Method to detect filler content in polymer composite

FIELD: measurement equipment.

SUBSTANCE: sample is heated to temperature of polymer binder decay. Filler content is calculated by variation of a sample mass, taking into account the ash residue in process of polymer binder decay defined under conditions identical to composite decay. At the same time the variation of the sample mass is defined according to a thermogram.

EFFECT: higher accuracy of detection of filler content in a polymer composite, reduced time of analysis, lower labour and power inputs.

3 dwg

 

The invention relates to the control and measurement technology, in particular, it is intended to determine the mass content of the filler in polymer composite materials. The invention may be used to control the technology of polymeric composites, as well as for quality control and homogeneity of the material obtained.

Composites are materials consisting of several components and having a heterophase structure with the surface of separation of the phases. Composites or composite materials may be polymeric, metallic or ceramic bases. Composite materials with polymeric continuous phase, which is the matrix, and one or more dispersed phases, referred to as polymer composites.

The invention is applicable to polymeric composites with particulate fillers, thermally stable at the temperature of decomposition of the polymeric binder. As such fillers can be particles of metals or their oxides, ceramics, allotropic modifications of carbon and other

Currently, the content of the filler is determined by x-ray, chemical etching, thermal debinding, scanning probe microscopy.

Each of the existing methods has its own advantages and disadvantages, so choosing the CSOs particular method depends on the goals and specific measuring conditions. For example, the determination of the content of the filler by x-ray method [www.physics-help.info Polymer composites based on measuring x-ray attenuation of plastic, despite the reliability and high accuracy (measurement error of 1-2%), has the disadvantages associated with the specifics of working with x-rays and the high cost of the assay. This method finds application in the control of the content of the filler in the finished parts that require non-destructive testing, and composites with organic fillers, which are destroyed when heated or interaction with the solvent.

Method of chemical etching, based on the removal of the binder with a solvent, has a low cost, but very time consuming, requires spending masses of time and is less precise than removing the binder by heating.

The method of determining the concentration and quality distribution of finely dispersed fillers in polymer compositions [Bykov V.A., A. Zaikin, Bikmullin R.S. Patent RU No. 2206882, G01N 1/32, publ. 20.06.2003] involves the formation of a smooth surface of the polymeric composition, the following analysis of this surface by scanning probe microscopy, and then etching this surface in the low-temperature plasma to a depth of not less than half. This is manual labor intensive and has a fairly narrow scope.

Closest to the claimed method is a method of determining the content of the filler in polymer composites removing the binder by heating [Vietos. News of Samara scientific center of Russian Academy of Sciences, t, No. 3(2), 2009, s-515]. The main parameter for the calculation of the content of the filler is the change in mass of the sample, determined by thermogravimetric (TG) curve in the temperature range of decomposition of the binder, which is determined by the curve of the differential thermogravimetry (DTG).

The content of the filler (by weight) is defined as the ratio of the residual mass of the sample after removal by heating a polymeric binder, to the initial mass of the sample (Fig 1)

β=mKm0(1)

where m0- initial mass of the sample, mto- weight of sample after removal of the polymer binder.

The disadvantages of the prototype can be attributed to the fact that when determining the content of the filler is not taken into account the ash content of the polymer, i.e. the rest mass, which is formed after the decomposition of the pure polymer binder. Ignoring it may lead to considerable error in the determination containing the Oia filler on this way, especially in those cases when a filling is used, oxidized in air (for example, ultra-fine metals), and heat in order to avoid large errors, should be conducted in an inert atmosphere. However, in this case, inevitably increases the ash content of the polymer, so that the accounting ash becomes even more necessary.

The present invention is to improve the accuracy of determining the content of filler in the composite polymer material.

Technical result achieved when using the present invention, is as follows:

- increase the accuracy of the content of the filler in polymer composite, especially if the particles are oxidized in the air and for this reason, the heating must be conducted in an atmosphere of inert gas;

the absolute error of measurement of mass percentage of filler is not more than ±2%

- the ability to control the homogeneity of the polymer composite material using the proposed method;

- reduction of analysis time in comparison with conventional removal of the binder;

- the possibility of reducing the heating temperature of the composite, and consequently, reduced labor and energy costs;

To solve the problem and achieve the technical result is available specoborudovanie content of filler in polymer composite, consisting of a polymeric binder and filler, comprising heating the sample to a temperature of decomposition of the polymeric binder and the calculation of the content of the filler to change the mass of the sample, determined by thermogravimetric curve, which according to the invention, pre-determine the mass of ash residue decomposition of pure polymeric binder, the conditions of decomposition of the composite and pure polymer binder must be identical. Calculation of the content of the filler is carried out taking into account the mass of bottom ash by the formula:

xn=β-α1-α100%

where β is the ratio of the mass of the residue to the initial mass of the sample composite;

α - content of the ash residue after decomposition of the pure polymer binder without filler.

In the present method takes into account the mass of bottom ash used polymeric binder, and the loss of mass as a pure binder and composite, is determined using the method of thermogravimetric analysis (TGA)and temperature range of decomposition using differential thermogravimetry (DTG). These methods are described, for example, in the monographs [Joseph P. Menczel, R. Bruce Prim. Thermal Analysis of Polymers. - John Wiley & Sons, Inc., 2009; U. Wendlandt. Thermal methods of analysis. - M.: Mir, 1978]. Identical conditions for the decomposition of the composite and pure polymeric binder together with other essential attributes important to improve the accuracy of the method.

The inventors have identified the following values:

α is the relative mass content of the ash residue after thermal decomposition of pure polymeric binder;

β is the ratio of the mass of the residue to the initial mass of the sample composite;

xwith- mass fraction of polymer binder;

xn=1-xwith- mass fraction of filler.

Hence the mass of the residue after decomposition of the composite is equal to the sum of the masses of the filler and the ash residue of a polymeric binder, i.e:

mto=m0·(1-xwith)+α·m0·xwith.

Combining the last relation with equation (1), we obtain:

xwith a=1-β1-α100%orxn=β-α1-α100%(2)

Use when calculating the content of n is politely equation (2) instead of equation (1), means that the ash content of the polymer binder, and, thus, increases the accuracy of the measurements used in this method. As a result, improves the accuracy of the control technology and the quality of the manufactured composite, as well as the accuracy of determining the homogeneity of the finished material.

In some composite materials are fillers that with increasing temperature interact with oxygen, and, as a consequence, the heat must be conducted in an atmosphere of inert gas. In this case, the mass of bottom ash increases substantially, and the use of the proposed method becomes even more reasonable and necessary.

Note that when multistage process of decomposition of the binder, using equation (2), the determination of the content of the filler can be performed without removing the polymeric binder, thereby significantly reducing labor and energy costs.

For example, when determining the ash content of the microspheres in composites based on polyurethane foam-240, is heated to 680°C, which takes quite a long time (up to 3 hours). The process of thermal decomposition of polyurethane foam-240 proceeds in 3 stages (2, 3), the beginning and the end of each of which can be identified by DTG curves. It is found experimentally that using the inventive method, it is possible to calculate the ash content m is crofer on the first two stages, heating the sample to 400°C, which reduces the process in 1.5-2 times.

Figure 1 shows the typical dependence of the mass change of the polymer material when it is heated. Here figure 1 shows the curve of weight loss (thermogravimetric, TG-curve), 2 - differential curve of weight loss (DTG curve), m0- initial mass of the sample, mto- weight of sample after removal of the polymer binder. Up to a certain point, the weight of the polymer remains constant, when the temperature reaches the beginning of thermal mass begins to decline at the expense of the escape of the products of thermal decomposition. In the TG curve is observed a sharp rise, and on the DTG curve peak, the minimum of which corresponds to the maximum speed of decomposition of the polymer.

Figure 2 and figure 3 presents thermograms of decomposition of pure polyurethane foam-240 and PU foam-240, modified fly ash microspheres. TG-curves, which are used to determine the change in mass for each stage identified by the number 1, DTG-curves, which define the beginning and end of each of the three stages - figure 2. On these figures it is shown that the processes of decomposition and in that and in other case proceed in three stages at the same temperatures, so it is safe to assume that the mass loss in this temperature interval, corresponds to the mass content of Chi is that of the polyurethane foam-240, and the rest is the content of the ash microspheres (in this temperature interval ash microspheres inert). In this case, it is possible to reduce the time of analysis, determining the content of the microspheres in the first two stages of decomposition.

Was conducted experimental testing of the proposed method of determining the polymer content of the filler in the composite. Consider the inventive method on the example of two composites: polymer pressmaterials based on polypropylene and graphite BCP-70 and polymer foam based on polyurethane foam-240, modified fly ash microspheres. The determination of the content of the filler in these composites was carried out according to the following scheme:

1. On thermoanalyzer Setaram conducted an analysis of thermal decomposition of pure, containing no fillers, polymers: 3 samples for each polymer. The heating rate was 10°/min stainless steel Crucibles had a cylindrical shape (diameter 11 mm, height 9 mm). Experiments with the samples was carried out in a continuously renewable air, which was implemented by purging (volumetric flow rate of 5 l/h), at a pressure close to atmospheric.

2. In our case, the software of thermoanalyzer automatically calculates the relative mass loss as the ratio Δm=(m0-mto)/m0. Measured so clicks the zoom by thermogravimetric curve of weight loss of the samples of pure polypropylene:

Δm=97.1% or 0.971;

Δm=96.4% or 0.964;

Δm=97.5% or 0.975.

The average value <Δm>=97.0% or 0.97. Thus, we define the value α=1-Δm=0.03 for the calculation of the content of the filler by the formula (2).

The measured mass loss of the samples of pure polyurethane foam-240 after the first two stages of thermal decomposition:

Δm=46.2% or 0.462;

Δm=44.6% or 0.446;

Δm=45.9% or 0.459.

The average value <Δm>=45.5% or 0.455. Then α=1-Δm=0.545.

The measured mass loss of the samples of pure polyurethane foam-240 with full termorasshirennyi in air atmosphere is practically 100%. The temperature of the beginning and end of the individual stages of the decomposition process, which was calculated the mass loss was determined according to international standard ISO [1] according to the TGA and DTG.

3. Conducted thermal analysis of composites under conditions identical to the conditions of thermal analysis of pure polymers.

4. Spent the calculation of the content of the filler (fly ash microspheres and graphite) by the formula (2) and, for comparison, according to the formula (1). The results are presented in tables 1 and 2.

Considering the fact that Δm=(m0-mto)/m0equation (2) takes the following form:

xn=1-α-Δm1-α100%(3)

Table 1
The content of the filler BCP-70
No. sampleΔm, %x1, %xgr, %
115.984.183.6
216.183.983.4
315.684.483.9
416.084.083.5
516.084.083.5
616.084.083.5
715.484.684.1
815.884.283.7
916.084.083.5
1016.783.382.8
Δm, % - weight loss BCP-70 (maximum temperature of 460°C);
x1, % - content of graphite excluding ash residue;
xgr, % - content of graphite with regard to ash residue.

Table 1 shows that when the content of filler ~85% of the difference between the measured values is small and amounts to 0.5-1.5% (within the errors), but reducing the mass fraction of filler, and, on the other hand, with increasing mass fraction of ash residue, this difference will increase.

As an illustration of this fact can lead to composites comprising a filler powder of molybdenum disulfide (MoS2that is entered in the amount of 5-15% [2]. Molybdenum disulfide (MoS2air oxidizes at temperatures above 360°C, and in an inert atmosphere it is stable up to 1100°C [3], so the heating to determine the content of the filler (MoS2in the composition of any polymer composite should be carried out in inert atmospheres the field. As a binder of such a polymer composite can be used, for example, polyurethane foam-307 (ρ=0.2 g/cm3), after thermal decomposition which in an inert atmosphere of argon, according to our measurements, ash is 27%, which significantly exceeds the above value (5-15%). Thus, in this case, an adequate determination of the content of the filler thermogravimetric method can only be carried out by using the formula (2).

Table 2
Weight loss when heated material PUF-240, modified fly ash microspheres
No. sampleΔm1, %xsm, %Δm2, %xsm, %
141.159.690.69.4
240.9210.189.810.2
340.6310.790.0 10
440.6310.789.510.5
540.3711.389.210.8
6At 41.059.890.59.5
740.7610.489.810.2
840.6310.789.910.2
940.6910.689.910.2
10At 40.5810.890.19.9
Δm1, % weight loss after completing the second stage of thermal decomposition (maximum temperature 400°C);
Δm2that % is the er masses after the third (final) stage of thermal decomposition (maximum temperature of 680°C);
xsm, % - content of microspheres, determined after completion of the second stage of thermal decomposition;
xsm, % - content of microspheres, determined after complete thermal decomposition.

As can be seen from table 2, the content of the filler, as determined by mass loss after the first two stages of decomposition, practically coincides with the content specified on the final termotasajero polymeric binder. Thus, at a heating rate of 10°C/min, the time spent on the experiment, decreased by 40%. The decrease in the temperature analysis also enables us to determine in this way the content of the fillers, which are destroyed at high temperatures.

The results presented in Tables 1-2, confirm the achievement of the technical result using the proposed method:

- increases the accuracy of determining the content of the filler in the composite material (the lower the content of the filler and the more ash pure polymeric binder, the greater the gain in precision is the result of application of the proposed method using the formula (2) instead of formula (1));

if the decomposition of the binder proceeds in two or more stages, possibly with the reduction of analysis time;

- the possibility of reducing the heating temperature of the composite, and consequently, reduced labor and energy costs, and the ability to determine the content of fillers, resistant to high temperatures;

the possibility for more precise control of the homogeneity of the polymer composite;

- the measurement of the mass percentage of filler is not more than±2% from the content of the filler.

Literature

1. INTERNATIONAL STAND ART ISO 11358-97. Plastics - Thermogravimetry (TG) of polymers - General principles.

2. Functional fillers for plastics / edited McIntosh. TRANS. from English. edited Selezneva NR. - SPb.: "Scientific fundamentals and technology", 2010.

3. Chemical encyclopedia / edited Wailotua, Vaganova and others - M.: "Great Russian encyclopedia", 1992.

The method of determining the content of the filler in polymer composite comprising a polymer binder and filler, comprising heating the sample to a temperature of decomposition of the polymeric binder and the calculation of the content of the filler to change the mass of the sample, determined by thermogravimetric curve, while the temperature range in which there is a change in weight due to decomposition of the binder is determined by the differential thermogravimetric curve, wherein the pre-determined mass of ash residue when is otlozhenii pure polymeric binder in the conditions, identical to the decomposition of the composite, and the calculation of the content of the filler is carried out taking into account the mass of bottom ash by the formula:
xn=β-α1-α100%,
where β is the ratio of the mass of the residue to the initial mass of the sample composite;
α - content of the ash residue after decomposition of the polymeric binder without filler.



 

Same patents:

FIELD: measurement equipment.

SUBSTANCE: method to display a temperature field of an object includes measurement of temperature in different points of its surface. Previously an object image is introduced into a computer base, and the image is displayed onto the screen, the points of temperature measurement on the surface of the object are displayed on the object image on the monitor screen, and after performance of measurements and treatment of results of measurements in the computer the image of the temperature field of the object is formed on its image with software.

EFFECT: simplified design of technical facilities used to vary temperature field of an object.

6 cl, 1 dwg

FIELD: measurement equipment.

SUBSTANCE: in the method to measure relative air humidity based on measurement of difference of oscillation frequencies of resonators - a working and a reference ones with subsequent amplification of an analytic signal and regeneration of film coatings with an inert gas, three piezoquartz resonators are used with internal oscillation frequencies of 13-16 MHz, two of which are working ones with different hydrophilic coatings, properties of which are optimised for operation in a certain range of temperatures, and one is a reference resonator without a film coating, which supports the permanent frequency of oscillations, at the same time the device is equipped with a switch of working resonators.

EFFECT: measurement of relative air humidity in a wide range of temperatures, also in the negative range, higher accuracy of measurements, reduced time of regeneration of film coatings of resonator electrodes.

2 dwg

FIELD: testing equipment.

SUBSTANCE: invention is used for testing of aircraft (AC) thermal protection to determine its thermal properties and serviceability. The proposed device comprises a heat vacuum chamber with a metering module placed in it, in which there is a high-temperature heater installed, being located between two tested fragments of thermal protection, behind which there are two calorimeters with thermocouples and security heat insulation, and an automated heating and measurement control system. Calorimeters are installed relative to tested fragments of thermal protection with a gap, and heat control coatings are applied onto opposite surfaces of the fragment and the calorimeter. Calorimeters are divided into sections. The automatic system is equipped with a block for control of gas pressure in the heat vacuum chamber and in the metering module.

EFFECT: higher accuracy of test results due to approximation of AC thermal protection testing conditions to conditions on location.

1 dwg

FIELD: fire-prevention facilities.

SUBSTANCE: in implementation of the method a check of individual values of quality of wood construction elements is carried out, then the dangerous sections are revealed, breed and type of wood, the value of its auto-ignition temperature, the type of rolling wood covering and ignitability values of its elements are revealed, the thickness and values of thermal diffusion of fire-retardant layer material for wood of the covering boarding is identified, and using the obtained values of quality of the elements, according to analytical expression, the fire resistance limit of wood covering of the building is revealed.

EFFECT: elimination of fire tests of wooden structures in the building, reduction of labour intensity in determining the fire resistance of wood covering with the structural fire protection, expanding the technological capabilities of determining the actual fire resistance of differently engineered wood coverings, the ability of the testing the wooden structures for fire resistance without violation of functional process in the building, improving the accuracy and expressiveness of testing.

9 cl, 7 dwg

FIELD: measurement equipment.

SUBSTANCE: method is proposed to determine specific volume burning heat (VBH) of combustible gas in a bomb calorimeter, including preliminary measurement of the calorimetric bomb measurement with the error higher than the required error of specific VBH determination, preliminary determination of an energy equivalent of the calorimeter, filling of the calorimetric bomb with analysed gas in working condition and then with compressed oxygen. When the bomb is filled with a calibrating and analysed gas, final pressure of gas in the bomb and bomb casing temperature are measured. The energy equivalent and specific VBH of analysed gas are calculated with account of water evaporation into the bomb volume. Also a device is proposed for filling of the calorimetric bomb with combustible gas, which additionally contains a vessel with a mixed fluid, having a thermometer for measurement of temperature of a fluid, in which the calorimetric bomb is installed.

EFFECT: improved accuracy of measurements.

3 cl, 1 dwg

FIELD: testing equipment.

SUBSTANCE: sample of a lubricant material of permanent volume is heated with mixing in presence of air, measured, and the light flux absorption coefficient is determined. At the same time, at first each sample of the lubricant material is pre-heated for a continuous period of time at atmospheric pressure and fixed temperature, which in process of each subsequent test of a new sample is increased, and after each heating a sample of a lubricant material is taken with permanent mass, which is then heated with mixing in presence of air within the time established depending on the base under permanent temperature and permanent speed of mixing, which after oxidation is measured, the light flux absorption coefficient is determined. Then the graphical curve is built for dependence of the light flux absorption coefficient on heating temperature. Thermal-oxidative stability of the lubricant material is defined by heating temperature with least value of the light flux absorption coefficient.

EFFECT: higher accuracy of determination of thermal-oxidative stability of lubricant materials.

1 dwg

FIELD: machine building.

SUBSTANCE: proposed method comprises heating the part to temperature whereat pressure of released gas expanding under the coating exceeds yield point of coating material to define gas content in part surface from relative area of coating swell.

EFFECT: faster, simpler and cheaper procedure.

1 ex

FIELD: machine building.

SUBSTANCE: proposed method comprises heating the part to temperature whereat pressure of released gas expanding under the coating exceeds yield point of coating material to define gas content in part surface from relative area of coating swell.

EFFECT: faster, simpler and cheaper procedure.

1 ex

FIELD: heating.

SUBSTANCE: on both sides of the building structure there installed opposite each other are flat heat insulated boxes with flat thermostats having linear sizes of three to five thicknesses of the building structure, which are located at the specified distance parallel to its surfaces and heating them to unequal temperatures between each other; density of heat flow passing through the building structure, as well as temperatures on both surfaces of the building structure, are measured at the specified time interval, differing by the fact that there controlled is resistance to heat transfer in relation to temperature difference of thermostats to density of heat flow after the specified heat release of surfaces of the enclosing structure is determined by adjustment of speed of air flows inside boxes.

EFFECT: providing the possibility of controlling resistance to heat transfer under conditions of equality to normalised values of heat transfer coefficients of surfaces of the tested building structure.

1 dwg

FIELD: measurement equipment.

SUBSTANCE: portion of controlled fluid is supplied to reservoir 1 through flow control 10 and inlet nozzle 2, which is heated by vapour generation of non-dissolved water. Acoustic waves occur at breakage of the cover with vapour, which are converted by means of acoustic receiver 5 to electric signals, which are supplied through amplifier 7 and counter 8 to indicator 11. Timer 9 controls counter 8 and flow control 10. Reservoir 1 is closed with cover plate 4, inside which cone insert 6 is located.

EFFECT: simpler design and higher measurement accuracy.

2 cl, 1 dwg

FIELD: building, particularly for investigating or analyzing materials.

SUBSTANCE: method involves performing adiabatic thermal action on surface of outer structure layer with the use of disc heater arranged in plane of test probe surrounded by protective heat-insulation ring; recording time dependence of investigated material surface temperature; arranging heat flow sensor on contact surface of the second probe instead of disc heater; installing two linear heaters at a distance from disc heater of the first probe and two linear heaters at a distance from heat flow sensor of the second probe; arranging thermoelectric batteries at fixed distance from linear heaters along line parallel to line of heaters location; applying single heat impulse from linear heat sources to outer structure layers to determine heat and physical properties thereof; determining time of temperature field relaxation in controlled points; performing action of heat pulses in both probes from linear heat sources; changing heat pulse frequency up to obtain temperature in points spaced the same distances from linear heaters equal to two pre-determined values along with determining frequencies of heat pulses for the first and the second outer layers correspondingly; determining heat and physical properties of outer structure layers with the use of above information and obtained mathematical relations; performing heat action on inner structure layer with the use of disc heater of the first probe to define heat and physical properties of inner layer; recording heat flux value by sensor arranged on contact surface of the second probe; measuring temperature in points located correspondingly under disc heater and on contact surface of heat flux sensor with the use of pre-measured temperatures in above points, pre-measured value of heat flux passing through structure layers and previously obtained values of heat and physical properties of outer structure layers; determining heat and physical properties of inner structure layer on the base of mathematical relations describing temperature drop in each of three layers.

EFFECT: increased accuracy of heat and physical properties determination in multi-layer articles.

2 dwg

FIELD: oil and gas extractive industry.

SUBSTANCE: method includes measuring in given sequence of appropriate parameters with following calculation of determined characteristics on basis of certain relation. Device for determining characteristics for sublimation of liquid oil products contains sublimation retort with dimensions, allowing to place 5-15 ml of analyzed probe therein, device for heating retort in its lower portion with constant and adjusted heating intensiveness, two inertia-less temperature sensors providing for continuous measurement of true value of temperature of sample in steam couple, device for continuous pressure measurement in stem phase of sample during sublimation, which includes pressure sensor as well as capillary and receiving and signals processing sensors, sent by temperature sensors and pressure sensor.

EFFECT: simplified construction, higher speed of operation.

2 cl, 4 ex, 10 tbl, 5 dwg

FIELD: measurement technology.

SUBSTANCE: working body of indicator is made in form of thin metal membrane which is subject to cooling according to linear law by means of thermo-electric cooler. Direct measurement of temperatures of body and cooler is provided. At the moment of water vapor condensation the speed of cooling of membrane reduces abruptly due to consumption of cold used for cooling of moisture that condenses on surface of membrane turned to atmosphere.

EFFECT: improved precision of indication.

4 dwg

FIELD: thermal physics.

SUBSTANCE: device has heater, movable heat-conductive rod, set of contacts one of which is connected with rod and the other one is able to move along axis of rod. Device also has temperature pick-up and registrar. Working end of rod sharpened in shape of a cone. Rod is connected with case of heater by spring which allows to regulate force. Temperature pick-up is attached to sharpened end of rod. Heat-insulating cup is located between heater and surface of sample. Melting point can be measured without preparing samples in case when inclination or curvature of surface is presented.

EFFECT: reduced labor input.

1 dwg

FIELD: investigating or analyzing materials.

SUBSTANCE: thermograph comprises differential thermocouple and aluminum thermal unit provided with two symmetrically arranged cylindrical holes for crucible with specimen and standard. The crucibles are made of cylinders with caps provided with copper pipes for hot junctions of Chromel-cupel thermocouples. The wires of the thermocouples are housed in the two-channel ceramic rods. The thermoelectric heating of the unit is provided with the use of temperature-sensitive resistor made of nichrome wire. The unit is mounted in the steel sealed housing with a lid and provided with a device for locking it inside the housing during cooling and heating.

EFFECT: simplified design and enhanced accuracy of measuring.

1 dwg

FIELD: investigating and analyzing of materials.

SUBSTANCE: method comprises heating the outer surface of the metallic layer with a disk heater and recording time dependence of the surface temperature. The heater is housed in the space of the central probe, which allows the heat flux to be directed normally to the surface of the contact of the probe with the article The ring probe is mounted concentrically to the central probe to keep the heat flux constant. To exclude the heat exchange with the ambient air, each probe is enveloped with one concentric guard ring.

EFFECT: enhanced speed of response.

1 dwg

FIELD: measurement technology; material quality control.

SUBSTANCE: method involves testing lubricant material sample in presence of air with stirring constant volume under optimum temperature selected with its dependence on lubricant base and a group of operational properties during a time interval characterizing equal oxidation degree taken into account. Acting in equal time intervals, absorption coefficient is measured for luminous flow absorbed by oxidized lubricant material by applying photometry methods. Viscosity and thermal oxidative stability coefficient Ktos are calculated by using relationship like Ktos = Ka μ0in, where Ka is the luminous flow absorption coefficient of oxidized lubricant material; μ0 and μin are the viscosities of oxidized and initial state lubricant, respectively. Graphic dependence of thermal oxidative stability coefficient against luminous flow absorption coefficient of oxidized lubricant material is plotted. Rate of oxidation end products release and their influence upon tested lubricant viscosity growth is determined from plot slope angle tangent with respect to abscissa axis after inflection point. The inflection point coordinates are used for determining the starting point the oxidation end products release begins.

EFFECT: high reliability of estimation method.

4 dwg

FIELD: measurement technology; material control.

SUBSTANCE: device has cool and hoot electrode, relay for supplying lowered voltage to heating element, thermocouple mounted on hot electrode and connected to it via variable resistor, galvanometer, potentiometer, transformer, unit for analyzing data and mechanism for positioning cutting tool. The mechanism has two mutually perpendicular carriages of longitudinal and transverse movement and is mounted on plate having mechanism for moving a movable throw-back cantilever having built-in hot electrode.

EFFECT: high accuracy in predicting metal-cutting instrument operation capacity.

1 dwg

FIELD: measurement technology.

SUBSTANCE: device has two units. The first one combines mechanical units and has casing, connection tube with gas duct. The tube branches into the main one and internal one placed inside, electrically connected to each other. Filter collecting moisture is mounted on entry to the internal tube. The third tube having entry closed from the gas flow side is formed above the internal tube surface. The fourth tube is located in the third tube. The fourth and the third tube go out from the main one. The fourth one is connected to pump which outlet is separately connected to cooler and heater. Dielectric layers cover external surface of the third tube and internal surface of the fourth one. Its dielectric properties depend on moisture amount. The dielectric layers are covered with reticular electrodes bearing temperature gages attached to them. The second unit is electric circuit for shaping, processing and recording electric signal. It has generator, bridge circuit, differential amplifier, recorder and two-channeled amplifier.

EFFECT: high accuracy in concurrently measuring humidity and temperature.

2 dwg

FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises determining the values of the inform-parameter for various reference petrols, plotting calibration dependence of the inform-parameter on the octane number, determining the value of the inform-parameter of a sample of petrol to be analyzed, determining octane number of the petrol to be analyzed from the calibration curve, and measuring density and temperature of the sample. The value of the inform-parameter is determined from measuring the surface tension of the sample. The octane number is calculated within temperature range 10-40oC.

EFFECT: enhanced accuracy of determining.

1 tbl cl, dwg

Up!