JPH0152354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides heat resistance, heat insulation, and abrasion resistance for metal members used in high-temperature gas flow passages in gas turbines, magnetohydrodynamic power generation, diesel engines, gasoline engines, gas burner cans, etc. The present invention relates to a bonded body with a ceramic member for imparting the same, and a method for bonding the same.

Hitherto, high-temperature sintered ZrO ₂ ceramics and plasma coating have been used as cylinder liners for diesel engines, but manufacturing costs are extremely high.On the other hand, it is difficult to fit, caulk, and bolt the FC and ceramics at the top of the piston. Although such methods have been proposed, they suffer from damage such as cracks and peeling during operation, and have problems in terms of reliability and cost, so they have not yet been put into practical use.

In order to eliminate these conventional problems, the present invention has been developed by using chromium between the ceramic members, which have excellent heat resistance, heat insulation, and abrasion resistance, and the metal members, which have a relatively large difference in thermal expansion, when joining them together. An intermediate layer consisting of a fiber structure with elasticity and flexibility reinforced with a compound is interposed, each member is bonded to each other with a bonding agent made of a concentrated solution of a soluble chromium compound, and heat treated at a relatively low temperature. The purpose is to provide a joined body of a ceramic member and a metal member at a low cost, which allows a very wide range of materials to be selected. An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the joined body of the present invention. As shown in the figure, a felt member 3 made of a fiber structure having elasticity and flexibility reinforced by treatment with a chromium compound is interposed between a ceramic member 1 and a metal member 2. A chromium compound solution or a chromium compound solution containing a small amount of metal oxide is applied as a bonding agent 4 to each bonding surface of the metal members 2, and the members are stacked together, and then heat treated preferably at a temperature of 460° C. or higher. By converting the chromium compound into Cr ₂ O ₃ , the ceramic member 1 and the metal member 2 are bonded via the fiber structure felt 3 with the bonding agent 4 based on the chromium compound.

The material of the ceramic member 1 used in the present invention should be selected depending on particularly important properties such as heat resistance, heat insulation, abrasion resistance, thermal shock resistance, and toughness. For example, Al ₂ O ₃ , 3Al ₂ O ₃・
2SiO ₂ (mullite), 2MgO・2Al ₂ O ₃・5SiO ₂ (cordierite), MgAl ₂ O ₄ (spinel), 2MgO・SiO ₂
(forsterite), ZrO ₂ , ZrO ₂・SiO ₂ (zircon), Ca (Sr) ZrO ₃ , MgO ・ZrO ₂ , MgO and oxides such as glass ceramics, SiC and Si ₃ N ₄
One type or one or more types of composite systems are used, without being limited by the coefficient of thermal expansion.

These ceramic members 1 are made by converting a molded body of raw material powder or a calcined body thereof into a concentrated aqueous solution of a soluble chromium compound.
For example H ₂ CrO ₄ , ZnCrO ₄ + H ₂ CrO ₄ and MgCrO ₄
Ceramics strengthened by impregnation with +H ₂ CrO ₄ and the like and bonded and hardened by heat treatment and high-temperature sintered bodies are used. In addition, to increase thermal shock resistance and heat resistance, the porosity is generally 10 to 18%, depending on the material.
It is also preferable that the bonding surface with the felt member 3 as the intermediate layer is roughened so that the contact area with the bonding agent 4 is increased.

Next, the metal member 2 is made of ferrous alloys and non-ferrous alloys commonly used as structural members of equipment and equipment, such as carbon steel, stainless steel, nickel steel, chrome steel, nickel-chromium alloy, Inconel, Hastelloy, and aluminum alloy. , using copper-based alloys, etc.
The material should be selected based on thermal conditions such as the surface temperature of the ceramic member 1 of the joined product, the temperature of the metal member 2, the heat flow velocity at the point of use, and the thermal conductivity of each member, and the structure of the structure. Not constant. However, when the metal member 2 is made of carbon steel, aluminum alloy, copper-based alloy, etc., and a chromium compound-based bonding agent 4 is used when joining these to the fiber structure felt 3, in order to obtain a better bond, the member 2 It is preferable to apply nickel or chromium plating to the joint surfaces in advance, and in the case of aluminum alloys, good results can also be obtained by applying an anodic oxide coating instead of this plating.

Further, the fiber structure felt members 3, 3' interposed between the ceramic member 1 and the metal member 2 are intermediate layers laid to alleviate thermal strain due to the difference in thermal expansion between the two members 1, 2. It is a felt consisting of a fiber structure of a synthetic or non-metallic inorganic material and a composite system thereof, such as stainless steel fiber, nickel chrome fiber, Inconel fiber, Hastelloy fiber, alumina fiber, silicon carbide fiber, silicon nitride fiber, glass fiber, copper nickel fiber, etc. Coated carbon fiber, glass-coated metal fiber, etc., filament diameter 5~
Felt, mat, and web are processed from 200μm.The bulk density of felt varies depending on elasticity, flexibility, wire diameter, etc., but it usually has a bulk density of 20 to 70% and is immersed in a concentrated aqueous solution of a soluble chromium compound. After the excess liquid is removed using a centrifuge, heat treatment is performed at a temperature of 460°C or higher. By repeating immersion in this solution and heat treatment 2 to 4 times, the points where the fibers intersect and contact are bonded due to chemical bonding caused by conversion to Cr ₂ O ₃ by heating the solution attached to these points. It hardens and strengthens the fibers.

Further, as the concentrated solution of the soluble chromium compound as the bonding agent 4, ZnO or MgO or a solution of both dissolved in a concentrated aqueous solution of H ₂ CrO ₄ is used.
The amount of dissolved MgO + ZnO etc. in H ₂ CrO ₄
The appropriate proportion is 0.15 to 0.5 mol per 1 mol of CrO ₃ , and the specific gravity of the aqueous solution is 1.2 to 1.5.

In addition, to prepare the bonding agent 4 for each member, a concentrated aqueous solution of a soluble chromium compound or ZrO ₂ , TiO ₂ ,
A small amount, preferably one or more of one or more fine powders of metal oxides such as SiO ₂ , Al ₂ O ₃ , Cr ₂ O ₃ , Fe ₂ O ₃ , MgAl ₂ O ₄ with a size of 44 μm or less, preferably 20 μm or less A total of 4 to 10% by weight of the concentrated liquid is added, ground and mixed using a ball mill to prepare an aqueous slurry. ZnO as a concentrated aqueous solution of soluble chromium compounds
Alternatively, a small amount of MgO or a mixture thereof, for example, 0.15 to 0.5 mol of oxide per 1 mol of CrO ₃ in a chromic acid solution is dissolved to give a specific gravity of 1.65 to 1.7.

Next, the manufacturing process of the joined body will be described.

In the process of manufacturing a bonded body using a chromium compound adhesive 4 to bond each member shown in FIG. A bonding agent consisting of a concentrated aqueous solution of a soluble chromium compound or a slurry of a chromium compound containing a small amount of oxide powder is applied to at least one of the surfaces to be bonded, preferably to both opposing surfaces;
Layer these parts together, preferably at a temperature of 460°C or higher,
Heat treatment is performed by raising the temperature at a rate of 3.5°C/min.
The heat treatment temperature and atmosphere vary depending on the material of each member, but for example, when the fiber structure felt is nickel-coated carbon fiber or when the copper alloy base is used, a temperature of 400°C or higher may be applied in an inert or reducing atmosphere, or when aluminum is used. When the substrate is an alloy, it is appropriate to set the maximum treatment temperature to 450 to 500°C.

Since the bonded body manufactured in this way has a fiber structure felt having elasticity and flexibility as an intermediate layer, it is not limited by the difference in thermal expansion between the ceramic member and the metal member, and each material can be used over a wide range. It is now possible to select with a degree of freedom, including gas turbines, magnetohydrodynamic power generation, diesel engines,
It can be used to great effect in heat-insulating, heat-resistant, and wear-resistant structural members such as high-temperature gas passage walls, liners, and pistons in gasoline engines and high-temperature gas burners.

Example 1 (1) SiC (α type) as a ceramic member 25 parts by weight of fine powder of 44 μm or less Si ₃ N ₄ (α + β type)
25 parts by weight of fine powder of 44 μm or less 3Al ₂ O ₃・2SiO ₂
A blend of 50 parts by weight of fine powder with a diameter of 20 μm or less was ground and mixed using an alumina ball mill, and this dried product was mixed with H ₂ CrO ₄ with a specific gravity of 1.65.
Add about 13% by weight of a concentrated aqueous solution to the powder, mix well, pack this wet powder into a mold, and
Pressure molded at Kg/ ^cm2 . This molded product is heated at a rate of 3.5°C/min in an electric furnace to a maximum temperature of 700°C.
The temperature was maintained for 40 min. This hardened body was further immersed in the above H ₂ CrO ₄ solution to impregnate it, and heat treated at 700°C in the same manner as above, and this impregnation and heat treatment were repeated 8 times to obtain an outer diameter of 50 mm.
Cylindrical ceramics with a wall thickness of 5 mm were prepared. The apparent porosity of the member thus obtained was 9.3.
% and showed a hardness of Rockwell 15-N93.5.

(2) Fiber structural member (intermediate layer) Composite of nickel-coated carbon fiber (filament diameter 10 μm, aggregate of 3000 fibers) and high silicon salt glass fiber (filament diameter 10 μm, aggregate of 1000 fibers) with a volume ratio of approximately 50/50 Inner diameter consisting of composition 50
mm, length 50mm, wall thickness 3.5mm cylindrical felt
Dissolve 17 _{g of ZnO in a concentrated aqueous solution of H 2 CrO 4} made by dissolving 100 g of CrO 3 to prepare an aqueous solution with a specific gravity of 1.4, and wet the felt by immersing it in this solution.
After applying this to a centrifuge to remove excess liquid adhering between the fibers, the treated material is heated at a rate of 5°C/min in an _electric furnace. ℃40min
Heat treatment was performed, and further, immersion in this liquid and heat treatment were repeated three times. Through this treatment, the contact points of each fiber that intersect with each other are exposed to the adhering solution.
By converting and bonding to Cr ₂ O ₃ , a significantly strengthened felt with a non-metallic inorganic fiber structure was formed, with a bulk density of about 50% and considerable elasticity.

(3) Metal parts Aluminum alloy castings (JIS AC-4C equivalent) were processed into cylinders with an inner diameter of 57.3 mm, a length of 50 mm, and a wall thickness of 8 mm, and H ₂ SO ₄ electrolyte was used on the inner surface to be joined. Anodized coating was applied to a film thickness of 45 μm.

(4) Preparation of binder First, dissolve 200g of CrO ₃ in water,
Make a concentrated aqueous solution of H ₂ CrO ₄ , dissolve 17 g of ZnO and 8 g of MgO in it, add water to make the specific gravity 1.65, and add powders of Al ₂ O ₃ and SiO ₂ of 10 μm or less to this solution by about 3.5 weight per solution. Add % increments,
An adhesive was prepared by grinding and mixing for 24 hours using an alumina ball mill.

(5) Bonding procedure After thoroughly applying the bonding agent in (4) to the surfaces of each member described in (1) to (3) to be bonded, stack them one on top of the other and heat them at a rate of 3.5℃/min. Fried, maximum 500℃
The temperature was maintained for 40 minutes to produce a joined body of the ceramic member and the metal member.

This cylindrical joined body was subjected to a rapid heating and cooling test at 500°C for 1 hour (electric furnace) and room temperature for 1 hour (air cooling) for 10 cycles.

After the test, this sample was cut and inspected for cracks and peeling of the ceramic member, and no abnormalities were found.

As described above, the present invention can provide a member that is extremely useful for imparting heat resistance, heat insulation, and wear resistance to metal structural members exposed to high temperatures, and the manufacturing cost is low, so it is suitable as an industrial manufacturing method.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the joined body of the present invention. 1...Ceramic member, 2...Metal member, 3...
...Fiber structure felt member (middle layer), 4...Binding agent.

Claims (1)

[Scope of Claims] 1. A felt member made of a fiber structure of a metallic or non-metallic inorganic material or a composite thereof, which has elasticity and flexibility and has been reinforced with a chromium compound, is placed between the metal member and the ceramic member. 1. A combination of a metal member and a ceramic member, characterized in that the metal member and the ceramic member are interposed and their joint surfaces are integrally bonded to each other by a chromium compound containing one or more metal oxides. 2. A felt member made of a fiber structure of an elastic and flexible metallic or non-metallic inorganic material or a composite thereof, which has been pre-immersed in a concentrated solution of a soluble chromium compound and has a coating layer of the concentrated solution on the surface.
The fibers are strengthened by heat treatment, and then a concentrated solution of a soluble chromium compound containing one or more metal oxides is applied to the joint surfaces on both sides or the joint surfaces on the metal member side and the ceramic member side. The felt member is interposed between the metal member and the ceramic member by applying Cr ₂ O ₃ in the concentrated solution, and then heat-treated in this state.
A method for joining a metal member and a ceramic member, characterized in that the mutual joining surfaces are integrally joined through a hardened layer formed by conversion into a ceramic member.