EP2420335A1 - Method for producing a ceramic metal matrix compound material and a moulded part produced according to this method - Google Patents

Abstract

Producing a ceramic or mineral metal matrix composite material, comprises loosely arranging ceramic granules (4) or a mineral material containing granules in a mold cavity (1), and subsequently casting the granules in metal. An independent claim is also included for a mold produced by the method, as a wear-resistant member.

Description

The invention relates to a method for producing a ceramic metal matrix composite and to a molded part produced by the method.

The prior art ( DE 20 2007 004 774 U1 ) includes a wear resistant part of ceramic metal matrix composite, wherein the wearing part is a wear section which is formed of a ceramic cake impregnated with metal, wherein the ceramic cake comprises ceramic grains of alumina and grains of the group consisting of boron carbide, silicon carbide or tungsten carbide.

According to this document, a ceramic cake is produced, which substantially corresponds to the molded part to be produced. After the cake is made from the grains, the cake is placed in a mold to encapsulate the cake with molten metal, which also penetrates into openings and pores of the cake to form a ceramic metal matrix composite.

This prior art method has the disadvantage that two operations are required: in the first step, the cake is made, requiring a first mold, and in a second step, the actual wear resistant part is made of the ceramic metal matrix composite. As a result, two forms and two steps are required.

It is also known in practice to produce ballistic shot protectors which consist of a composite of at least one layer of a synthetic fabric and at least one layer of ceramic plates or ceramic components.

From practice is also known to arrange ceramic plates of solid material in a composite of a synthetic fabric. Here is usually a bond. The ceramic plates serve to make a bullet on the ceramic fragmented. The tissue serves to stop the individual fragments of the projectile.

These well-known shotguards are used, for example, in bullet-proof vests or in bullet-proof motor vehicles.

The shotguards are arranged in the motor vehicles in the form of ceramic components in the outer skin of the car. The ceramic components are hereby produced as special molded components, so that they can be installed in the bodywork of motor vehicles.

In bulletproof vests, the ceramic plates are formed such that a plurality of plates are juxtaposed in the vest. The panels are moveable relative to each other to give the vest a degree of flexibility.

The shot protectors known from practice also have the disadvantage that they are relatively expensive to manufacture.

The technical problem underlying the invention is to provide a method for producing a ceramic metal matrix composite, according to which - shaped parts of ceramic metal matrix composite can be produced easily and inexpensively. In addition, moldings are to be specified, which are designed as shot protectors or wear-resistant parts, which can also be produced in the simplest manner.

This technical problem is solved by a method according to claim 1 and by a molding according to claim 9 or a molding according to claim 10.

The inventive method for producing a ceramic metal matrix composite is characterized in that in a mold ceramic granules or granules consisting of a mineral material is arranged loosely and that subsequently the granules are encapsulated with metal.

As a result, molded parts made of a ceramic or mineral metal matrix composite can be produced in a very simple manner. It is only a single casting process required to form the desired molding. In addition, only one mold is necessary. According to a particularly preferred embodiment of the invention, the liquid metal is passed through at least one filter disposed on at least one pouring hole of the mold into the mold. This ensures that the granules loosely arranged in the mold do not get into the at least one sprue.

Another possibility is to cover the at least one pouring hole with the metal with at least one metal plate before pouring the granules. This metal plate melts away during the pouring of the liquid metal. This means that before the casting process, the metal plate prevents the granules from entering the at least one sprue. During the casting process, when the metal plate is melted away, the granules remain in the actual casting space due to the casting pressure.

According to a particularly preferred embodiment of the invention, the mold is completely filled with granules before casting. This ensures that the granules are evenly distributed in the mold and not unintentionally and unevenly distributed by the casting pressure.

A further advantageous embodiment of the invention provides that the filter arranged on the at least one pouring hole has a hole size which is smaller than the diameter of the granulate. This ensures that the granules do not settle in the filter. Since the granules have different granule sizes, the filter should have a hole size that is smaller than the smallest diameter of the granules.

The at least one filter is advantageously arranged directly on the casting. This ensures that the granules remain in any case in the casting chamber of the mold.

It is advantageous to use granules consisting of solid material as granules. The granules may consist of a ceramic material, but it may also consist of a mineral substance, such as corundum.

A further advantageous embodiment of the invention provides that the granules are pressed in the mold before casting encapsulated. This ensures that the mold is completely filled with the granules. In addition, the granules can not be distributed unevenly in the mold by the casting pressure.

With the method according to the invention, various molded parts can be produced, for example, wear-resistant parts can be formed or molded parts which are designed as weft protectors.

Wear-resistant parts are required, for example, in industrial applications that involve components that wear out over the service life. The applications of parts that must be wear resistant are commonplace in the cement, mining and heat generation industries. A concrete application can be seen for example in the arrangement of wear-resistant excavator teeth in mining. If a composite consumable is worn, the part must be replaced. Consequently, during the replacement of the worn part, the device can not be used. The replacement of the worn part leads to a loss in terms of the operating time of the device. By the method according to the invention molded parts can be produced, which have a significant improvement in wear resistance.

As already stated, according to a further advantageous embodiment, molded parts can be produced which are designed as weft protectors. The moldings produced by the process according to the invention, on the one hand, have a very high level of safety, since spheres of different weapons do not penetrate the moldings produced by the process or only with extreme difficulty. By encapsulating ceramic material in the weft protectors, the weft protectors are not as heavy in weight as weft protectors made entirely of metal.

According to a possible embodiment of the invention it is provided that the ceramic or mineral granules are perforated or porous, that is, the granules has cavities. As a result, a further reduction in weight is achieved while maintaining stability. The granules advantageously consist of a predominantly aluminum oxide-containing or silicon carbide-containing (SiC) or zirconium oxide-containing or boron carbide-containing material.

For example, it is possible to use granules of aluminum oxide (Al ₂ O ₃ ) with proportions of silicon oxide (SiO ₂ ).

Other materials such as silicon nitride (SN), titanium boride (TiB ₂ ) or aluminum nitride (ALN) and other materials are also possible.

For example, one possible composition is 96% Al ₂ O ₃ and 4% SiO ₂ and other trace elements.

Another advantageous composition consists of 40% to 60% Al ₂ O ₃ , 35% SiO ₂ and other additives.

The silicon carbide or zirconium oxide granules also make sense for the most part (60 to 100%) of the respective main component SiC or zirconium oxide and other additives.

The molded parts according to the invention for weft protectors have the advantage that they have a relatively low weight.

The molded parts according to the invention can be produced in any shape, so that, for example, special shaped components for the use of the body can be realized.

The moldings according to the invention can, as already stated, be used as wearing parts or, for example, also as armor plates for various applications. The moldings according to the invention have the advantage that they can be welded. It is also possible to recast the parts produced by the process according to the invention. Since the moldings produced according to the invention have metal as the outer layer, a very good bond can be produced with a further material, in particular metal.

According to a further particularly preferred embodiment, a filling opening for the ceramic or mineral particles may be provided in the mold, so that the ceramic or mineral particles can be filled into the mold cavity after closing the mold. Here, the granules are filled through one or more openings. Subsequently, the filling opening can be closed by a suitable component, for example a locking core. The suitable component may for example consist of a porous sand core or be formed by a split core. The split core or the sand core may in turn have a filter. Through the filter in turn the flushing of the granules is prevented while venting possibility. This results in further design options, since the granules can not otherwise be held in position.

Fig. 1

einen Querschnitt durch eine Gussform mit einem Filter;

Fig. 2

einen Querschnitt durch eine Gussform mit einer Metallplatte;

Fig. 3

ein geändertes Ausführungsbeispiel.

Further features and advantages of the invention will become apparent from the accompanying drawings, in which several embodiments are shown by way of example only. In the drawing show:

Fig. 1

a cross section through a mold with a filter;

Fig. 2

a cross section through a mold with a metal plate;

Fig. 3

a modified embodiment.

Fig. 1 shows a mold (mold cavity) 1, which is embedded in a sand mold (mold) 2. A casting channel 3 leads to the casting mold 1. The casting mold 1 is completely filled with ceramic granules 4.

In the sprue 3, a filter 5 is arranged directly on the mold 1. The filter 5 may be made of a ceramic material. Openings 6 of the filter are smaller in cross-section than the granule size 4. The granules 4 are loosely arranged in the casting mold 1 and are encapsulated by liquid metal, which is fed through the pouring channel 3 of the casting mold 1.

The sand mold 2 is formed along a line 8 divided. In addition, a vent channel 9 is provided, in which a further filter 10 is arranged, so that the granules does not reach the ventilation channel 9 by the casting pressure, that is, in order to avoid flushing out of the granules 4.

The mold cavity 1 is arranged completely in a lower box 11 of the sand mold 2. The lower box 11 is the lower part of the divided sand mold 2.

Fig. 2 shows the mold 1, which in turn is arranged in a sand mold 2. The sand mold 2 is also formed divided along the line 8.

A casting channel 3 leads to the casting mold 1. Granules 4 are again arranged in the casting mold 1. To prevent the granules 4 before the actual Vergießvorgang it to get into the channel 3, this is closed with a metal plate 7. The metal plate 7 melts during the casting process by the liquid metal (not shown). During the casting process, the granules 4 is prevented from flowing back into the pouring channel 3 by the casting pressure. This embodiment is recommended when the granules at least partially have a very small grain size.

Also in this embodiment, a vent channel 9 is provided. In the vent channel 9, in turn, a filter 10 is arranged, which prevents the granules 4 enters the venting channel 9 through the casting pressure.

Fig. 3 shows a sand mold 2, in which the subdivision is not horizontal. The dividing line 8 identifies the subdivision. FIG. 4 shows a system which makes it possible to fill the granulate 4 into the mold cavity 1 after closing the mold 2. Here, the granulate 4 is filled through an opening 12 and the filling opening 12 is closed by a suitable component 13 in the form of a locking core. The locking core 13 may for example consist of a porous sand core or be formed by a split core, which in turn contains a filter (not shown), which prevents the flushing of the ceramic particles 4 while venting possibility. This results in more design options, since the granules 4 can not otherwise be held in position.

reference numerals

1

Mold (mold cavity)

2

sandbox

3

pouring

4

granules

5

filter

6

Pores of the filter

7

metal plate

8th

line

9

vent channel

10

filter

11

lower box

12

opening

13

lock core

Claims (16)

Method for producing a ceramic or mineral metal matrix composite
characterized in that in a mold (1) ceramic granules (4) or consisting of a mineral material granules is arranged loosely, and that subsequently the granules (4) is encapsulated with metal. A method according to claim 1, characterized in that the metal is passed through at least one at least one pouring hole of the mold (1) arranged filter (5) in the mold (1). A method according to claim 1 or 2, characterized in that the at least one pouring hole before pouring the granules (4) is covered with metal with at least one metal plate (7). Method according to one of the preceding claims, characterized in that the mold is completely filled with granules before pouring. A method according to claim 2, characterized in that the filter (5) has a hole size which is smaller than the diameter of the granules (4). A method according to claim 2, characterized in that the at least one filter (5) is arranged directly on the casting. Method according to one of the preceding claims, characterized in that a granulate (4) consisting of solid material is used as granules (4). Method according to one of the preceding claims, characterized in that the granules (4) in the casting mold (1) is arranged compressed before pouring. Method according to one of the preceding claims, characterized in that the granules (4) in the mold (1) after closing a sand mold (2) by means of one or more openings (12) is filled. A method according to claim 9, characterized in that the at least one opening (12) by means of a closure core (13) or closure parts after filling of the granules (4) is closed. A method according to claim 10, characterized in that the at least one opening (12) is closed with a split core and / or with a filter having a locking core (13). Molded part, produced by the method according to claim 1, characterized in that the molded part is designed as a wear-resistant part. Molding, produced by the method according to claim 1, characterized in that the molded part is designed as a weft protector. Molding according to claim 13, characterized in that the molded part has a body-adapted form. Molding according to claim 13, characterized in that the molded part has a body-adapted form. Molding according to claim 13, characterized in that the molded part is arranged in a composite with textile material.

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