DE2263692A1 - DRY LUBRICATED MATERIALS - Google Patents

Description

Patent attorney

Dr. Ing.H. Negendank

Dipl. Ing. H. H-iut - π: i ~ i Γ 173. VV. Schmitz

WpI. Ing. E. Gföai "- '■: .t. ~ G. -V. V / ohnert

* MIlRCkWi 2. Kf (KSTtMTaOe 25

Telephone 5330586

Chrysler Corporation

120Q0 Oakland Avenue

Highland Park, Michigan, USA December 27, 1972

Attorney file M-2389

Dry-lubricated materials

Invention relates to a material for dry

te ^ components that rub on each other, such as those for example can be used in rotary engines, and in particular on components manufactured using such materials for turbine engine regenerators as well as a new sealing arrangementi which contains such a material.

4 ^ b refers to the applicant's two German patent applications referred to on the same filing date.

In dry lubrication arrangements, a component rubs on a Gregenbautei ^., For example in a turbine regenerator, where a kegenerator core with rubbing contact between one Arrangement of seals and cross bars at high temperatures and without the use of ITuid liners. Most assemblies of this type have so far been made with sintered, metallic, abrasive work surfaces

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as in the one of the above mentioned patent applications or they were coated with graphite and did not work satisfactorily or were not suitable for use in gas turbine engines and the like.

According to the invention, a new material is created which, when used under operating conditions which occur with dry cutting at elevated temperatures, has the desired friction and wear properties. The material forms a working surface for one of two frictionally interacting components and is particularly suitable for use at temperatures such as those that occur, for example, in certain sections of regenerators in gas turbine engines, ie temperatures in the range of about 530 ° O. According to the invention, such a work surface initially essentially contains a structural layer of iron oxide, preferably Pe.0 ,, which is applied to a carrier. The iron oxide layer contains a mixture of wound graphite, boron nitrite (BiO and Na ₂ St) distributed in it. or an equivalent given below. During a break-in period, for example at operating temperatures of the engine, that is about 425 to 535 ° O, affect the graphite and boron nitride as a solid lubricant for the components and assist in the formation of a iiu substantially continuous, highly oriented crystalline # eo0 _v -0berfläehenüberzug3auf the working surface of the rider

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Component. The coating has a high degree of alignment, since as a result of the retraction the oxide particles align themselves for the most part automatically as a result of the friction effect during retraction, their base surfaces running essentially parallel to the rubbing outside of the work surface. The Ha ₂ SO acts as a particle trap in which the abraded oxide particles automatically embed, orient and sinter, creating the essentially continuous coating of highly oriented 3? ΒρΟ.-.

In accordance with the invention, there is also a regenerator in the area of his hot edge formed in such a way that an arrangement with an abrasion-Auffangxiut using the material mentioned arises.

Overall, the invention creates an improved sealing arrangement i'for a gas turbine regenerator that is starting a new training

the
and has a üer / iieibdichtungen a material wears, the first having a working surface, of a iiickelgraph.it Eisenozyagefüge having dispersed therein mixture of boron nitride and Liatriumsulfat-üiaoSO a »liatriurnphosphat-Ha ^ PO, or Kalziuiafluorid-Ua" j ? ₂ exists.

further features of the invention result au ;; uon iuii.check and the following description in

ijiijuurj ^ with uoii drawing on. since ζgigen: "

C OHiGM /

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1 is a schematic view of a portion of a gas turbine engine including the regenerator section j

Fig. 2 is a side view of a regenerator core;

3 is a side view of an inner sealing arrangement of a regenerator section including FIG hot edge seals and hot cross bars;

Figs. 4a and 4b are schematic representations of the structure of the material according to the invention before and after the retraction process.

In the arrangement according to FIG. 1, a regenerator core 10 rotates in frictional contact between an outer (cold) sealing arrangement 12 and an inner (hot) sealing arrangement 14. The sealing arrangement 14 contains a hot edge seal 16 and a hot transverse strip seal 18. The material according to the invention is suitable in particular for use as a work surface on the hot edge seal 16 and is described in connection with this application, but is not necessarily restricted thereto. In the area of the hot edge seal the material characteristically operating temperatures on the order of about 315 to 53 is exposed 3 ^0! O.

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Before moving in, the material of such a work surface consists of an iron oxide structure, preferably FeJO ,, on the surface of a support, such as stainless steel 430, 442 or the like, or generally ferritic stainless materials. The exact material of the carrier is not critical as long as it has the required compatibility with regard to the coefficient of thermal expansion and the like with the material of the working surface layer. The other iron oxides FeO and Fe ₂ O., or various mixtures thereof, can also be used for the initial oxide structure. The iron oxide contains a mixture of boron nitrite, nickel graphite and a sodium sulfate, sodium phosphate or calcium fluoride (Na ₂ SO., Na ₃ PO, or CaF ₂ ) catching substance distributed therein, as shown in FIG. 4a. These materials are preferably in mutual proportions of about 55% by weight Fe ^ O., 20% by weight nickel graphite, 20% by weight Na ₂ SO, or its equivalent and about 5% by weight? » Boron nitride. The boron nitrite can be varied from about 1 to 10%, the capture material from about 5 to 30 ^L / o and the nickel graphite from about 10 to 50 % , with Fe ₃ O making up the remainder.

The initial work surface is best applied to the support by flame or plasma spraying of a granular mixture of Fe ^ O, powder, nickel graphite, boron nitride and the _{catching substance Na 2} SO, NaJPO ₂ , OaF ₂ or mixtures thereof. Nickel graphite is used in the case of spraying because it is

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consists of graphite particles coated with nickel, so that the graphite is protected during spraying. It is commercially available in various compositions ranging from about 50 to 85% nickel and 5 to 15 % graphite. Otherwise, ordinary graphite granules can be used. It has been found that the design of the regenerator section is important in order to be able to fully utilize the advantages of the material according to the invention when used in turbine engines. 2 shows a regenerator core 10 with a circumferential groove 24 formed on the end face and spaced apart grooves 26 which run radially from the circumferential groove to the edge of the core. FIG. 3 shows the hot edge seals 16 and the crossbar 18 cooperating with the regenerator core, the edge seals, the crossbars and the core being in frictional contact during operation of the engine, as shown in FIG. As Fig. 5 shows, the surfaces of the sealing arrangement are smooth.

The circumferential and radial grooves 24 and 26 on the regenerator core are decisive for a long service life of the sealing arrangements of this type. The grooves provided according to the invention are used as channels for removing contaminants so that any Excess debris that forms is removed can, namely those particles that are not needed to build up the continuous coating. The excess on Abraded particles that do not automatically become part of the trapping material

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the work surface embeds, causes abrasion of the interacting surfaces.

The design and the material of the work surfaces together result in the embedding of part of the abraded iron oxide particles in the work surface, where they automatically orient themselves in a preferred orientation during the retraction, in which their base surfaces run parallel to the work surface, and sinter together, so that one in essentially continuous, highly oriented Pe ₂ O. ^ - coating builds up on the sealing sliding surface, as in Pig. 4b is shown. The grooves serve to remove the excess particles which do not automatically embed themselves in the work surface, so that these particles are prevented from being caught between the components and grinding off the sliding surfaces, which would lead to damage.

As a result of the running-in process, iron oxide and catching material are also transferred from the sealing arrangement to the End face of the generator core, so that on this one Opposite surface arises, which consists of the same, oriented i'e ^ O ^ coating.

It has been found that the above-described training together with the material described above for a

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provide significantly extended life of the regenerator section. It was also found that minor changes, for example the arrangement of the dirt grooves on the. Sealing, arrangement instead of on the regenerator core significantly affect this improved operating behavior.

While an edge seal produced in this way was being run in at a temperature of the order of 425 ° C. on a joint surface such as the lying core 10, Fe, O. and loose particles abraded and oxidized to Pe ₂ O ₇ . The loose oxide particles embedded themselves automatically in the catch material. The result was an essentially continuous ΓβρΟ -, - coating on the working surface of aligned hexagonal Fe _? 0, cells, the bases of which were oriented parallel to the working surface, as shown in FIG. 4b.

The break-in can take place under a wide range of operating conditions take place. The following tables show some of the operating conditions that can be used if a component that is part of the regenerator section of a gas turbine engine should form, "retracted". As the tables show, the retraction process can be carried out in a rotating Bracket or in the actual engine.

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Tabel Circumferential bracket

Time,
Run ¹¹ A " min.
Barrel ¹¹ B " 15th 50 15th 50 15th 50 15th 50 15th 50 15th 30th 120 120 Engine run ¹¹ H "

Operating condition

^P 3 ID ₃ ⁰ C 315 • 27.2 55 510 42.2 55 650 65.5 230 650 98.5 250 690 141.0 250 730 200.0 230 750 240.0 230

1. 1 hour idle (23,000-24,000 rpm), I ₀ - 480 - 510 ⁰ O

2. 1 hour at 70 % speed during

of iSin grinding,

3. 1 hour at 80 % speed,

4. 15 minutes at 90 % speed,

5. 15 minutes at 95 % speed,

6. 15 minutes at 97.5 % speed,

7. 15 minutes at 97.5 % speed,

8. 15 minutes at 97.5 % speed,

Definition of the specified value

T ₈ - 600 - 620 - 650 C ■ Έ -

"8th

65O ⁰ O

- 65O ⁰ O

- 65O ° E

- 65O ⁰ O

- 690 ° 0

- 730 ⁰ G

Pressure in cm Hg of the regenerator, for example at 24 according to Pig. 1 incoming cold gas.

Temperature of the cold face of the regenerator, such as the one on the outer sealing arrangement of the Regenerators according to Pig. 1 is present.

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T ° C a temperature of the hot regenerator face, As they exist, for example, on the inner sealing arrangement of the Regenex * ators according to FIG. 1 is.

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Claims (8)

Attorney's file: 14-2389 claims 1. Component, especially for use for dry lubrication purposes, characterized by a carrier with a work surface, those from an iron oxide structure with a Mixture of boron nitrite, graphite or Mickelgraph.it and sodium sulfate, sodium phosphate or Calcium fluoride is made. 2. Component according to claim 1, characterized in that the distributed mixture has about 1 part by weight of boron nitrite, 4 weight parts by weight of nickel graphite and 4 parts by weight of sodium sulfate contains. 3. Component according to claim 1 or 2, characterized in that the carrier consists of stainless steel. 4. generator section for a gas turbine engine, at the at least two components are in frictional contact during operation, characterized in that one of the components (16, 18) initially one made of an iron oxide structure with a mixture of nickel graphite distributed in it, -12- 309828/0 83 3 Comprising boron nitride and sodium sulfate, sodium phosphate and calcium fluoride working surface formed, and that after taking place during a running-in period ¹ conversion in the working surface a substantially continuous FepCU coating on the working surface of the one component (16,18) is present, and further on the associated other Component (10) a second Fe ₂ 0 ~ coating is formed as a result of a transfer from the first to the second component. 5. Regenerator according to claim 4, characterized in that one component (16, 18) has a regenerator edge seal (16) and / or separating strip (18) and the counter surface is formed on the regenerator core (10). 6. Regenerator according to claim 5, characterized in that the opposite surface auf.dem Regeneratorkern (10) one in the circumferential direction Has running dirt collecting groove (24) and the edge seal (16) and the separating strip (18) are provided with substantially smooth working surfaces. 7. Regeneratoijhach claim 6, characterized in that on the regenerator core (10) additional, spaced radial grooves (26) are formed, which between the circumferential groove (24) and the edge of the regenerator core run. -13- 309828/0833 8. Regenerator according to one of claims 4 t> is 7 »thereby characterized in that the oxide structure initially essentially is made of Fe ^ Ch. ' 309828/0833 Blank page