WO2024130327A1 - Composition de verre pour revêtement protecteur - Google Patents

Composition de verre pour revêtement protecteur Download PDF

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Publication number
WO2024130327A1
WO2024130327A1 PCT/AU2023/051349 AU2023051349W WO2024130327A1 WO 2024130327 A1 WO2024130327 A1 WO 2024130327A1 AU 2023051349 W AU2023051349 W AU 2023051349W WO 2024130327 A1 WO2024130327 A1 WO 2024130327A1
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WO
WIPO (PCT)
Prior art keywords
glass
mol
coating
glass composition
electrochemical device
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Application number
PCT/AU2023/051349
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English (en)
Inventor
Sudath Dharma Kumara Amarasinghe
Pulahinge Don Dayananda Rodrigo
Babak Navak
Original Assignee
SolydEra Australia Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2022903931A external-priority patent/AU2022903931A0/en
Application filed by SolydEra Australia Pty Ltd filed Critical SolydEra Australia Pty Ltd
Publication of WO2024130327A1 publication Critical patent/WO2024130327A1/fr

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  • the present invention relates to a glass composition for forming a protective coating on metallic components exposed to high temperature corrosive environments including electrochemical devices or electrochemical cells, for example solid oxide fuel cell stacks and similar apparatus, such as solid oxide electrolyser cell stacks.
  • the invention also extends to use of the glass composition, a coating material comprising the glass composition and a method of forming a coating on a metallic substrate.
  • Electrochemical devices or electrochemical cells are devices capable of either generating electrical energy from chemical reactions or using electrical energy to cause chemical reactions.
  • An example of an electrochemical device is a solid oxide fuel cell (SOFC) device, which is used to convert chemical energy of a gaseous fuel such as hydrogen into electrical energy by electrochemical oxidation.
  • SOFC solid oxide fuel cell
  • a typical SOFC stack consists of a number of cells connected to each other, where each cell has a porous ceramic cathode and a porous ceramic anode separated by a dense, ionically conducting solid oxide electrolyte.
  • the stacks typically include a support structure made up of one or more supports made of a suitable material, for example made of suitable metals.
  • a fuel such as natural gas is supplied to the anode and an oxidant such as air is supplied to the cathode of each cell.
  • the cell components are assembled in such a way the fuel and the oxidant can be supplied to the anode and the cathode of each cell respectively.
  • SOEC solid oxide electrolyser cell
  • SOEC solid oxide electrolyser cell
  • the operating environment inside an electrochemical device can be a high- temperature corrosive environment.
  • the lifetime of metallic components inside these devices for example fuel cells, and accordingly, the lifetime of the device or fuel cell itself, may be extended by providing a protective coating of the metallic components.
  • SOFC and SOEC stacks During operation, SOFC and SOEC stacks reach elevated temperatures, usually in the range of about 500°C to about 1000°C, and are subjected to both intentional and unintentional temperature fluctuations (thermal cycles) ranging from as low as ambient temperature up to the operating temperature with varying heating and cooling rates.
  • thermal cycles intentional and unintentional temperature fluctuations
  • the protective coating(s) on the metallic components must maintain their integrity and fulfil all the above requirements under the thermal cycling conditions as well as under the constant temperature operation for many thousands of hours.
  • the mismatch between the thermal expansion and contraction of the coating material and the metallic components of the SOFC or SOEC stack should be sufficiently low to prevent cracking or peeling of the coating under the thermal stresses developed during thermal cycling.
  • the coating should not have adverse interactions with other components of the SOFC or SOEC stack, either by way of emitting undesirable volatile species that alter the chemical or physical nature of the other components or by reacting with the other components with which the coating is in contact.
  • These protective coatings can be classified into two categories: electrically conducting and electrically insulating.
  • the electrically conducting coatings are typically applied on the area of the metal that is in contact with the cell electrodes. They facilitate current passage while protecting the electrode by reducing the emission of harmful materials from the metal.
  • Such coatings are typically fabricated with either reactive metal oxides or spinels. However, these coatings are generally not suitable in areas where the glass seals are applied as they may react with glass seals leading to a possible failure thereof.
  • YSZ and alumina coatings are examples of electrically insulating coatings.
  • Alumina coatings can tend to delaminate due to high GTE (Coefficient of Thermal Expansion) difference with the metals.
  • Dense YSZ coatings can be difficult to fabricate, particularly with simple, low cost methods. Coatings which are too thin or which are porous provide relatively low protection from harmful emissions from the metal substrate, such as Cr.
  • the inventors have developed a glass composition capable of forming a protective coating on metal components for use in high-temperature corrosive environments.
  • the glass coating advantageously comprises one or more crystalline phases and a glassy phase.
  • the present invention provides a glass composition comprising, as mol% of the glass composition: about 40 to about 50 mol% SiOs; about 5 to about 8 mol% B2O3; about 2 to about 5 mol% AI2O3; about 0.5 to about 7 mol% TiCte;
  • the invention provides a glass composition comprising, as mol% of the glass composition:
  • the glass composition consists essentially of the components listed above.
  • the glass composition is substantially free of alkali metal oxides.
  • the glass composition is substantially free of BaO.
  • the glass composition is substantially free of MgO and CaO.
  • coatings formed from the compositions do not substantially include undesirable crystalline phases, for example 2MgO.2Al2Os.5SiO2 and CaO.Al2Os.2SiO2. These crystalline phases which have very low GTE are preferably avoided.
  • the glass composition comprises, as mol% of the glass composition: about 42 to about 48 mol% SiO2; preferably about 44.5 to about 45.5 mol% SiO 2 ; about 5 to about 7 mol% B2O3; preferably about 5.8 to about 6.2 mol% B2O3; about 2.5 to about 4.5 mol% AI2O3; preferably about 3.2 to about 3.8 mol% AI2O3; about 2 to about 6 mol% TiC ; preferably about 4.2 to about 4.8 mol% TiC ; about 1 to about 2.5 mol% CeC ; preferably about 2 to about 2.5 mol% CeC ; about 35 to about 42 mol% SrO; preferably about 37 to about 39 mol% SrO.
  • the glass composition may comprise, as mol% of the glass composition:
  • the glass composition consists essentially of the components listed above.
  • the present disclosure provides a glass composition for coating metallic components.
  • the metallic components are in an electrochemical device.
  • the present invention provides a coating material for use in an electrochemical device comprising the glass composition described herein.
  • the electrochemical device may be any electrochemical device that has metallic components that are exposed to high temperatures and/or an oxidative environment.
  • the electrochemical device is a SOFC or SOEC stack.
  • the coating material comprises one or more crystalline phases and a glass phase.
  • the one or more crystalline phases of the glass coating each comprise crystals having a structure selected from 2SrO.SiO2, SrO.SiO2, 3SrO.B2Os, 2SrO.TiO2.2SiO, SrO.3B2Os, and SrO.B2Os, and combinations thereof.
  • the coating material as described herein comprises about 40 to about 60 vol% of the one or more crystalline phases and about 40 to about 60 vol% of the glassy phase, based on the total amount of glass coating material.
  • the coating material as described herein has a thermal expansion and contraction mismatch with the metal on which it is coated, defined as: Expansion 100 of about -0.02 to about 0.18 at any temperature (T) up to the glass transition temperature (T g ) of the glassy phase.
  • the coating material has a coefficient of thermal expansion (CTE) of about 10 x 10’ 6 /°C to about 13 x 10’ 6 /°C.
  • the present invention provides an electrochemical device comprising one or more cells, each cell comprising a cathode, an anode and a solid electrolyte; a support structure comprising one or more supports; and the glass coating composition described herein.
  • the electrochemical device includes a seal, such as a glass seal overlying the glass coating of the present invention.
  • the electrochemical device is a SOFC or SOEC stack.
  • the present invention provides a method of forming a coating on a metallic substrate for use in an electrochemical device, the method comprising: applying the coating material described herein on a metallic substrate; and subjecting the metallic substrate and coating material to a heat treatment , wherein the glass composition of the coating material softens to provide a sintered glass while minimising interconnected pores and subsequently undergoes controlled crystallisation to provide a glass-ceramic comprising one or more crystalline phases and a glassy phase, thereby forming the coating on the metallic substrate.
  • the heat treatment comprises a soaking step wherein the glass composition is heated to a minimum temperature being the higher of the glass transition temperature of the composition or at least 50°C above the intended operating temperatures for the metallic components.
  • the glass composition is heated to a temperature of from about 550°C to about 1050°C.
  • the soaking step has a duration of from about 2 hours to about 5 hours.
  • the glass composition is applied to the metallic substrate as a slurry of glass powder.
  • the coated metallic components are in an electrochemical device, preferably a SOEC or SOFC stack.
  • the metallic components are coated prior to being placed in an electrochemical device, preferably a SOEC or a SOFC stack.
  • the present invention provides the use of the glass composition described herein or the coating material described herein for forming a protective coating on metallic components.
  • the metallic components are in an electrochemical device, preferably a SOFC or SOEC stack.
  • Figure 1 is a schematic diagram of a portion of a solid oxide fuel cell stack with cell components shown in an exploded view.
  • Figure 2 is a scanning electron microscopy image of a metal substrate coated with the glass coating with a glass seal on top of the glass coating.
  • Figure 3 diagrammatically illustrates a repeating unit of a fuel cell stack showing the metallic components coated with a glass coating.
  • the term “about” refers to a quantity, value, dimension, size, or amount that varies by as much as 30%, 25%, 20%, 15% or 10% to a reference quantity, value, dimension, size, or amount.
  • the present invention relates to a glass composition which comprises, as mol% of the glass composition: about 40 to about 50 mol% SiC>2; about 5 to about 8 mol% B2O3; about 2 to about 5 mol% AI2O3; about 0.5 to about 7 mol% TiO2;
  • the term “substantially free” in the context of the glass composition is intended to mean that the glass composition does not comprise the specified oxide(s) or only comprises the oxide(s) in amounts that do not have a measurable effect on the properties and/or performance of the glass coating formed from the glass composition. Therefore, the term “substantially free of BaO” will be understood to mean that the glass composition does not comprise BaO, or comprises BaO in amounts that do not have a measurable effect on the properties and/or performance of the glass coating formed from the glass composition. Hence, the glass coating may comprise small amounts of BaO provided that these amounts do not have a substantial effect on the properties and/or performance of the glass coating formed from the composition.
  • BaO may readily react with Or present in the metal to form BaCrO4 at the interface.
  • BaCrO4 has a CTE (Coefficient of Thermal Expansion) significantly higher than that of the metallic components. Such a large difference in CTE between BaCrO4 and the metallic components on which the glass composition is coated may thus contribute to the coating separating from the metallic component under thermal stress.
  • the combination of CeO2 and TiC is essential to the composition of the invention. From extensive testing carried out by the inventors, it was surprisingly found that microstructures of similar compositions without CeC>2 formed undesirably large crystals, so reducing the homogeneity of the resulting structure. In a thin film ( ⁇ 5-10pm) coating, the presence of crystals of such a size can lead to heavy internal stresses at the crystal/matrix boundaries, and hence a relatively high risk of failure, particularly when subjected to thermal cycling. Concurrently, the absence of TiO2 in a similar composition was found to result in a product too highly crystalline.
  • the inventors studies revealed that the particular combination of TiO2 and CeO2 is essential to control both the level of crystallisation and the size of individual crystals in the resulting material, ie. to produce a crystallised glass-ceramic product with the desired proportions of glassy and crystalline phases, and with sufficiently small crystals to ensure suitable homogeneity of the coating.
  • the high AI2O3 content of the compositions disclosed in US 2013/0108946 may potentially be suitable for the compositions containing CaO, MgO, La20s, etc., such a high concentration of AI2O3 in compositions that do not contain these oxides (such as the compositions of the present invention) will result in a material with a CTE that is unacceptably low.
  • the compositions of the present invention rely on a different combination of crystalline phases than those proposed or used in prior materials, in order to achieve a seal with characteristics suitable for using as a coating for metals used in SOFC/SOEC products.
  • the glass composition is substantially free of alkali metal oxides.
  • alkali metal oxides may cause rapid erosion of a metal coated with the glass composition.
  • alkali metals may interact with components in contact with the glass coating, for example a glass seal in a SOFC/SOEC stack in contact with the glass coating may be altered due to interdiffusion of alkali metal oxides.
  • coatings formed from glass compositions without alkali metal oxides may thus have better protective properties and be suitable for use in combination with a glass seal.
  • the glass composition comprises no further metal oxides, i.e., no other metal oxides in addition to SiO2, B2O3, AI2O3, TiC>2, CeO2 and SrO.
  • the glass composition is substantially free of CaO, and/or MgO, and/or ZnO, and/or Iron Oxides.
  • the glass composition is substantially free of MgO and CaO.
  • MgO and CaO in the presence of AI2O3 and SiO2 may form undesirable crystalline phases with low CTE, such as 2MgO.2Al2Os.5SiO2 and CaO.Al2Os.2SiO2
  • the presence of low CTE crystalline phases in the glass coating may cause thermal stress leading to peeling of the coating from the metal substrate.
  • the terms “consists essentially of” and “consisting of’ will be understood to imply that the composition does not include any meaningful amount of any further oxides, that is, the composition is substantially free of any oxides other than those specified in the composition.
  • the glass composition may contain any suitable range of oxide component within the broadest range specified for each oxide.
  • the amounts of each metal oxide in the composition may be suitably selected depending on the desired properties of the glass coating to be formed by the glass composition.
  • the glass composition comprises, or consists essentially of, the following, as mol% of the glass composition:
  • TiO2 2 to 6 mol% TiO2; especially about 3.5 to about 5.2 mol% TiC , in particular 4.2 to 4.8 mol% TiO2;
  • the glass composition of the invention may be prepared by methods known in the art.
  • the glass compositions are typically provided in the form of glass powders.
  • the glass can also be provided in frit form, where the glass frit is milled to a powder with desired particle size distribution for use in a coating material.
  • the oxide components of the glass composition or their precursors are each weighed in correct proportions that would result in the desired glass composition.
  • the weighed powders are mixed to produce a homogeneous mixture and then smelted.
  • the melt is poured onto a suitable surface, such as a marver or a mould, and then rapidly cooled to provide a smelted glass frit.
  • the smelted glass frits may be milled, for example using a ball mill, to produce glass powders.
  • the milled glass powder may be suitably sieved to provide glass powders having the desired particle size or particle size distribution (PSD).
  • PSD particle size or particle size distribution
  • the glass composition of the invention may be used for providing a coating on a metallic substrate in an electrochemical device. Accordingly, the present invention also provides the use of the glass composition of the invention for forming a coating on a metallic component to be used in an electrochemical device, especially a SOFC or SOEC stack.
  • the glass compositions of the invention are capable of forming protective glass coatings which have properties that make them suitable for use in SOFC (and SOEC) stacks.
  • the glass composition of the invention may be used to form a glass coating on a metallic substrate.
  • the glass coating is for metallic components for use in an electrochemical device including a SOFC or SOEC stack. Accordingly, the present invention provides a coating material formed from the glass composition described herein.
  • Having a protective layer on the metallic components in the electrochemical device may assist in improving the lifetime of the device in two ways. First, by protecting the metal components from high-temperature corrosion, and second, by preventing any harmful emissions (eg Cr) from the metallic components. For example, if the electrochemical device is a SOFC or SOEC stack, harmful emissions such as Cr could degrade the fuel cells in the device over time.
  • harmful emissions eg Cr
  • the coating material may comprise one or more fillers.
  • the fillers are substantially chemically inert toward the coating formed from the glass composition, which allows the fillers to be used without affecting the performance of the coating.
  • the fillers may also preferably have a CTE similar to that of glass, and/or have high strength. Examples of suitable fillers include, but are not limited to, ZrC in powder or fibre form, ceria and strontium silicates.
  • the coating material comprises from about 80 to about 100 vol% of the glass composition and from 0 to about 20 vol% of the one or more fillers, based on the total amount of coating material.
  • the glass composition of the coating material may be subjected to a suitable sintering thermal cycle to provide a glass coating on a metallic substrate suitable for use in an electrochemical device, especially a SOFC or SOEC stack.
  • a suitable thermal cycle may include a first step which allows the glass powder particles of the glass composition to soften and sinter together to provide a sintered glass having a relatively low viscosity, and a second step which allows the sintered glass to turn into a stable glass coating having a relatively high viscosity by forming crystals of many different compositions.
  • the glass coating which may be subsequently formed from the sintered glass, comprises one or more crystalline phases and a glassy phase.
  • the glass coating comprises about 40 to about 60 vol%, especially about 45 to about 55 vol%, of the one or more crystalline phases and about 40 to about 60 vol%, especially about 45 to about 55%, of the glassy phase, based on the total amount of glass coating.
  • the one or more crystalline phases of the glass coating comprise crystals having a structure selected from 2SrO.SiC>2, SrO.SiC>2, 3SrO.B2C>3, 2SrO.TiO2.2SiO, SrO.3B2Os, and SrO.B2Os and combinations thereof.
  • Exclusion of BaO from the glass coating may advantageously increase the lifetime of the device comprising the coated metallic components.
  • BaO may react with Or in the metallic components forming BaCrO4.
  • BaCrO4 has a CTE markedly different to the metallic components. Without wishing to be bound by theory, the inventors hypothesise that the presence of BaCrO4 at the interface may cause the separation of the coating from the metallic components during thermal cycling.
  • the presence of TiO2 in the specified amount may facilitate the completion of the formation of desired crystals in the glass coating during the soaking step, helping result in a stable glass coating.
  • the presence of some TiO2 in the retained glassy phase may improve the coating’s barrier properties to the undesirable interactions between Cr-containing metal components and Ba- containing components of an electrochemical device.
  • glass seals which may be in contact with the glass coating are a potential source of Ba ions.
  • the presence of TiO2 in the glassy phase of the coating may help to form stable crystalline phases with the Ba ions at the seal-coating interface.
  • the presence of CeC>2 facilitates the formation of finer and more uniformly distributed crystals in the resultant glass coating thereby making it more homogeneous.
  • the glass seal when the electrochemical device also comprises a glass seal, the glass seal may be a source of BaO.
  • the glass coating can act as a protective barrier from other sources of BaO in the electrochemical device.
  • Advantageously SOEC/SOFC stacks comprising metallic components coated with the glass coating of the present invention may reduce Cr emissions from the metallic components, increasing the useful life of the SOEC/SOFC stacks.
  • the Cr emissions from a SOEC/SOFC stack comprising the coated metallic components as described herein may be from about 100 times less to about 1000 times less compared to a SOEC/SOFC stack with uncoated metallic components.
  • Cr emission tests carried out on metal samples coated with a composition of the present invention showed that the Cr emission from coated metal surfaces is around 900 times to around 1000 times less compared to uncoated metal samples.
  • the inventors have determined that the presence of SrO in the concentration of the composition of the present invention has the function of scavenging Cr emitted by the metal substrate.
  • the glass coating may preferably have thermal expansion and contraction characteristics that closely match with those of other components of the electrochemical device, which is especially a SOFC or SOEC stack, in the range of temperatures where the glass is rigid, i.e. , below the glass transition temperature. This may advantageously allow the thermal stresses generated during the operation of the electrochemical device not to exceed the mechanical strengths of the components of the electrochemical device. Accordingly, in some embodiments, the glass coating has a thermal expansion and contraction mismatch with the metallic components it is coated upon of about -0.02 (negative 0.02) to about 0.18 (positive 0.18) at any temperature up to the glass transition temperature of the glassy phase, where the thermal expansion and contraction mismatch is defined as:
  • Glass refers to the glass coating and Other refers to the metallic component.
  • the glass transition temperature of the glassy phase is dependent on its composition and may be determined by methods known in the art, for example by conducting a dilatometry test.
  • glass samples prepared from the glass compositions of the invention have a stable expansion mismatch when subjected to an air environment or a fuel environment at elevated temperatures for extended periods of time.
  • the glass coating may have a coefficient of thermal expansion (CTE) which allows the glass coating to be suitable for use in an electrochemical device, especially a SOFC or SOEC stack.
  • the CTE may be substantially the same as the CTE of the coated metallic components in the SOFC or SOEC stack, or other electrochemical device.
  • the glass coating has a CTE of about 10 x 10 -6 /°C to about 13 x 10' 6 /°C.
  • the coating material of the invention may be useful for forming a glass coating on a metallic substrate for use in an electrochemical device, especially a SOFC or SOEC stack.
  • the present invention provides an electrochemical device, preferably a SOFC or SOEC stack, comprising one or more cells, each cell comprising a cathode, an anode and a solid electrolyte; a support structure comprising one or more supports; and the coating material described herein.
  • the present invention also provides an electrochemical device, preferably a SOFC or SOEC stack, comprising one or more cells, each cell comprising a cathode, an anode and a solid electrolyte, a support structure comprising one or more supports, a glass coating material and a glass seal, wherein the glass coating material is described herein and wherein the glass seal is as described in WO 2022/165554 A1 , the entirety of which is hereby incorporated within this application by reference.
  • the glass coating may be formed using a suitable sintering thermal cycle as described herein.
  • the support structure is an interconnected support structure which comprises one or more supports made of a suitable material, for example, made of a suitable metal such as steel.
  • the support structure is a set of interconnected plates. It will be understood that each plate may be interpreted as a support of the support structure, and each cell may comprise one or more of the plates.
  • the present invention also provides a method of forming a coating on a metallic substrate for use in an electrochemical device which is a SOFC or SOEC stack, the method comprising: applying the coating material described herein on a metallic substrate; and subjecting the metallic substrate and coating material to a heat treatment , wherein the glass composition of the coating material softens to provide a sintered glass while minimising interconnected pores and subsequently undergoes controlled crystallisation to provide a glass coating comprising one or more crystalline phases and a glassy phase; thereby forming the coating on the metallic substrate.
  • the coating material turns into a stable glass coating by forming crystals of many different compositions such as 2SrO.SiO2, SrO.SiC , 3SrO.B2Os, 2SrO.TiO2.2SiO, SrO.3B2Os, and Sr0.B20s.
  • These crystals favourably impart a higher mechanical strength and also thermal expansion and contraction characteristics that closely match with those of other components of the SOFC/SOEC stack.
  • the constituent oxides are consumed during the soaking step to form stable crystalline phases leaving a silicate glass matrix of low reactivity.
  • the heat treatment comprises a soaking step wherein the glass composition is heated to a minimum temperature being the higher of the glass transition temperature of the composition or at least 50°C above the intended operating temperatures for the metallic components.
  • the intended operating temperature may be from about 500°C to about 1000°C and the soaking step comprises heating the glass composition to at least a temperature of from about 550°C to about 1050°C.
  • the soaking step has a duration of from about 2 hour to about 5 hours.
  • the glass composition is applied to the metallic substrate as a slurry of glass powder.
  • the glass powder slurry is made with a suitable medium for example an alcohol.
  • the glass powder particles soften and sinter together to minimise interconnected pores and establish a glass coating on the metal surface.
  • the metallic substrate comprises metallic components for an electrochemical device.
  • the metallic components are coated prior to being placed inside the electrochemical device, or SOEC or SOFC stack. That is, the glass composition is applied to the metallic components and subjected to a heat treatment step prior to the metallic components being assembled in the electrochemical device.
  • the glass composition is applied to the metallic components prior to being placed in the electrochemical device and the heat treatment step occurs in-situ in the electrochemical device.
  • FIG. 1 is a schematic diagram of a portion of a SOFC stack (1 ) with cell components, namely the cathode (2), anode (3) electrolyte (4), support structure (5) and glass seal (6) shown in an exploded view.
  • FIG. 3 of a number of stacked units in a fuel cell stack shows a support structure of metal interconnect plates, each metal plate with applied glass coatings in accordance with the invention, as well as glass seals providing a seal between the electrolyte layers and the coated support layers.
  • SOFC stacks operated at standard operating temperatures over extended periods of time comprising metallic components coated with the coating material of the present invention degrade less than those with uncoated components. Accordingly, in some embodiments, the SOFC (or SOEC) stacks of the invention undergo a total performance degradation of less than 10%, especially less than 6%, more especially less than about 3%, even more especially less than about 2%, when operated for about 2,000 or about 5,000 hours and subjected to multiple thermal cycles from room temperature (about 20°C to about 25°C) up to the intended operating temperature of the SOFC (or SOEC) stack. [0085] It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.
  • Example 1 Glass compositions.
  • the percentage of the thermal expansion and contraction mismatch of the glass coating compared to the metal component on which the glass coating is applied is from -0.02 to 0.18 for temperatures below the glass transition temperature of the retained glassy phase.
  • Glass coatings with the Expansion Difference% in the prescribed range have a lower risk of generating tensile thermal stresses in the coating when the coated metallic components are exposed to higher temperature and corrosive operating environments, for example during the operation of a SOFC/SOEC stack.
  • the glass coating should be continuous and well adhered to the metal substrate.
  • compositions 1 -5 which have each component of the composition falling within the required ranges also satisfied all conditions for a well performing glass coating.
  • Compositions 6-9 have at least one component of the composition with a concentration outside the required range. Compositions 6-9 failed on at least one of the conditions required for a well performing glass coating.
  • SEM Scanning Electron Microscopy
  • an overlying glass seal is not essential to the use of the glass composition coating of the present invention, and in many applications the glass coating may be used without such an overlay.
  • Example 3 Results of Cr emissions tests on metal surfaces with and without the glass coating.
  • the Cr emission from the metal plates coated with the present invention is over 1000 time less compared to the Cr emission from uncoated metal.
  • Metal coated with glass coatings as herein described showed an improvement of at least 5% or at least 10% in Cr emission compared to alternative coatings.
  • the reduction in Cr emissions demonstrates the protective nature of the coating and the ability of the glass coating to protect the metallic components in a high temperature and corrosive environment.
  • Example 4 Increased lifetime of SOFC/SOEC stacks comprising the glass coating.
  • SOFC/SOEC stacks comprising a plurality of fuel cells and interconnects, comprising metallic components coated with the glass coating of the present invention and sealed with a suitable glass be operated for up to 5,000 hr and subjected to multiple thermal cycles from room temperature to normal operating temperature. Said fuel cells are expected to undergo a total performance degradation of less than 10%.

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Abstract

La présente invention concerne des compositions de verre et des matériaux de revêtement les comprenant appropriés pour revêtir des composants métalliques pour utilisation dans des environnements à haute température et corrosifs, par exemple dans des dispositifs électrochimiques et en particulier des empilements de piles à combustible à oxyde solide (SOFC) et d'électrolyseur à oxyde solide (SOEC).
PCT/AU2023/051349 2022-12-21 2023-12-21 Composition de verre pour revêtement protecteur WO2024130327A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2022903931 2022-12-21
AU2022903931A AU2022903931A0 (en) 2022-12-21 Glass composition for protective coating

Publications (1)

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WO2024130327A1 true WO2024130327A1 (fr) 2024-06-27

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