' of the thermal barrier layer
15''' has a porosity of preferably greater than 15% and has been
produced by means of an APS process. However, the pores have been
produced by spraying a ceramic powder, preferably by means of
polymers.
[0036] This gives a characteristic microstructure of the pores.
[0037] The lower ceramic layer 10''' can preferably have a layer
thickness of a plurality of millimeters, in particular .gtoreq.2
mm.
[0038] The minimum layer thickness of the outermost, ceramic layer
13 is 30 .mu.m, in particular at least 50 .mu.m.
[0039] FIG. 4 shows a further layer system 10.sup.IV according to
embodiments of the invention.
[0040] The lower ceramic layer 10.sup.IV of the two-ply, ceramic
thermal barrier layer 15.sup.IV has been produced by the suspension
plasma spraying (SPS) process and has a ductile columnar structure
having a certain porosity of 4% and cracks up to <8%.
[0041] The outermost layer 13 in FIG. 4 is configured with the
minimum layer thickness and structure and maximum layer thickness
in FIGS. 1-3.
[0042] Possible materials for the outermost, ceramic thermal
barrier layers 15', . . . 15.sup.IV are yttrium oxide, partially
stabilized zirconium oxide or thermal barrier layers composed of
fully stabilized zirconium oxide.
[0043] It is likewise possible to use pyrochlores such as
gadolinium zirconate, gadolinium hafnate, lanthanum zirconate,
gadolinium zirconate.
[0044] Here, the materials for the lower, ceramic layer 10', 10'',
. . . and the outermost layer 13 can be varied as a function of use
conditions and production possibilities.
[0045] The two-ply outermost ceramic layer 15 is preferably the
outermost layer of the layer system 1', 1'', . . . .
[0046] FIG. 6 shows a perspective view of a rotor blade 120 or
guide blade 130 of a turbomachine, which extends along a
longitudinal axis 121.
[0047] The turbomachine can be a gas turbine of an aircraft or of a
power station for generating electricity, a steam turbine or a
compressor.
[0048] The blade 120, 130 has, in succession along the longitudinal
axis 121, a fastening region 400, a blade platform 403 adjoining
this and also a blade leaf 406 and a blade tip 415. As guide blade
130, the blade 130 can have a further platform (not shown) at its
blade tip 415.
[0049] In the fastening region 400, there is a blade foot 183 which
serves for fastening the rotor blades 120, 130 to a shaft or a disk
(not shown).
[0050] The blade foot 183 is, for example, configured as a hammer
head. Other configurations as Christmas tree foot or swallowtail
foot are possible.
[0051] The blade 120, 130 has a leading edge 409 and a trailing
edge 412 for a medium flowing past the blade leaf 406.
[0052] In the case of conventional blades 120, 130, all regions
400, 403, 406 of the blade 120, 130 are, for example, made of
massive metallic materials, in particular superalloys. Such
superalloys are known, for example, from EP 1 204 776 B1, EP 1 306
454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949.
[0053] The blade 120, 130 can have been made by a casting process,
including by means of directional solidification, by a forging
process, by a milling process or combinations thereof.
[0054] Workpieces having a monocrystalline structure or structures
are used as components for machines which are subjected to high
mechanical, thermal and/or chemical stresses during operation.
[0055] The manufacture of such monocrystalline workpieces is
carried out, for example, by directional solidification from the
melt. This involves casting processes in which the liquid metallic
alloy solidifies to form a monocrystalline structure, i.e. the
monocrystalline workpiece, or directionally.
[0056] Here, dendritic crystals are aligned along the heat flow and
form either a columnar crystalline grain structure (i.e. grains
which run over the entire length of the workpiece and here referred
to, in keeping with general language usage, as directionally
solidified) or a monocrystalline structure, i.e. the entire
workpiece consists of a single crystal. In these processes, the
transition to globulitic (polycrystalline) solidification has to be
avoided since transverse and longitudinal grain boundaries are
necessarily formed by nondirectional growth and these nullify the
good properties of the directionally solidified or monocrystalline
component.
[0057] If general reference is made to directionally solidified
microstructures, this encompasses both single crystals which have
no grain boundaries or at most low-angle grain boundaries and also
columnar crystal structures which do have grain boundaries running
in the longitudinal direction but no transverse grain boundaries.
These crystalline structures mentioned second are also referred to
as directionally solidified microstructures.
[0058] Such processes are known from U.S. Pat. No. 6,024,792 and EP
0 892 090 A1.
[0059] The blades 120, 130 can likewise have coatings to protect
against corrosion or oxidation, e.g. (MCrAlX; M is at least one
element from the group iron (Fe), cobalt (Co), nickel (Ni), X is an
active element and is yttrium (Y) and/or silicon and/or at least
one element of the rare earths, or hafnium (Hf)). Such alloys are
known from EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP
1 306 454 A1.
[0060] The density is preferably 95% of the theoretical
density.
[0061] A protective aluminum oxide layer (TGO=thermally grown oxide
layer) forms on the MCrAlX layer (as intermediate layer or as
outermost layer).
[0062] The layer composition preferably comprises
Co-30Ni-28Cr-8Al-0, 6Y-0.7Si or Co-28Ni-24Cr-10Al-0.6Y. Apart from
these cobalt-based protective coatings, preference is also given to
using nickel-based protective layers such as Ni-10Cr-12Al-0.6Y-3Re
or Ni-12Co-21Cr-11Al-0.4Y-2Re or Ni-25Co-17Cr-10Al-0.4Y-1.5Re.
[0063] A thermal barrier layer can be additionally present on the
MCrAlX and is preferably the outermost layer and consists, for
example, of ZrO.sub.2, Y.sub.2O.sub.3--ZrO.sub.2, i.e. it is
unstabilized, partially stabilized or fully stabilized by yttrium
oxide and/or calcium oxide and/or magnesium oxide.
[0064] The thermal barrier layer covers the entire MCrAlX layer.
Columnar grains are produced in the thermal barrier layer by
suitable treatment processes, e.g. electron beam vaporization
(EB-PVD).
[0065] Other coating processes are conceivable, e.g. atmospheric
plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier layer
can have grains which are porous, have microcracks or have
macrocracks for better thermal shock resistance. The thermal
barrier layer is thus preferably more porous than the MCrAlX
layer.
[0066] Refurbishment means that components 120, 130 have to be
freed of any protective layers (e.g. by sand blasting) after they
have been used. This is followed by removal of the corrosion and/or
oxidation layers or products. Cracks in the component 120, 130 are
optionally also repaired. This is followed by recoating of the
component 120, 130 and renewed use of the component 120, 130.
[0067] The blade 120, 130 can be hollow or solid. When the blade
120, 130 is to be cooled, it is hollow and optionally has film
cooling holes 418 (indicated by dashes).
[0068] Although the present invention has been disclosed in the
form of preferred embodiments and variations thereon, it will be
understood that numerous additional modifications and variations
could be made thereto without departing from the scope of the
invention.
[0069] For the sake of clarity, it is to be understood that the use
of `a` or `an` throughout this application does not exclude a
plurality, and `comprising` does not exclude other steps or
elements.
* * * * *