JPS5877575A - Method and device for production of solid thin film on surface of work - Google Patents

Abstract

PURPOSE:To form solid thin films having electrical and mechanical properties better than those of raw materials by accelerating the particles of solid powder at high velocity by utilizing an electrostatic method, and bombarding the same onto the surface of the solid work thereby sticking and depositing the particles thereon. CONSTITUTION:DC high voltage is applied to a vibration diaphragm 8 and the work 4 from a voltage power source 5 to constitute electrodes corresponding to the anode and the cathode. The diaphragm 8 is electromagnetically oscillated by the effect of the alternating magnetic fields generated by an electromagnetic coil 16 and the powder particles 1 packed in a particle supply system P are supplied through the fine holes of the diaphragm 8 to the spacing between the electrodes. The electrically neutral powder particles 1 existing near the surface of the diaphragm 8 which is the anode are charged to a positive polarity as the transfer of electrones from the particles 1 to the anode is induced by an electric field effect. The charged particles 1 are electrostatically accelerated in the direction of the electric field to have high velocity at which the particles impinge upon the surface of the work 4 which is the cathode, and receive strong impulsive and plastic deformation, so that said particles are stuck and deposited on the surface of the work 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a thin film manufacturing method in which solid fine powder particles accelerated at high speed collide with the surface of a solid workpiece using an electrostatic method and are deposited to form a solid thin film. The present invention relates to a method and an apparatus thereof.

Conventional techniques for producing films by applying kinetic energy to minute units of matter using some kind of acceleration means, colliding with the surface of a solid material, and depositing the kinetic energy include, for example, ionization, which is based on the collision of atomic units of ions. There is evaporation (plasma method, sputtering method), ion beam evaporation, and thermal spraying technology based on the collision of large units of thermally melted solid materials. nif /
Although comparatively good quality membrane materials can be obtained in 〒, J'
It is difficult to set the conditions for film formation, and the peripheral technology required for this purpose, such as control of atmospheric gas, becomes complicated, and the apparatus tends to become large-scale. On the other hand, in the latter method, a high-temperature substance melted in the air is sprayed onto the surface of the workpiece to build up the material, which inevitably leads to quality deterioration of the formed film material or thermal deterioration of the workpiece. There were some unavoidable drawbacks.

The thin film manufacturing method of the present invention can be said to have the same principle as the former method in that it uses electrostatic acceleration means, but the object of acceleration is a fine solid substance (powder particles) that is much larger in size than ions, and moreover, It is characterized by the use of high-speed impact phenomena between substances for film formation. Therefore, the film formation mechanism or the properties of the formed film material will be different in both cases. In other words, when a fine solid substance hits the surface of a solid material at high speed, a high temperature and high pressure state occurs due to the supply of energy with high power density, resulting in changes in the crystallographic structure of the impacted substance or changes in the structure of different materials. A chemical reaction can be expected.

Figure 1 (a) shows the basic principle of this thin film manufacturing method, showing the process in which a single powder particle is charged and electrostatically accelerated in an electric field to obtain high speed, collide with and adhere to the surface of the workpiece. represents. That is, the flat electrodes 15 and 15 connected to the DC high voltage power supply 5 constitute an anode and a cathode, respectively, and an electric field E is created between these electrodes, the strength of which depends on the distance d between the electrodes and the applied voltage. join. Initially, in the electrically neutral powder particles 17 that existed near the anode surface, field emission of electrons due to the action of the electric field or conduction due to contact with the electrode surface occurs, and electrons ℃ transfer from the powder particles to the anode. occurs, and a positive charge is applied ((A) in the figure).

As a result, the charged powder particles are electrostatically accelerated in the direction of the electric field E in the figure to obtain a high speed, and the velocity reaches the maximum speed just before colliding with the cathode surface ((B) in the figure). When high-speed powder particles collide, they instantly release their kinetic energy, so they undergo impact-plastic strength and are deposited on the cathode surface. , practical fine powder particles, which are usually in an aggregated state, are separated from the aggregated state into single fine particles in an electric field, and participate in film formation through the above-mentioned charging and electrostatic acceleration behavior. In other words, as a result of the agglomerated particle group being charged near the anode surface based on the above-mentioned charging mechanism ((D) in the figure), the repulsive force between the charged charges causes the particles to become statically divided into smaller particle groups. The separated particle group that is electrodispersed ((E) in the same figure) has a positive charge, so it is electrostatically accelerated toward the cathode and collides with the surface, where it is mechanically accelerated by the impact force. The particles that collide with the cathode surface are separated ((F) in the same figure).
Groups of relatively small diameter particles that achieve high speed will adhere to the surface, but those with relatively large diameters that do not have enough kinetic energy to attach will revert to negative polarity (
Electrostatically accelerated toward the anode 3. In this way, between the opposing flat electrodes, electrostatic dispersion and mechanical separation are repeated during the reciprocating motion between the electrodes in the direction of the electric field. The initial aggregated collective particles progress through smaller aggregated particles and then separate into individual single particles. Further, when the aggregated particles are separated, a space charge field due to the large number of charged powder particles is formed between the poles, so that the individual powder particles are mutually interconnected by the electrostatic force. Therefore, the powder particles between the electrodes are repeatedly charged and accelerated in the direction of the applied electric field, and move back and forth to diffuse toward the electrode periphery.

Due to electrostatic acceleration between the plate-like electrodes, the velocity obtained by the powder particles is theoretically V − (2q Va /FBI) − (6βεo E2 (
1jr p o)'' (where q, +11, γ and ρ., respectively, are the charge amount, mass, radius and density of the powder particles 1θ:, v, , r> and d are the applied voltage between the electrodes, the applied It is given by the electric field strength and distance, β is the charge coefficient, and ε is the vacuum permittivity, and indicates that powder particles with small particle diameters (J) obtain high speed. Therefore, during the reciprocating motion between the electrodes, As the particle size continues to become finer, the high-speed particles that have acquired enough kinetic energy to adhere selectively land on the surface of the workpiece, resulting in the formation of a thin film. Figure 4 demonstrates that during the reciprocating motion based on the charging and acceleration between +lLl parallel electrodes, the initial aggregated particles are separated into almost single powder particles. This is an example of experimental results. That is, the average specific charge I of charged powder particles pulled out from between the electrodes without reciprocating motion.
f q/nr (self-skipping circle) is extremely low, whereas reciprocating motion l) 7. - case q 7m (black circle) shows a value close to the theoretical value for a single powder particle, indicating that the drawn particles have reached the theoretical velocity mentioned above. In this way, the ability to accelerate fine powder particles with strong agglomeration to a high speed that conforms to the theory of electrostatic acceleration is an effect of the flat electrode and also a feature of the present thin film manufacturing method. Furthermore, due to the diffusion movement caused by the space charge field of the powder particles, a substantially uniform thin film can be formed on the surface 1- of the fractured workpiece over a fairly wide range. In addition, in Fig. 1 (a) and fb), it is assumed that particles adhere to the cathode surface -, but the same phenomenon occurs also on the cathode surface l-. For negatively charged particles that are accelerated, the concentration of the electric field tends to cause a reversal of the charged electrode 1 due to radiation from the particles, which increases the proportion of particles that cannot collide with the surface of the anode. Considering this, the number of 1.1 units is relatively small.

Therefore, it is more advantageous in terms of film formation efficiency to use the cathode side as a limb processed product.

Hereinafter, the present invention will be explained in detail by way of embodiments with reference to the drawings.

FIG. 2 shows, as an example, the L' section of the membrane manufacturing apparatus used in this embodiment. The aperture/supply system 1 for supplying powder particles, which are the raw materials for the membrane, into a high electric field is a 11. (Moving plate) 3. Loosen (fasten) this diaphragm to the powder filling container 7. Attach the vibrating temporary holding ring 9 and the diaphragm ring 10, such as GOL 01J, and the diaphragm. It consists of an iron core (i) installed for electromagnetic vibration and a cylindrical 11°C magnet (16). ) and (J, the former is the anode 1) 1 is the target 1ifi: high voltage) 1 is the high voltage power supply 5
By connecting the anode and the diaphragm, the diaphragm and the anode are connected.
; the electrode configuration corresponding to the λ pole and jr 6 ′,, 1
1rJ"1 is formed in the electromagnetic coil by J: , ffi
'l alternating magnetism □140) action te vibration & wo1(i (
a N+Q ll1Il sase, l+'! , Powder grains r-+, which had been distributed 16 times in the r-fj line, are supplied between the electrodes by the thinning of the diaphragm, and according to the Ji ln principle of Then proceed to 1- and form r 14 (r ++ Samurai; (. Also,
The film formation is carried out by the vacuum pump 11 in order to remove the dirt, etc. r”C]j’!
The process is carried out in a vacuum vessel 12 evacuated to an air space of □1″↓.

In the example shown in the same figure, the diaphragm is used as an anode, but another flat anode is inserted and installed directly under the diaphragm, and the supply system is connected between this anode and the workpiece (cathode). Powder particles may also be provided. Furthermore, as a method other than the above-mentioned particle supply method using electromagnetic vibration, there is a method in which powder particles are electrostatically charged to form an atomized r-beam and flowed between an anode and a workpiece. Motori 14ru.

FIG. 3 shows an example of an apparatus for carrying out the Ike method of the present invention, and parts corresponding to those in FIG. In this example, the workpiece that was also used as a cathode in the example of FIG. is pulled out through a hole in the cathode and irradiated onto the surface of the workpiece as a high-speed powder particle beam (-1 to form a deposited film 3. In the method shown in Fig. 2, the powder particles are charged and Since a conductive plate-shaped electrode is required for acceleration, liquid additives are also limited to those materials and shapes. Because the parts are separated, constraints on the workpiece are lifted.For example, even if the target workpiece has a sharp protrusion shape.
In addition, in terms of processing costs, not only conductors and semiconductors but also insulators can be used, so the range of application for forming 11 is expanded. Furthermore,
It is also possible to perform controls such as electrostatic focusing and re-acceleration on the extracted accelerated powder particles.

As an example of the implementation of this film formation method, the applied voltage between the electrodes is 80
KV, distance between poles 5u, degree of vacuum IX, 1(]-'
Under the formation conditions of Tor r, the average particle size is 1 μm
When carbon black particles of m are collided with and adhered to the surface of carbon tool steel (SK3), a smooth and dense carbon film with a surface roughness in the microscopic range corresponding to the particle diameter is formed at 7QA/min. It was confirmed that it could be fabricated at a formation speed of . This carbon film has good adhesion to the surface of the workpiece, so it has a thickness that has never been reported in conventional carbon film formation methods such as vacuum evaporation, ionization evaporation, and ion beam J-evaporation. It was possible to form a thick film with a thickness of about 711 μm. This superiority over the conventional method is due to the high-speed impact between the solids, which creates strong bonds between the particles and the liquid material and between the particle materials. Although the formation of the present carbon film proceeds under conditions other than those described in Section 1111, when the applied voltage is 80 KV or higher, it is difficult to obtain a speed sufficient to adhere even relatively large-diameter particles in an agglomerated state. Therefore, such particles may be incorporated into the film, and the structure of the formed film material may lack homogeneity.
Of course, if the applied voltage is extremely low, the film formation will not proceed because the deposition rate will be insufficient.

Regarding the characteristics of the carbon film produced using this film formation method,
List the main items confirmed so far and their uses.

First, regarding the knowledge regarding electrical properties and their uses, (a) The electrical resistivity at room temperature is measured to be 10 Ω・on, and that of the raw material carbon particles (10 Ω・on
We were able to synthesize a new thin-film semiconductor material with significantly higher resistance than that of conventional semiconductors. Further, the conductivity type as a semiconductor was determined to be P type based on the measurement of thermoelectromotive force based on the Seebeck effect.

(1)) The temperature dependence of resistivity is p = Ac xP
(13/(ゝA 'I') (Here, ρ is resistivity, A, I3 are shrines '41
1 constant and To is the absolute temperature.
Considering that this carbon film material has a small heat capacity [11- Application to the thermistor element r- for temperature measurement is iiJ
It is Noh.

(C) The dependence of resistivity on electric field showed non-O, Z, and Z-types in which the resistivity value decreased significantly when a high electric field was applied.

In other words, at this time, a change in the current occurs, so it can be applied to, for example, a varistor element for controlling a large current.

Furthermore, this carbon film, which is a P-type semiconductor, is ++,! l,!
7.Characteristics of a 1]-1 junction die formed on a silicon semiconductor ((1) As a current-voltage characteristic, Zener breakdown phenomenon occurs under a certain magnitude of reverse bias voltage. There is a steep rise in current due to ff.The characteristics of this p-n junction surface can be used not only as a constant voltage diode and a switching diode (but also suggests its application to transistor wires). The generation of photovoltaic voltage was observed when irradiated with incandescent light and sunlight, and the possibility of application to photovoltaic cells was discovered.3 Next, regarding the knowledge regarding mechanical properties and its applications, see (f) Micro The hardness of this carbon film in the Vickers test was evaluated as I(, -1100 to 1900, which was a significantly higher value than that of the raw material carbon.

In addition, in the sliding friction test, the coefficient of friction between the membrane materials was about 0.1. This is a fairly low value for solid-solid friction, and since the frictional atmosphere is constant regardless of whether it is in the air or in a high vacuum, it was found that it has good frictional properties. Furthermore, abrasive wear for sliding wear caused by solid-solid friction and scratches from hard abrasive grains! It has been found that it exhibits excellent abrasion resistance even against These findings suggest various applications in the mechanical industry as a hard protective film that stabilizes lubricity, such as application to cutting tools for the purpose of improving cutting performance and extending life, or 11114 III. It is conceivable to use white clay of /1 as 1'1 and apply it to each f.1'i H1 machine part having a sliding part.

In the following Examples, the electrical and mechanical bending properties of the membrane formed in accordance with the present invention are shown to be significantly different from that of the I material. I actually did it.

This special +1 change is carbon black lt'+ I
This may be due to local crystal structure conversion to a diamond structure caused by the 3'il Jl impact.

As described above, according to the present invention, a membrane abrasion material having a unique l'l quality can be synthesized using relatively simple equipment and technology. It should be noted that the present invention is not limited to the above embodiments, and the raw abrasive powder +1"t, r- has a fine diameter, does not exhibit conductivity in a high electric field, and is of abrasive quality. If it is, it can be used.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the basic principle of the present invention, Figs. 2 and 3 are cross-sectional explanatory diagrams of the membrane manufacturing apparatus used in the present invention, and Fig. 4 shows that aggregated collective particles are formed into single powder particles between parallel plate electrodes. This is a table of experimental results showing that (j-) Powder particles, (?) Accelerated charged powder particles, () Adhesive film, (4) Fractured T object, (5) High electric power source, (0) Iron core, (7) Powder filling container, (6) Vibration plate, (head vibration plate holding ring, q()) elastic ring, zero pump, 0(2)
Vacuum container, (l:i) electrode, V electrode, (1φ flat electrode, ljφ electromagnetic filter, (j7) powder particle patent applicant
Atsushi Ide and 3 other people = 40 1st session Figure 2 3 1'Q

Claims (1)

[Claims] ■) In a high electric field applied in a vacuum, solid powder particles are electrostatically charged and accelerated to a high speed, and the particles are impacted and adhered to the surface of the workpiece to form a thin film. A method for producing a solid thin film on the surface of a workpiece, characterized by: 2) A method for producing a solid thin film on the surface of a workpiece according to claim 1, which uses fine agglomerated particles separated by the action of an electric field as solid powder particles. 3) A method for producing a solid thin film on the surface of a workpiece according to claim 1, which utilizes single particles separated by electric field action as solid powder particles. 4) Solid powder particles are electrostatically charged and accelerated by using parallel plate electrodes, and the particles in agglomerated state are reciprocated between the facing electrodes, thereby being charged and accelerated. A method for producing a solid thin film on the surface of a workpiece according to item 1, item 2, or item 3. 5) A vacuum chamber connected to a high vacuum evacuation system, a container installed in the vacuum chamber and containing solid powder particles, and a solid powder particle supply tip located at the bottom of the container and associated with a vibration device. It consists of a diaphragm with holes and a liquid supply placed directly below the diaphragm, and is electrically connected directly between the container side and the workpiece so that a high voltage can be applied. A device for producing a solid thin film on the surface of a workpiece. 6) The solid thin film manufacturing apparatus according to claim 5, wherein the vibration device includes a cylindrical electromagnetic coil provided outside the container and an iron core arranged inside the container so as to face the diaphragm. 7) a vacuum chamber connected to a high vacuum evacuation system; a container installed in the vacuum chamber and containing solid powder particles; and a container located at the bottom of the container and associated with a vibration device for supplying solid powder particles. It consists of a diaphragm provided with pores, a flat electrode placed directly below the diaphragm and provided with pores for drawing out solid powder particles, and a workpiece placed below the electrode, An apparatus for producing a solid thin film on the surface of a workpiece, characterized in that a container, an electrode, and a workpiece are electrically connected directly so that a high voltage can be applied to the workpiece. 8) A vacuum chamber connected to a high vacuum evacuation system, a container installed in the vacuum chamber and containing solid powder particles, and a container located at the bottom of the container and associated with a vibration device for supplying solid powder particles. A diaphragm provided with pores, a plate-shaped charging acceleration anode fixed to the lower surface of the diaphragm, and arranged at regular intervals below the anode, with a pore in the center for charging acceleration and powder particle extraction. It consists of a cathode for extracting accelerated particles, and a workpiece placed below the cathode, and is directly electrically connected to the container side so that a high voltage can be applied between the cathode and the workpiece. A device for producing solid thin films on the surface of workpieces.