JPH02126152A - Electrostatic type solid-state surface analyzer - Google Patents

Abstract

PURPOSE:To measure the quantity of charged electric charge of a sample layer with a high precision and to analyse the chemical composition of a contact face by flowing a reference powdery material to an inclined sample plate and receiving the reference powdery material dropped along the sample layer by a conductive receiver and measuring the quantity of electric charge. CONSTITUTION:A sample layer 12 is formed on a conductive substrate 11 of a sample plate 13, and this sample plate 13 is fixed at a prescribed angle to a fixing member 14. A reference powdery material 17 is stored in a reference powdery material supply device 18, and the inside of a closed vessel 32 is set to a desired atmosphere, and a shutter member 22 is operated to flow down the powdery material 17 on the sample layer 12. The powdery material 17 gets contact charged electric charge by contacting with the layer 12 and is gathered into the conductive receiver 25. The quantity of this electric charge is measured through an electric charge measuring terminal 27 by an electric charge measuring system 28. Thus, the inclining method is used to measure the quantity of charged electric charge of the sample layer with a high precision, and the chemical composition of the contact face is analyzed.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides an electrostatic solid surface that can accurately measure contact charge and detect components on the solid surface or changes thereof. Regarding analysis equipment.

(Prior Art) It is generally well known that when two different substances are brought into contact and separated, contact charges of equal amount and opposite polarity are generated on the surfaces of the two. The polarity and charge amount of this contact charge sensitively reflect the chemical composition constituting the contact interface between the two, and its sensitivity is said to be comparable to that of ESCA (X-ray photoelectron spectroscopy). Therefore, by utilizing this phenomenon, it is possible to analyze the chemical composition of the surface of a substance.

One way to use this contact charging phenomenon to analyze the chemical composition of the contact interface between the two is to pour a reference powder onto a sample plate held at an angle, and then calculate the amount of charge on the sample plate from the amount of charge on the sample plate. A method for measuring the chemical composition of a plate (hereinafter referred to as the gradient method) has been announced.

(7) However, in the conventional gradient method, no technology has been established to increase the 7I-1 constant volume to the extent that changes in surface composition can be detected with high precision, and the necessary conditions are not clear. Therefore, the current situation is that no flllll device that satisfies this purpose has been announced yet.

(Problems to be Solved by the Invention) The present invention has been made in order to address the above-mentioned problems, and it is possible to measure the contact charge with high precision by the gradient method, and therefore, it is possible to measure the contact charge with high accuracy. The purpose of the present invention is to provide an electrostatic solid surface analysis device P2 that can detect chemical components constituting the surface or changes thereof.

[Structure of the Invention] (Means for Solving the Problems) The electrostatic solid surface analysis device of the present invention includes a sample plate in which a sample layer is closely provided on a conductive substrate, and a sample plate that is tilted. a sample plate holding means for holding the sample plate in the same state; a powder supply means for pouring reference powder onto the sample layer of the sample plate; and an electrically insulated means for receiving the reference powder that has fallen onto the sample layer of the sample plate. It is characterized by comprising a supported conductive receptor and a charge itt+ constant device for measuring the amount of charge on the conductive receptor or the sample plate.

Examples of the sample layer provided closely to the conductive substrate of the above device include plates and films made of organic or inorganic substances, or powder layers made of solid or powdered organic or inorganic substances. These are applied in the form of a solution or dispersion onto a conductive substrate and dried to form a coating film.

The inclination angle of the sample plate is selected as appropriate in the range of 45 to 75'' depending on the type and particle size of the reference powder, or the type of sample layer, and is adjusted and fixed to the optimal value that allows measurement values with good reproducibility to be obtained. In general, a low angle of inclination is selected for a reference powder with a large particle size, and a high angle is selected for a reference powder with a small particle size and a large amount of contact zone?!S or a sticky sample plate.

Further, as the reference powder to be dropped onto the sample layer, an organic or inorganic powder having an average particle size of about 30 to 1000 μm is used, and for example, iron powder, glass powder, resin powder, etc. can be used. It is desirable that these reference powders be as spherical as possible.

It is preferable that the entire device of the present invention is placed in a sealed container and the measurement is performed in an atmosphere of constant temperature and constant humidity.

(Function) In the electrostatic solid surface analysis device of the present invention, when the sample plate is arranged at an angle and the reference powder is poured from above, the falling reference powder and the sample layer are JI8! By rubbing, charges are generated in the reference powder and the sample layer with opposite polarities and equal absolute values, and the reference powder falls in a charged state into the conductive receptor.

Then, if the conductive substrate of the sample plate is grounded and the conductive receptor is connected to the input terminal of the charge measuring device, the electric charge on the sample plate will be discharged through the conductive substrate and will be transferred to the conductive receptor. The charge Q of the fallen reference powder is measured by a charge measuring device.

The measured charge is determined by Q-CV.

(However, C is the capacitance of the capacitor built into the charge measuring device, and ■ is the potential measured by the charge measuring device.) (Example) Next, an example of the present invention will be described with reference to the drawings. explain.

In FIG. 1, a sample plate 1 comprising a conductive substrate 1 and a closely spaced sample layer 2 formed thereon with a sample to be measured.
3 is fixed to a support base 15 at a predetermined angle by a fixing member 14.

[Conductive substrate] The material for 1 is usually a metal such as aluminum, iron, copper, brass, or stainless steel, or a conductive composition made of a base plastic mixed with a conductive substance such as metal powder or carbon black. However, it is also possible to use an insulating plastic that is molded into a predetermined shape and then made conductive by metal plating or coating the surface with a conductive composition.

The sample to be measured may be any solid, inorganic or organic, and is formed closely on the conductive substrate 11 in the form of a film, plate, or fine powder. When the sample is dissolved or dispersed in a solvent to form a paint, it is coated on the conductive substrate 11 and dried to form a film, or if it can be formed into a plate, it is formed into a plate and made conductive with a conductive paint. It is used by being attached onto the substrate 11. When the sample is a powder, it is applied as a sample layer by spraying or the like onto an undried film of conductive paint applied on the conductive substrate 11.

The fixing member 14 is generally made of an insulating material, but when the support base 15 is made of an insulating material such as polystyrene resin, polytetrafluoroethylene resin, polyacrylic resin, or other plastics. A conductive material such as a metal material can be used. in short,
It is only necessary that the conductive substrate 11 be electrically insulated from the ground by one of the fixing member 14 and the support base 15.

The device of this embodiment has a long groove 16 in the fixing member 14.
The adjusting mechanism 16 includes a pin 16b that supports the conductive substrate 11 and is engaged with the long groove 16a. By changing the locking position of the bin 16b using this adjustment mechanism 16, the inclination angle can be adjusted to any angle in the range of 45 to 75'' from the horizontal plane.

A reference powder supply device 18 is arranged on the sample plate 13 to drop the reference powder 17 onto the surface of the sample layer 12 at a constant supply speed. This reference powder supply device 18 supplies the reference powder 1
7 and a supply pipe 20, and a shutter member 22 for controlling the start and stop of supply is inserted into the supply hole 21 of the supply pipe 20. The shutter member 22 is moved up and down by an actuating device 23 using electromagnetic force or air pressure to adjust the supply speed of the reference powder, and the supply hole at the tip of the supply pipe is moved according to a preset time of a timer 24. 21 is opened and closed. The actuating device 23 and the shutter member 22 can be controlled from the center of the supply pipe 20, or the supply hole 2 can be opened and closed by moving them back and forth or from side to side as a flat shutter at the tip of the supply pipe. It looks like this.

The reference powder supply device 18 moves in the direction of the arrow as shown in FIG. 2 while maintaining a constant distance from the sample layer 12, and feeds the reference powder from any position on the surface of the 14 test plates 3. 17 is fixed on a moving device (not shown) through which it can be poured.

In addition, a reference powder 1 is poured onto the lower end of the sample plate 13.
A conductive receptor 25 for collecting 7 is arranged. The conductive receptor 25 is supported by an insulating support base 26 while being insulated from the ground, and is connected to a charge measurement system 28 through a charge measurement terminal 27 .

The charge measurement system 28 consists of two capacitors (electrostatic capacitors C) and an electrometer 30, and its measurement terminal 31
By connecting with the terminal 27 of the conductive receptor 25,
The structure is such that the electric charge of the reference powder that has come into contact with the sample layer and flowed into the conductive receptor 25 is determined from the Q-CV relational expression. This amount of charge can be displayed on a recording unit (not shown). The recording unit may be a normal recorder or may be one controlled by a computer and managed by an FD.

These measurement systems 28 are housed in a sealed container 32, and the inside of the container can be set to any desired atmosphere such as pressurized, vacuum, air, nitrogen gas, carbon dioxide gas, etc., and the reference powder 17 is poured onto the samples 111 and 213. Setting the position, setting the powder pouring time (amount) using a timer, etc. can all be performed outside the container 32.

The device of this embodiment is used as follows.

First, the sample layer 12 is formed on the conductive substrate 11 of the sample plate 13, and the sample plate 13 is fixed to the fixing member 14 at a predetermined angle. Next, the reference powder 17 is stored in the reference powder supply device 18 , the airtight container 32 is made into a desired atmosphere, and the shutter member 22 is operated 17 to transfer the reference powder] 7 onto the sample layer 12 of the sample plate 13 . flow down to. Standard powder 17
While flowing down the sample layer 12, it acquires a contact charge due to contact with the sample layer 12, and is then collected on the conductive receptor 25.

The reference powder 17 collected in this conductive receptor 25
The charge nl is determined by the charge 'API constant system 28 via the charge measurement terminal 27. At this time, the sample plate 13 is
It is grounded by 3.

In Figure 3, a vinyl chloride film was coated as a sample layer on an aluminum plate, which is a conductive substrate, and a reference powder, iron powder with an average particle size of 100 μl, was repeatedly flowed (two times) on top of this, and the charge was measured. This is a measurement curve showing the change in the amount of charge measured by System 28. As is clear from FIG. Furthermore, the amount of charge generated when a certain amount of iron powder is repeatedly poured is also the same.

In the above embodiment, an example was explained in which the charge measurement system 28 was used to measure the conductive receptor 25, but the present invention is not limited to such an embodiment, and the charge measurement system 28 was mounted on the conductive substrate 11. The charge on the conductive substrate 11 may be measured by connecting it to the attached terminal 33 and grounding the terminal 27. In this case, the amount of charge determined by API after a certain amount of powder flows down the surface of the sample layer 12 is the same amount and opposite polarity to the amount of charge of the powder as in the above-described embodiment.

Furthermore, the terminal 36 of the current A11l constant system 34 having the ammeter 35 is connected to the charge measurement terminal 27 and the conductive substrate 11 (connected to the 1-digit terminal 33), and the charge amount of the reference powder and the conductive substrate 1
The amount of charge of 1 can also be measured as a discharge current as shown in FIG. 3(b).

(Effects of the Invention) As is clear from the above examples, according to the apparatus of the present invention, the amount of charge on the sample layer can be measured with high precision by the gradient method, and the chemical composition of the contact surface can be measured with high accuracy. It is possible to perform analysis.

Therefore, the device of the present invention can be used for characterization in many fields, such as:

■It is possible to trace the coating film oxidation reaction by detecting the increase in the amount of negative charge due to oxidation with high precision.

■It is possible to track the coating film curing reaction by measuring the change in the amount of charge caused by the curing reaction.

■The oozing of lubricants and dispersants can be detected by the amount of charge, and the oozing (bleeding) characteristics of additives can be evaluated.

- It is possible to evaluate various mixing states, such as the dispersion state of pigments and dyes, and the mixing state of different types of polymers.

■It is possible to collect data for charge control of materials and evaluate coating film charge characteristics.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing the structure of the present invention, FIG. 2 is a top view of the sample plate portion thereof, and FIG. 3 is a graph showing the effects of the present invention. 11... Conductive substrate 12... Sample layer 14... Fixed member 16... Adjustment mechanism 18. ......Reference powder supply device 17...
...Reference powder 19...Storage section 20...Feed pipe 21...Feed hole 22... ...Shutter part 23...
...Actuation device 24... Timer 25... Conductive receptor 28... Charge measuring system 32...・・・Airtight container

Claims (3)

[Claims] (1) A sample plate having a sample layer closely spaced on a conductive substrate, a sample plate holding means for holding the sample plate in an inclined state, and a reference powder being poured onto the sample layer of the sample plate. a powder supply means; a conductive receptor supported in an electrically insulated manner for receiving the reference powder that has fallen on the sample layer of the sample plate;
An electrostatic solid surface analysis device comprising: a charge measuring device for measuring the amount of charge of the conductive receptor or the sample plate. (2) The inclination angle of the sample plate is 45 to 75 degrees with respect to the horizontal plane.
The electrostatic solid surface analysis device according to claim 1, wherein the electrostatic solid surface analysis device is set to. (3) The sample plate, sample plate holding means, powder supply means, and conductive receptor are housed in a sealed container, and the position at which the reference powder is poured onto the sample layer and the amount of the reference powder poured are controlled. 3. The electrostatic solid surface analysis device according to claim 1, wherein the electrostatic solid surface analysis device is capable of being controlled from the outside.