JPH05214555A - Parts having film containing powder - Google Patents

Abstract

PURPOSE:To form a film excellent in adhesion without being thermally affected by filling a resin in the void of a compressed powder bed and forming a resin layer in the bed. CONSTITUTION:In the parts having a skeletal structure with the compressed powder bed formed with a powder, a resin such as epoxy resin is filled in at least a part of the void of the bed. A film of >=1 layer consisting of a resin layer for bonding the parts or the lower bed is formed in the bed. A metal or alloy powder, a ceramic powder and a pigment or resin powder are utilized as the powder to constitute the bed. The adhesion between the bed and the resin layer is increased by the resin filled in the void of the skeletal structure, the skeletal structure is reinforced, and the strength of the bed is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various parts having a film formed on the surface thereof. The various parts referred to here are various machines, mechanical parts used in automobiles and other vehicles, ships, airplanes, etc., electric / electronic parts, decorative articles, metal fittings, magnets, toy parts, etc. ,
Various parts except large-scale structural members such as vehicle outer panels. The material of the member is metal, alloy, intermetallic compound, inorganic compound, plastic, ceramics, or the like. In addition, various parts may already have various known films such as a resin coating film and plating formed on the surface thereof, or may be surface-modified.

The "coating" as used in the present invention can be applied to all uses to which conventional powder coatings and resin coatings have been applied, but it is mainly used for anticorrosion, imparting mechanical strength, forming an insulating layer or a conductive layer. And / or applied to aesthetics,
Further, it is applied to the formation of a base layer for forming various known films. Further, the coating of the present invention is not only for these purposes but also for the physical properties of the powder substance used in the coating,
It can also be used for the purpose of effectively utilizing chemical properties.

[0003]

2. Description of the Related Art The following are conventionally known as a film composed of a powder substance related to the present invention.

Resin-Coated Film The resin-coated film is obtained by applying a paint prepared by dispersing various pigments to a resin or other vehicle on the surface of a component, volatilizing the solvent in the paint, and polymerizing the resin. The coating method is brush coating, spray coating, pickling coating, electrodeposition coating,
For example, electrostatic painting. During the drying of the coating film, the resin is solidified by polymerization, and in the case of oil paint, it is solidified by the oxidation of oil. In the powder coating film, the resin softened by the temperature rise during drying is solidified by cooling. As a result of these solidifications, the required hardness of the coating is obtained.

Vehicles used for resin coating films include epoxy, acrylic, phenol, polyester,
Resins such as polyethylene, polyvinyl chloride, nylon, polypropylene, fluorine-based polymers, alkyds and cellulose derivatives, and linseed oil, safflower oil, soybean oil and other drying oils or semi-drying oils can be used. Examples of pigments that may be used in resin coating films include iron oxide, magnesium oxide, various oxides such as titanium oxide, carbon black,
Various coloring pigments such as quinacridone red and metal powders such as zinc and aluminum are available. In the following description, the resin does not include such a pigment, and the resin coating film includes only the resin or, in some cases, the film including the resin and the pigment.

[0006] Powder coating A coating method using powder as a raw material includes a thermal spraying method for metals and the like. The coating obtained by thermal spraying has defects such as bubbles due to partial or complete melting of the powder. It is a continuous film.

If a layer of green compact made by powder metallurgy is adhered to a part by brazing or the like, a layer made of powder can be obtained, the thickness of which is at least 500 microns to 1 mm, and It is almost impossible to accurately prepare a green compact according to the thickness of the coating applied to the part and according to the shape and size of the part. Therefore, the technique for forming a powder film is very limited, and one of them is the method disclosed in Japanese Patent Laid-Open No. 2-71872. In this publication, a powder substance is brought into contact with the surface of a member to which tackiness has been given in advance, the member is vibrated to compress the powder adhered to the surface of the component to a bulk density or less, and then the powder not adhered to the component is removed. A method of removal is disclosed. A screen of a color television is shown as a part, and a fluorescent toner is shown as a powder as a concrete example.

Yet another alternative is US Pat.
There is a barrel mechanical plating method described in No. 40001, 4849258, etc. According to this method, powder of tin, aluminum, etc. is dispersed in a dispersion medium selected from oils and fats such as vegetable oil, grease, silicone oil, etc. to perform barrel plating. It is plated on the parts by the method of.

The above-mentioned US Pat. No. 4,849,258 also discloses a method of supplementarily using a silicone resin in order to improve lubricity in addition to these oils and fats. Incidentally, the object to be plated and the steel balls or glass balls further rubber pieces are mixed with the powder and the dispersion medium, and since the whole is rotated, when the steel balls or the glass pieces and the rubber pieces collide with the object to be plated, The powder present between them is mechanically bonded to the latter. In this method, a flux such as an acid is also used to activate the surface of the object to be plated. In addition, it is described that when a fat or oil as a lubricant forms a film on the surface of a component, the plating film formation is hindered, and a large amount of emulsifier is used to prevent this.

The coatings produced by the method of the above-referenced US patents are specifically directed to the uniform formation of metal plating layers such as Zn on small parts. It is also stated in the U.S. patent that if a layer other than a metal such as a resin is deposited on the component, then no film formation occurs.

[0011]

The anticorrosion performance, aesthetics, mechanical strength, etc. of the resin coating film depend on the types of resin and pigment,
And it changes with these compounding ratios. Among these performances, the anticorrosion performance is more excellent as the amount of pigment is larger. In recent years, parts, especially parts related to automobiles, precision machines and electronics, are required to have a thin film and have high dimensional accuracy and good corrosion resistance. From the viewpoint of the corrosion resistance, it is preferable to increase the amount of the pigment, but if the amount of the pigment is too large, the fluidity of the coating is almost lost, and it is practically impossible to form a film. Therefore, the compounding ratio of the pigment in the conventional coating film does not exceed 40% by volume, however high.

On the other hand, if the pigment blending ratio in the film becomes high, another problem occurs. Generally, it is extremely difficult to disperse a pigment powder in a vehicle completely uniformly in a resin coating film, and a cluster-like powder aggregate is often formed. Such aggregates increase as the blending ratio of the pigments increases, and as a result, the distribution of the pigments in the film becomes uneven and the difference in density is large. As a matter of course, the coating on the sparse portion of the pigment is inferior in the ability to block corrosive components such as water, and as a result, the anticorrosion performance of the coating is dominated by this sparse portion. Therefore, even if a large amount of pigment is blended, it cannot be said that sufficient anticorrosion properties are obtained because all of them are not effectively used.

As a rust-preventive paint for large structures such as bridges, zinc-rich paint in which zinc powder accounts for 40 to 50% by volume is used, but this is applied to parts targeted by the present invention. Absent. The reason is that since zinc rich paint contains too much pigment, it is difficult to spray paint and it is applied by brushing.
The present invention is not applied to the target parts.

Next, the powder coating described in JP-A-2-71872 contains many voids and is not suitable for purposes such as anticorrosion, and its use is limited.

In the thermal spraying method of metal or ceramics, the temperature of the parts rises, so that it is not suitable for coating parts such as plastics having a low softening temperature, or permanent magnets whose electromagnetic properties are deteriorated by the temperature rise. Since the voids in the film formed when the powder is partially or entirely melted and adhered to the component are independent pores, it is impossible to take measures such as filling the voids with resin. The thermal sprayed film and the plating film described later adhere mainly to the film due to the anchor effect of the part and partly due to heat diffusion, and the adhesive force directly acting between the part and the film is not very high.

It is the continuous or semi-continuous coating itself that has the extremely high strength and adhesion required of the sprayed coating or plated coating for sliding parts, and is composed of extremely tough materials such as metals and ceramics. This is because it has been done. If you try to peel off such a film from a part,
In addition to overcoming the fixing force such as the anchor effect that acts between the film and the part to separate the film, it is necessary to deform or destroy the film itself, which requires an extremely large force. When such a film has flaws or cuts on its surface and a part of the film is cut off from other parts of the film, peeling occurs extremely easily. Therefore, there is a drawback in that a sprayed coating is weak in an adhesion test such as a cross-cut test in which a film is flawed. This tendency is remarkable in the case of joining dissimilar materials such as metal and non-metal (ceramic, plastic), which have a small adhesive force at the interface. In addition, if there are pores that reach the surface of the component from the surface of the coating, the corrosive components that infiltrate from there will rapidly diffuse to the interface between the coating and the component, further weakening the adhesion force at the interface and causing easy peeling of the coating.

If the surface of the component is not sufficiently cleaned and activated by shot blasting, pickling, etc., the adhesion of the coating will be reduced; since the powder pressure is high,
If the part is a small item, it must be firmly fixed so as not to be blown off; the thermal sprayed coating has drawbacks such as uneven film thickness depending on where the spray hits.

The coating subsequently disclosed in US Pat. No. 4,849,258 is extremely clean and active on the surface of the component, as judged by the fact that it consists of a metal layer deposited directly on the component which has been activated by an acid or the like. The adhesion of the coating is very sensitive to oxides and foreign substances. If the object to be plated has been subjected to normal degreasing and is not subjected to activation treatment with the flux during barrel processing, it is considered that the film will not be formed or the adhesion of the film will be very poor even if it is formed. .. In addition, since lubricants, emulsifiers and fluxes used in large amounts are mixed in the coating, impurities such as carbon may be mixed in the coating.

When the component is plastic, the adhesion of the film is small by the mechanical plating method described in US Pat. No. 4,849,258 or the like or the generally used electroless plating method. The adhesion of the electroplated or electroless plated film applied to the metal parts whose surface has dirt and oxides is low. Further, when the surface is active and chemically unstable like a Nd-Fe-B magnet, it is difficult to obtain a film with high adhesiveness, and therefore the original adhesion of the film causes poor magnetism. Magnetic properties are not obtained, causing product defects.

Therefore, in the conventional powder coating, (a) the proportion of the powder is high, the distribution is uniform and there is no thermal influence on the surface of the component, and / or (b) the cleanliness is of a normal level. There was no coating that satisfied the requirement for high adhesion on the part surface. In particular, the ratio of the powder exceeds 60% by volume, and a film that is accurately formed with a thin film thickness suitable for small parts has not been known. Also in the case of a coating suitable for large parts, a coating having a powder content of 60% by volume or more and containing a resin and having excellent adhesion was not known. That is, since the thermal spray coating causes thermal influence on the surface of the component, (a) is satisfied only incompletely, and regarding (b), the adhesiveness is very sensitive to the surface condition of the component, and pretreatment requires time and effort. However, there are drawbacks such as very strict conditions and difficult management. It is also very weak in the cross-cut test. The film of the above-mentioned US patent does not satisfy (b). Further, the zinc rich paint coating film satisfies the condition (a) only incompletely because the powder distribution is non-uniform.

[0021]

A part having a film according to the present invention has a skeletal structure in which a powder compression layer is composed of a powder substance, and a resin is present in at least a part of the voids of the powder compression layer. One or more coatings having a filled powder compression layer and a resin layer for adhering the powder compression layer to a component or to a lower powder compression layer are formed.

The structure of the present invention will be described below. In the present invention, as the resin, melamine resin, epoxy resin, phenol resin, furan resin, urethane resin, unsaturated polyester resin, polyimide resin, thermosetting resin such as urea resin, acrylic resin, polyester, polyethylene,
Thermoplastic resins such as polyethylene terephthalate, polypropylene, polyvinyl chloride, polyvinyl alcohol, nylon, polystyrene and polyvinyl acetate, cellulose derivatives and the like can be used. It is also possible to use liquid prepolymers or monomers, organic binders generally used for powder molding, such as paraffin, camphor and the like. As the resin, natural products such as gelatin, glue and sumac can be used. Further, the resin may contain an inorganic pigment. Further, in place of the resin, or together with the resin, an inorganic adhesive substance such as silicate represented by water glass can be used. The resin is a constituent material of the resin layer, and at least partially fills the voids in the film, that is, the voids in the skeleton of the powder compression layer and the voids in which the skeleton structure is disturbed, which will be described below. ..

Next, the powder substance is a constituent substance of the powder compression layer, and may be incorporated into a part of the resin layer to become the constituent substance. As the powder substance, various metals, alloy powders, ceramic powders and pigments or resin powders can be used.

As an example, the metal powder is A
l, Cu, Fe, Cr, Co, Ni, Zn, Pb, S
There are powders of n, Rh, Ir, Pd, Pt, Ag, Au, Mo, W and the like, and alloy powders containing them as a main component.
All of these metals are superior in strength to resins and are also excellent in corrosion resistance because they are less likely to deteriorate due to water or salt water. Among the characteristics of each metal, stainless steel, Cr, Ni, Mo, W, etc. have a strong passivation film on the surface, and therefore have excellent corrosion resistance. Therefore, these metals enhance the strength and corrosion resistance of the coating. Rh, Ir, Pt,
Since Pd, Ag, Au, etc. have good aesthetics and corrosion resistance, they impart these properties to the film. Further, since Cu and the like have good corrosion resistance and electric conductivity, they are favorably used for forming a conductive film, a corrosion resistant film, a plating base film, and the like. Ni is also used favorably for forming a plating base film. Zn and Sn protect almost all metals by the sacrificial anode effect.

Ceramic powder is chemically more stable than metal, has electrical insulation, and is excellent in corrosion resistance. Examples of these ceramics include oxides, MgO,
PbO, PbO ₂ , Al ₂ O ₃ , SiO ₂ , TiO ₂ ,
CrO ₂ , MnO ₂ , Fe ₂ O ₃ , FeO, Fe ₃ O
₄ , CoO, NiO, CuO, ZnO, ZrO ₂ , Mo
O, PbO, PbO ₂ and complex oxides based on them, various stable nitrides such as TiN and BN, SiC,
Various stable carbides such as WC and TiC can be used.

When the film is used for improving appearance, various pigments such as carbon black, quinacridone red, permanent yellow, phthalocyanine blue and phthalocyanine green can be used as the powder substance.
Further, the above various powders may be mixed.

The particle size of the powder substance depends on the size of the member to be treated,
It depends on the thickness of the coating and the material of the powder material. In the case of powder that is hard and difficult to deform such as ceramic powder, it is desirable that the particle size is small, and in the case of metal powder that is rich in ductility, it may be larger than this, but generally 0.01 to 500 μm.
The range of is preferable. More preferably 0.01 to 300
μm. More preferably, it is within the range of 0.01 to 100 μm.

The coating structure will be described following the description of the constituent materials of the coating according to the present invention. In the powder compression layer, skeletons are formed like powder compacts in the powder metallurgy method, in which the particles of the powder are in surface contact with each other and are three-dimensionally connected. In the skeleton, powder particles with low ductility are compressed while maintaining the particle shape during powder production, while powder particles with high ductility are deformed into pieces when the compressive force is high so that small pieces can be stacked. May be compressed. Voids are present in the spaces between particles or particles. The voids are much smaller than the volume ratio of the particles, and are completely filled with the resin so as to have no space or are partially filled with the resin. Space may remain, but its volume is extremely small compared to the skeleton, and its effect on strength etc. is practically small.
Therefore, the powder compression layer present in the film of the present invention contains a high volume ratio of powder which cannot be realized by the conventional resin coating film.

For example, in the case of the coating of the present invention made of Ni powder which is relatively hard among metals, it is possible to form a coating in which the Ni powder occupies a volume of 55% and the rest is filled with resin.
Ag, which is a relatively soft metal, can form a film in which Ag occupies a volume of 65%. Note that Ni and A
The typical bulk density of the powder of g is about 20% of the theoretical density, and the typical tap density is 25 to 30% of the theoretical density.
Is. In a normal resin coating film using such powder, the powder content does not increase beyond the bulk density. In addition, the bulk density of the powder cannot be reached by the coating film because the powder content ratio of the coating film is reduced by the resin content.

If the powder has a wide particle size distribution and good dispersibility or good wettability on the powder surface, the bulk density may be about 40%. The membrane can have a high volume ratio. For example, zinc rich paint is an example. Such a coating film has a powder ratio as high as that of the coating film of the present invention, but does not have a skeletal structure.

Further, in the powder compression layer, the connection of the powder may locally become two-dimensional. The powders are naturally two-dimensionally connected on the upper and lower surfaces of the powder compression layer, but locally two-dimensionally connected inside the powder compression layer, which may disturb the skeleton structure. The voids in the regular skeletal structure (that is, the “skeletal structure” in the present invention) have a size comparable to or smaller than the particle size, whereas the voids in the disordered skeletal structure are smaller than the particle size. Remarkably large.
Since the strength of the powder compression layer is reduced in this void portion, the reinforcement by the resin filling is effective. In the following description, the filling of the voids in the regular skeletal structure will be mainly described, but this description also applies to the filling in the portion where the skeletal structure is disturbed.

At the contact surface between the powder particles, a bonding force is generated by pressure contact due to plastic deformation, frictional force, etc., similarly to the powder compact by the powder metallurgy method. Particularly in the case of soft and low melting point metal powders and resin powders, some thermal diffusion occurs, and this bonding force almost determines the mechanical properties of the skeleton. The mechanical properties of conventional resin coating films are mostly determined by the resin when the amount of pigment is small, and the mechanical properties of the resin coating film are related to the fact that the powder is dispersed without forming a skeleton and the amount is small. Little impact. In addition, in a general resin coating film, when the volume ratio of the pigment is high, the distribution of the pigment is non-uniform and the difference in density is large, and a cluster-shaped aggregate may be formed. Such an aggregate does not have a strong binding force enough to form the above-mentioned skeleton structure, and the resin does not sufficiently spread inside the cluster, so that the aggregate becomes extremely brittle and easily crumbles. Therefore, the higher the pigment ratio, the more the number of such aggregates in the coating increases, so that the mechanical properties of the coating, particularly the abrasion resistance, are disadvantageously reduced. Further, not only the ratio of the resin decreases, but also the distribution thereof becomes non-uniform, so that the adhesive force of the film rapidly decreases.

On the other hand, the skeleton of the coating film of the present invention has a small difference in the density of the particle distribution, and therefore does not have a fragile portion such as the cluster-like aggregate. It becomes homogeneous and has excellent mechanical properties. In particular, wear resistance is improved. Most of the voids existing in the skeleton are open pores having openings on the surface of the coating, and the resin in the coating is connected to the resin layer through the open pores. As a result, in the powder compression layer, the resin in the void acts like a long pin or bolt to exert a strong fixing effect. Moreover, since the resin in the voids is not straight but meandering, this also enhances the fixing effect.

The resin filled in the voids of the skeleton structure has the role of enhancing the adhesion between the powder compression layer and the resin layer, and also has the role of reinforcing the skeleton structure and enhancing the strength of the powder compression layer. ..
The powder compression layer is reinforced by the bonding force of the skeleton structure and the bonding force of the resin.

As described above, since the skeleton made of ductile metal powder is formed by laminating flatly deformed metal pieces, voids between metal pieces (hereinafter referred to as "flat voids") are formed in the powder compression layer. There are few passages that communicate with each other in the vertical direction, and they extend horizontally. On the other hand, the voids of the skeleton composed of the ceramic powder (hereinafter referred to as “isotropic voids”) have the same size in the vertical direction and the horizontal direction of the powder compression layer.
The shape of the void is roughly classified into two types as described above, but if the porosity is the same, the bond strength of the skeleton is almost the same. Further, when the porosities are the same, the higher the filling rate of the resin into the pores, the larger the bonding force.

Regarding the relationship between the binding force and the structure of the voids, generally, the anchor effect is unlikely to occur in the flat voids, but a sufficient contact force is obtained because the contact area between the powder and the resin layer is large. The filling rate can be increased by filling the resin at the same time as forming the voids. That is, the resin is filled immediately after the skeleton and the flat voids are formed, or the resin is included and the powder is compressed around the resin to form the skeleton. In the isotropic void, the anchor effect is likely to occur and the resin filling rate can be easily increased.

There may be so-called isolated voids, in which voids of approximately the same size as the powder are isolated from other similar voids. The isolated voids can exist within the skeletal structure or where the skeletal structure is disturbed. By filling at least a part of the resin into the isolated voids, it is possible to strengthen the skeleton similarly to filling the continuous voids. The resin can be filled into the isolated voids at the same time when the voids are formed. As described above, since the particles are bonded by the resin existing in the voids of the skeleton structure, that is, the continuous pores and the isolated pores, the coating film of the present invention hardly causes the powder to fall off unlike the coating film containing many pigments.

In the present invention, since the resin layer is interposed between the powder compression layer and the component surface, the skeleton structure is firmly fixed to the latter. If it is attempted to bond the skeleton structure onto a part that does not have a resin layer, the bonding force between them is mainly the friction between the powder particles or between the particles and the surface irregularities of the part, so it is very difficult. Get smaller. Therefore, in the present invention, the resin layer plays a very important role in fixing the skeleton structure to the component. On the other hand, in the case of the continuous film of US Pat. No. 4,849,258, the resin layer becomes an obstacle to the formation of the powder film as described in the specification. In addition, the film of the above-mentioned U.S. Patent has poor properties such as adhesion in parts in which the problem that the parts are eroded by the activation treatment poses a problem, whereas the film of the present invention has a poor adhesion performance to such parts. Excel.

In the continuous pores of the voids of the skeleton structure of the present invention, the resin can be permeated from the outside of the film. Furthermore, the anchor effect between the resin in the void and the resin layer can be exerted to create a strong film adhesive force.

The thickness of the powder compression layer is not particularly limited and needs to be appropriately selected depending on the size of parts and required performance, but 500 μm is usually the upper limit, and the thickness of the powder compression layer exceeding this is increased. There is no advantage associated with the above, resulting in non-uniformity of film thickness and deterioration of dimensional accuracy. In the case of coatings applied to precision machinery and electronics-related parts that require high dimensional accuracy in recent years, the thickness of the powder compression layer is preferably 50 μm or less. On the other hand, if the thickness of the powder compression layer is 0.1 μm or less, the required performance as a film such as corrosion resistance cannot be obtained.

The volume ratio of the powder substance in the powder compression layer is 30.
If it is less than 100%, the void ratio in the skeleton increases, and the contact area of the powder particles decreases, so that sufficient performance such as anticorrosion cannot be obtained. A more desirable volume ratio of the powder substance is 40% or more, and a more desirable range is 45% or more. Most preferably, it is 50% or more. In the present invention, the voids are filled with the resin even though the volume ratio of the skeleton is large and the percentage of the voids is small and it is inappropriate for the resin to be impregnated from the outside.

The resin layer interposed between the powder compression layer and the component may include a transition region in which the amount of the powder substance gradually decreases toward the lower portion in the upper portion thereof, and the pigment in the ordinary coating film is included. Although the powder substance may be contained in an amount of about 1, the resin is mainly used to cover the entire surface or almost the entire surface of the component, and it has a role of adhering the powder compression layer to the surface of the component. The resin layer interposed between the powder compression layer and the component enters into the fine irregularities on the component surface side, and the fixing effect (anchoring effec
t) and adhesive force to form a layer with excellent adhesion to parts.
On the powder compression layer side of the resin layer, the resin is impregnated into the voids of the skeleton of the powder substance, and the powder compression layer is adhered to the component due to the adhesive force and fixing effect of the resin. The thickness of the resin layer is usually 0.1 to 20.
If it is less than this lower limit, the above-mentioned action is not sufficiently exhibited, while if it exceeds 20 μm, the thickness of the entire coating increases, and the same problem as in the thick powder compression layer occurs. Also 0.1
If it is less than μm, sufficient adhesion cannot be obtained. A more desirable thickness range is 0.5 μm or more and 10 μm or less, and further desirably 1.0 μm or more and 5 μm or less.

Each of the above-mentioned film thicknesses has only to satisfy the requirement as an average value, and may take a value that is locally outside the desired range. However, the range of the variation is, for the powder compression layer, from the viewpoints of corrosion resistance and dimensional accuracy,
It is desirable that the resin layer is as small as possible in terms of adhesion. The smaller the amount of the powder substance in the resin layer is, the less the direct contact between the powder and the parts is, so that the adhesion is further improved.

If perfect metal or molecular bonding can be realized between the coating and the component, the strength of the coating will be higher if the resin layer is not interposed. However, the activation of the surface of the component, which is essential for that purpose, causes the problems mentioned above with respect to the above-mentioned US patents. According to the present invention, by interposing a resin layer, the resin layer removes the adverse effects of adhesion inhibiting factors such as stains, foreign substances, and oxide films on the surface of the underlying component, and facilitates the powder compression layer for components with normal surface cleanliness. To be formed.

Two or more layers of the film according to the present invention can be formed, and in this case, two or more layers of different kinds of powder and / or resin may be formed. If the number of layers of the film increases, the film thickness becomes too large, and the process becomes long and uneconomical. Therefore, the total number of layers is preferably 3 or less. The resin layer may be formed of two or more layers of the same or different resins.

The film of the present invention is formed by a method of adjusting the film-forming force at the time of forming the powder film so that the powder particles aggregate and bond in the presence of the resin, but do not form a continuous body. One of the methods is as follows:
No. 2220 (hereinafter, referred to as “prior application”), a part to be treated, a resin that is at least partially uncured at least at the beginning of the film formation process, and a powder substance (harder than the resin in the film formation process). Resin powder), and a method of applying vibration or agitation in a container to a film-forming medium whose size is substantially smaller than that of the part to be treated and whose size is substantially larger than the powder substance. .. A resin film may be previously formed on the surface of the component, and the above method or the method of removing the resin in the above method may be carried out in a state where the film is uncured. Further, after forming the film by the above method, a resin film may be formed on the surface of the film and the same method may be performed again. Further, by repeating the above method, a multilayer film can be formed.

When the resin, the powder substance and the component to be treated are vibrated or stirred together with the film forming medium in the container, a layer of resin is first formed on the surface of the component to be treated. The thickness of the resin layer varies depending on the powder material, the resin, the film forming medium, the order in which the parts to be treated and the mixing method are used. And, because the contact between the component surface and the powder particles occurs at the same time, the layer of the resin alone formed on the component surface becomes very thin, or
It may be difficult to detect with an optical microscope.

Following the resin film formation, the powder substance is captured and fixed to the resin layer by the adhesive force of the resin layer. Similarly, when the resin layer cures on the surface of the component to be treated, it captures and cures the powder substance. The film forming medium that is being vibrated or stirred is
Similarly, a striking force is applied to the powder substance that is being vibrated or stirred to form a powder compression layer.

The film-forming medium generates a striking force to mediate the formation of the film, but does not itself substantially become a component of the film. A film-forming medium that is larger than the part to be treated cannot generate a uniform striking force on the former surface, and if it is smaller than the powder, the film-forming medium is trapped in the film. However, as long as the volume ratio is 70% or less, a medium larger than the component to be processed may be included. Also,
When the impact force is concentrated to some extent, the powder press-fitting proceeds better. Therefore, for example, when using a spherical medium, the diameter should be 0.3 mm or more, more preferably 0.5 mm or more, and in the case of other shapes. The same applies to this. Also, when it is smaller than the part to be processed, it means that when each of the media is replaced by a sphere of the same volume, the diameter is smaller than the largest one of the sizes I of the part to be processed. Also, for powders, if the average size meets the requirements, a desired impact force can be created. That is, even if some of the particles forming the film-forming medium are finer than the powder substance, if the former is larger than the latter in average size, a desired striking force can be produced. However, media smaller than these powder substances may be trapped in the coating film, and it is desirable that the media should not be included as much as possible.

The material of the film-forming medium must meet the following requirements. There is no large change in shape that is visible to the naked eye when the film forming medium is observed after film formation due to plastic deformation, and
Elastic deformation does not become extremely large during the film formation process. Therefore, soft rubber does not meet this requirement. No cracks, chips, or sudden wear (may be slightly worn over long-term use).

If a film-forming medium made of a material that does not meet these requirements undergoes plastic deformation due to collision with a material to be treated or extremely large elastic deformation such as soft rubber, the impact given to the latter is insufficient. As a result, desired film formation does not occur. Further, if cracking, chipping or sudden wear occurs, the useful life of the medium is shortened, which is uneconomical.

The powder material must be smaller than the film-forming medium in order to be incorporated into the film. The nature of the powder substance is not particularly limited, but in the case of resin powder, it is necessary that the resin is harder than the above-mentioned resin in the film forming process.

The particle size of the powder substance depends on the size of the part to be treated,
It depends on the thickness of the coating and the material of the powder material. In the case of a powder that is hard and difficult to deform such as ceramics powder, it is desirable that the particle size be small, and in the case of a metal powder that is rich in ductility, it may be larger than this, but it is generally in the range of 0.01 to 500 μm. It is preferably 0.01 to 300 μm, more preferably 0.01 to 100 μm. Generally, the smaller the particle size of the powder, the easier the powder is to be captured by the resin. Further, particles having a small particle size are apt to be pushed between the particles of the powder substance dispersed on the resin film by hitting, and are likely to be pressed and bonded to each other or to the material to be treated due to plastic deformation. Therefore, the smaller the particle size of the powder substance, the smaller the impact force, and the smaller the surface roughness of the coating.

The film forming medium includes iron, carbon steel, other alloy steels, copper and copper alloys, aluminum and aluminum alloys,
Other various metals, alloys, Al ₂ O ₃ , SiO
Made of ceramics such as ₂ , TiO ₂ , ZrO ₂ , SiC,
Glass or hard plastic can be used. Hard rubber can also be used as long as a sufficient striking force is applied to the film formation. The size and material of these media must be appropriately selected according to the shape and size of the parts and the material of the powder used. It is also possible to mix and use media of a plurality of sizes and materials.
In some cases, surface treatment or surface coating may be applied before use. Also, a composite medium composed of a plurality of the above materials may be used. In addition, softening medium such as wood powder, soft rubber, and soft plastic is used in the range of 50% or less of the volume ratio with respect to the medium in order to alleviate and average the impact force and suppress the film homogeneity and the variation in film thickness. May be mixed appropriately. These alone produce almost no striking force, so they are always used in combination with the film-forming medium. It is also possible to form a film of a cured resin, an uncured resin or a volatile liquid on the surface of the film forming medium. Such a coating helps to deposit the powder on the surface of the film-forming medium evenly once and then separates the powder during mixing or stirring,
A film is attached to the surface of the member to be treated. Through such a process, the powder adheres to the member to be treated more uniformly. The same effect is brought about by depositing a metal or other plating film from the film forming medium.

The film-forming medium has a spherical shape, an elliptical shape, a cube, a triangular prism, a cylinder, a cone, a triangular pyramid, a quadrangular pyramid, a rhombohedron,
An amorphous shape and various other shapes can be used.

The ratio of each component (element) of the film-forming mixture is determined so that the desired action of each component is exerted and the whole is balanced without being biased to any element. The amount of powder and resin is determined by the total thickness of the coating applied to the part and the surface area of the part. However, it is preferable that the ratio of the resin to the powder is set to 0.5% or more in terms of the volume after the resin is cured. If it is less than this, the adhesion of the powder to the parts becomes insufficient. Further, the mixing ratio of the medium and the component varies depending on the shape of the component, but unless the medium is blended in an amount of 20% or more in terms of the apparent volume ratio, a uniform and sufficient impact to the surface of the component is not achieved and a good film can be obtained. difficult.

Vibration or agitation in the container can be carried out by various methods as described below. An arm 3 (see FIG. 1) provided in the container 2 and fixed to the rotary shaft 4, a blade 5 (see FIG. 2) fixed to the rotary shaft 4, or a stirrer (not shown) such as an impeller or a blade. Done by. In the figure, 10 is a film-forming mixture. Further, as shown in FIG. 3, the drum or the pot-shaped container itself may be rotated on the roller 6. Further, as shown in FIG. 4, the drum-shaped container 2 fixed to the rotating shaft may be rotated. The container may be open at the top or sealed. In addition, the container 2 may be shaken as shown in FIG. Stirring may be performed during rocking. Further, as shown in FIG. 6, the arm 7 symmetrically fixed to the rotary shaft 4 is provided.
The powder mixture 10 may be placed in the container 2 attached to the tip of the and the powder mixture may be mixed by centrifugal force. At this time, it is preferable to rotate the container 2 by itself. If the operation of the container is the same, the rotation mechanism is not limited to this, and for example, a disc-shaped holder may be used.

Alternatively, the film-forming mixture may be vibrated by a shaker 8 provided inside or outside the container 2 (see FIG. 7). The magnitude of the force (excitation force) applied to the film-forming mixture will be described below by taking an example of a method of applying vibration.
The impact that the film-forming medium exerts on the parts to be treated is the value (hereinafter referred to as "excited force" -dimensionless number)) averaged by the gravity of the container and the film-forming mixture (hereinafter referred to as "oscillating gravity") It is an index of strength. As a specific example, the weight of a 2.8-liter container-1 kgf, steel ball (film forming medium)
-10 kgf and the weight of the part to be processed-1 kgf, the oscillating gravity is 12 kgf. 40 at this time
A preferable exciting force in the Hz cycle is 20 to 50 kgf.
Therefore, the excited force is 1.67 (= 20/12) to 4.
It becomes 17 (50/12).

In the case of using a larger container, as a specific example, the weight of a container of 20 liters-4.5 kgf, the weight of steel balls (film forming medium) -70 kgf, and the weight of parts to be treated-5.5 kgf. , Vibrating gravity is 8
It becomes 0 kgf. At this time, the preferable excitation force in the 25 Hz cycle is 150 kgf to 450 kgf. Therefore, the force to be excited is 150/80 = 1.88 to 450/80 = 5.
65.

When the parts to be treated are made of a strong material such as a steel material, the upper limit of the force to be excited may be about 10, but the brittle materials such as rare earth magnets, bond magnets, ceramics, and glass may be excited. It is preferable that the upper limit of the force is 5 or less. The lower limit of the force to be excited is preferably 1 or more, and particularly preferably 1.5 or more. If the force to be excited is smaller than this lower limit, the film growth rate will be slow, while if it is larger than the upper limit, the parts to be treated will be liable to break if they are made of a brittle material, and the film forming medium will be easily deformed. The frequency of vibration is not particularly limited, but is preferably in the range of 2 Hz to 600 Hz.

Subsequently, in the case of the stirring method, it is desirable that the centrifugal force generated by the rotation is within the range of the force to be excited with respect to the total weight of the film-forming mixture and the container.

In order to compress the powder with high density in the powder compression layer, it is desirable to apply a relatively small impact force uniformly to the surface of the component. By doing so, the powder is uniformly compressed and press-fitted, and the once-pressurized compression layer does not fall off, and the skeleton density becomes high.

Applying a resin protective coating on the surface of one or more of the above-mentioned coatings is effective for improving the strength and corrosion resistance of the entire coating. In particular, if the powder compression layer is exposed on the surface of the coating, the powder substance may fall off or the coating may be localized if the impact force or strong force is applied from the outside during handling or mounting the parts to the machine. May be destroyed.
It is effective to apply a resin film to prevent such inconvenience. The resin film smoothes the surface and improves aesthetics, fills pinholes, and prevents moisture from penetrating. The resin of the protective film may be the same as or different from the resin of the above film. The film thickness is preferably 0.5 μm or more and 300 μm or less. If it is 0.5 μm or less, the function of the protective film is lost, and if it is 300 μm or more, it is a thick film, and the same problem as described above occurs.

As the protective film, in addition to the resin film, metal or alloy plating or metal and nonmetal dispersion plating (electroplating or electrolytic plating) can be applied. If at least the uppermost layer of the film is a powder compression layer of a conductive substance such as a metal or an alloy, the electric conductivity of the film surface is improved, and various electroplating can be easily applied on it. Further, since there is at least one compressed layer of metal powder under the plated film, the corrosion resistance is superior to that of the conventional plated film. When the film is composed of a plurality of powder compression layers, the intermediate layer other than the uppermost layer can be a metal or alloy powder compression layer.

Since the metal powder compression layer of the present invention, which is the base of the plating film, has a skeleton gap, more pinholes than usual may be formed in the plating film. In this case, it is desirable to make the plating film a little thick. Alternatively, pinholes in the plating film can be prevented by forming the electroless plating film on the base of the plating film to be extremely thin.

As the plating film, any known metal or alloy plating film can be formed. At this time, the underlying metal powder can be freely selected according to the type of the plating film formed thereon.

The demand for rare earth permanent magnets is ever increasing due to their excellent magnetic properties. Most of the rare earth permanent magnets currently produced are of Sm-Co system containing Sm and Co as main components, and Nd-Fe-B system, and the manufacturing method is a resin bond that is made by sintering with a resin. Most are magnets. The resin-bonded magnet is manufactured by a method of mixing the magnetic powder and the resin, followed by compression molding, and then hardening the resin, an injection molding method, a method of pressing the magnetic powder and then impregnating the resin. Since rare earth magnets contain a large amount of active rare earth elements,
If it is used in a hot and humid environment, performance deterioration and variations in performance will occur due to corrosion, and the corrosion product will be a pollution source. In particular, since Nd-Fe-B magnets have iron as a main component, they have low corrosion resistance and it is essential to provide an anticorrosion coating. Currently, Ni plating is applied to sintered magnets by spraying epoxy resin or the like or electrodeposition coating. Is performed on the sintered and resin-bonded magnets. However, Ni plating applied to Nd-Fe-B sintered magnets, which has many small parts, has problems such as complicated plating operation and waste liquid treatment, and if the removal of the oxide of the base is insufficient, the adhesion of the plating There is also the problem of being inferior. The resin coating also has a problem that it takes time and effort for the coating operation as described above.

Also, since bonded magnets are inexpensive and multilayer coating of resin is not practical, single layer coating is predominant. For this reason, the corrosion resistance of resin-bonded magnets remains at a level lower than that of sintered magnets. As a measure for eliminating this drawback, it has been proposed to perform electroplating on an electroless plating base (Japanese Patent Laid-Open No. 3-116703), but there are the above-mentioned problems. Corrosion resistance is slightly improved by using electrodeposition coating compared with spray coating, but this requires large-scale coating and waste liquid treatment equipment, and basically costs more because it is hooked down to a jig. Further, since the resin-bonded magnet is more porous than the sintered product, it is not a good base unless the electroless plating is considerably thickened. In addition, it is said that it is very difficult to control the bath composition of an electroless plating solution using an Nd-Fe-B system as a member to be treated.

The film-formed rare earth magnet of the present invention has the following advantages and can solve the conventional problems. In the case of sintered magnets: Stable oxides such as TiO ₂ , MgO and Fe ₂ O ₃ powders are dispersed in the coating film compared to conventional resin coatings, and the content is especially high on the coating surface. By doing so, the corrosion resistance can be improved.

In the case of resin-bonded magnet: Corrosion resistance comparable to that of a multi-layer film is obtained with respect to a conventional resin coating film, so that the corrosion resistance is significantly improved as compared with a conventional single-layer resin film; By press-fitting the powder substance or resin into the pores, the pore-sealing effect can be increased, which has the advantage of improving the corrosion resistance. In contrast to conventional electroless plating-electrolytic plating, the coating of the present invention using a conductive powder substance has a very high industrial application potential.

According to the present invention, the following advantages can be obtained by forming a plating film on the powder film formed on the surface of the rare earth magnet. In the case of a sintered magnet (compared to a conventional plating film), no pretreatment is required; the film forming conditions are gradual (that is, the conditions are strictly set with the Nd-Fe-B magnet in mind). No need). Since the plating underlayer according to the method of the present invention is firmly adhered to the surface of the base material, a plating film having excellent adhesion can be obtained by appropriately selecting the type of plating underlayer for the plating layer formed thereon. Is obtained. Also, the plating film usually has some pinholes, but if these pinholes are conventional plating films, they reach the base metal surface directly, so the corrosive components penetrating from the pinholes are the interface between the plating layer and the base metal surface. Permeates into
The film was likely to peel off. In particular, when an oxide layer remains on the surface of the base material, film peeling is extremely likely to occur.
However, in the method of the present invention, since a powder coating with good anticorrosive property exists under the plating coating, almost all the corrosive components from the pinholes are stopped by this underlayer and do not penetrate into the surface of the base material, so the film peeling does not occur. Disappear.

In the case of resin-bonded magnet (compared with conventional electroless plating): Electroless plating is costly because the bath is generally expensive and a large amount of waste liquid treatment is required. In addition, the adhesion of the electroless plated film to the base is inferior to that of the resin film. Generally, it is difficult to increase the thickness of the electroless plated film and the film is limited to a thin film of 5 μm or less. In particular, since the bond magnet is a porous body, it becomes an extremely porous film following the pinholes on the surface of the base material. Such a film has almost no ability to block the corrosive components penetrating from the pinholes of the electroplated film formed on the film, and the film peeling easily occurs. Further, the electroless plating solution is likely to remain in the pinholes of the bonded magnet, which is also a major cause of film peeling. Due to these problems, the Nd-based bonded magnet provided with electroless plating has not yet been mass-produced.

According to the method of the present invention, the pinholes on the surface of the magnet are sealed with the resin layer, and the resin layer firmly adheres the metal layer (powder compression layer) which is the base of plating. The plating film formed on top also has good adhesion. Similar to this underlayer, since the corrosion component is prevented from diffusing to the magnet surface, as a result, the corrosion resistance far superior to that of the conventional method can be obtained. Although the rare earth magnet has been described above as an example, the coating of the present invention applied to another base material also exhibits excellent characteristics.

The present invention will be described in detail below with reference to examples.

【Example】

Example 1 The film of the present invention was formed on a glass plate (30 mm × 20 mm × 2 mm) to facilitate observation of fracture surfaces. First, 10 kg of steel balls having a diameter of 3.0 mm (apparent density of about 5 kg / liter) were placed in a circular pot having a volume of 2.8 liters and a depth of 150 mm, and the frequency was 2500 c. p.
m. (Cycle per minute), while applying vibration with an amplitude of 0.5 to 2 mm, ₂ particles of TiO ₂ powder having an average particle size of 0.3 μm are added.
0 g was added and vibration was applied for 5 minutes.

Next, a glass piece whose surface was covered with a resin was dipped in methyl ethyl ketone (MEK) in which 10% of an epoxy resin (94% of a resin and 6% of a curing agent) was previously dissolved.
0 pieces were put in, vibrated for 15 minutes, and then taken out. 120
The mixture was heated at 0 ° C. for 2 hours, and finally, 2.0 kg of walnut shells having an average particle diameter of 2 mm was put into a pot of the same size and vibrated for 5 minutes to remove excess powder remaining on the surface. Then, the glass piece was taken out, fractured, and the fracture surface was observed by SEM. SEM images are shown in FIG. 8 (4000 times) and FIG.
(13000 times).

The thickness of the resin layer is l. The thickness of the powder compression layer is 5 μm, and the thickness is 15 μm. Fixing of resin layer and powder compression layer (an
choring) shows that these interfaces are intermingled with each other.
Shown in.

The skeleton structure of the powder compression layer is apparent from FIG. That is, since the grain size of TiO ₂ is small, the skeleton structure can be observed with a microscope having a magnification of 10,000 times or more. In the figure, the contours of the particles appear to be blurred locally on the surface of the particles because the resin coats the particles, indicating that the resin is filled up to the inside of the powder compression layer. The powder particles in the powder compression layer are 30% by volume or more.

Further, in the powder compression layer, a large missing portion which is generated when the test piece is cut out at the time of observing the cross section is observed.
Excluding this, when observing the particles in the powder compression layer, it can be seen that there is almost no unevenness in the particle distribution. There is disorder in the skeletal structure in the upper center and lower right of the photograph, and the resin is filled in the voids that appear to be relatively large isolated holes created by this.

Example 2 A circular pot having a volume of 2.8 liters and a depth of 150 mm was charged with 10 kg (apparent density of about 5 kg / liter) of steel balls having a diameter of 3.0 mm and a vibration frequency of 3500 c. p.
m. (Cycle per minute), while applying vibration with an amplitude of 0.5 to 2 mm, 20 g of atomized Al powder having an average particle size of 3 μm was charged and vibration was applied for 5 minutes.

Next, a glass piece whose surface was covered with resin was dipped in methyl ethyl ketone (MEK) in which 10% of an epoxy resin (97% of resin and 3% of a curing agent) was previously dissolved.
0 pieces were put in, vibrated for 15 minutes, and then taken out. 120
The mixture was heated at 0 ° C. for 2 hours, and finally, 2.0 kg of walnut shells having an average particle diameter of 2 mm was put into a pot of the same size and vibrated for 5 minutes to remove excess powder remaining on the surface. Then, the glass piece was taken out and broken, and the SEM image of the fractured surface is shown in FIG. 10 and the SEM image of the surface is shown in FIG.

The powder resin layer has a thickness of 8 μm, and the powder content is 50% by volume or more, and locally there is a portion of 70% by volume or more. The resin layer has a thickness of 1 μm. The atomized Al powder has a substantially spherical particle shape, but the shape of the Al powder particles in the powder compression layer is a flat piece, and the edges thereof have sharp irregularities. Further, the skeletal structure is a stack of flat pieces, and the resin is sandwiched in layers in a part of the voids between the flat pieces.

Example 3 In a circular pot having a volume of 2.8 liters and a depth of 150 mm, 10 kg of steel balls having a diameter of 3.0 mm (apparent density 5
(kg / liter), and the vibration frequency is 3000 c. p. m.
(Cycle per minute), 20 g of TiO ₂ powder with an average particle size of 0.3 μm while applying vibration with an amplitude of 0.5 to 3 mm
It was charged and shaken for 5 minutes.

Then, 20 magnets whose surfaces were covered with resin were immersed by immersing in methyl ethyl ketone (MEK) in which 10% of epoxy resin (97% of resin, 3% of curing agent) was dissolved in advance, and after vibrating for 15 minutes. I took it out. After heating for 2 hours at 120 ° C, finally walnut shell pieces with an average particle size of 2 mm 2.0
It was put together with kg in a pot of the same size and vibrated for 5 minutes to remove excess powder remaining on the surface.

This operation was repeated once again. However, 2
The vibration time for the second time was 8 minutes. Finally, it is immersed in methyl ethyl ketone (MEK) in which epoxy resin 30% (resin 97%, curing agent 3%) is dissolved in advance, and the temperature is 120 ° C.
After heating for 2 hours, break the glass piece and SEM the fracture surface.
Observed by. This is shown in FIG.

The thickness of the first resin layer is 1 μm, the thickness of the powder compression layer is 18 μm, the thickness of the second resin layer is 1 μm, the thickness of the powder compression layer is 12 μm, and The thickness of the resin layer on the outermost surface is 9 μm. The powder content is 40% by volume or more in both the first and second layers. In this example, the magnification of the photograph is set to 260 in order to fit all the layers in the visual field.
The skeleton structure is unclear due to the fact that the resin covers the powder particles because it is made 0 times and the powder content of the powder compression layer is relatively low. Magnification of the photo is 2000
A skeleton structure was observed at 0 times.

Example 4 A circular pot having a volume of 2.8 liters and a depth of 150 mm was charged with 10 kg of a steel ball having a diameter of 3.0 mm (the surface of which was coated with a semi-cured resin) (apparent density: 5 kg /
Liter) and the frequency is 2500 c. p. m. (Cycl
e per minute), while applying vibration of 5 mm in amplitude, 30 g of Al powder having an average particle size of 3 μm was added and the Al powder was vibrated for 5 minutes.

Next, a glass piece whose surface was covered with a resin was dipped in methyl ethyl ketone (MEK) in which 15% of an epoxy resin (97% of a resin and 3% of a curing agent) was previously dissolved.
0 pieces were put in, vibrated for 20 minutes, and then taken out. 120
The mixture was heated at 0 ° C. for 2 hours, and finally, 2.0 kg of walnut shells having an average particle diameter of 2 mm was put into a pot of the same size and vibrated for 5 minutes to remove excess powder remaining on the surface. Subsequently, electrolytic Ni plating using a normal Watt bath is performed,
A Ni plating layer of about 4 μm was formed, and the glass piece was broken. The SEM image of the fracture surface is shown in FIG. 13 (magnification 1300 times) and 1
4 (magnification of 930 times).

The resin layer has a thickness of 3 μm, the powder compression layer has a thickness of 15 μm, and the powder content is 50% by volume or more. In FIG. 14, when the cross section of the test piece was cut out,
The cracks of peeling generated between the plating layer and the powder compression layer are visible.

Example 5 A powder for a quenched bonded magnet having a composition of Fe ₈₁ Nd ₁₃ B _{6 and} a particle size of 100 μm or less was used. 3 wt% of an epoxy resin was added to and mixed with this powder, and compression molding was performed under a pressure of 5 ton / cm ² to obtain 140 compacts of 22 mmφ × 20 mmφ × 10 mm. This was cured at 150 ° C. for 1 hour to obtain a resin-bonded magnet.

With respect to this magnet, 20 similar films were formed by the same method as in Examples 1 to 4. However, the average film or layer thickness (μm) is as follows. Examples Resin layer Powder or resin or total compression layer Plating layer ───── ────────────────────────────────────── 1 1 10 − 11 2 1 19 − 10 3 1 × 2 8 × 2 2 20 4 1 5 10 16 16 ────────────────────────────────

Further, as comparative examples, the following (5) to (7)
I went. (5) A resin-bonded magnet was spray-coated with an epoxy resin containing 20% of TiO _{2 and} cured at 120 ° C. for 6 hours to form a coating film (single film) having an average film thickness of 20 μm (Comparative Example). ). (6) A zinc phosphate chemical conversion treatment solution is sprayed onto a resin-bonded magnet, dried, and then an epoxy resin containing 20% of TiO ₂ added is spray-coated, followed by curing at 120 ° C. for 6 hours to obtain a film thickness of 20 μm. The coating film (single film) was formed (comparative example). (7) The resin-bonded magnet was tested without being coated (Comparative Example).

20 resin-bonded magnets each having various films formed as described above were subjected to a wet test to evaluate the corrosion resistance.
Test conditions: 85 ° C. × 90% RH left (check item: appearance) The results are shown in the following table.

[0093]

[Table 1] Judgment Criteria A All No rusting at all B Macroscopically no rusting. Less than 10% of all rust spots on the order of a microscope C Less than 10% of all rust spots visibly visible D: 10% or more and less than 30% of the entire rust E Large rust, film swelling of 30% or more , Peel off

From the results of the above tests, it became clear that the coating film according to the present invention is superior in corrosion resistance to the conventional resin coating film.

Example 5 20 mm × 20 m from a low carbon (0.03% C) rolled steel plate
A test piece of m × 3 mm was cut out. Next, in a circular pot with a volume of 2.8 liters and a depth of 150 mm, diameter φ3.0 mm
10 kg of steel balls are put in and the frequency is 1000 c. p.
m. , 30 kinds of various powders while applying vibration with an amplitude of 5 mm
g, and Al and other powders and steel balls were vibrated for 5 minutes. Next, 10 steel plates each of which had been dipped in an epoxy resin (10% MEK solution) in advance and the surface of which was covered with the resin were put therein, vibrated for 15 minutes, and then taken out. 120 ° C magnet
After 2 hours of heating to cure the epoxy resin, 2 kg of walnut shells having an average particle diameter of 2 mm was put into a pot of the same size as for film formation and vibrated for 5 minutes to remove excess powder remaining on the surface. Finally, epoxy 30% (Resin 9
It was dipped in a MEK solution containing 4% and a curing agent 6%), dried, and cured at 120 ° C. for 2 hours. The powder used is as follows.

Material Average particle size Thickness of powder compression layer (μm) (μm) ────────────────────────── 1 Al 3 10 2 Cu 2 10 3 Ti 8 10 4 Stainless Steel 3 10 5 Cr 2 10 6 Co 2 10 7 Ni 2 10 8 Zn 2 15 9 Pb 1 10 10 Sn 2 15 11 Ag 1 5 12 Au 1 5 13 13 MgO 0.5 10 14 Al ₂ O ₃ 0.5 10 15 SiO ₂ 0.7 10 16 TiO ₂ 0.3 10 17 CrO ₂ 0.6 10 18 MnO ₂ 0.9 10 19 Fe ₂ O ₃ 1.0 10 20 CoO 0.8 10 21 NiO 0.5 10 22 CuO 0.9 10 23 ZnO 0.3 10 24 ZrO ₂ 0.3 10 25 MoO 0.4 10 (40% or more by volume)

As a comparative example, the amount of TiO ₂ added was 20% by volume.
Was spray-coated and cured at 120 ° C. for 6 hours to form a coating film (single film) having an average film thickness of 20 μm (comparative example). For the test piece that has been subjected to the above treatment,
Neutral salt spray test according to JIS corrosion test method (35 ℃,
When 5% NaCl) was applied for 16 hours, in the comparative example, rusting was observed from all edge parts, but no rusting was found in 1 to 25.

Example 6 Twenty pieces of the same iron pieces as in Example 5 were prepared, and a coating film was formed using Zn powder for the ten pieces of iron under the same conditions as in Example 5. After cleaning the surface of the remaining 10 pieces by shot blasting, a Zn coating having a thickness of 40 μm was formed by the flame spraying method. The film peeling test of these film-formed pieces was conducted by the following method. That is, five vertical and horizontal groove lines were formed at intervals of 1 mm so as to penetrate the film with a knife. Next, an adhesive tape (cellophane tape) was adhered to the film on which the groove lines were engraved, and peeled off to perform a peeling test. As a result, all of the sprayed coatings were peeled off, but the coating of the present invention did not peel at all.

Example 7 A total of 10 kg of nickel-plated steel balls having a diameter of 2.0 mm and a diameter of 3.0 mm were placed in a circular pot having a volume of 2.8 liters and a depth of 150 mm, respectively, and a total of 10% of Epokin resin was melted. MEK 20cc, frequency 250
0c. p. While applying vibration of m and amplitude of 5 mm, 20 g of Al powder having an average particle diameter of 3 μm was charged and vibration was applied for 5 minutes. Next, in advance, 10% epoxy resin (97% resin,
Methyl ethyl ketone (MEK) with a curing agent (3%) dissolved
MQ bond magnet (external diameter 2
0mm, inner diameter 16mm, height 9mm) 20 pieces,
After vibrating for 15 minutes, it was taken out and heated at 120 ° C. for 2 hours. After that, the bond magnet was immersed in MEK in which 5% of epoxy resin was melted, the surface was covered again with resin, and the second vibrating barrel treatment was performed for 10 minutes together with Al particles having an average particle diameter of 3 μm. Remove the magnet from the pot,
Immerse the magnet in MEK containing 10% epoxy and
Curing was carried out at 20 ° C. for 3 hours. The double-coated magnet by the above treatment showed extremely good corrosion resistance. In order to observe the state of this film by SEM, a magnet was embedded in an epoxy resin, a sample cross section was observed by polishing with emery paper and buffing polishing using a diamond base. SEM images of the polished sample are shown in FIGS. 15 (a) and 15 (b). The following structure is clear from this figure. Originally spherical Al powder is crushed and connected horizontally to form a skeletal structure; Al in the first and second layers
A resin layer is sandwiched between the layers; the resin layer between the first Al layer and the bond magnet is connected to the resin layer in the bond magnet.

Example 8 On the same bonded magnet as in Example 7, 2 mmφ chrome-plated steel balls were used as poles, the same vibrating barrel as in Example 7 was used, and 0.1 μm to 1 μm Ag was used under the same conditions. 20 g of the powder was used to form a film of Ag having a skeletal structure. However, in this example, the bonded magnet was dipped in a MEK solution containing 10% of epoxy, ultrasonic waves were applied for 2 minutes to form a resin film in advance, and after that, the resin was vibrated in a vibrating barrel for 20 minutes, and then from the vibrating barrel. Take out, 20
It was dried at room temperature for 1 minute and cured at 120 ° C. for 2 hours. FIG. 16 shows a cross-sectional SEM image of the SEM observation sample observed by polishing in the same manner as in Example 7. 17 shows an SEM image of the surface of the Ag film having a skeleton structure. The Ag film obtained in this example was prepared by vibrating barrel treatment in air. However, Ag had a very high conductivity because it was difficult to oxidize. The Ag film thickness was about 10 μm, but the surface resistance was 0.1 Ω / □ or less. For comparison, Ag powder and epoxy resin were mixed, diluted with MEK and applied to a sample to form an Ag film, and the surface resistance was measured. The amount of Ag was increased to the limit of spray coating, but it was 10 for a 10μm film.
It could not be lower than Ω / □.

Example 9 Ni powder having an average particle size of 0.8 μm and an average particle size of 10
Using Cu powder of μm, the same conditions as in Example 7, except that the vibration treatment atmosphere of the Cu powder was nitrogen gas, and Cu, Ni
The film of SEM images of the cross-section (polished surface) and the surface (non-polished surface) of the skeleton structure of the formed film are shown in FIGS. 18 and 19 (Cu) and FIGS. 20 and 21 (Ni), respectively. For comparison, an SEM cross-sectional image (polished surface) of a Cu-based conductive coating film (without a skeleton structure) obtained by spray coating the same powder with a resin and a solvent is shown in FIG.
The image is shown in FIG. Comparing these drawings, it can be seen that the skeletal structure film has a very high powder filling rate. The surface electric resistance of the Cu film having a skeletal structure is
With a film thickness of 25 μm, good electrical conductivity of 0.2 Ω / □ was obtained. On the other hand, spray coating C shown in FIGS.
The u film (not the skeletal structure) has a film thickness of 70 μm.
It was about 5Ω / □.

[0102]

As described above, the present invention relates to a component having a powder coating having a structure that has not been found in the past. A film in which a high proportion of powder is evenly distributed without heat effect on parts,
By forming it on a component, a film can be formed on a component such as a precision component or an electronics-related component that should avoid thermal influence, and the physical and chemical properties of the powder can be utilized to a higher degree than before. Among these properties, particularly with respect to corrosion resistance, the performance requirements are becoming severer in the industry in which such parts are currently used, so the present invention can meet these requirements immediately.

Furthermore, since it is possible to form a film having excellent adhesion on a part having a normal cleanliness, degreasing of the part,
The method of the present invention is very meaningful when there is a risk of deterioration of parts due to extremely careful removal of rust. One example is the Nd-Fe-B magnet, but this material often has poor adhesion of the coating in the usual pretreatment, resulting in poor corrosion resistance.
The present invention makes it possible to obtain sufficient corrosion resistance. Further, the cost of the pretreatment can be reduced by simplifying the cleaning by the pretreatment for the normal component rather than the component sensitive to the pretreatment.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment in which stirring according to the present invention is performed by an arm.

FIG. 2 is a view showing an example in which the stirring according to the present invention is performed by a blade.

FIG. 3 is a diagram showing an example in which stirring according to the present invention is performed by rotating a rotary container.

FIG. 4 is a diagram showing an example in which stirring according to the present invention is performed by rotating a cylindrical container.

FIG. 5 is a diagram showing an example in which stirring according to the present invention is performed by rocking a cylindrical container.

FIG. 6 is a diagram showing an example in which stirring according to the present invention is performed by rotating a container around a rotation axis.

FIG. 7 is a diagram showing an embodiment in which vibration according to the present invention is performed by vibrating a pot.

FIG. 8 is an electron micrograph (magnification: 4000 times) showing a structure of particles of a film in Example 1.

FIG. 9 is an electron micrograph (magnification: 13,000 times) showing the structure of the particles of the film in Example 1.

FIG. 10 is an electron micrograph (magnification: 7,000 times) showing a structure of particles of a film in Example 2.

11 is an electron micrograph (magnification: 500 times) showing a particle structure on the surface of the coating in Example 2. FIG.

FIG. 12 is an electron micrograph (magnification: 26000 times) showing a structure of particles of a film in Example 3.

FIG. 13 is an electron micrograph (magnification: 13000 times) showing the structure of particles of a film in Example 4.

FIG. 14 is an electron micrograph (magnification: 9300 times) showing a structure of particles of a film in Example 4.

FIG. 15 is an electron micrograph (magnification: 1600 times) showing a structure of particles of a film in Example 7.

16 is an electron micrograph (magnification: 760 times) showing a structure of particles of a film in Example 8. FIG.

FIG. 17 is an electron micrograph (magnification: 380 times) showing a structure of particles of a film in Example 8.

FIG. 18 is an electron micrograph (magnification: 760 times) showing a structure of particles of a film in Example 9.

FIG. 19 is an electron micrograph (magnification: 380 times) showing a structure of particles of a film in Example 9.

FIG. 20 is an electron micrograph (magnification: 760 times) showing a structure of particles of a film in Example 9.

FIG. 21 is an electron micrograph (magnification: 760 times) showing a structure of particles of a film in Example 9.

FIG. 22 is an electron micrograph (magnification: 380) showing the structure of particles of a coating film in a coating film.

FIG. 23 is an electron micrograph (magnification: 150 times) showing a structure of particles of a coating film.

[Explanation of symbols]

 2 container 3 arm 4 rotating shaft 5 blade 6 roller 8 vibrator 10 film forming mixture

Claims (6)

[Claims] 1. A powder compression layer having a skeleton structure composed of a powder substance, wherein at least a part of voids in the powder compression layer is filled with a resin, and the powder. A component having a coating containing powder, characterized in that one or more coatings comprising a resin layer for adhering the compression layer to the component or to the powder compression layer below are formed. 2. The powder compression layer contains 30% by volume of a powder substance.
A component having a film containing the powder according to claim 1, which is contained above. 3. A component having a film containing a powder according to claim 1, wherein a resin film is provided on the film. 4. The powder according to any one of claims 1 to 3, wherein the film is a film having two or more layers, and the resin layers of the respective films are made of the same or different resins. A part having a coating containing. 5. The coating comprises a powder compression layer in which the powder substance is a metal or an alloy, at least in its uppermost layer,
A part having a coating containing the powder according to any one of claims 1 to 4, wherein the surface of the coating is covered with a metal or alloy plating layer. 6. A film containing the powder according to claim 1, wherein an inorganic adhesive substance constitutes a film in place of a part or all of the resin. parts.