JPS60230913A - Composition for fixing metallic powder molding during sintering - Google Patents

Abstract

PURPOSE:To prevent a metallic powder molding consisting of metallic powder and synthetic resin binder from exfoliating from a base material surface during sintering in the stage of forming a sintered metallic layer on the surface of the metallic base material of said metallic powder molding by using a specifically composed compsn. for fixing. CONSTITUTION:The sheet-shaped metallic molding consisting of wear-resistant metallic powder and acrylic resin binder is adhered to the surface of the metallic base material to 0.5-5mm. thickness and is sintered in a non-oxidizing atmosphere. The polyimide soln. compsn. formed by compounding an epoxy compd. having >=2 epoxy groups on one molecule with an org. solvent soln. of the polyimide precursor consisting of the polyamide acid synthesized of the tetracarboxylic dianhydride consisting of 10-90mol% aliphat. tetracarboxylic dianhydride and 90-10mol% arom. tetracarboxylic dianhydride and org. diamine or the polyamide acid imide formed by partial conversion to amide thereof in such a way that the epoxy groups are incorporated at >=0.3 equiv. by 1 equiv. acid group of the above-mentioned precursor is coated and interposed between the base material and metallic powder powder molding in the above-mentioned stage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves rolling a mixture of metal powder and a synthetic resin binder, and placing a metal powder compact made of a non-sheet-like material or similar product on a metal base material. The present invention relates to a composition for fixing during sintering, which is used when sintering the same to form a metal layer on the surface of a base material to improve the wear resistance of the surface of the base material.

When a metal powder sheet is placed on a metal base material and sintered, even if the binder contained in the sheet has an adhesive effect, it burns out and volatilizes during the temperature rise process, resulting in the adhesion. It loses its functionality and loses its adhesion to the base material.

Therefore, when the weight of the metal powder sheet acts on the adhesive surface with the base material, such as on a sloped, curved, or downward surface of the base material, the weight of the sheet cannot be supported, and the sheet moves away from the base material. will peel off or fall off.

Particularly when carrying out sintering processes that are subjected to vibrations and shocks during transportation in the furnaces, such as continuous sintering furnaces with mesh belt type or pusher set, or vacuum sintering furnaces, sheets may peel off due to the vibrations and shocks mentioned above. and become more likely to fall off.

The inventors have already discovered that, as an effective method for solving the above problem, a specific composition is interposed between the sheet and the base material when a metal powder sheet is placed on the base metal. This composition helps in adhesion and fixation of the sheet to the base material surface until the sheet is sintered, thereby making it possible to use a specific mounting mode as mentioned above or to perform a sintering process that applies vibration or impact. proposed a method for preventing the sheet from peeling off or falling off (Japanese Patent Application No. 59-34887).

However, the composition used in this proposed method is mainly composed of a (meth)acrylic acid alkyl ester polymer, and in this case, the temperature is 250 to 380°C during the specific sintering operation, that is, at the initial stage of heating. It is necessary to maintain the temperature at a temperature of Such a sintering operation is not necessarily practical, and there is a problem that it is somewhat lacking in industrial versatility.

In addition, when a metal powder sheet is placed on a metal base material and sintered, there is a problem that this type of sheet shrinks by about 20% in the plane direction during sintering. In order to obtain the desired dimensions, it was necessary to set the dimensions in advance to take into account the above-mentioned shrinkage. However, this type of dimension setting is actually extremely troublesome and impractical.
Since fluctuations in the shrinkage rate due to variations in the thickness of the metal powder sheet and the mixing ratio of the metal powder and the binder cannot be avoided, it is difficult to set the dimensions after sintering to the specified dimensions. In particular, as the size of the sheet increases, the variation in shrinkage rate also increases accordingly, making the above-mentioned difficulties more pronounced.

Therefore, it would be very convenient if such shrinkage could be suppressed by interposing such a composition according to the above proposal, but such a shrinkage suppressing function could not be expected with the above composition.

This invention was discovered as a result of further studies from the above viewpoint, and its gist is a metal powder molding formed by rolling a mixture of metal powder and a synthetic resin binder. When the body is placed on a metal base material and sintered in a non-oxidizing atmosphere, the molded body is interposed between the molded body and the base material until the molded body is sintered. A composition used for adhesion and fixation on the base material, comprising 10 to 90 mol% of an aliphatic tetracarboxylic dianhydride and 90 to 10 mol% of an aromatic tetracarboxylic dianhydride. The above epoxy compound having two or more epoxy groups in one molecule is added to an organic solvent solution of a polyimide precursor consisting of a polyamic acid synthesized from an anhydride and an organic diamine or a polyamic acid imide obtained by partially imidizing this. Sintering of a metal powder molded body comprising a polyimide solution composition in which epoxy groups are blended in a ratio of 0.3 equivalents or more to 1 equivalent of acid groups (carboxyl groups) of a polyimide precursor. It is in a time fixing composition.

When the composition of the present invention is interposed between a metal powder compact and a metal base material and subjected to a sintering treatment at a constant temperature increase rate, the initial stage of temperature increase is usually about 120 to 250 °C. First, the solvent is scattered, and then a curing reaction (partly imidization reaction) occurs between the polyimide precursor and the epoxy compound, increasing the adhesive strength and helping the molded body to adhere and fix on the base material, which then continues. During the heating process, gaseous pyrolysis products are desorbed to produce carbon precursors, which help the molded body to be adhesively fixed to the base material in the temperature range up to about 700°C, when the molded body begins to sinter. Demonstrate function. Therefore, even when the compact is placed on an inclined, curved, or downward surface of the base material and subjected to a sintering process where vibrations or shocks are applied during transportation in the furnace, the There is no problem of peeling or falling off of the molded body.

Moreover, since the above composition uses a polyimide resin, particularly a polyimide resin containing aromatic tetracarboxylic dianhydride as a synthetic raw material, the amount of carbon remaining after sintering is approximately 10 to 10%. It occupies a considerable proportion of about 50% by weight, and this gives very good results to the adhesion and fixing force of the metal powder molded body during the sintering process, and has an effect on the shrinkage of the molded body in the planar direction during the sintering process. This results in the formation of a highly dimensionally stable metal layer that is substantially similar in size to the original shape that has shrunk only in the thickness direction.

In addition, when polyamic acid or polyamic acid imide, which is a precursor of polyimide resin, is used alone, an intramolecular ring-opening reaction (imidization reaction) occurs in the early stage of the sintering process.
There is a risk that the free water generated at this time may reduce the adhesion and fixing force of the molded object, but this invention avoids the above problem because it uses an epoxy compound together with the polyimide precursor. be done.

In other words, the epoxy compound has the function of reacting with acid groups (carboxyl groups) contained in the polyimide precursor at the early stage of the sintering process to crosslink and harden the precursor, thereby minimizing the generated water. can be reduced. Moreover, this epoxy compound also contributes to improving the adhesive force when temporarily adhering the molded bodies, giving good results in the sintering operation.

On the other hand, when such an epoxy compound is blended into a solution of a polyimide precursor, the stability of this solution may pose a problem. However, this problem can be solved by using aliphatic tetracarboxylic dianhydride as one of the raw materials for synthesizing the polyimide precursor. That is, the dianhydride gives better stability to the solution when used as a polyimide precursor than aromatic ones, and makes it possible to produce a uniform liquid composition. In addition, aromatic tetracarboxylic dianhydride increases the amount of carbon remaining during sintering treatment and gives good results for the adhesion fixing force and shrinkage prevention function of the molded body, so it is used in this invention. It is designed to be used in combination with an aliphatic type.

As described above, according to the composition of the present invention, by interposing the composition between the metal powder compact and the metal base material, it is possible to achieve a certain increase in temperature without requiring special sintering operations as previously proposed. By performing a normal sintering process using a temperature rate, there is no problem of peeling or falling off during the sintering process, and there is almost no shrinkage during the sintering process. By bonding the metals together, it is possible to form a desired metal layer that is firmly fixed on the base material and has good dimensional stability.

The polyimide precursor in this invention is obtained by reacting a tetracarboxylic dianhydride and an organic diamine in an organic solvent. That is, polyamic acid can be obtained by reacting both components at a temperature of usually 0 to 100°C, preferably 5 to 40°C, and particularly preferably around room temperature. In addition, imidization proceeds by further heating this at a temperature of usually 80° C. or higher to the boiling point of the solvent, preferably 100 to 200° C., thereby forming a partially imidized product having an amic acid structural unit and an imide structural unit. Polyamic acid imide is obtained.

The degree of partial imidization of this polyamic acid imide is such that the ratio of the number of amic acid structural units/imide structural units is usually 0.0.
It is preferable to set it in the range of 3 to 4, preferably 0.05 to 1. This ratio can be determined by measuring the acid value of the reaction product.

By proceeding with imidization in this way, the amount of epoxy compound involved in the curing reaction is reduced as much as possible, and the adhesive fixing power and shrinkage suppressing function of the molded object due to the use of polyimide resin are better exhibited. be able to.

However, if the imidization is excessively advanced, the compatibility between the polyamic acid imide and the epoxy compound will decrease, making it difficult to obtain a uniform solution composition.

In this invention, for the reasons mentioned above, aliphatic and aromatic tetracarboxylic dianhydrides are used in combination. The combined proportion of the aliphatic tetracarboxylic dianhydride is 10 to 90 mol%, preferably 20 to 80 mol%.
In mole%, aromatic tetracarboxylic dianhydride is 90 to 1
0 mol%, preferably 80 to 20 mol%. If it deviates from the above range, either the stability of the solution or the adhesive fixing force of the molded article will be impaired.

As the aliphatic tetracarboxylic dianhydride, butane,
Tetracarboxylic dianhydrides such as pentane, hexane, cyclopentane, bicyclohexene, 5-(2.
5-Dioxotetrahydrofuryl)-3-methyl-3-
Examples include cyclohexene-1,2-dicarboxylic anhydride, bicyclo-(2,2,2)-octene-2,3,5,6-tetracarboxylic dianhydride, and the like. Of course, the skeleton of these tetracarboxylic dianhydrides may be substituted with a substituent such as an alkyl group. It is also possible to use partially aliphatic tetracarboxylic acids, dicarboxylic acids, tricarboxylic acids, or anhydrides thereof. These combined ingredients are 30 mol% of the total amount with aliphatic tetracarboxylic dianhydride.
It is desirable to keep it below.

Further, specific examples of aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4
- Examples include 4'-biphenyltetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, etc., even if the aromatic ring has a substituent such as an alkyl group. good. Further, as in the case of aliphatic tetracarboxylic dianhydride, aromatic tetracarboxylic acids, dicarboxylic acids, tricarboxylic acids, or their anhydrides can be used in combination. The content of these combined components is preferably 20 mol % or less based on the total amount of the aromatic tetracarboxylic dianhydride.

The organic diamine to be reacted with the tetracarboxylic dianhydride having such a structure has the general formula: H,N-R
-NH, in which R is a divalent organic group, such as an aromatic, aliphatic, alicyclic, or heterocyclic group, or a combination thereof, or , nitrogen, sulfur, phosphorus, silicon, etc. In this case, R may have a substituent that does not quantitatively react with the amino group or acid anhydride group under the reaction conditions. This is because these groups can impart desirable properties such as solubility, processability, or adhesiveness to the resulting polyimide precursor. It is also possible to use a commonly used organic triamine or organic tetraamine in combination.

These combined ingredients are 20 mol% of the total amount with organic diamine
It is preferable that it is as follows.

Aromatic diamines are desirable as organic diamines, but specific examples of diamines used in this invention include meta-phenylene diamine, para-phenylene diamine, 4.4
'-Diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, benzidine, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3
'-Diaminodiphenylsulfone, para-bis~(4-
aminophenoxy)benzene, meta-bis-(4-aminophenoxy)benzene, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3'-
Dimethyl-4,4'-diaminobiphenyl, 3,4'-
Diaminobenzanilide, 4-(para-aminophenoxy)-4-aminobenzanilide, 3,4'-diaminodiphenyl ether, 3,3'-dimethoxybenzine,
2,4-bis(β-amino-tert-butyl)toluene, bis(para-β-amino-tert-butylphenyl) ether, meta-xylylene diamine, para-xylylene diamine, di(para-amino-cyclohexyl) )
Methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-dimethylhebutamethylenediamine, 3-methoxy-hebutamethylenediamine, 2,11-diaminododecane, ■4-diaminocyclohexane , 2・2'-
Diaminodiethyl ether, 2,2'-diaminodiethyl thioether, 3,3'-diaminodipropoxyethane, 2,6-diamitubiridine, guanamine, 2,5-
Diamino-1,3,4-oxadiazole, 2-(3′-aminophenyl)-5-aminobenzoxazole,
bis-(4-amino-phenyl)phosphine oxyto,
bis-(4-amino-phenyl)diethylsilane, which may be used alone or as a mixture.

The reaction between the tetracarboxylic dianhydride and the organic diamine in this invention is usually carried out in an organic solvent as described above. The reaction for obtaining polyamic acid is an exothermic reaction, and the reaction temperature can be controlled by providing some kind of cooling means during the reaction. At this time, one of both components is added to an organic solvent,
It is preferable to add the other component in appropriate amounts. If the reaction can be sufficiently controlled, there is no problem even if both components coexist.

After the production of this polyamic acid, the imide ring-closing reaction is carried out under the more severe conditions of 80° C. or above, and the desired polyamic acid imide can be obtained by measuring the acid value. In the synthesis reaction of such a precursor, the highest molecular weight can be obtained by setting the molar ratio of both components to 1:1.

Solvents used in the above reaction include N-N-dimethylformamide, N-N-diethylformamide, N-N-
dimethylacetamide, N-methyl-2-pyrrolidone,
N-methylcaprolactam, dimethyl sulfoxide, tetramethylene sulfone, tetramethylurea, hexamethylphosphoamide, pyridine, quinoline, T-butyrolactone, N-acetyl-2-pyrrolidone, phenol, cresols, nitro compounds, glycols, cellosolve and carpitols. The amount of this organic solvent to be used is 20 to 95% by weight of the reaction system, but the amount may be appropriately determined so as to provide a concentration that shows a practical viscosity including the epoxy compound to be added later.

In addition, if you want to obtain a polyimide precursor that has been sufficiently imidized in the synthesis of the polyimide precursor, select a solvent with a relatively high boiling point, achieve the desired imidization, and reconstitute it into a poor solvent as necessary. It is also possible to precipitate, dry, and redissolve in other low-boiling solvent systems to incorporate epoxy compounds.

A polyimide solution composition can be obtained by adding an epoxy compound having two or more, usually 2 to 4, epoxy groups in one molecule to a solution of such a polyimide precursor.

The epoxy compound used in this invention is selected from those having at least two cyclic epoxy groups or chain epoxy groups in the molecule and an epoxy equivalent of about 100 to s, ooo. That is, it is a compound containing a 1,2-epoxy group inside, and is commercially available as epoxidized diolefin, diene, cyclic diene, diolefinic unsaturated carboxylic acid ester, etc.
01゜206.269 (all product names manufactured by Chisso Corporation)
, Araldite CY179.178, 181, 185.
175 (all product names manufactured by Ciba Corporation).

In addition, compounds having a chain epoxy group include polyglycidyl esters and polyglycidyl esters,
The former can be obtained by a known method by alkaline condensation of aliphatic diols, polyhydric alcohols, bisphenols, phenol novolaks or talesol novolaks with epichlorohydrin or β-methylepichlorohydrin.

Commercially available products include Epicor) 82B, 1001.100
2.1004.100? , 1009.1031 (all product names manufactured by Shell), DEN431, 438, D
ER661, 542 (all product names manufactured by Dow Corporation), Araldite ECN1273.1280 (all product names manufactured by Ciba Corporation), Chissonox UNOX201 (Chisso U
Many products are known, including CC (trade name) and Epiclon 1000 (Dainippon Ink Chemical Co., Ltd. (trade name)).

The latter polyglycidyl ester can be obtained by a known method of reacting dicarboxylic acid with epichlorohydrin or β-methylepichlorohydrin in the presence of an alkali. Commercially available products include Araldite CY183 (trade name manufactured by Ciba), Epicote 190.191 (both manufactured by Shell), Lexerm xioo (trade name manufactured by Bayer), and Epiclon 400 (trade name manufactured by Dainippon Ink Chemical Co., Ltd.). triglycidyl isocyanurate, etc.

These epoxy compounds contain 0.3 or more equivalents of epoxy groups, usually 0.5 to 1 equivalent of acid groups in the polyimide precursor.
It is blended at a ratio of 2 equivalents. The blending ratio of epoxy groups is 0
．． If the amount is less than 3 equivalents, the above-mentioned effects such as the crosslinking reaction of the polyimide precursor will be lost. If the amount is too large, the influence of the epoxy compound will be large, so This is not preferable since the above-mentioned characteristics of the polyimide resin may be impaired.

In addition, in this invention, after blending these epoxy compounds, it is also possible to carry out a curing reaction in advance in a solution state. In this case, it is preferable to reduce the amount of acid groups by half when both components are mixed. If the preliminary reaction is carried out further than this, gelation etc. will occur, which is not desirable as a polyimide solution composition. Materials include xylene resin, paraffin wax, process oil, abiethyl alcohol as softeners, calcium carbonate, silica, talc as fillers, dioctyl phthalate, dioctyl adipate, triphenyl phosphate, dibutyl phthalate, etc. as plasticizers, as necessary. Various additives can be blended.

When the above-mentioned composition comprising such constituent components is interposed between the metal powder molded body and the metal base material and sintered, the amount of residual carbon after sintering is approximately 10 to 50% by weight. This gives good results in increasing the adhesion and fixing force of the molded body during high-temperature heating and suppressing its thermal shrinkage. In addition, the above composition usually has pressure-sensitive adhesive properties due to the epoxy compound blended therein, and has the characteristic that temporary adhesion of a metal powder compact to the metal base material surface is easy. ing.

Next, the method of using the composition for fixing during sintering of the present invention will be explained. First, when placing a metal powder compact formed by rolling a mixture of metal powder and a synthetic resin binder on a metal base material, the above-mentioned method of the present invention is placed between the base material and the compact. A fixing composition is provided during sintering. This intervention is usually carried out by applying the composition to either or both of the base material and the molded article.

The coating thickness of the above-mentioned composition to be interposed is generally 5 to 5.
The thickness is preferably about 50 μm, preferably about 10 to 30 μm. If the above-mentioned thickness is too thin, the effect of this invention cannot be obtained, and if it is too thick, the amount of gas generated at the interface between the base material and the molded body increases, resulting in fixation during sintering or bonding after sintering. Both are unfavorable because they cause problems such as a decrease in strength.

The metal powder compact used above is formed by rolling a mixture of metal powder and a synthetic resin binder into a sheet shape or a similar shape.
A material having a thickness of about 5 to 5 cranes is used.

As the metal powder, various metal powders can be used depending on the properties to be imparted to the surface of the metal base material, such as self-fusing alloy powder and wear-resistant alloy powder. As a typical metal powder, Fe-M-C multi-component eutectic alloy powder, which is a wear-resistant alloy powder, can be mentioned. The above M has at least one of Mo, B, and P as a main component, and may contain Cr, V, W, Nb, Ta, and Ti as secondary elements, and other elements include St, It can contain Ni, Mn, etc. Such multi-component eutectic alloy powder has a relatively low sintering temperature, and generally has a liquid phase of lo-;'Go volume % in the temperature range of 1,000 to 1°150°C, and this liquid phase is It is characterized by excellent wettability.

The particle size of these alloy powders is generally preferably 150 mesh or less, since this affects the porosity after sintering. If it is larger than this, it becomes difficult to form a dense alloy layer.

The synthetic resin binder to be mixed with the metal powder is preferably one having pressure-sensitive adhesive properties, particularly an acrylic polymer consisting of an alkyl (meth)acrylic acid ester or a monomer copolymerizable therewith, or An acrylic pressure-sensitive adhesive composition containing an adhesion-imparting resin such as an alkylphenol resin, a rosin resin, a petroleum resin, or a coumaron indene resin is preferably used.

The above synthetic resin binder is diluted with an appropriate organic solvent such as acetone, toluene, methyl ethyl ketone, etc., and the above metal powder is added in an amount of usually 10 to 100% per 1 part by weight of the solid content.
The desired metal powder is produced by adding parts by weight and kneading, pouring this into a mold generally covered with release paper, evaporating the solvent, and forming it into a sheet or other shape by passing it through a rolling roll. A molded body is obtained.

This molded body is sintered in a non-oxidizing atmosphere with the sintering fixing composition of the present invention interposed between it and the metal base material as described above. The rate of temperature increase at this time may be constant, and there is no particular need to hold the temperature on the low temperature side for a certain period of time as previously proposed.

At the initial stage of heating, the above composition exhibits strong adhesive strength due to the curing reaction of the polyimide precursor after the solvent is scattered, and then it is converted into a carbon precursor that effectively contributes to adhesion, and then the composition is heated to the sintering temperature. Until then, the molded body is stably adhesively fixed onto the base material.

Note that the reason why the sintering treatment is performed in a non-oxidizing atmosphere is obvious; in an oxidizing atmosphere, the molded body is oxidized and degraded during the treatment, making it impossible to form a desired metal layer. The non-oxidizing atmosphere may be a vacuum such as a hydrogen gas atmosphere or a nitrogen gas atmosphere.

When the temperature is raised to the sintering temperature and maintained for a predetermined time in this manner, the carbon precursor is finally completely carbonized. The amount of residual carbon at this time is about 10 to 50% by weight as mentioned above.
The preferred amount is 15 to 35% by weight. In addition, while similar substances in the molded body disappear by carbonization, the metal components in the molded body diffuse into the base material, resulting in a metal layer with good dimensional stability that closely resembles the original size and is strongly adhesively bonded to the base material. is formed.

The present invention will be explained in more detail below by describing examples. Note that in the following, parts and % mean parts by weight and % by weight, respectively.

Example 1 Into a 500cc four-lobe flask equipped with a thermometer, N2 gas inlet, cooling tube with trap, and stirring device, 1.2.
19.8 g of 3,4-butanetetracarboxylic dianhydride (
0.1 mol), 32.2 g (0.1 mol) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 368 g of N-N-dimethylformamide were added and heated in a water bath under dry N2 gas flow. Stir on top. Contents are approximately 5℃
4,4'-diaminodiphenyl ether 40.0g
(0,2-t-L) was added little by little while monitoring the degree of exotherm. This addition takes approximately 30 minutes and the temperature of the reactants is 1
The temperature rose to 5°C.

After the addition, the water bath was removed and stirring was continued for about 2 hours at room temperature to obtain a viscous polyamic acid solution with an acid value of 0.88 milliequivalents/g. To 100 g of this solution, add bisphenol A type liquid epoxy resin (epoxy compound! 1184~
14.8 g of 194) was blended to obtain a composition for fixing during sintering of the present invention. When this composition was carbonized under the same conditions as the sintering treatment described below, the amount of residual carbon was 25%.

On the other hand, Mo10.5%, Cr2.5%, P2.4%.

Particle size: 58.8% multi-component eutectic alloy powder with a chemical composition of 3.6% C, the balance being Fe, and 5US
410 powder with a particle size of 150 mesh or less 39.2
% and further 2% of acrylic acid (meth)alkyl ester resin were wet-kneaded using acetone as a solvent, and then rolled into a product with a thickness of 1 mm and a density of 4.65 g/c.
An alloy powder sheet of d was prepared.

This sheet was cut into a size of 1CII+×1CI11, and the above-mentioned composition for fixing during sintering was applied to a thickness of 20 pm, and then adhered to the vertical surface of a steel base material. Thereafter, the temperature was raised to 1,080°C at a rate of 20'C/min in a hydrogen gas atmosphere, maintained at this temperature for 15 minutes, and then slowly cooled.

In this way, the alloy powder sheet does not fall off or shrink in the plane direction during the sintering process, and is firmly bonded and fixed onto the steel base material with a thickness of 0°62 to 0.65 mm.
, hardness is HRC terror 1-63. Density is 7.6-1.1
A wear-resistant alloy layer of g/ca could be formed.

Example 2 Into the same flask as in Example 1, 19.8 g (0° 1 mol) of ■2,3,4-butanetetracarboxylic dianhydride,
Add 32.2 g (0.1 mol) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 368 g of N-N-dimethylformamide, and proceed in the same manner as in Example 1 under dry N2 gas flow. Then 39.6 g (0.2 mol) of 4,4'-diaminodiphenylmethane was added. After addition, a heater was attached to heat the mixture, and stirring was continued at 120° C. for about 2 hours, and then the temperature was lowered to obtain a polyamic acid imide solution in a slightly cloudy state.

20 g of triglycidyl isocyanurate as an epoxy compound was added to 100 g of this solution to obtain a fixing composition during sintering of the present invention. When this composition was carbonized under the same conditions as the sintering treatment described below, the amount of residual carbon was 28%.
Met.

On the other hand, 38°6% of the multi-component eutectic alloy powder used in Example 1, 57.9% of 5US410 powder with a particle size of 150 mesh or less, and 3.5% of acrylic acid (meth)alkyl ester resin, After wet kneading using toluene as a solvent, roll rolling was performed to give a thickness of 1.5 m and a density of 4.
An alloy powder sheet of 8 g/ad was produced.

This sheet was cut into a size of 1 cIl x 1 cIl, and the above-mentioned composition for fixing during sintering was applied to the sheet to a thickness of 20 μm, and then adhered to the vertical surface of a steel base material. After that, the temperature was raised to 1.100°C at a rate of 10°C/min in a hydrogen gas atmosphere,
After being maintained at this temperature for 20 minutes, it was slowly cooled.

In this way, the alloy powder sheet can be firmly bonded and fixed onto the steel base material with a thickness of 0.9 to 0.95 m, without falling off or shrinking in the plane direction during the sintering process. Saga HRC is 60-62. Density is 7゜5~7.7 g/
A wear-resistant alloy layer of cJ could be formed.

Patent applicant: Nitto Electric Industry Co., Ltd.

Claims (1)

[Claims] (1) When a metal powder molded body formed by rolling a mixture of metal powder and a synthetic resin binder is placed on a metal base material and sintered in a non-oxidizing atmosphere, the molded body is A composition interposed between the base material and used for adhesively fixing the molded body onto the base material until the molded body is sintered, the composition comprising 10 aliphatic tetracarboxylic dianhydrides. A polyimide precursor consisting of a polyamic acid synthesized from a tetracarboxylic dianhydride consisting of ~90 mol% and an aromatic tetracarboxylic dianhydride of 90 to 10 mol% and an organic diamine, or a polyamic acid imide obtained by partially imidizing the same. An epoxy compound having two or more epoxy groups in one molecule is added to the acid group (
1. A composition for fixing a metal powder compact during sintering, comprising a polyimide solution composition containing 0.3 equivalents or more of epoxy groups per equivalent (carboxyl group).