SU1341592A1 - Method of measuring surface resistance of dielectric material - Google Patents

Abstract

The invention can be used in the woodworking, chemical industry, etc. to analyze the properties of materials by electrical methods. The aim of the invention is to increase the accuracy of measurements by eliminating methodological errors, the influence of atmospheric factors, uneven structure. material plots, etc. First, pre-breakdown current I and voltage and g are determined at a fixed interelectrode distance} ff. Next, a section of the material under study is treated with a conductive composition and, moving the electrode pair with a distance of 1 ”along the interface, when one electrode is on the wire, the other side is outside it, the point of the plane is determined where the interelectrode resistance reaches a pre-selected the values of R, then at the pre-breakdown current 1, the voltage on the electrodes U is determined, and at the point where at the current, the voltage reaches the potential of the material under study, the movement is stopped and the inter-reflector is measured The battery resistance R ,. According to the results of joint measurements of U, R, U, R, the value of surface resistance is determined. It is possible to increase the accuracy of measurements when using flat electrodes orthogonal to each other. 1 3.p.f-ly. i (L

Description

ISO. Breezing refers to the physical analysis of the properties of materials by electrical methods and can be used in the woodworking, chemical, and other industries in determining the surface electrical resistance of dielectric materials.

The aim of the invention is to increase the measurement accuracy.

The method is carried out as follows.

Choose the size of the dielectric sample under study not less than twice the size of the electrodes used. The electrodes are superimposed on the dielectric sample, they are supplied with a voltage from a high-voltage source, and the interelectrode distance (1) is changed to form an electrical breakdown. This point is fixed by a sharp current jump and a decrease in voltage. For a given operating point, the distance 1 is fixed, the prebreakdown current I t

Next, a part of the sample area is treated with a conductive compound, which is applied by rubbing. One electrode is installed on the treated area, the other is out of it at a distance of 1 from the first. The interelectrode distance does not change the electrode pair along the interface between the processed and untreated current-conducting composition of sections of the dielectric sample, simultaneously measuring the value of the interelectrode resistance R. After the last preselected value is reached, the electrode pair is fixed, a current equal to the voltage recorded on the electrodes U Uj. Not changing the interelectrode distance 1 Ij, continue to move the electrode pair along the interface, simultaneously measuring the voltage on the electrodes U. When the voltage reaches U Uq, where and is the ionization potential for a given dielectric (reference value determined by calculating the average the ionization potential of the elements constituting the chemical basis of the dielectric material under study), the movement of the electrodes is stopped. At this operating point, the interelectrode resistance R, is measured. According to the results of joint measurements, the surface electrical resistance of the material under study is determined:

RM

R; and

RO. and.

where R is the surface electrical resistance of the material under study;

R, is the resistance of the material at the ionization potential and current 1 ";

 maximum prebreakdown voltage;

R 1 is the selected resistance value determined by the conductivity of static charges (R 10 Ohm);

and is the voltage across the electrodes at current I and resistance R.

The accuracy characteristics of the method can be improved by using flat electrodes with axes arranged orthogonally.

The method allows to classify

dielectric materials by their

electrostatic properties, which, under normal conditions, presents considerable difficulties, since it is necessary to take into

only the characteristics of charge carriers and their variability, but also the various conditions for their relaxation, the combined result of which is largely influenced by atmospheric conditions, chemical oco6ieHHOCTH, unevenness in the surface structure of materials, etc. With the proposed measurement procedure these methodological errors

eliminated.

Claims (2)

1. A method for measuring the surface resistance of a dielectric material, which consists in imposing measuring electrodes on the material under test, connecting them to a high voltage source, measuring the electrical circuit parameters at various interelectrode gaps, and using the results of joint measurements resistance, which is due to the fact that, in order to improve the accuracy, the interelectrode distance is changed to form an electrical breakdown and the distance 1 "is fixed to the value of and I and voltages U, processing part of the area of the material under investigation, conducts with a wire and sets one electrode to the worked area, another - outside it at a distance of 1 "; not changing the electrode distance, moving the electrode pair to achieve the interelectrode resistance value, equal to preselect The value of R and then, at current I, the value of voltage is fixed and, and at the point where at current 1 the value of voltage is reached, the ionization potential of the material under study is Uj., the movement is stopped and the resistance R, is measured. 2. Method POP.1, differing ayushu and with the fact that, for the purpose of increase of accuracy, measurements are made with the help of electrodes arranged orthogonally relative to each other.