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US-12623961-B2 - Thermal protection method

US12623961B2US 12623961 B2US12623961 B2US 12623961B2US-12623961-B2

Abstract

A method for thermally protecting a part according to which a protective screen is placed in an in-use position in which the screen physically isolates at least one portion of the part from a heat source. The heat source is configured to bring the temperature of the at least one portion of the part to a temperature between 400° C. and 900° C. in the absence of the protective screen. The protective screen includes a substrate of glass strands at least partially coated with a coating that includes protective particles of a crystalline material that have a melting point above 1000° C. and is composed of one or more oxides in an amount of more than 95 wt. %. The coating covers more than 50% of the outer surfaces of more than 50% of the number of strands of the substrate.

Inventors

  • Audrey Durand
  • Franceline Villermaux

Assignees

  • SAINT-GOBAIN CENTRE DE RECHERCHES ET D'ETUDES EUROPEEN

Dates

Publication Date
20260512
Application Date
20210302
Priority Date
20200303

Claims (20)

  1. 1 . A method for thermally protecting a part chosen from: a drive shaft, an engine attachment harness, an element for isolating an engine, a cylinder, a pipe, a cable, a conveyor roller, a system for attaching and driving said rollers, an insulation mat used in the thermal protection of a nacelle of an engine, an insulation mat used in the thermal protection of an engine, a suspension structure of an engine, a thrust reverser, a fluid supply element of an engine, and a tube in which a fluid flows, said method comprising: placing a protective screen in an in-use position, in which said protective screen physically isolates at least one portion of said part from a heat source, said heat source being configured to bring the temperature of said at least one portion of said part to a temperature of between 400° C. and 900° C. in the absence of said protective screen, the protective screen comprising a support of glass yarns, said yarns being at least partially coated with a coating consisting of a dry binder and of protective particles of a crystalline material having a melting point above 1000° C. and consisting of one or more oxides in an amount of more than 95% of its mass, said coating covering more than 50% of the outer surfaces of more than 50% by number of the yarns of said support, the coating having a mean thickness of greater than 0.05 μm and less than 2 μm; the mass of the coating, on the basis of the mass of the protective screen, being greater than 3% and less than 25%; corundum, zircon, zirconia, mullite, cordierite, eskolaite, spinel, steatite, enstatite, and mixtures thereof, representing more than 80% of the mass of the crystalline phases of the material of the protective particles.
  2. 2 . The method as claimed in claim 1 , wherein more than 50% of the thickness of the support comprises coated yarns.
  3. 3 . The method as claimed in claim 2 , wherein the entire thickness of the support comprises coated yarns.
  4. 4 . The method as claimed in claim 3 , wherein the coating: covers more than 80% of the outer surfaces of more than 80% by number of the yarns of the support.
  5. 5 . The method as claimed in claim 1 , comprising a production of the protective screen, said production comprising the following steps 1) to 3): 1) preparing the support and a suspension comprising a liquid binder and the protective particles and/or precursors of protective particles; 2) applying said suspension to the yarns of the support so as to cover more than 50% of the outer surfaces of more than 50% by number of the yarns of the support; 3) drying so as to reduce the water content in order to convert the suspension into a coating which is in a solid form, so that the coating has a mean thickness of greater than 0.05 μm and less than 2 μm.
  6. 6 . The method as claimed in claim 5 , wherein the applying of the suspension to the yarns is carried out by impregnation of the support.
  7. 7 . The method as claimed in claim 5 , wherein, in step 1), a suspension not comprising protective particle precursors is prepared.
  8. 8 . The method as claimed in claim 1 , wherein the protective screen has a stiffness “c”, measured according to standard ASTM D1388-18, option A, but at room temperature with a relative humidity equal to 50%, of greater than 5 mm and less than 150 mm.
  9. 9 . The method as claimed in claim 8 , wherein said stiffness is less than 110 mm.
  10. 10 . The method as claimed in claim 8 , in which said stiffness is greater than 20 mm so as to retain a shape given after deformation.
  11. 11 . The method as claimed in claim 1 , wherein the support is a textile.
  12. 12 . The method as claimed claim 11 , wherein the support essentially consists of glass yarns organized in the form of a knit, of a braid or of a fabric.
  13. 13 . The method as claimed in claim 1 , wherein more than 90% by number of the yarns of the support have a length of greater than 10 mm, said yarns being an assembly of fibers having an equivalent diameter, measured at half-length, of greater than 2 μm and less than 50 μm.
  14. 14 . The method as claimed in claim 1 , wherein the glass yarns constituting the support consist of an amorphous material having an SiO 2 content of greater than or equal to 55%, as mass percentage on the basis of the mass of the yarns.
  15. 15 . The method as claimed in claim 14 , wherein the glass yarns constituting the support consist of a material having, as mass percentages on the basis of the mass of the yarns: an SiO 2 content of greater than 90% and an Al 2 O 3 content of greater than 0.1% and less than 5%, the oxides other than SiO 2 and Al 2 O 3 constituting the remainder to 100%, or an SiO 2 content of less than 79.9%, an Al 2 O 3 content of greater than 12.5% and less than 32%, and an MgO content of greater than 4% and less than 20%, the oxides other than SiO 2 , Al 2 O 3 and MgO constituting the remainder to 100%, or an SiO 2 content of greater than 99.9%.
  16. 16 . The method as claimed in claim 1 , wherein the amount of protective particles, as mass percentage on the basis of the total mass of the coating, is greater than 29% and less than 99.5% and/or the protective particles have a median size of greater than 50 nm and less than 500 nm.
  17. 17 . The method as claimed in claim 1 , wherein more than 90%, as mass percentage, of the protective particles exhibit a chemical analysis such that the total content of Al 2 O 3 +ZrO 2 +MgO+Cr 2 O 3 +Fe 2 O 3 +SiO 2 is greater than 80%, provided that SiO 2 <50%, as mass percentage on the basis of the oxides.
  18. 18 . The method as claimed in claim 17 , wherein the Al 2 O 3 content is greater than 95%, as mass percentage on the basis of the oxides.
  19. 19 . The method as claimed in claim 1 , wherein, before the protective screen is placed in the in-use position, the coating of said screen is at least partially debound.
  20. 20 . The method as claimed in claim 19 , wherein the protective screen is made to fit the part to be protected before being sold.

Description

TECHNICAL FIELD The invention relates to a method for thermally protecting a part subjected to a temperature of between 400° C. and 900° C. PRIOR ART The use of a textile of glass yarns for protecting a part from a temperature of between 400° C. and 900° C. is known, in particular for the thermal protection of pipes. To this effect, fabric can be deformed to fit the part to be protected. There is thus a need for a fabric which has good deformability. Moreover, prolonged exposure of the glass yarn fabric to a temperature of between 400° C. and 900° C. results in degradation of the mechanical properties of the yarns, and is detrimental to the longevity of the protection. There is thus also a need to increase the lifetime of such protection. The present invention aims to at least partially meet this need. DISCLOSURE OF THE INVENTION Summary of the Invention The invention proposes a method for thermally protecting a part according to which a protective screen is placed in an in-use position in which it physically isolates at least one portion of said part from a heat source, said heat source being configured to bring the temperature of said at least one portion of said part to a temperature of between 400° C. and 900° C., preferably between 400° C. and 800° C., in the absence of said protective screen, the protective screen comprising, preferably consisting of, a support made of glass yarns which is at least partially coated with a coating comprising protective particles of a crystalline material having a melting point above 1000° C. and consisting of one or more oxides in an amount of more than 95% of its weight, preferably consisting of a dry binder and of said protective particles. Before it is placed in the in-use position, the protective screen can be optionally deformed, preferably according to the shape of the part. Before the protective screen is placed in the in-use position, the coating of said screen can be optionally at least partially debound, or even totally debound, in particular when the protective screen has been made to fit the part to be protected before being sold. As will be seen in more detail in the remainder of the description, the inventors have discovered that such a coating, in particular when it comprises a dry binder, improves the deformability of the protective screen. After debinding, the coating confers excellent protection on the yarns. The lifetime of the in-use protective screen, during exposure to a temperature of between 400° C. and 900° C., preferably between 400° C. and 800° C., is thereby improved. A method according to the invention can also comprise one or more of the following optional and preferred characteristics: the support is a textile, preferably essentially consisting of glass yarns organized in the form of a knit, of a braid or of a fabric;more than 90% by number of the yarns of the support have a length greater than 10 mm, said yarns being an assembly of fibers having an equivalent diameter, measured at half-length, greater than 2 μm and less than 50 μm;the part is chosen from a driveshaft, an engine attachment harness, an element for isolating an engine, in particular a housing, a cylinder, a pipe, a cable, a conveyor roller, in particular for conveying glass sheets, a system for attaching and driving said rollers;the glass yarns constituting the support consist of an amorphous material having an SiO2 content of greater than or equal to 55%, as a mass percentage on the basis of the mass of the yarns;the glass yarns constituting the support consist of a material having, as mass percentages on the basis of the mass of the yarns: an SiO2 content of greater than 90% and an Al2O3 content of greater than 0.1% and less than 5%, the oxides other than SiO2 and Al2O3 making up the remainder to 100%, oran SiO2 content of greater than 55% and less than 79.9%, an Al2O3 content of greater than 12.5% and less than 32%, and an MgO content of greater than 4% and less than 20%, the oxides other than SiO2, Al2O3 and MgO making up the remainder to 100%, oran SiO2 content of greater than 99.9%; the dry binder is organic;the dry binder comprises a film-forming agent and/or a coupling agent;the amount of protective particles, as a mass percentage on the basis of the total mass of the coating, is greater than 29% and less than 99.5% and/or the protective particles have a median size of greater than 50 nm and less than 500 nm;more than 90%, as mass percentage, of the protective particles exhibit a chemical analysis such that the total content of Al2O3+ZrO2+MgO+Cr2O3+Fe2O3+SiO2 is greater than 80%, provided that SiO2<50%, as mass percentage on the basis of the oxides;more than 90%, as mass percentage, of the protective particles exhibit a chemical analysis such that the Al2O3 content is greater than 95%, as mass percentage on the basis of the oxides;the coating covers more than 30%, preferably more than 40%, preferably more than 50%, preferably more than 60%, p