GB2075674A - Method and apparatus for the calorimetric study of composite materials - Google Patents

Method and apparatus for the calorimetric study of composite materials Download PDF

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Publication number
GB2075674A
GB2075674A GB8010025A GB8010025A GB2075674A GB 2075674 A GB2075674 A GB 2075674A GB 8010025 A GB8010025 A GB 8010025A GB 8010025 A GB8010025 A GB 8010025A GB 2075674 A GB2075674 A GB 2075674A
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flux
composite material
component
temperature
heat flux
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INST CERCETARI CHIM
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INST CERCETARI CHIM
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Priority to GB8010025A priority Critical patent/GB2075674A/en
Priority to GB8109401A priority patent/GB2075675A/en
Publication of GB2075674A publication Critical patent/GB2075674A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
    • G01N25/4846—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation for a motionless, e.g. solid sample
    • G01N25/4866—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation for a motionless, e.g. solid sample by using a differential method
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
    • G01N25/4806—Details not adapted to a particular type of sample
    • G01N25/4826—Details not adapted to a particular type of sample concerning the heating or cooling arrangements
    • G01N25/4833—Details not adapted to a particular type of sample concerning the heating or cooling arrangements specially adapted for temperature scanning

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)

Abstract

A composite material (e.g. a crystalline metal, alloy, organic or inorganic) and a reference sample are incrementally heated in a DTA device (1). A signal indicating the temperature difference between the reference sample and the composite material is converted into to the total heat flux for the transformation process by means of a converter (3) and from this flux and heat flux absorbed or lost by the inert component of the composite material is obtained and compared. A subroutine (5) gives the difference between the total flux and the flux of the inert component; a chronometer (8) measures the time periods from the moment of application of heat to the moments corresponding to the maxima of the absolute values of the total flux, and the flux of the transformation component; two subroutines (6, 7) integrate the total flux and that of the transformation component, against their respective baselines; and a data recorder (9) records the temperatures before and after increments, the total flux, the flux of the transforming component, the time periods, the integrated values of these two fluxes and the calibrated value of the inert component. <IMAGE>

Description

SPECIFICATION Method and apparatus for the calorimetric study of composite materials This invention relates to a method and a device for the calorimetric study of the composite materials used for the rapid evaluation and evidentiating of the correlation existing between the processing conditions and the operating properties of an end product.
There are several known rapid methods for the study of the composite materials which are based on the electronic microscopy or on the correlation between the composition and the fracture mechanism realized under terminal conditions.
The disadvantages of these methods arise from the fact that the informations on the operating behaviour of the end product are rather approximate. There are also isothermal methods, nonisothermal methods and adiabetic methods. The isothermal methods require a certain constant temperature of the composite material to be investigated and evaluates the thermal flux of the conversion processes within the respective material; the nonisothermal methods require a linear increase or decrease of the composite material temperature and the evaluation of the flux in the respective temperature range while the adiabatic methods stipulate the transfer of a quantity of thermal energy to the composite material followed by the measuring of its temperature change.
The common disavantages of the above mentioned calorimetric methods arise from the fact that they allow only the overall evaluation of the thermal effects and of other cinetic parameters characterising the conversion processes within the composite materials without separating the effects due to the coupling of the components.
In the present invention the disadvantages present in the prior known methods have been overcome by the fact that in order to study the conversion processes of a composite material due to a temperature step change it uses the thermal flux separation of the inert component from the overall thermal flux thus resulteing the caloric flux of the component during the conversion, flux representing the coupling of the two components and the apparatus of this invention is made of a basic device of a differential thermal analyser in which we introduce in thermally separated enclosures a sample of composite material and a sample of an inert reference material, device connected to a temperature programmer, two calibration and comparison subroutines, two integration subroutines, a chronometer and a data recording-displaying device.
In this invention an example with unlimited application character is presented with reference to the figure, presenting the block diagram of the apparatus.
In accordance with the application example of the invention a composite material made of two components C1 and C2 dissipatively coupled is considered. The method of the invention comprises the study of the conversion process of the composite material by the separation of the thermal flux W2(t) of the component C2 from the thermal flux W1(t) of the inert component C1 of the purely dissipated flux of the overall material.
In this way the nature of the coupling between the components of a composite material can be studied for one or a sequence of such temperature steps. The apparatus is made of a basic device 1 of a differential thermal analyser in which we introduce in respective thermally separated enclosures a Cp sample and a CR sample from a reference material considered as inert within the temperature range applied, a temperature programmer 2 attached to the device 1 which performs several temperature steps of heating or cooling which can be adjusted so that the samples Cp, CR are transferred from an initial temperature T; to a final one Tf by means of a transfer function R0 after which the temperature difference of the samples is transformed into thermal flux through a differential temperature-flux convertor, 3.
The totally dissipated thermal flux W(t) is introduced into the calibration subroutine 4 and into a comparison subroutine 5 in which the separation of the thermal flux W1(t) due to the inert component C, from the totally dissipated thermal flux W(t) is performed, W2(t) = W(t) - W1(t) respectively.
The above mentioned apparatus has two subroutines, 6 and 7, for the integration of the fluxes W(t) and W2(t) in the time interval t1, t2 and t3, t4 respectively, measured by means of a chronometer 8 with a view to obtain the respective energies, E1, E2 and E, as well as E0, corresponding to the inert component from the investigated material.
The results of the measurements are introduced in a recording-displaying device 9, in order to analyse the data which represent the cinetic values of the energetic circuit of the components within the calorimetric method.
In the case of the purely dissipative coupling between the components C1 and C2 of a certain composite material, the equation in (tm T) = - E/(R T) + 1 n (ERoCo/R) can be used for discussing the data, where E denotes the activation energy of the transformation process, R -the gas constant, trn -the period of time between the moment 0 and the maximum moment of the thermal flux W2(t),Ro denotes the transfer function while CO is a parameter of the reference sample.
The advantages of the application of the method and apparatus of this invention reside in the rapidity and precision of the determinations.
The invention is thus concerned with a method for the caiorimetric study of a composite material characterized by the fact that in order to study the conversion of the composite material due to a temperature change, it separates the thermal flux of the inert component from the overall thermal flux thus giving the thermal flux of the transforming component containing also the coupling of the two components.In order to determine the initial and the final temperature, To and Tf, respectively, of the composite system subjected to temperature change, the periods of time t1, t2 and t3, t4 from the moment of applying this step to the moments of thermal fluxes delimitation W and W2, respectively, of the maximum moment of the flux of the component subjected to the change, trn, and of the inert component energies E0, of the overall flux E and of the transforming component E2, use is made of a basic device 1 (a differential thermal device) in which is introduced into thermally separated enclosures a sample of a reference material CR and a sample of the composite material Cp, a temperature programmer 2 which accomplishes temperature changes so that the temperature of the CR and Cp samples can be used and modified by means of a transfer function R0 from an initial value Tj to the final value Tf, a converter 3 which converts the temperature difference between cells into thermal flux W, a calibration subroutine 4 and a comparison subroutine 5 for the total flux and the inert component, two subroutines 6 and 7 for integration of the total flux and the changing component, a chronometer 8 and a data recording-displaying device 9.

Claims (5)

1. A method for thermal analysis of a composite material, which method comprises heating or cooling a test sample of composite material and a sample of reference material under the same conditions, the heating or cooling being such that a component of the test sample undergoes transformation while another component thereof remains unchanged, monitoring temperature difference between the test and reference samples, obtaining from the monitored temperature difference the total heat flux in the composite material, and obtaining from this heat flux that due to the transforming component.
2. A method of calorimetric study of composite materials in which a composite material is subjected to an incremental or decremental temperature variation of a previously established value, and the total heat flux absorbed or released by the composite material during this variation is separated from the flux absorbed or released by an inert component of the composite material to obtain the heat flux absorbed or released by a transforming component of the composite material.
3. Apparatus for the calorimetric study of composite materials comprising: (a) a basic DTA device whose temperature is adjusted by means of a programmer which brings about incremental or decremental changes with a varying pre-established amplitude when the difference of temperature between a reference and composite materials in the DTA device, measured at a certain sensitivity, is at a baseline; (b) a temperature detector that measures the temperature variations in the DTA furnace; (c) a converter that continuously converts the signal indicating the temperature difference between the reference and composite material into a total heat flux for the transformation process occuring in the composite material when it is submitted to an incremental or decremental temperature variation;; (d) a subroutine that calibrates the heat flux absorbed or released by an inert component of the composite material, when the variation of temperature occurs, by amplifying or attenuating the heat flux of a known standard material by a factor equal to the ratio of the first peak above the baseline of the total heat flux of the composite material, to the height of the first peak above the baseline corresponding to the total flux or the flux of the inert component of the standard material, both materials being subjected to the same incremental or decremental temperature variation by the same DTA device; (e) a subroutine that continuously gives the difference between the total heat flux and the calibrated heat of flux of the inert component to obtain the heat flux of a transforming component of the composite material;; (f) two subroutines for integration of the total heat fluxes absorbed or released by the composite material and the transforming component, respectively, the integration taking place against the corresponding baselines of the two fluxes and starting from the moment when the incremental or decremental variation of temperature is applied, and ending when the two fluxes vanish, respectively; (g) a chronometer that measures the time periods from the moment of applying the incremental or decremental temperature variant tion in the basic DTA device to the moments corresponding to the maximum of the absolute values of the total heat flux and the flux of the transforming component, respectively; and (h) a display to record the variations with respect to time of the following parameters: the total heat flux obtained by (c) above, the flux of the transforming component obtained by (e) above, the temperature variation of the DTA furnace measured by the detector (b) above, the calibrated value of the inert component of the composite material obtain by (d) above, the integrated values of the total flux of the transforming component resulting from the subroutines (f) above, and the periods of time obtained by (g) above.
4. A method of calorimetric study of composite materials, the method being substantially as hereinbefore described.
5. Apparatus for the calorimetric study of composite materials, the apparatus being substantially as hereinbefore described.
GB8010025A 1980-03-25 1980-03-25 Method and apparatus for the calorimetric study of composite materials Withdrawn GB2075674A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB8010025A GB2075674A (en) 1980-03-25 1980-03-25 Method and apparatus for the calorimetric study of composite materials
GB8109401A GB2075675A (en) 1980-03-25 1981-03-25 Method and apparatus for the calorimetric study of composite materials

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Application Number Priority Date Filing Date Title
GB8010025A GB2075674A (en) 1980-03-25 1980-03-25 Method and apparatus for the calorimetric study of composite materials

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0695938A1 (en) * 1994-08-03 1996-02-07 Hispano-Suiza Procedure for determing the percentage constituent of a material composed of at least two distinct constituents
CN106324026A (en) * 2016-09-29 2017-01-11 奈申（上海）智能科技有限公司 Device for measuring electric card performance by direct method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0695938A1 (en) * 1994-08-03 1996-02-07 Hispano-Suiza Procedure for determing the percentage constituent of a material composed of at least two distinct constituents
FR2723445A1 (en) * 1994-08-03 1996-02-09 Hispano Suiza Sa METHOD FOR DETERMINING THE PERCENTAGE OF A CONSTITUENT OF A MATERIAL COMPRISING AT LEAST TWO DISTINCT CONSTITUENTS
CN106324026A (en) * 2016-09-29 2017-01-11 奈申（上海）智能科技有限公司 Device for measuring electric card performance by direct method

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