Measuring arrangement and method for a thermal analysis of a sample
11237123 · 2022-02-01
Assignee
Inventors
Cpc classification
International classification
Abstract
A measuring arrangement for a thermal analysis of a sample, having a crucible for storing a sample in the crucible, as well as a sensor for measuring a sample temperature of the sample when the crucible is arranged on the sensor. To reduce the risk of damages to or even the destruction of used components as a result of chemical or physical reactions, it is provided according to the invention that the measuring arrangement further has a washer arrangement, which is inserted between the crucible and the sensor and which has a first layer, which contacts the crucible, of a first material and a second layer, which contacts the sensor, of a second material, which differs from the first material. The invention further includes a method for the thermal analysis of a sample, which is performed by using such a measuring arrangement.
Claims
1. A measuring arrangement for a thermal analysis of a sample, having: a crucible for storing a sample in the crucible, a sensor for measuring a sample temperature of the sample when the crucible is arranged on the sensor, a washer arrangement inserted between the crucible and the sensor, the washer arrangement having a first layer, which contacts the crucible, of a first material and a second layer, which contacts the sensor, of a second material, wherein the second material differs from the first material.
2. The measuring arrangement according to claim 1, wherein the washer arrangement has a first washer forming the first layer and, separately therefrom, a second washer forming the second layer.
3. The measuring arrangement according to claim 2, wherein a lateral expansion of the first layer is smaller than a lateral expansion of the second layer in the washer arrangement.
4. The measuring arrangement according to claim 2, wherein the first layer is embedded on a top side of the second layer in the washer arrangement.
5. The measuring arrangement according to claim 2, wherein the first layer protrudes beyond the second layer towards the top in the washer arrangement.
6. The measuring arrangement according to claim 2, wherein a top side of the sensor has a sensor edge protruding upwards or a different edge limitation and a centering of the washer arrangement on the sensor is thereby realized by means of positive connection.
7. The measuring arrangement according to claim 2, wherein the first material or the second material is a metal or a metal alloy.
8. The measuring arrangement according to claim 2, wherein the second material or the first material is a ceramic material, in particular a ceramic material on the basis of Al.sub.2O.sub.3 or Y.sub.2O.sub.3.
9. The measuring arrangement according to claim 1, wherein the washer arrangement is a composite washer, which includes the first layer and the second layer so as to be connected to one another.
10. The measuring arrangement according to claim 1, wherein a lateral expansion of the first layer is smaller than a lateral expansion of the second layer in the washer arrangement.
11. The measuring arrangement according to claim 1, wherein the first layer is embedded on a top side of the second layer in the washer arrangement.
12. The measuring arrangement according to claim 1, wherein the first layer protrudes beyond the second layer towards the top in the washer arrangement.
13. The measuring arrangement according to claim 1, wherein a top side of the sensor has a sensor edge protruding upwards or a different edge limitation and a centering of the washer arrangement on the sensor is thereby realized by means of positive connection.
14. The measuring arrangement according to claim 1, wherein the first material or the second material is a metal or a metal alloy.
15. The measuring arrangement according to claim 14, wherein the first material or the second material is tungsten or a tungsten alloy.
16. The measuring arrangement according to claim 1, wherein the second material or the first material is a ceramic material, in particular a ceramic material on the basis of Al.sub.2O.sub.3 or Y.sub.2O.sub.3.
17. A method for the thermal analysis of a sample, comprising: temperature-controlling a sample arranged in a sample chamber according to a temperature program, in the course of which a chamber temperature in the interior of the sample chamber is changed, using a measuring arrangement having: a crucible for storing a sample in the crucible, a sensor for measuring a sample temperature of the sample when the crucible is arranged on the sensor, a washer arrangement inserted between the crucible and the sensor, the washer arrangement having a first layer, which contacts the crucible, of a first material and a second layer, which contacts the sensor, of a second material, wherein the second material differs from the first material; and measuring a sample temperature of the sample in the course of the temperature program.
18. The method according to claim 17, wherein the chamber temperature has a maximum value of at least 500° C. in the course of the temperature program.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will be further described below by means of exemplary embodiments with reference to the enclosed drawings. In each case schematically:
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DETAILED DESCRIPTION
(14)
(15) The crucible 10 is made of a crucible material, such as typically, e.g., graphite or metal and has a circular cylindrical form in the illustrated exemplary embodiment comprising a circular disk-shaped bottom 12, to the edge of which a cylindrical jacket 14 protruding upwards is attached.
(16) Terms, such as “top” or “top side”, respectively, “bottom” or “bottom side”, respectively, “laterally”, etc., used here in each case refer to the arrangement of the respective component in the situation of use (in response to performing the thermal analysis).
(17) The crucible 10 can (optionally) further have a cover 16, which is illustrated in a dashed manner in
(18) In the situation of use of the measuring arrangement, the sensor 20 is used in order to be able to arrange a crucible, such as, e.g., the illustrated crucible 10, thereon and to thus arrange the crucible together with sample P, which may be included (including “reference sample”) in a sample chamber in a defined manner, and to measure a temperature on the bottom side of the crucible 10 or thus the sample temperature (in the case of the crucible 10 containing the sample P), respectively. The latter requires a more or less low heat transfer resistance emanating from the sample P, further across the bottom 12 of the crucible 10 to the actual temperature measuring device (e.g., thermal element) on the surface or in the interior of the sensor 20.
(19) In the illustrated exemplary embodiment, the sensor 20 has the form of a circular even disk of uniform thickness, so that a good thermal contact between sample P and sensor 20 results in interaction with the bottom 12 of the crucible 10, which is also circular disk-shaped.
(20) Deviating from the illustrated complete abutment of the bottom 12 on the top side of the sensor 20, a different thermal contacting, however, could also be provided, for example along a ring-shaped contact surface between the bottom 12 and the sensor 20, e.g., in that the bottom 12 as a whole or at least on its bottom side is provided with a recess or a curvature.
(21) In the illustrated example, a lateral expansion of the sensor 20, measured as the diameter of the circular disk form, is at least as large as or, as illustrated, even larger than a corresponding lateral expansion of the crucible 10 in the area of the bottom 12 thereof.
(22) All of the features of the crucible 10 and of the sensor 20 described above with regard to the exemplary embodiment of
(23) In particular, e.g., the risk of damage or even a destruction of the sensor 20 by means of chemical and/or physical reactions on the contact surface existing between the crucible material and the sensor material is disadvantageous in the case of the known measuring arrangement illustrated in
(24) It is to further be considered to be disadvantageous that there is no well-defined arrangement position of the crucible 10 on the sensor 20 in the case of the measuring arrangement of
(25)
(26) In the following description of the exemplary embodiments according to
(27)
(28) With regard to the configuration of such an inner crucible, it is preferably adapted to the configuration of the crucible 10, as in the case of the illustrated inner crucible 18, for an abutment (of the outer side of the inner crucible 18 on the inner side of the crucible 10), which is as well-defined as possible and/or as complete as possible. Similar to the crucible 10, the illustrated inner crucible 18 has a circular disk-shaped bottom and a cylindrical jacket attached thereto so as to protrude upwards, wherein the bottom as well as the jacket each abut completely on the respective inner side of the bottom or of the jacket of the crucible 10, respectively, in the illustrated example.
(29) This modification has the advantage, e.g., that a larger freedom is created in response to the selection of the crucible material of the crucible 10.
(30) A second modification lies in that the measuring arrangement further has a washer 30-1, which is inserted between the crucible 10 and the sensor 20 and which has a top side contacting the crucible 10 on the bottom 12 thereof and a bottom side contacting the sensor 20 on the top side thereof.
(31) This modification has the advantage, e.g., that a larger freedom is created thereby in response to the selection of the crucible material and of the sensor material.
(32) In the illustrated example, the washer 30-1 is made of a ceramic material. A diffusion welding and a chemical reaction between the crucible material and the sensor material of the sensor (which is generally very “valuable”) is prevented by means of the washer 30-1, which is highly advantageous in particular in situations of use with relatively high temperatures occurring thereby.
(33) The examples according to
(34) To avoid this disadvantage, embodiments can be considered, which are shown in an exemplary manner in
(35)
(36) Deviating from the embodiment according to
(37) Deviating from the illustrated example, the positive connection can also be realized by means of a different edge limitation instead of by means of the sensor edge 22, which is to be understood to be a component of the measuring arrangement, which is arranged to be stationary with regard to the sensor 20 in such a way that said measuring arrangement represents a limitation for the crucible 10, viewed in the lateral direction, with regard to the arrangeability thereof on the sensor 20.
(38)
(39) It is disadvantageous however that, in practice, not all desired sensor-crucible-sample-material combinations can be accomplished with the help of an inner crucible 18 and/or a washer 30-1 with regard to unwanted reactions between sensor and crucible as well as between crucible and sample. For example, some samples have to be arranged in a crucible 10 made of graphite, whereby reactions with the sensor 20 can occur at high temperatures. A ceramic washer 30-1 does not reliably resolve this issue, because it can react with the graphite crucible at high temperatures.
(40) To avoid this problem, embodiments can be provided, which will be described below in an exemplary manner with reference to
(41)
(42) The washer arrangement 30 can thereby have a first washer forming the first layer 30-1 and, separately therefrom, a second washer forming the second layer 30-2.
(43) This alternative can also be viewed as modification of the example of
(44) In the case of this alternative, it can be provided, in particular in the case of graphite as crucible material, that the first washer or first layer 30-1, respectively, is made of a metallic material (e.g., tungsten or, e.g., tungsten alloy) and the second washer or second layer 30-2, respectively, is made of a ceramic material.
(45) Deviating therefrom, an alternative is also possible in
(46) This alternative is well suited, e.g., for the case that the first material and the second material can be welded to one another, thus, e.g., that a suitable combination of two metals or metal alloys, respectively, is selected for this purpose.
(47) The layers of the composite washer, which are connected to one another, can also be embodied in such a way, e.g., that the one layer is embodied as a sputter layer on the other layer.
(48) In the example of
(49) In the example of
(50) In order to in particular prevent a shifting or an incorrect positioning, respectively, of the top layer 30-1 even in the case of a separate design of the two layers 30-1 and 30-2, or in order to then also realize a centering of the top layer 30-1, respectively, deviating from
(51)
(52) It is thereby provided in the example of
(53) In addition to the embodiment with two washers, which are separate from one another, a composite washer, e.g., in the case of which one is formed by first layer 30-1 and second layer 30-2 by means of sputtering or otherwise coating (e.g., the respective other one of these two layers), can in particular be considered with regard to the washer arrangement (with layers 30-1, 30-2) described in
(54) The stacking of two separate washers 30-1, 30-2 has the advantages that each individual washer can also be used alone (or in combination with a different second washer), depending on the application, and that, in the case of a contamination of one of the washers (in particular, e.g., of the washer 30-1), only the latter needs to be exchanged. In the latter case, the contaminated layer would quasi be a useful layer, which can be replaced easily and cost-efficiently.
(55) The described washer arrangement is in particular advantageous in applications, in the case of which the crucible material is graphite and the sensor material is a metallic material. Deviating therefrom, however, a crucible of metallic material (in particular, e.g., tungsten or tungsten alloy), e.g., can also be provided and/or an additional inner crucible (in particular, e.g., of graphite).
(56)
(57) In contrast to the examples of
(58) It is mentioned in this regard that an “outer crucible” in terms of the invention consists of a base body or comprises a base body, also referred to as “outer crucible body” hereinbelow, which has at least approximately the shape of a shell or of a cup, wherein with regard to the intended use (storage of the crucible), the outer crucible body has at least one section, which can be referred to as (outer crucible) “jacket”, which represents a lateral limitation of the outer crucible body, and which can optionally have a section, which is to be referred to as (outer crucible) “bottom”, which represents a lower end section of the outer crucible body facing the sensor (in the situation of use) and which is connected on the bottom side of the jacket. An interior of the outer crucible, which is limited by the jacket (and the bottom, which may be present), on the inner side of the jacket, is to be dimensioned in such a way thereby that the crucible of the measuring arrangement can be stored therein.
(59) In the case of the exemplary embodiment of
(60) In the illustrated example, the bottom of the outer crucible 30-1 abuts completely on a bottom 12 of the crucible 10. In the alternative, however, it could also be provided, e.g., that the bottom of the outer crucible 30-1 abuts on the bottom 12 of the crucible 10 along a rings-shaped contact surface.
(61) This can be realized, e.g., in that, deviating from the example according to
(62) It is important to note in this context that the outer crucible, deviating from the example according to
(63) Returning to the example of
(64) Such a complete abutment between the jacket of the crucible and the jacket of the outer crucible can (contrary to
(65) In the case of such embodiments, a design can advantageously also be provided, which is also realized in the case of the example of
(66) In the case of the shown example of
(67) Under the exemplary assumption that the crucible 10 as well as the sensor 20 are each made of a metallic material, in particular ceramic material, e.g., is suitable as outer crucible material. The outer crucible 30-1 quasi takes over the role of the washer 30-1 shown in
(68)
(69) As compared to the embodiment according to
(70) According to an alternative approach, the example of
(71) With regard to this alternative approach, it is further noted that, deviating from the example according to
(72) In the case of the measuring arrangements shown in
(73)
(74) In the case of the example of
(75)
(76) In an alternative approach, the embodiment according to
(77) In the case of the example of
(78) With regard to the outer crucible material, the latter can be suitably selected in an advantageous manner for a corresponding material compatibility with the material of the respective crucible 10 and the material adjoining downwards, e.g., sensor material or possibly material of a washer 30-2 or second layer 30-2, respectively.
(79) In corresponding applications, the outer crucible material of the outer crucible 30-1 can be, e.g., a metal or a metal alloy, in particular, e.g., tungsten or a tungsten alloy.
(80) In other applications, an outer crucible material of the outer crucible 30-1, e.g., can be more advantageous, which is selected as a ceramic material, for example, on the basis of Al.sub.2O.sub.3 or Y.sub.2O.sub.3.
(81) In the case of a measuring arrangement according to the invention, the features and embodiment details of the individual components described above with reference to
(82) The aspect of a centering of the crucible 10, which has already been discussed in the examples according to
(83) To eliminate this problem, a measuring arrangement, in particular, e.g., a measuring arrangement of the type as already described here with regard to
(84)
(85) In this exemplary embodiment, a predetermined rotational position of the crucible 10 with respect to the sensor 20 is ensured by means of a positive engagement of a protrusion 21 with a depression 19, wherein the protrusion 21 in
(86) As an alternative to the shown arrangement of the depression 19 directly on the outer side of the crucible jacket, it can also be considered to arrange the depression 19 at a different location in the area of the outer side of the crucible 10, for example on an outer side of a component surrounding the crucible 10, such as, e.g., of an “outer crucible” of the type, as has already been described above.
(87) Under the assumption that the crucible 10 is not separated from a corresponding outer crucible between different measurements in the context of one or a plurality of thermal analyses, an anti-rotation protection provided directly only for the outer crucible is then synonymous with an anti-rotation protection for the crucible 10.
(88) As an alternative to an outer crucible as attachment location for a depression, which ensures the anti-rotation protection, it could furthermore be considered to arrange such a depression on a component, which is provided specifically for this purpose and which surrounds the respective crucible 10 in a sleeve-like manner.
(89) With regard to the arrangement of the protrusion 21 on the sensor 20 (or on a further components, which is arranged in a stationary manner to the sensor 20), it can in particular be provided that the protrusion 21 is arranged directly on the inner side (inner circumference) of the sensor edge, when a “sensor edge” of the type, as has already been described, which protrudes upwards, on the top side of the sensor 20 is present.
(90)
(91) All of the designs (in particular concrete arrangement locations) described with regard to the depression 19 and the protrusion 21 of
(92) In the case of the examples of
(93) A straight course of the above-mentioned elongated cross sectional surface of the depression (19 or 21′, respectively) and, corresponding thereto, of the protrusion (21 or 19′, respectively), is preferably oriented in the vertical direction of the measuring arrangement.
(94) It is further preferred, as can also be seen in the examples of
(95) Deviating from the example according to
(96) In the alternative or in addition to the design described in the example according to
(97) Such a marking can in particular be embodied, e.g., as a marking protrusion or as a marking depression. The crucibles 10 shown in
(98) The designs of the anti-rotation protection described above with regard to