JP2610381B2 - Manufacturing method of ceramic parts with pores using firing bonding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a ceramic part having a pore, and more particularly, to a power generation ceramic gas turbine vane and a blade having a cooling hole, and in particular, to 130.
The present invention relates to a method for producing a ceramic part having pores using firing bonding which can be suitably used as a ceramic part used in a high temperature environment of 0 ° C. or higher.

[0002]

2. Description of the Related Art Ceramic materials such as silicon nitride, silicon carbide and partially stabilized zirconia have excellent properties such as high heat resistance, high wear resistance, high hardness and high corrosion resistance. Research and development of mechanical parts utilizing characteristics are being actively pursued. Such ceramic components are being used in a wider range of fields through successive improvements and design optimization. By the way, about such ceramic parts,
There is a demand to form a pore having a predetermined diameter at a predetermined position. For example, in the case of a moving blade and a stationary blade of a gas turbine used in a high temperature environment of 1000 ° C. or more, appropriate cooling holes are provided in the member in order to lower the material temperature and improve reliability.

Conventionally, a ceramic component having such pores is formed by pressing ceramic powder, isostatic pressing (CIP), then calcining the binder, and then drilling the pores by dry processing. Or by forming pores after firing. The perforation of the fine holes is usually performed by mechanical processing using a drill or a diamond grindstone, ultrasonic processing, laser processing, or the like.

[0004]

However, in the above-described conventional pore forming method by drilling, non-linear pores cannot be machined, and the pore diameter is 1 mm.
Processing of the following ultrafine pores was also difficult. In view of such circumstances, an object of the present invention is to provide a method of manufacturing a ceramic component having pores capable of forming ultrafine pores having a pore diameter of 1 mm or less and pores having an arbitrary shape as desired.

[0005]

According to the present invention, the entire shape of a target ceramic part is divided into an inner side and an outer side with a surface passing through a predetermined pore forming position of the ceramic part as a boundary. It has the same shape as the obtained divided body,
And, those having the outer side divided body shape, separately molding a plurality of molded bodies having a larger firing shrinkage ratio than those having the inner side divided body shape, at least having the inner side divided body shape A pore is formed on one of the outer surface of the molded body (hereinafter, referred to as “inside molded body”) and the inner surface of the molded body having the outer divided body shape (hereinafter, referred to as “external molded body”). A method for manufacturing a ceramic part with pores is provided, wherein after forming grooves corresponding to the formation planned positions, these are combined and fired, and are integrally joined by utilizing the difference in firing shrinkage. In the above,
The "target ceramic component overall shape" refers to the overall shape when no pores are formed.

Further, according to the present invention, the entire shape including the pore forming portion of the target ceramic component can be obtained by dividing the whole shape into an inner side and an outer side with a surface passing through the pore forming portion as a boundary. Having a shape equivalent to the divided body, and having an outer divided body shape, a plurality of molded bodies having a larger firing shrinkage than those having the inner divided body shape, in the pore forming portion Each of these is separately molded using a molding die having a corresponding groove shape, and thereafter, these are combined and fired, and are integrally joined by utilizing a difference in firing shrinkage ratio. A manufacturing method is provided.

[0007]

According to the present invention, a groove is formed on the side surface of a molded body having a divided body shape, instead of forming a pore by drilling after calcining or firing as in the prior art. Is molded using a molding die having grooves in advance in a state where grooves are formed on the side surfaces, and these are integrally joined by utilizing the difference in firing shrinkage to form pores. That is, in the present invention, the groove formed on the outer surface of the inner molding and the inner surface of the outer molding, the groove formed on the inner surface of the outer molding and the inner surface of the inner molding, or Pores are formed by the grooves formed on the outer surface of the side molding and the grooves formed on the inner surface of the outer molding. As described above, since the pores can be obtained by forming grooves instead of drilling, it is possible to form ultrafine pores having a pore diameter of 1 mm or less and non-linear pores.

Hereinafter, the manufacturing method of the present invention will be described with reference to the drawings, taking a ceramic gas turbine stationary blade as an example.
First, with respect to the overall shape 1 of the target ceramic gas turbine stationary blade as shown in FIG. 2, the inner surface obtained by dividing into the inner side and the outer side with the surface 3 passing through the expected pore formation position 2 as a boundary. The inner molded body 6 and the outer molded body 8 having the same shape as the side divided body 4 and the outer divided body 5 are separately molded. At this time, in order to make the firing shrinkage of the outer molded body 8 larger than the firing shrinkage of the inner molded body 6, each of the forming materials is selected and the molding process is adjusted. The control means will be described later in detail.

Next, as shown in FIG. 1C, a groove 9 corresponding to a position where a pore is to be formed is formed on the outer surface 7 of the inner molded body 6 shown in FIG. It is inserted and fitted inside the outer molding 8 shown in b). Then, firing is performed in this state, and the outer molded body 8 having a large firing shrinkage is shrunk in the inward direction so as to be joined to and integrated with the inner molded body 6 having a small firing shrinkage. A ceramic gas turbine stationary blade firing joint 10 is obtained. Pores are formed in the integrated ceramic gas turbine stator blade firing joint 10 by the groove 9 formed on the outer surface of the inner molded body 7 and the inner surface 11 of the outer molded body 8.

According to the manufacturing method of the present invention, in addition to the linear pores as in the above example, ceramic parts having spiral pores as shown in FIG. A ceramic component having shaped pores can be manufactured.
The cross-sectional shape and pore diameter of the pores are not limited, but are particularly effective for forming pores having a pore diameter of 1 mm or less.

In the above example, for convenience of explanation, the case where two compacts are fired and joined has been described. Similarly, three or more compacts are fired and joined to form a ceramic component having multilayer pores. Can also be prepared. FIG.
An example in which three molded bodies are joined by firing is shown.
In this case, the molded body in FIG. 6B is an outer molded body for the molded body of FIG. 7A and is an inner molded body for the molded body of FIG. Therefore, in this case, the relationship between the firing shrinkage ratios of the molded bodies is set to increase in the order of (a), (b), and (c). As described above, in the present invention, when three or more molded bodies are joined by firing, all molded bodies other than the molded body inserted and fitted to the innermost part and the molded body located at the outermost part are internal molded bodies. At the same time, it is also an outer molded body, and the firing shrinkage of each molded body increases in order from the innermost to the outermost.

Further, these compacts may be calcined before assembling, and these calcined bodies may be combined and subjected to firing bonding. Alternatively, only the innermost portion of the compact may be calcined in advance. A fired body may be combined with the above-mentioned molded body or calcined body for firing bonding.

In the present invention, the molded article to be subjected to firing bonding may be any of an injection molded article, a press molded article, and a cast molded article.
Any combination is possible. Means for controlling the firing shrinkage include, for example, control of molding raw materials, control of CIP molding pressure and interference. To control the molding raw material, specifically, a method of using a raw material powder having a fine particle size for the outer molded body and using a raw material powder having a coarse particle size for the inner molded body, or an additive aid for the outer molded body For example, there is a method of increasing the amount and decreasing the amount of the auxiliary additive of the inner molded body. Also, CIP
The molding pressure is controlled by lowering the molding pressure of the outer molding and increasing the molding pressure of the inner molding.

The amount of control of interference at the time of joining depends on the material and product shape of the ceramic used (inner diameter, outer shape, wall thickness)
Depends on etc. The amount of interference between the inner part and the outer part must be a value that minimizes the unit size after firing so that the relationship of at least the inner part outer diameter> the outer part inner diameter is satisfied. is there. The maximum value is determined based on the ceramic material used and the product shape so that cracks, cracks and the like do not occur after firing. In the present invention, by using the control method of the firing shrinkage rate as described above alone or in combination,
The firing shrinkage of the outer molded body is set to be larger than the firing shrinkage of the inner molded body.

The grooves may be formed on the inner surface of the outer formed body, or on both the outer surface of the inner formed body and the inner surface of the outer formed body. It is preferable to form a groove on the outer surface of the inner molded body as in the example of the gas turbine vane described above. The groove can be formed by a method such as machining using a cutting tool and an end mill. The groove may be formed immediately after the molding of each compact, but if the calcining is performed before the combination as described above, or if only the compact at the innermost position is previously calcined, It may be carried out after calcination or after calcination. Further, in the present invention, when molding a molded body, a molded body having grooves formed in advance may be obtained by using a molding die having a groove shape corresponding to a pore portion.

[0016]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Example 1) A ceramic gas turbine vane having a fine hole as shown in FIG. 1 was manufactured according to the manufacturing process shown in FIG. That is, first, the molded bodies of the two divided parts as shown in FIGS. 1B and 1C were separately molded by injection molding. As a molding raw material, a silicon nitride powder having an average particle size of 0.5 μm for the portion shown in (b), and a silicon nitride powder having an average particle size of 0.6 μm for the portion shown in (c).
5 parts of Y ₂ O ₃ as an auxiliary agent for 100 parts by weight of each
Parts by weight, 3 parts by weight of MgO, and 0.5 parts by weight of ZrO ₂ were added and mixed, and the firing shrinkage ratio of the part (b) of the outer molded body was that of the inner molded body (c). Was controlled to be larger than the site. The groove of the molded body at the position shown in (c) was formed at the time of molding using a mold having a groove shape corresponding to a desired pore.

Next, both molded articles obtained by injection molding were degreased in the air at 400 ° C. for 3 hours, and then subjected to CIP at a pressure of 7 ton / cm ² . Next, the two compacts were combined and fired and joined in an N ₂ atmosphere at 1700 ° C. for 2 hours to obtain a sintered body of a ceramic gas turbine stationary blade having pores as shown in FIG. The obtained sintered body was subjected to finish processing of diamond by grinding using a grindstone to obtain a final product.

Example 2 A cylindrical ceramic part having spiral non-linear pores as shown in FIG. 3 was produced according to the manufacturing process shown in FIG. That is, first, FIG.
(a) and (b) were separately molded by press molding, respectively. As a molding raw material,
In both parts (a) and (b), 5 parts by weight of Y ₂ O ₃ , 3 parts by weight of MgO, and ZrO ₂ were added to 100 parts by weight of silicon nitride powder having an average particle size of 0.5 μm. Was added and mixed by 0.5 part by weight.

Next, the two compacts obtained by the press molding were fired such that the firing shrinkage of the part (b), which is the outer molded body, was greater than that of the part (a), which was the inner molded body. In order to control the shrinkage rate, the part of (a) is 7
at a pressure of ton / cm ^2, the site of (b) is performed each CIP under a pressure of 4 ton / cm ^2. At this time, with respect to the molded body at the portion (a), the outer diameter after firing is φ20 mm,
Further, with respect to the molded body at the part (b), the dimensions of each molded body were controlled such that the inner diameter after firing was φ19 mm. The thickness of the molded body shown in FIG.
mm.

Next, a spiral groove was formed on the outer surface of the molded body shown in FIG. 1A by dry white processing as shown in FIG. In this dry white processing, an end mill and an NC processing machine were used, and a groove having a width and a depth of 0.8 mm was formed. Thereafter, the molded bodies of both parts shown in (b) and (c) are combined, and fired and bonded in an N ₂ atmosphere at 1700 ° C. for 2 hours to form non-linear pores as shown in FIG. A sintered body was obtained. The obtained sintered body was subjected to finish processing of diamond by grinding using a grindstone to obtain a final product.

Example 3 A cylindrical ceramic part having a multi-layered pore as shown in FIG. 4 was manufactured according to the manufacturing process shown in FIG. That is, first, FIG.
The three-part molded body as shown in (c) was separately molded by press molding. As a molding raw material, silicon nitride powder having an average particle size of 0.7 μm was used for the portion shown in FIG.
For the part shown in (b), silicon nitride powder with an average particle diameter of 0.6 μm, and for the part shown in (c), silicon nitride powder with an average particle diameter of 0.5 μm, each with respect to 100 parts by weight, As an auxiliary, 5 parts by weight of Y ₂ O ₃ , 3 parts by weight of MgO, and 0.5 part by weight of ZrO ₂ are added and mixed, and used.
The part located at the innermost position (a) to the outermost position (c)
Was controlled so that the firing shrinkage ratio increased in order toward the part.

Next, each molded product obtained by press molding was subjected to CIP at a pressure of 7 ton / cm ² . In addition,
In this example, the firing shrinkage of each molded product was controlled such that the unit size after firing of the molded product at each of the parts (a), (b), and (c) was as follows. (a) ・ ・ ・ Outer diameter: φ15mm (b) ・ ・ ・ Outer diameter: φ20mm, inner diameter: φ14.6mm (c) ・ ・ ・ Outer diameter: φ30mm, inner diameter: φ19.6mm

Next, grooves were formed on the outer surfaces of the molded bodies at the portions (a) and (b) by dry white processing as shown in FIGS. For this dry white processing, an end mill and an NC processing machine are used. Both width and depth are 0.8m.
m grooves were formed. Further, the molded body shown in (d) in which the groove was formed was subjected to primary firing at 1700 ° C. for 2 hours in an N ₂ atmosphere. The obtained primary fired body was combined with the molded body shown in (e) and (c) and fired and bonded in an N ₂ atmosphere at 1700 ° C. for 2 hours to form multilayer pores as shown in FIG. A sintered body was obtained. The obtained sintered body was subjected to finish processing of diamond by grinding using a grindstone to obtain a final product.

[0025]

As described above, according to the present invention,
Since it is possible to produce a ceramic component having an extremely fine pore having a pore diameter of 1 mm or less or a non-linear hole which has been impossible so far, it is extremely useful as a method for manufacturing a ceramic component requiring a cooling pore. Useful. In addition, it is possible to divide each part and manufacture it, and it becomes easy to manufacture a complex-shaped part and a large-sized part.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a production example of a ceramic gas turbine stationary blade according to the present invention.

FIG. 2 is a view for explaining the shape of each compact to be subjected to firing bonding.

FIG. 3 is an explanatory view showing a production example of a ceramic component having a spiral pore according to the present invention.

FIG. 4 is an explanatory view showing an example of producing a ceramic component having multi-layered pores by firing and joining three molded bodies according to the present invention.

FIG. 5 is a manufacturing process diagram of one embodiment of the present invention.

FIG. 6 is a manufacturing process diagram of another embodiment of the present invention.

FIG. 7 is a manufacturing process diagram of still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 The whole shape of a ceramic gas turbine stationary blade 2 Predetermined pore formation position 3 Dividing boundary surface 4 Internal dividing body 5 External dividing body 6 Internal molding 7 Outside surface of internal molding 8 External molding 9 Groove 10 Ceramic Gas Turbine Stator Blade Sintered Joint 11 Inner Surface of Outer Molding

Claims (2)

(57) [Claims] 1. A shape obtained by dividing the entire shape of a target ceramic component into an inner side and an outer side by dividing a surface passing through a predetermined pore forming position of the ceramic part into a boundary. And, those having an outer divided body shape, a plurality of molded bodies having a larger firing shrinkage than those having an inner divided body shape, each molded separately, at least the inner divided body shape After forming a groove corresponding to the expected pore formation position on either the outer surface of the molded body having the shape or the inner surface of the molded body having the outer side divided body shape, these are combined and fired, and the firing shrinkage ratio A method for producing a ceramic part having pores, wherein the ceramic part is integrally joined by utilizing the difference between the two. 2. A shape equivalent to a divided body obtained by dividing an entire shape including a pore forming portion of a target ceramic component into an inner side and an outer side with a surface passing through the pore forming portion as a boundary. And having a shape having an outer side divided body, a plurality of molded bodies having a larger firing shrinkage ratio than those having an inner side divided body shape, having a groove shape corresponding to a pore forming portion. Each molded separately using a mold,
Thereafter, a method for producing a ceramic part with pores, characterized by combining and firing these, and joining them together utilizing the difference in firing shrinkage.