JPS61216767A - Method for coating fine powder - Google Patents

Abstract

PURPOSE:To uniformly apply a fine powder even to an object having unevenness in a desired thickness, by mixing the fine powder with a solvent and placing matter to be coated in the resulting suspension under a state stirred by ultrasonic vibration and subsequently stopping stirring to sediment the fine powder. CONSTITUTION:A predetermined amount of a fine powder such as powdery glass or ceramic and a solvent such as methyl alcohol or water are respectively received in a storage tank 8 which is, in turn, arranged in a water received ultrasonic vibration tank 4. Matter 10 to be coated is fixed to a support stand 12 so as to direct the surface 14 to be coated thereof upwardly and the height (h) thereof is adjusted so that the thickness of the fine powder to be coated comes to a desired value. In this state, ultrasonic vibration is applied to the storage tank 8 to stir the fine powder and the solvent to prepare a uniformly mixed suspension and stirring due to ultrasonic vibration is subsequently stopped to wait the natural sedimentation of the fine powder in the suspension 6. After a predetermined time, the fine powder is sedimented to the surface 14 to be coated and, therefore, the matter 10 to be coated is gently drawn up from the suspension.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for uniformly applying fine powder such as powdered glass to an object.

(b) Prior art and its problems When coating the surface of metal materials, ceramics, semiconductors, etc. with a thin glass film, or when bonding ceramic parts or ceramic and metal parts, the surface of the part After applying powder glass etc. to
A method may be employed in which the temperature is raised and powdered glass or the like is welded to coat the surface, or a method in which the object to be coated and another object are bonded to each other.

To do this, it is first necessary to uniformly apply a fine powder such as powdered glass to the parts. Conventionally, methods for applying fine powder include, for example, a spray coating method, a brush coating method, a screen printing method, and the like.

Although the spray coating method has the advantage of being easy to apply, it is difficult to apply to powdered glass having a relatively large particle size, and uniform coating is difficult. Even the method of applying with a brush is difficult to achieve uniform application. Screen printing is effective for uniformly coating a flat surface, but it is difficult to coat a curved or uneven surface, and it is also difficult to coat a minute object. Furthermore, after coating, a preheating step is required to scatter the organic binder, which is undesirable from the standpoint of process omission and energy saving.

The present invention has been made in view of these circumstances, and aims to provide a method that can uniformly apply fine powder such as powdered glass to minute objects with curved or uneven surfaces. purpose.

(c) Means for Solving the Problems In order to achieve the above object, the present invention mixes fine powder with a solvent, applies ultrasonic vibration to the mixture, and thereby solves the problems involved. The object to be coated is placed in the suspension with its surface to be coated facing upward, and then agitation by ultrasonic vibration is stopped to allow the fine powder to settle, thereby applying the fine powder onto the surface to be coated. I try to do that.

(d) Examples Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

The figure is a sectional view of a coating device used for applying the method of the invention. In the same figure, the symbol l is a coating device;
2 is an ultrasonic vibration tank that applies ultrasonic vibrations, and 4 is water stored in the ultrasonic vibration tank 2. Further, 6 is a suspension mixed with a fine powder such as powdered glass and a solvent, 8 is a storage tank such as a beer force for storing the suspension 6, 10 is an object to be coated such as an electronic component, 12 is a support stand that supports the object 10 to be coated. This support stand 12 has a means for setting the height h so that the surface to be coated 14 is maintained at a predetermined position in the suspension 6, and a means for setting the height h of the surface to be coated 14 so that the surface to be coated 14 is kept at a predetermined position in the suspension 6, and a means to prevent the position of the object to be coated lO from shifting due to ultrasonic vibration. (both not shown).

Next, this coating device! A method of applying fine powder to the object 10 to be coated by applying the method will be described.

First, a fine powder and a solvent are mixed in a predetermined amount in the storage tank 8. The mixing ratio in this case is appropriately set depending on the target thickness of the fine powder to be applied.

Further, as the fine powder, powdered glass is mainly used, but it is not limited to this, and for example, ceramic powder may be used. In addition, the particle size of the fine powder should be 50 mesh or more (30
0μ or less) is preferable.

The solvent can be selected as appropriate depending on the coating conditions, but
Organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and acetone, and water can be used.

Next, the storage tank 8 is placed in the ultrasonic vibration tank 4 containing water. On the other hand, the object to be coated 10 is fixed to the support stand 12 with its surface to be coated 14 facing up, and the surface to be coated 14 is placed in a predetermined position in the suspension 6 in consideration of the thickness of the fine powder to be coated. Adjust the support base 12 so that the height is maintained at h. Then, the object to be coated 10 is immersed and placed together with the support base 12 in the suspension 6 .

Next, ultrasonic vibration is applied to the storage tank 8 to agitate the fine powder and the solvent to form a uniformly mixed suspension 6.

Thereafter, the agitation by ultrasonic vibration is stopped and the fine powder in the suspension 6 is allowed to settle naturally. After a predetermined period of time, the fine powder is deposited on the surface 14 to be coated, so that the object 1 to be coated is
0 from the solvent solution. At this time, to prevent the fine powder from being washed away, it is necessary to gently pull it up at a speed slower than the sedimentation speed of the fine powder. In the case of an organic solvent, it is also possible to wait for evaporation. In the case of water, evaporation may be accelerated by heating to a temperature that does not generate bubbles.

Then, if the fine powder deposited on the application surface 14 is dried, the fine powder is applied to the object 10 to be coated.

Thereafter, by heating and welding the fine powder applied to the surface 14 of the object 10 to be coated, the surface of the object to be coated can be uniformly coated with a glass film. When it is desired to join the object to be coated with another object, welding using powdered glass is possible by overlapping them and applying an appropriate surface load and increasing the pressure.

(E) As described above, according to the present invention, fine powder such as powdered glass can be uniformly applied to minute objects having uneven curved surfaces or uneven surfaces. In this case, the film thickness of the fine powder to be applied can be easily controlled by adjusting the amount of the fine powder mixed in the solvent and the height of the surface to be coated in the suspension. Furthermore, unlike conventional screen printing, the preheating step for scattering the organic binder can be omitted, which is advantageous in terms of energy saving.

[Brief explanation of the drawing]

The drawing is a sectional view of a coating device used for applying the method of the invention. DESCRIPTION OF SYMBOLS 1... Coating device, 2... Ultrasonic vibration tank, 6... Suspension, 10... Object to be coated, 14... Surface to be coated. Applicant Shimadzu Corporation Agent Patent Attorney Oka 1) Kazu Hide 1: Coating it 2°B difference kJ FW! 6: 1 o: Norhi 1, 1,000 8 collar India, 14:
blushing

Claims (1)

[Claims] (1) Mix the fine powder with a solvent, stir it by applying ultrasonic vibrations, place the object to be coated in the suspension thus produced, with the surface to be coated facing upward, and then, A method for applying fine powder, characterized in that the fine powder is applied onto the surface to be coated by stopping agitation by ultrasonic vibration and allowing the fine powder to settle.