JPS60246274A - Metal composite ceramic sintered body and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application to Which the Present Invention Pertains] The present invention relates to a new ceramic sintered body that has dramatically improved the brittleness that is a drawback of conventional ceramics, and a method for producing the same.

[Prior art and its problems]

Conventional ceramic sintered bodies are generally hard and have excellent corrosion resistance, but on the other hand, they have many drawbacks such as being brittle, weak against impact, easily cracking, and having low toughness values. Therefore, in order to improve these drawbacks, material composites, i.e. 2
Attempts are also being made to develop and research materials that utilize the characteristics of each material by combining different types of materials. Composite materials of ceramic materials and metals include Cr-Al system, known as cermet, or W-Cr-
There are Al-based and 'l'1c-Nl-based materials, and their constituent materials, such as chromium and tungsten 4 titanium, have strong oxidation resistance even at high temperatures, and due to their heat resistance and high hardness, they are used in aircraft engines. It is used in cutting tools, etc.

However, since these cermets are actually pressed by mixing metal powder and non-metal inorganic powder, although the compressive strength may be increased, there are no structural features that particularly improve brittleness. However, tungsten, titanium, etc. are high-grade materials and are expensive, so they have the disadvantage of not being versatile. Also chrome.

Tungsten, titanium, etc. are limited materials that are least susceptible to oxidation even at high temperatures, and firing is performed under oxidation-prevented conditions such as a hydrogen atmosphere, and the manufacturing method uses a hot press etc. However, it also has the drawbacks of high cost and lack of versatility.

Therefore, it can be said that no general method has been established for improving the brittleness of general-purpose ceramics by using relatively inexpensive general-purpose metals such as iron-based and copper-based metals.

[Object of the present invention, that is, the problem to be solved by the present invention]

The present invention eliminates and improves the above-mentioned drawbacks of the prior art, and combines a general-purpose metal material with a low-cost general-purpose ceramic material, thereby eliminating the drawbacks of conventional ceramics, such as brittleness, weak impact, and easy cracking. It is a general-purpose ceramic that has significantly improved the various drawbacks such as, and can therefore be used for everyday use by ordinary people. The purpose is to provide improved ceramic products and their manufacturing methods.

[Configuration of the present invention, that is, means for solving the above problems]

The present invention relates to a manufacturing method for a versatile material in which fibers and/or pieces of general-purpose metals such as iron-based and/or copper-based are combined and sintered into a general-purpose ceramic raw material such as clay-based, and the above-mentioned conventional technology This is a particularly new idea compared to the previous one.

That is, the metal composite ceramic sintered body according to the present invention contains metal fibers and/or pieces, including general-purpose metals that are easily oxidized at high temperatures, such as iron-based and copper-based metals, by weight of 5% to 70%. This product is characterized by being dispersed in Ceralax.

In addition, when sintering general-purpose metals that are easily oxidized at high temperatures, the manufacturing method is used to prevent oxidation of metals such as metals, which is conventionally considered difficult. It also makes it possible to uniformly disperse certain metal materials, and facilitates the integration of metals and ceramic materials with greatly different coefficients of thermal expansion, and also improves manufacturing efficiency in the combination of art materials. This is a method that can prevent deformation and cracking, which had been considered a critical drawback. Further, as a specific means for this, first of all, the metal fibers etc. to be used are pre-treated. The method is to heat the metal fibers, etc. above 250 ('C) and below 900 [°C], immerse them in an aqueous solution such as phosphoric acid, and then immerse them in a liquid such as silica sol or alumina sol to coat the surface of the metal fibers with silica gel or alumina gel. By reducing the apparent specific gravity of metal fibers, etc., and by selecting the range of water content to improve the workability of the mixed slurry, it is possible to evenly distribute multiple materials with very different specific gravity. Mix and disperse, further adjust the moisture content to make plastic clay,
For example, injection molding is performed using a vacuum clay kneading machine, etc., and if necessary, the molded product is formed so that the metal fibers, etc. are oriented and aligned, and after drying,
00 ('C: For 3 or higher, heat at a temperature increase rate of 20 to 40 [℃/min] and sinter at 700 to 1300 (℃) to integrally composite metal materials such as fibers and ceramic materials. Due to this, there is almost no brittleness and it is difficult to crack.
This manufacturing method is characterized by the production of innovative new ceramic scales that have great toughness and are virtually unbreakable even if dropped.

The above-mentioned metals include all metals other than mercury, as well as precious metals such as gold and silver, to which the present invention can be applied. Suitable materials include carbon steel, stainless steel, other special steels, and copper. The metal fiber preferably has a diameter of 10 to 500 μm and a length of 1 to 10 μm, and the thickness of the metal fiber in the form of a section is 5 to 100 μm.
m]+Aspect ratio is preferably 5 or more. Also, if metal foil is used, the thickness is 5 to 100 (μm).
+ Width 100 to 500 (μmps Length 1 to 10 (
+n] is desirable.

The mixing ratio of metal fibers, etc. is the ratio to the whole after mixing, and if it is less than 5% by weight, the characteristics of the present invention will be lost.
Moreover, if it exceeds 70 [%], injection molding using a vacuum kneading machine or the like becomes difficult, so anything outside this range is unsuitable. Further, the term "dispersion" as used herein means that the metal fibers and the like are scattered approximately uniformly within the ceramic body, and may include cases where the direction of the fibers, etc. is random and cases where the fibers and the like are aligned in a certain direction.

The structure of the manufacturing method will be explained along with its properties and effects. First, metal fibers, etc. are heated to 250 [°C] or more and 900
The purpose of heating is to soften the metal fibers and/or pieces, and to appropriately form a thin oxidized film on the surface. For this purpose, heating at an excessively high temperature is inappropriate, so the temperature range is as described above. Next, the fibers and the like are immersed in a solution containing phosphate ions to adhere phosphate ions to the surface, and then treated by being immersed in an aqueous solution of K, sodium silicate, silica sol, and/or alumina sol. This is done by changing these sols into gel-like substances and attaching them to the surface of metal fibers, etc. using the previously applied phosphate ions. This is to cover the area.

On the one hand, ceramic compositions containing glassy substances such as glass cullet, frit, etc., such as clay, feldspathic substances,
5 [%] or more by weight of the above-mentioned treated metal fibers or pieces are added to ordinary ceramic raw materials such as talc.7
Add so that it is uniformly 0 [%] or less. This specific gravity is 35
As mentioned above, it was difficult to uniformly mix materials that are different by a factor of 4 to 4. However, in the present invention, the problem was solved by the following new method in addition to the above-mentioned pretreatment means for metal fibers, etc. ing. Specifically, this is done by conveniently adding it to the mixer in stages and adjusting the slurry condition. That is, for example, about 70% of the above ceramic raw material mixture is put into a rotating mixer in the form of a slurry with a specific gravity of 1.5 to 1.6 (9r/cc"J), stirred, and mixed with the above-mentioned gold) PA fibers, etc. When the treated metal materials are added to the mixer little by little, the gel-like film that forms on the interface layer of the metal material treatment absorbs water and further swells, preventing the ceramic particles from adhering to each other and forming individual metal material treatment materials. has a large volume and therefore has a light overall specific gravity, and is uniformly mixed into the ceramic composition by floating and dispersing due to its buoyancy.At this point, the remaining amount, for example, about 30 [:%] If the slurry concentration is increased by sequentially adding ceramic raw material mixtures without stirring and forming a paste with a specific gravity of, for example, 1.7 to 1.758, separation will no longer occur. The water content is, for example, about 32 to 35 [%], so if the water content is reduced to about 15 to 20 [%] by vacuum dehydration or the like and kneaded in a bag mill, a raw material composition suitable for injection molding will be obtained.

Also, the reason for adding a vitreous substance to the ceramic raw material mixture will be explained along with its effects. A molded body of an ordinary ceramic composition expands in volume by about 0.5 to 1.0% from SOO to 900 degrees Celsius during the firing process, but the composition of the present invention 500 to 60, where oxidation progresses rapidly
Since it is necessary for the structure to shrink from a relatively low temperature range of 0° C. and to have a high density, it is necessary to mix a low-melting vitreous raw material in the above ratio.

Next, regarding the conditions for sintering the molded product, the atmosphere in the furnace may be the atmosphere of a general ceramic firing furnace, but a reducing atmosphere is preferable in order to prevent the oxidation of the metal from proceeding. However, in the present invention, since the periphery of each metal fiber is densely covered with a coating as described above, oxidation can be prevented to a certain extent even in an oxidizing atmosphere. In addition, heating is performed gradually up to 500 ('C) depending on the content of the clay raw material in order to dehydrate the crystallized water of the clay raw material as much as possible.
In the temperature range exceeding 'C), it is efficient to raise the temperature at a rate of 30°C/min or more.

In addition, to add a more detailed explanation, the oxide film produced during surface treatment of metals is FeO
, FezO3, Feas4 are the main components, and in the case of copper, C
These include uO, Cu2O, etc. These oxides are very easy to react with phosphoric acid, which is a surface treatment liquid. Even if the preheat treatment is performed at [° C.] only once, the oxide film on the surface layer will be small, so it is better to perform the treatment with a phosphoric acid solution again after that.

Furthermore, if the sintering temperature of the molded body is less than 700 ('C), the ceramic composition will not be sintered sufficiently;
If the temperature exceeds 0 [°C], metal fibers, etc. will melt, oxidize and foam, making it impossible to maintain the shape and physical properties of the fibers or sections.
A temperature range between these is appropriate.

However, it is necessary to keep in mind that there are some differences in practice regarding this high temperature limit depending on the type of metal used.

For example, in the case of copper-based materials, if the temperature exceeds 1000 [C], the structure becomes significantly foamed, which is not preferable. Therefore, in the case of copper-based materials, a large amount of low-melting vitreous raw materials such as frits are added, and the raw material composition is adjusted so that the firing temperature is 900°C (approximately 3°C).The firing rate is also 500°C or higher. A fast speed of about [:'C:/min] is required.

In the case of ferrous materials, the firing temperature for ordinary steel is about 1100 [℃], and the temperature increase rate is 40 to 5
0('C/C/distribution.

Furthermore, when the composition of the present invention contains a metal with high thermal conductivity, sintering can be completed in a significantly shorter time than ordinary ceramic compositions.

〔Example〕

Next, the present invention will be explained in more detail using Examples.

First, the following points are common to the plurality of embodiments described below.

The treatment conditions for the fibrous or sectioned metal materials of the present invention are that the temperature for heat treatment of carbon steel, special steel such as stainless steel, and copper is 600 [°C] for 5 [minutes], and The phosphoric acid solution treatment time was 5 [minutes], and the silica sol treatment was performed using a commercially available product, and the treatment time was 2 hours. The diameter of the fibrous metal material is 50 (μml), the length is 3 [my], and the thickness of the section is 20
(μm) and aspect ratio of 20.The mixed composition of ceramics and the treated metal material had a water content of 19.
．． 2 (%) of plastic clay, kneaded with a vacuum clay kneader, and then injection molded to obtain 300 Cqi) x 300 (,
AII: ] x 7 slabs were formed, dried and then fired and sintered.

"Example ■" This example is a case where a relatively small amount of carbon steel fiber is used.

1) Blending ratio (weight ratio) Carbon steel fiber treated material 10 [%] Frog-eye clay 40 [%] Tsuyoshi stone 43 [mm] Plate glass cullet 7 [%] 2) Firing conditions Firing temperature 1100 [℃] Temperature increase rate, From room temperature to 500 ['C] 10 [℃/
500 ('C) or more 1100 [℃] 50 CC/min] 3) Physical properties of sintered product Water absorption 76 [%] Bulk specific gravity 2.45 Bending strength 780 ± 10 (kg/c + J) Thermal conductivity
4.7 [: kcal /111. hr.

°C] Thermal expansion coefficient 75 x 10-7 The bending strength was approximately double that of ordinary ceramic products.

"Example ■" This example is a case where a relatively large amount of carbon steel fiber is used.

1) Compounding ratio (weight ratio) Carbon steel fiber treated material 30 [%] Frog's eye clay 40 [%] Talc 20 [%] Frit for steel plate enamel 10 [%] 2) Firing conditions Firing temperature 1060 [℃] Temperature increase rate , from room temperature to 500 [℃] 10 [℃/min] 〃 From 500 [℃] to 1060 [:℃] 45 ("
C/min] 3) Physical properties of sintered product Water absorption rate 10.5C%] Bulk specific gravity 3.6 Bending strength 1120±100'=97cd] Thermal conductivity
10.6 (kcal/m, hr.

°C] Coefficient of thermal expansion: 82 x 10-' Toughness: 13 (MN-m-3/2) The bending strength is nearly three times that of ordinary ceramics, and the toughness is about 9, the highest value of ordinary ceramics. This was an increase of 40%.

“Example mj In this example, a piece of copper is used as the metal.

1) Mixing ratio (weight ratio) Copper slices 10 [%] Frog-eye clay 40 [%] Talc stone 40 [mm] Frit for copper enamel 10 [%] 2) Firing conditions Firing temperature 920 [:℃''] Temperature increase rate , from room temperature to 500 [℃] 10 [:℃/min] From 500 [℃] to 920 [℃] 60 [℃/min] 3) Physical properties of sintered product Water absorption rate 12.5C%] Bulk specific gravity 2. 55 Bending strength 820-f 10 (kg/i) Coefficient of thermal expansion 80 This was an increase of approximately 60%.

[Effects of the present invention]

Based on the above description, the effects of the present invention can be summarized as follows.

(1) The metal composite ceramic sintered body according to the present invention is different from the conventional combination of powders, and the bending strength and toughness of this sintered body are significantly improved compared to ordinary ceramics. A new ceramic material was obtained in which the disadvantages such as brittleness were almost completely eliminated while retaining the advantages of corrosion resistance etc., and the reinforcement effect with metal fibers etc. was excellent.

(2) In the manufacturing method of the present invention, metal fibers, etc. are evenly distributed within the ceramic body and fired, so it has very good thermal conductivity and can be fired and sintered at relatively low temperatures and in a short time. The top heat efficiency is also extremely good.

(3) In the present invention, electrical properties such as electrical resistance can be freely changed to a certain extent by manufacturing with varying content of metal fibers and/or pieces.
Silicon and other semiconductor materials, dielectric materials, silicon carbide,
Through various combinations with silicon nitride and other fine ceramics, we have obtained a powerful basic means for developing a wide variety of high-strength, high-toughness new ceramic materials with various levels of performance.

(4) The metal composite ceramic viscosity according to the present invention has much better toughness than conventional products, so it does not generate cracks during processing. In other words, it was possible to obtain the effect of being able to process the material into a free shape since it is a massisoplue.

(5) The product and manufacturing method of the present invention have a great advantage in that they mainly use general-purpose metals and general-purpose ceramics, rather than using only high-class and expensive materials such as cermet.

1 other person

Claims (2)

[Claims] (1) A metal composite ceramic sintered body, characterized in that 5% to 70% by weight of fibrous and/or sliced metal is dispersed in ceramic. (2) Delicate and/or sectioned metals are heated to 250°C in advance.
] After heat treatment at 900 [:'C] or less, (pH)
The metal is immersed in an aqueous solution of 1 to 2 phosphoric acid and/or phosphate for 1 minute to 5 e'3 to form a 11-phosphate film on the surface, and then The metal is recovered from an aqueous phosphate solution, immersed in an aqueous solution of a sol containing silica and/or alumina, and then dried, and then added to a ceramic composition containing 2 [%] to 30 (2) by weight of a glass-like material. Add to the slurry so that the overall weight is 5% to 70%, add water to make a slurry with a water content of 30C% to 45%, and stir with a mixer. Dehydrate under reduced pressure to reduce water content to 10%
230c% or less], molded, dried and heated to 500%
In the temperature range of 1- below [:”C] 20 [℃/min] or above 4
A method for producing a metal composite ceramic sintered body, characterized in that the temperature is raised at a rate of 0 [:'C/min] or less and sintered at a temperature of 700 [°C] or more and 300 [:'C] or less. .