MATERIAL LIFE EXTENSION FOR REFURBISHED 2-FOR-1 CARBON BRAKES VIA CERAMIC SOLUTIONS

A method is provided for refurbishing a C/C disk of a first thickness and coated with a first ceramic solution for a second life. The method includes machining the C/C disk of the first thickness to remove a coating of the first ceramic solution from the wear surfaces of the C/C disk of the first thickness. Removing the coating of the first ceramic solution further removes a portion of the C/C disk thereby forming a C/C disk of a second thickness. The second thickness is less than the first thickness. The method further includes coating the wear surfaces of the C/C disk of the second thickness with a second ceramic solution, thereby forming a C/C disk of the second thickness coated with the second ceramic solution. Additionally, the method includes drying the C/C disk of the second thickness coated with the second ceramic solution.

FIELD

The present disclosure relates generally to aircraft carbon brakes and, more specifically, to extending the material life of refurbished 2-for-1 carbon brakes via ceramic solutions.

BACKGROUND

Aircraft typically utilize brake systems on wheels to slow or stop the aircraft during landings, taxiing, and rejected takeoffs. The brake systems generally employ a brake stack or heat sink comprising a series of friction disks that may be forced into sliding contact with one another during brake actuation to slow or stop the aircraft. The brake stack typically comprises rotor disks and stator disks that, in response to axial compressive loads, convert the kinetic energy of the aircraft into heat through frictional forces experienced between the friction disks.

SUMMARY

A method for refurbishing a C/C disk of a first thickness and coated with a first ceramic solution for a second life is disclosed. The method includes machining the C/C disk of the first thickness to remove a coating of the first ceramic solution from the wear surfaces of the C/C disk of the first thickness thereby forming a C/C disk of a second thickness and wherein the second thickness is less than the first thickness; coating the wear surfaces of the C/C disk of the second thickness with a second ceramic solution, thereby forming a C/C disk of the second thickness coated with the second ceramic solution; and drying the C/C disk of the second thickness coated with the second ceramic solution.

In various embodiments, removing the coating of the first ceramic solution from the wear surfaces of the C/C disk of the first thickness further removes a portion of the C/C disk. In various embodiments, the second ceramic solution is applied to a wear surface of the C/C disk of the second thickness via at least one of spraying, painting, smearing, brushing, sorption, cold spraying, sputtering, pouring, sprinkling, peptization, or infiltration. In various embodiments, the second ceramic solution comprises at least one of nano ceramic binary oxide particulates, doped nano ceramic binary oxide particulates, or nano ceramic ternary oxide particulates.

In various embodiments, the nano ceramic binary oxide particulates comprise at least one of zirconium dioxide (ZrO2), aluminum oxide (Al2O3), or magnesium oxide (MgO). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of lithium oxide (Li2O), beryllium oxide (BeO), calcium oxide (CaO), strontium oxide (SrO), or barium oxide (BaO). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of scandium (III) oxide (Sc2O3), yttrium oxide (Y2O3), cobalt (II) oxide (CoO), or nickel oxide (NiO). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of silicon oxide (SiO2), titanium oxide (TiO2), zirconium oxide (ZrO2), or hafnium (IV) oxide (HfO2). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of vanadium (II) oxide (VO), vanadium (III) oxide (V2O3), vanadium oxide (VO2), niobium (II) oxide (NbO), tantalum oxide (Ta2O5), tungsten (IV) oxide (WO2), or tungsten trioxide (WO3). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of gallium oxide (GaO), indium oxide (In2O3), or tin (IV) oxide (SnO2). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of lanthanum oxide (La2O3), cerium dioxide (CeO2), praseodymium (III,IV) oxide (Pr6O11), or neodymium oxide (Nd2O3). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of samarium oxide (Sm2O3), europium oxide (Eu2O3), gadolinium oxide (Gd2O3), terbium oxide (Tb2O3), or dysprosium oxide (Dy2O3). In various embodiments, the nano ceramic binary oxide particulates comprise at least one of holmium oxide (Ho2O3), erbium oxide (Er2O3), thulium oxide (Tm2O3), ytterbium oxide (Yb2O3), or lutetium oxide (Lu2O3). In various embodiments, the doped nano ceramic binary oxide particulates comprise at least one of yttrium oxide stabilized zirconium (IV) oxide (YSZ) or zirconium (IV) oxide toughened aluminum oxide (ZTA). In various embodiments, the nano ceramic ternary oxide particulates comprise at least one of lithium silicate (Li2SiO3), mullite (Si2Al6O13), calcium silicate (Ca2SiO4), or hafnium orthosilicate (HfSiO4). In various embodiments, the nano ceramic ternary oxide particulates comprise at least one of lithium titanate (Li2TiO3), aluminum titanate (Al2TiO5), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), or hafnium titanate (HfTiO4). In various embodiments, the nano ceramic ternary oxide particulates comprise at least one of strontium zirconate (SrZrO3) or barium zirconate (BaZrO3).

Also disclosed herein is a method for refurbishing a C/C disk of a second thickness and coated with a second ceramic solution for a third life. The method includes machining the C/C disk of the second thickness to remove a coating of the second ceramic solution from the wear surfaces of the C/C disk of the second thickness thereby forming a C/C disk of a third thickness and wherein the third thickness is less than the second thickness; pairing with and mechanically attaching the C/C disk of the third thickness with another C/C disk of the third thickness thereby forming a C/C split-disk of a fourth thickness, wherein the fourth thickness is greater than the third thickness; coating the wear surfaces of the C/C split-disk of the fourth thickness with a third ceramic solution, thereby forming a C/C split-disk of the fourth thickness coated with the third ceramic solution; and drying the C/C split-disk of the fourth thickness coated with the third ceramic solution.

In various embodiments, removing the coating of the second ceramic solution from the wear surfaces of the C/C disk of the second thickness further removes a portion of the C/C disk. In various embodiments, the third ceramic solution is applied to a wear surface of the C/C split-disk of the fourth thickness via at least one of spraying, painting, smearing, brushing, sorption, cold spraying, sputtering, pouring, sprinkling, peptization, or infiltration. In various embodiments, the third ceramic solution comprises at least one of nano ceramic binary oxide particulates, doped nano ceramic binary oxide particulates, or nano ceramic ternary oxide particulates.

Also disclosed herein a method for refurbishing a C/C split-disk of a fourth thickness and coated with a third ceramic solution for a fourth life. The method includes machining the C/C split-disk of the fourth thickness to remove a coating of the third ceramic solution from the wear surfaces of the C/C split-disk of the fourth thickness thereby forming a C/C split-disk of a fifth thickness and wherein the fifth thickness is less than the fourth thickness; coating the wear surfaces of the C/C split-disk of the fifth thickness with a fourth ceramic solution, thereby forming a C/C split-disk of the fifth thickness coated with the fourth ceramic solution; and drying the C/C split-disk of the fifth thickness coated with the fourth ceramic solution.

In various embodiments, removing the coating of the third ceramic solution from the wear surfaces of the C/C split-disk of the fourth thickness further removes a portion of the C/C split-disk. In various embodiments, the fourth ceramic solution is applied to a wear surface of the C/C split-disk of the fifth thickness via at least one of spraying, painting, smearing, brushing, sorption, cold spraying, sputtering, pouring, sprinkling, peptization, or infiltration. In various embodiments, the fourth ceramic solution comprises at least one of nano ceramic binary oxide particulates, doped nano ceramic binary oxide particulates, or nano ceramic ternary oxide particulates.

DETAILED DESCRIPTION

The detailed description of embodiments herein makes reference to the accompanying drawings, which show embodiments by way of illustration. While these embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the spirit and scope of the disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not for limitation. For example, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Further, any steps in a method discussed herein may be performed in any suitable order or combination.

By itself, carbon provides good wear resistance, but the addition of ceramic particulates to the C/C brakes may decrease wear rates and increase brake life. Provided herein, in accordance with various embodiments, are methods where a carbon/carbon (C/C) disk with a ceramic solution applied may be refurbished to extend refurbished brake stack or heat sink life without a need to produce a new brake stack or heat sink. In various embodiments, a C/C disk of a first thickness, i.e. a “thick” C/C disk, which has previously received a coating of the ceramic solution and is at an end of the C/C disk's first tour life (1st life), is received. In embodiments relating to C/C disks, as used herein, a “thick” C/C disk would have a thickness of between about 0.75 inches and about 2.0 inches, although preferably a thick C/C disk would have a thickness of between about 0.75 inch and about 1.5 inches. In various embodiments, the ceramic application, which was coated onto the “thick” C/C disk previously, is removed via machining thereby forming a new “thin” C/C disk of a second thickness that is less than the first thickness of the “thick” C/C disk and with no ceramic solution applied. In various embodiments, a “thin” C/C disk would have a thickness of between about 0.75 inches and about 1.75 inches. In various embodiments, the “thin” C/C disk is then applied with a new ceramic solution coating, thus forming a refurbished C/C disk with ceramic solution coating (2nd life). In various embodiments, a ceramic solution coating may be comprised of one or more of a nano ceramic binary oxide, a doped nano ceramic binary oxide, or a nano ceramic ternary oxide particulates which is suspended in a ceramic solution known as a “sol.” In various embodiments, the sol may be applied via numerous routes like spraying, painting, smearing, brushing, sorption, cold spraying, sputtering, pouring, sprinkling, peptization, or infiltration, among others, but is generally applied in small quantities at the disk surfaces as a surface coating. In various embodiments, during the operation of the brake, the nano ceramic binary oxide, doped nano ceramic binary oxide, or nano ceramic ternary oxide is mixed into the carbon wear debris as its generated which then has the ability to drastically reduce wear rates and increase brake life. In various embodiments, in response to other carbon wear debris oxidizing away, the already oxidized ceramics remain, without needing to be regenerated like current wear debris and may regenerate carbon wear debris quickly to assist in brake lubrication.

In various embodiments, this refurbished “thin” C/C disk of the second thickness may be received for overhaul again and the sprayed on ceramic solution would be removed via machining. In various embodiments, the resulting “thinner” disk with a third thickness that is less than the second thickness may be paired with and mechanically attached to another overhauled “thinner” C/C disk to form a combined “thick” C/C split-disk of a fourth thickness that is greater than the third thickness. In various embodiments, a “thick” C/C split-disk would have a thickness of between about 1.0 inches and about 1.75 inches. In various embodiments, the combined “thick” C/C split-disk is then sprayed with a new ceramic solution coating, thus forming a refurbished combined “thick” C/C split-disk with ceramic solution coating (3rdlife). In various embodiments, the refurbished combined “thick” C/C split-disk of the fourth thickness may be received for overhaul again and the sprayed on ceramic solution would be removed via machining, thereby forming a combined “thin” C/C split-disk of a fifth thickness that is less than the fourth thickness, which is sprayed with a new ceramic coating, thus forming a refurbished combined “thin” C/C split-disk (4thlife). In various embodiments, a “thin” C/C split-disk would have a thickness of between about 0.8 inches and about 1.25 inches. If the refurbished combined “thin” C/C split-disk is received, the refurbished combined “thin” C/C split-disk is discarded.

Referring toFIG.1, a multi-disk brake system20is illustrated according to various embodiments. The system may include a wheel10supported for rotation around axle12by bearings14. Axle12defines an axis of multi-disk brake system20and the various components thereof. Any reference to the terms axis and axial may include an axis of rotation defined by axle12or a dimension parallel to such axis. Wheel10includes rims16for supporting a tire, and a series of axially extending rotor splines18(one shown). Rotation of wheel10is modulated by multi-disk brake system20. Multi-disk brake system20includes torque flange22, torque tube24, a plurality of pistons26(one shown), pressure plate30, and end plate32. Torque tube24may be an elongated annular structure that includes reaction plate34and a series of axially extending stator splines36(one shown). Reaction plate34and stator splines36may be integral with torque tube24, as shown inFIG.1, or attached as separate components.

Multi-disk brake system20also includes a plurality of friction disks38. The plurality of friction disks38includes at least one non-rotatable friction disk (stator)40, and at least one rotatable friction disk (rotor)42. Stators40may include a carbon/carbon (C/C) disk. Rotors42may include a carbon/carbon (C/C) disk. Each friction disk38includes an attachment structure. For example, stators40include a plurality of stator lugs44at circumferentially spaced positions around an inner circumference of stators40, and rotors42include a plurality of rotor lugs46at circumferentially spaced positions around an outer circumference of rotors42.

Torque flange22is mounted to axle12. Torque tube24is bolted to torque flange22such that reaction plate34is near an axial center of wheel10. End plate32is connected to a surface of reaction plate34facing axially away from the axial center of wheel10. Thus, end plate32is non-rotatable by virtue of its connection to torque tube24. Stator splines36may support the pressure plate30such that pressure plate30is also non-rotatable. Stator splines36also support the stators40. Stators40engage stator splines36with gaps formed between stator lugs44. Similarly, rotors42engage rotor splines18with gaps formed between rotor lugs46. Thus, rotors42are rotatable by virtue of their engagement with rotor splines18of wheel10.

In various embodiments, rotors42are arranged with end plate32on one end, pressure plate30on the other end, and stators40interleaved such that rotors42are adjacent to non-rotatable friction components. Pistons26are connected to torque flange22at circumferentially spaced positions around torque flange22. Pistons26face axially toward wheel10and contact a side of pressure plate30opposite rotors42. Pistons26may be powered electrically, hydraulically, or pneumatically. In response to actuation of pistons26, a force towards reaction plate34is exerted on friction disks38such that rotors42and stators40are pressed together between pressure plate30and end plate32.

Referring now toFIG.2, in accordance with various embodiments, a fibrous preform200utilized to manufacture a carbon/carbon (C/C) disk is illustrated. Fibrous preform200may be employed to form a stator40or a rotor42, as described above. Fibrous preform200may comprise a porous structure comprised of a plurality of stacked textile layers202. Each textile layer202having a thickness in a first dimension (i.e., the Z-direction) that may be substantially less than a thickness of the layer202in the other two dimensions (i.e., the X-direction and the Y-direction). As used herein, the “in-plane” direction refers to directions parallel to the thicker two dimensions (i.e., parallel to the X and Y directions and perpendicular to the Z-direction).

A porous structure may comprise any structure derived from a fibrous material such as carbon fibers or the like. In various embodiments, the carbon fibers may be derived from polyacrylonitrile (PAN), rayon (synthetic fiber derived from cellulose), oxidized polyacrylonitrile fiber (OPF), pitch, or the like. The starting fiber may be pre-oxidized PAN or fully carbonized commercial carbon fiber. Fibrous preform200may be prepared by needling the textile layers202of fibrous preform200. Needling the textile layers202of fibrous preform200tends to push fibers from one layer202to the next layer202, thereby forming z-fibers that extend axially across the layers202. Needling pulls fibers from the in-plane direction and forces the fibers into the z-fiber direction. After needling, fibrous preform200may comprise fibers extending in three different directions: the radial direction, the circumferential direction, and the axial direction (or the X, Y, and Z directions).

Fibrous preform200may be fabricated using a net shape preforming technology or may be cut from a needled board. Fibrous preform200may be a lay-up of woven, braided or knitted textile layers202. The fibrous material may be in the form of chopped carbon fibers molded to form layers202. Prior to the densification process, the fibrous material may be formed into a preform having any desired shape or form. For example, the fibrous preform may be in the form of a disk having any shape such as, for example, a polygon, a cylinder, a triangle, annular, square, rectangle, pentagon, hexagon, octagon, or the like. In various embodiments, layers202and fibrous preform200may have a generally annular shape. In accordance with various embodiments, the outer circumferential (or outer perimeter) surfaces204of layers202may form an outer diameter (OD)206of fibrous preform200, and the inner circumferential (or inner perimeter) surfaces208of layers202may form an inner diameter (ID)210of fibrous preform200. Each layer202includes a first axial face212and a second axial face214opposite the first axial face212. First and second axial faces212,214extend from outer circumferential surface204to inner circumferential surface208. Layers202are stacked such that the first axial face212of one layer202is oriented toward the second axial face214of the adjacent layer202. First axial face212of the uppermost layer202forms the upper axial end216of fibrous preform200and the second axial face214of the bottommost layer202forms the lower axial end217of fibrous preform200(i.e., the two layers202that are farther apart from one another in the axial direction form the axial ends216,217of the fibrous preform).

As shown inFIG.3, in accordance with various embodiments, fibrous preform200utilized to manufacture a carbon/carbon (C/C) disk being placed in a carbonization furnace302for carbonization is illustrated. The carbonization process may be employed to convert the fibers of the fibrous preforms200into pure carbon fibers, as used herein only “pure carbon fibers” means carbon fibers comprised of at least 99% carbon. The carbonization process is distinguished from the densification process described below in that the densification process involves infiltrating the pores of the fibrous preform200and depositing a matrix (e.g., carbon, phenolic resin, or any other desired matrix material) within and around the carbon fibers of the fibrous preform, and the carbonization process refers to the process of converting the fibers of the fibrous preform200into pure carbon fibers.

In various embodiments, a plurality of fibrous preforms200may be placed on top of one another with separator plates304and spacing stops306disposed between adjacent fibrous preforms200. For example, the bottommost fibrous preform200may be placed on a base plate308at the bottom of carbonization furnace302. A separator plate304may be placed on top of the bottommost fibrous preform200. Another fibrous preform200may then be placed on the separator plate304, and another separator plate304may be placed on that fibrous preform200. A stack of fibrous preforms200and separator plates304may be constructed in this manner, with each fibrous preform200being separated from superjacent and subjacent fibrous preforms200by separator plates304. Spacing stops306may be placed between each of the separator plates304. The spacing stops306may comprise a height that is less than the thickness of the fibrous preform200prior to carbonization. Spacing stops306may define a target thickness of the fibrous preform200after carbonization. In that regard, after the stack of fibrous preforms200is constructed, and before the carbonization process has started, gaps may exist between the spacing stops306and adjacent separator plates304. During carbonization, a compressive load may be applied to the fibrous preforms200, thereby compressing the fibrous preforms200until spacing stops306contact adjacent separator plates304.

In various embodiments, compressive pressure may be applied to fibrous preforms200during the carbonization. The compressive pressure may be applied by placing a weight310over fibrous preforms200, or by applying a compressive load to the fibrous preforms200by other suitable means. The compressive pressure may be applied along the direction of the z-fibers. It will be appreciated by those skilled in the art that the mass of weight310and/or the compressive force generated by weight310may vary depending on the size of fibrous preforms200, the pre-carbonization fiber volume of fibrous preforms200, the desired post-carbonization fiber volume of fibrous preforms200, and/or the number fibrous preforms200being compressed. As used herein, “fiber volume” refers the percentage of the total volume of the fibrous preform that is formed by the fibers of the fibrous preform. For example, a fiber volume of 18% means the fibers of the fibrous preform form 18% of the total volume of fibrous preform. In various embodiments, after carbonization, fibrous preform200includes a fiber volume of between 10% and 50%. In various embodiments, after carbonization, fibrous preform200includes a fiber volume of between 15% and 25%. In various embodiments, fibrous preforms200having a low fiber volume may be desirable for the infiltration methods disclosed herein. In various embodiments, after carbonization, fibrous preform200may comprise a fiber volume of less than 25%. For example, in various embodiments, after carbonization, fibrous preform200may comprise a fiber volume of 21% or, in various embodiments, fibrous preform200may comprise a fiber volume of 18%. In various embodiments, the carbonized fibrous preform200is then densified via chemical vapor infiltration (CVI) with pyrolytic carbon at a predetermined temperature for a predetermined time interval as is known in the art, which results in a finished C/C disk.

Referring now toFIG.4, in accordance with various embodiments, a flowchart of a method400for refurbishing a “thick” C/C disk coated with a ceramic solution applied to its wear surfaces for a second life is illustrated. In various embodiments, at block402, a carbon/carbon (C/C) disk of a first thickness, i.e. a “thick” C/C disk, which is at an end of the C/C disk's first tour life (1st life) and that has previously received a coating of the ceramic solution to its wear surfaces, is received. In various embodiments, at block404, the “thick” C/C disk is machined to remove the ceramic solution coating from the wear surfaces, which may also remove a portion of the “thick” C/C disk, thereby forming a carbon/carbon (C/C) disk of a second thickness, i.e. a “thin” C/C disk, where the second thickness is less than the first thickness. In various embodiments, at block406a new coating of the ceramic solution, i.e. nano ceramic binary oxide, doped nano ceramic binary oxide, or nano ceramic ternary oxide particulates suspended in a ceramic solution, referred to as a “sol,” is applied to the wear surfaces of the “thin” C/C disk. In various embodiments, the particulates have an average particle size of between 10 nanometers (0.3937 microinch) and 250 nanometers (9.843 microinches). In various embodiments, the particulates have an average particle size of between 10 nanometers (0.3937 microinch) and 150 nanometers (5.906 microinches). In various embodiments, the particulates have an average particle size of between 10 nanometers (0.3937 microinch) and 50 nanometers (1.969 microinches). In various embodiments, the sol may be applied via numerous routes such as spraying, painting, smearing, brushing, sorption, cold spraying, sputtering, pouring, sprinkling, peptization, or infiltration, among others to physically coat the wear surface of the C/C disk. In various embodiments, the sol may be applied in small quantities at the disk wear surfaces like a surface coating. In that regard, in various embodiments, an amount of sol applied may be between 0.025 cubic centimeters (0.001526 cubic inches) and 3 cubic centimeters (0.1831 cubic inches) per unit of disk surface. In various embodiments, an amount of sol applied may be between 0.075 cubic centimeters (0.004577 cubic inches) and 2.5 cubic centimeters (0.1526 cubic inches) per disk surface. In that regard, in various embodiments, an amount of sol applied may be between 0.125 cubic centimeters (0.007628 cubic inches) and 2 cubic centimeters (0.122 cubic inches) per disk surface. In various embodiments, during the operation of the brake, the nano ceramic binary oxide, doped nano ceramic binary oxide, or nano ceramic ternary oxide is mixed into the carbon wear debris as its generated which then has the ability to drastically reduce wear rates and increase brake life. In various embodiments, in response to other carbon wear debris oxidizing away, the already oxidized ceramics remain, without needed to be regenerated like current wear debris coatings.

In various embodiments, the nano ceramic binary oxide particulates may include zirconium oxide (ZrO2), aluminum oxide (Al2O3), or magnesium oxide (MgO), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include lithium oxide (Li2O), beryllium oxide (BeO), calcium oxide (CaO), strontium oxide (SrO), or barium oxide (BaO), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include scandium (III) oxide (Sc2O3), yttrium oxide (Y2O3), cobalt (II) oxide (CoO), or nickel oxide (NiO), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include silicon oxide (SiO2), titanium oxide (TiO2), or hafnium (IV) oxide (HfO2), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include vanadium (II) oxide (VO), vanadium (III) oxide (V2O3), vanadium oxide (VO2), niobium (II) oxide (NbO), tantalum oxide (Ta2O5), tungsten (IV) oxide (WO2), or tungsten trioxide (WO3), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include gallium oxide (GaO), indium oxide (In2O3), or tin (IV) oxide (SnO2), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include lanthanum oxide (La2O3), cerium oxide (CeO2), praseodymium (III,IV) oxide (Pr6O11), or neodymium oxide (Nd2O3), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include samarium oxide (Sm2O3), europium oxide (Eu2O3), gadolinium oxide (Gd2O3), terbium oxide (Tb2O3), or dysprosium oxide (Dy2O3), and various combinations of the same, among others. In various embodiments, the nano ceramic binary oxide particulates may include holmium oxide (Ho2O3), erbium oxide (Er2O3), thulium oxide (Tm2O3), ytterbium oxide (Yb2O3), or lutetium oxide (Lu2O3), and various combinations of the same, among others. In various embodiments, the doped nano ceramic binary oxide particulates may include yttrium oxide-stabilized zirconium (IV) oxide (YSZ) or zirconium (IV) oxide toughened aluminum oxide (ZTA), and various combinations of the same, among others. In various embodiments, the nano ceramic ternary oxide particulates may include lithium silicate (Li2SiO3), mullite (Si2Al6O13), calcium silicate (Ca2SiO4), or hafnium orthosilicate (HfSiO4), and various combinations of the same, among others. In various embodiments, the nano ceramic ternary oxide particulates may include lithium titanate (Li2TiO3), aluminum titanate (Al2TiO5), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), or hafnium titanate (HfTiO4), and various combinations of the same, among others. In various embodiments, the nano ceramic ternary oxide particulates may include strontium zirconate (SrZrO3) or barium zirconate (BaZrO3), and various combinations of the same, among others. In various embodiments, at block408, the ceramic solution coated “thin” C/C disk may then be dried before being installed in a multi-disk brake system, such as the multi-disk brake mechanism100ofFIG.1, thereby starting its second life.

Referring now toFIG.5, in accordance with various embodiments, a flowchart of a method500for refurbishing a “thin” C/C disk coated with a ceramic solution applied to its wear surfaces for a third life is illustrated. In various embodiments, at block502, a carbon/carbon (C/C) disk of a second thickness, i.e. a “thin” C/C disk, which is at an end of the C/C disk's second tour life (2ndlife) and that has previously received a coating of the ceramic solution to its wear surfaces, is received. In various embodiments, at block504, the “thin” C/C disk is machined to remove the ceramic solution coating from the wear surfaces, which may also remove a portion of the “thin” C/C disk, thereby forming a carbon/carbon (C/C) disk of a third thickness, i.e. a “thinner” C/C disk, where the third thickness is less than the second thickness. In various embodiments, at block506, the “thinner” disk is pair with and mechanically attached to another overhauled “thinner” C/C disk thereby forming a “thick” C/C split-disk of a fourth thickness that is greater than the third thickness. In various embodiments, at block508a new coating of the ceramic solution, i.e. the ceramic solution described previously with regard toFIG.4, is applied to wear surfaces of the “thick” C/C split-disk. In various embodiments, at block510, the ceramic solution coated “thick” C/C split-disk may then be dried before being installed in a multi-disk brake system, such as the multi-disk brake mechanism100ofFIG.1thereby starting its third life.

Referring now toFIG.6, in accordance with various embodiments, a flowchart of a method600for refurbishing a “thick” C/C split-disk coated with a ceramic solution applied to its wear surfaces for a fourth life is illustrated. In various embodiments, at block602, a carbon/carbon (C/C) disk of a fourth thickness, i.e. a “thick” C/C split-disk, which is at an end of the C/C disk's third tour life (3rdlife) and that has previously received a coating of the ceramic solution to its wear surfaces, is received. In various embodiments, at block604, the “thick” C/C split-disk is machined to remove the ceramic solution coating from the wear surfaces, which may also remove a portion of the “thick” C/C split-disk, thereby forming a carbon/carbon (C/C) disk of a fifth thickness, i.e. a “thin” C/C split-disk, where the fifth thickness is less than the fourth thickness. In various embodiments, at block606a new coating of the ceramic solution, i.e. the ceramic solution described previously with regard toFIG.4, is applied to wear surfaces of the “thin” C/C split-disk. In various embodiments, at block608, the ceramic solution coated “thin” C/C split-disk may then be dried before being installed in a multi-disk brake system, such as the multi-disk brake mechanism100ofFIG.1thereby starting its fourth life.