JP5922561B2 - Conductive paste preparation condition evaluation system - Google Patents

Description

  The present invention relates to a preparation condition evaluation system for conductive paste. More specifically, the present invention relates to a system for evaluating preparation conditions of a conductive paste used to form a conductive material such as an electrode.

  Conventionally, a conductive paste has been widely used as an IC circuit forming material, an electrode forming material, a resistor forming material, a conductive adhesive, an electromagnetic wave shielding material and the like used for manufacturing battery members and electronic devices. By supplying such a conductive paste to the surface of a substrate or the like by a technique such as printing and baking, a conductive film having a predetermined function and characteristics can be obtained. In recent years, along with improvements in performance and quality of battery members and electronic devices, it has been required to strictly control the characteristics such as the electrical conductivity or resistivity of the conductive film obtained after firing for this conductive paste. ing. For example, in the case of a conductive paste for electrode formation, the electrical conductivity of the conductive film obtained by firing is set to a predetermined value for each target product or for each use site of the paste. The electrical conductivity is also required to have an accuracy of about ± 0.01 Ω · cm, for example.

  In general, the conductive paste is prepared by dispersing conductive particles having functions and characteristics according to the purpose in a solvent together with a binder. For example, conductive particles are selected according to desired electrical conductivity or resistivity (hereinafter, unless otherwise specified, “electrical conductivity or resistivity” is simply referred to as “electrical conductivity”). The conductive particles are used alone or in combination of two or more kinds of conductive particles. It is possible to adjust the characteristics such as electrical conductivity of the conductive paste by selecting conductive particles and mixing a binder and a solvent each time. In many cases, a paste having a desired performance is obtained by preparing several kinds of basic conductive pastes with known properties.

  The blending ratio of this basic paste sample (that is, an individual paste-like sample before blending for preparing a desired conductive paste; the same shall apply hereinafter) is usually through, for example, the following procedure. It is determined. That is, first, a plurality of basic paste-like samples are mixed in several combinations and kneaded with a roller to prepare a conductive paste. Next, this conductive paste is printed on a substrate and baked to produce several conductive films. Then, by evaluating the characteristics of the produced conductive film to determine whether it has the desired characteristics, the blending ratio of the paste sample that is the most suitable for realizing the characteristics is determined. Here, the prepared conductive paste may be greatly affected by its characteristics due to slight differences in raw material production conditions and paste production methods. Therefore, the preparation of the blending ratio of the conductive paste as described above is an essential process that is performed once a day, for example. And the determination of the blending ratio of this conductive paste is carried out by almost all steps manually.

Japanese Patent Laid-Open No. 2002-033283 Special table 2003-53370 gazette JP 2001-219052 A JP 2003-083855 A JP 2008-246328 A Patent No. 4009712 JP 2003-215069 A

  By the way, in the field of organic materials represented by pharmaceuticals and the like, combinatorial techniques have been utilized for the purpose of exhaustive search for medicinal ingredients and the like. In recent years, in the fields of inorganic solid materials and metal materials, it has been proposed to use a combinatorial technique as a technique for searching for new materials (see, for example, Patent Documents 1 to 5). By adopting combinatorial methods in the fields of inorganic solid materials and metal materials, it is possible to achieve a comprehensive search in a short time for material compositions that express unique functions from combinations of raw materials in various components and various quantitative ratios. It is said that.

  However, the conductive paste can be a highly viscous suspension having a viscosity of, for example, 10 to 2000 Pa · s at 25 ° C., and the conductive particles contained in the paste are precipitated over time. It has been difficult to automatically perform sampling with few errors because the suspension state cannot be maintained. Therefore, when a paste sample is blended at a ratio different from the target blending ratio, characteristics such as electrical conductivity are measured with respect to the conductive paste whose blending ratio is shifted, and correct evaluation cannot be performed. There was a possibility. On the other hand, in order to automatically perform sampling with few errors, for example, the sampling rate is reduced sufficiently, or the sampling amount is monitored by a plurality of functions such as a weigh scale during sampling, and the sampling amount is corrected on the spot. It was necessary to do so, and even the combinatorial method had to take time.

  On the other hand, the method of determining the basic paste sample mixing ratio by hand requires a long time for the work, and also increases the waste loss because the sample is prepared in a certain amount. There was a problem that should be improved. Another problem is that human error is unavoidable because each work is carried out manually. In order to suppress such an error, it was necessary to perform a longer and careful work. Therefore, since the number of conditions that can be practically evaluated is limited, there is a problem that the range in which the characteristics of the obtained conductive film can be managed becomes relatively rough.

  The present invention was created to solve the above-described conventional problems, and the object of the present invention is to provide a highly reliable combination ratio of two or more types of paste samples using a combinatorial technique. In addition, an object is to provide a preparation condition evaluation system for a conductive paste that can be efficiently performed.

  The conductive paste preparation condition evaluation system disclosed herein (hereinafter sometimes simply referred to as “evaluation system”) is a system for evaluating the preparation conditions of a conductive paste for producing a conductive material. It is. Such an evaluation system uses a blending ratio of two or more types of paste samples for constituting a conductive paste as at least one parameter, and changes the parameters to mix the two or more types of paste samples so as to have different compositions. Combinatorial sample preparation means for preparing a plurality of conductive pastes at predetermined positions on a substrate, firing means for firing the plurality of conductive pastes to form a plurality of fired bodies, and electrical conductivity of the plurality of fired bodies For each of the fired bodies, and for each of the fired bodies, the blending ratio of the two or more types of paste samples is corrected based on the results of the composition analysis. And a means for evaluating the preparation conditions of the conductive paste from the relationship between the blending ratio and the measurement result of the electrical conductivity.

In the above combinatorial sample preparation means, it is possible to prepare conductive pastes of various compositions by changing the blend ratio of the paste sample, which is a constituent material of the conductive paste, as at least one parameter. However, when using a means such as a combinatorial sample preparation apparatus conventionally used for sampling a paste sample, accurate sampling of the paste sample may be difficult. In practice, a conductive paste having the desired composition is obtained. An unforeseen situation can occur. In addition, when the sampling amount is monitored or corrected by a plurality of means in order to increase the accuracy of preparation, the sampling time is lengthened.
On the other hand, according to the preparation condition evaluation system disclosed here, electrical conductivity measurement and composition analysis are performed on the formed fired body (for example, conductive film). Therefore, even if the blending ratio of the fired body is randomly deviated from the set value, the blending ratio can be corrected based on the actual composition. Therefore, the preparation conditions of the conductive paste can be evaluated with high accuracy.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

In a preferred embodiment of the conductive paste preparation condition evaluation system disclosed herein, the paste sample includes conductive particles, a binder, and a solvent, and has a viscosity at 25 ° C. and 10 rpm of 10 Pa · s to 2000 Pa.・ It is characterized by being s.
The composition of the paste sample used to prepare the conductive paste varies, and there are low viscosity to high viscosity. The preparation condition evaluation system disclosed here is preferable because the effect can be clearly obtained by applying it to a paste sample having a relatively high viscosity in the above-described range. The viscosity of the paste sample may be 10 Pa · s or more, depending on the application, for example, 50 Pa · s or more, and further 100 Pa · s or more. The upper limit of the viscosity of the paste sample cannot be generally described because it depends on the performance of the combinatorial sample preparation means to be used, but can be set to about 2000 Pa · s or less as an approximate guide, for example, about 1500 Pa · s or less. Further, it is more preferably 1000 Pa · s or less.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

In a preferred embodiment of the conductive paste preparation condition evaluation system disclosed herein, the combinatorial sample preparation means is configured to be capable of preparing each of the plurality of conductive pastes in an amount of 10 g or less. Yes.
According to such a configuration, even if there is an error or variation in the sampling amount of the paste sample, the blending ratio can be corrected. Therefore, even when the amount of one conductive paste to be prepared is as small as 10 g or less, it is sufficient. The preparation conditions can be evaluated with high accuracy. More specifically, such a conductive paste can be prepared in an amount of 1 g or less, for example. In addition, the conductive paste may be prepared in an amount necessary for testing or analysis without considering the sampling accuracy, and the waste loss of the conductive paste can be reduced.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

In a preferred embodiment of the conductive paste preparation condition evaluation system disclosed herein, the means for measuring the electrical conductivity is configured to be able to simultaneously measure the plurality of fired bodies with a single measurement operation. It is characterized by being.
The means for measuring the electrical conductivity (hereinafter sometimes referred to as the electrical conductivity measuring means) is configured to measure the electrical conductivity so that all the electrical conductivities of the fired bodies placed at predetermined sample positions on the substrate can be measured simultaneously. It has multiple functions for measuring rates. For example, a function of measuring electrical conductivity is provided at a position corresponding to each sample position on the substrate. Thereby, the electrical conductivity of a plurality of fired bodies can be measured instantaneously, and the preparation conditions can be evaluated in a shorter time.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

In a preferred embodiment of the conductive paste preparation condition evaluation system disclosed herein, the means for measuring the electrical conductivity is configured to be able to measure the electrical conductivity of the plurality of fired bodies at a high temperature of 500 ° C. or higher. It is characterized by being. The conductive paste can be used in various temperature ranges such as a low temperature region (for example, about −20 ° C.) to a high temperature region of 500 ° C. or higher depending on the application of the fired body. More specifically, for example, a solid oxide fuel cell (SOFC) has a relatively high operating temperature of about 500 ° C. to 1000 ° C. According to the preparation condition evaluation system having such a configuration, since the electrical conductivity measuring means enables measurement of electrical conductivity at a high temperature of 500 ° C. or higher, for example, the use of the fired body is a component of SOFC, and 500 Even when it is used at a high temperature of ℃ or higher, it is possible to evaluate the characteristics in the usage situation.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

In a preferred embodiment of the conductive paste preparation condition evaluation system disclosed herein, the system further comprises means for measuring the coefficient of thermal expansion of a plurality of fired bodies, and the means for evaluating the preparation condition is the measurement of the coefficient of thermal expansion. It is characterized by being able to evaluate the preparation conditions of the plurality of conductive pastes including the results. The conductive paste is typically used by using a ceramic material, a metal material, or a composite material of these materials as a base material and applying it to form a laminated structure of conductive films. . For example, in manufacturing such a laminated structure, it is important to manage the coefficient of thermal expansion so that deformation such as warpage does not occur. According to such a configuration, for the fired product obtained by firing the conductive paste, the preparation conditions of the conductive paste can be evaluated including the thermal expansion coefficient in addition to the electrical conductivity as described above. Therefore, it is possible to evaluate the preparation conditions of a conductive paste having more desired characteristics and functions.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

  In a preferred aspect of the conductive paste preparation condition evaluation system disclosed herein, the means for measuring the coefficient of thermal expansion has a function of measuring the coefficient of thermal expansion of the fired body in an air atmosphere and a reducing atmosphere. The means for evaluating the preparation conditions is as follows:

で定義される還元膨張率の算出が可能であるとともに、上記還元膨張率を含めて上記複数の導電性ペーストの調製条件を評価可能に構成されていることを特徴とする。
還元膨張率は、上記式（１）で表されるとおり、酸化雰囲気（例えば、大気雰囲気）と還元雰囲気とにおける熱膨張状態の差を、酸化雰囲気における熱膨張状態を基準として表した値である。例えば、ＳＯＦＣは複数の無機固体材料が例えば層状に接合された複雑な構造を有しており、また、動作温度が高いため、起動および停止等の際に温度勾配が生じると熱膨張差により各材料の界面に応力が発生する。また、ＳＯＦＣは、固体電解質膜を挟んでカソードが還元雰囲気、アノードが酸化雰囲気となるため、上記式（１）で示される還元膨張率が大きいと製品に反り等をもたらし得る。そのため、ＳＯＦＣの開発において還元膨張率は無視することのできない特性である。ここに開示される評価システムによると、例えば、ＳＯＦＣ用途の導電性ペースト等のように還元膨張率が重要な評価指標とされる場合にこの還元膨張率を考慮して導電性ペーストの調製条件の評価を行うことができる。なお、還元膨張率は、例えば室温（典型的には２５℃）を基準とすると、室温状態が１で表され、一般的には温度が高くなるほど値が１より大きくなる。かかる還元膨張率は、１に近い値であるか、接合される材料同士で近似した値であることが好ましい。
また、かかる導電性ペーストの調製条件評価システムを用いた導電性ペーストの調製条件の評価方法もが提供される。

It is possible to calculate the reductive expansion coefficient defined by the above, and to be able to evaluate the preparation conditions of the plurality of conductive pastes including the reductive expansion coefficient.
The reductive expansion coefficient is a value representing the difference in thermal expansion state between the oxidizing atmosphere (for example, the air atmosphere) and the reducing atmosphere as represented by the above formula (1) with reference to the thermal expansion state in the oxidizing atmosphere. . For example, SOFC has a complicated structure in which a plurality of inorganic solid materials are joined in layers, for example, and since the operating temperature is high, if a temperature gradient occurs during start-up and stop, etc. Stress is generated at the interface of the material. In addition, since the SOFC has a reducing atmosphere and the anode has an oxidizing atmosphere with the solid electrolyte membrane sandwiched therebetween, the product can be warped if the reduction expansion coefficient represented by the above formula (1) is large. Therefore, the reduction expansion coefficient is a characteristic that cannot be ignored in the development of SOFC. According to the evaluation system disclosed herein, for example, when the reductive expansion coefficient is an important evaluation index, such as a conductive paste for SOFC applications, the conditions for preparing the conductive paste are taken into account. Evaluation can be made. For example, when the room temperature state (typically 25 ° C.) is used as a reference, the reductive expansion coefficient is represented by a room temperature state of 1, and generally increases as the temperature increases. Such a reduction expansion coefficient is preferably a value close to 1 or a value approximated between materials to be joined.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

In a preferred embodiment of the conductive paste preparation condition evaluation system disclosed herein, the means for measuring the coefficient of thermal expansion is capable of controlling the measurement atmosphere, and crystals in a region from at least room temperature to a high temperature of about 1200 ° C. A function having a function capable of structural analysis, and the means for evaluating the preparation condition calculates the reduction expansion coefficient based on a change in lattice constant in a measurement temperature range, and includes the reduction expansion coefficient of the plurality of conductive pastes. It is characterized by being able to evaluate preparation conditions.
In general, the thermal expansion coefficient of an inorganic solid material is measured by a thermomechanical analyzer (TMA) or the like. This measurement method is applied to a very small amount of fired body sample prepared by a combinatorial technique. It is difficult to apply. On the other hand, according to the technique for obtaining the reduction expansion coefficient from the lattice constant obtained by the crystal structure analysis, even a small fired body sample (so-called library-like sample) by the combinatorial technique can be used in an oxidizing atmosphere and a reducing atmosphere. By performing the crystal structure analysis in a predetermined temperature range, it is possible to calculate the reduction expansion coefficient continuously and quickly with high accuracy for a plurality of fired bodies. As such a crystal structure analysis technique, for example, a crystal structure analysis method using an X-ray or a neutron beam is typically known. In the preparation condition evaluation system disclosed here, it is preferable to use a more general-purpose X-ray diffraction analyzer as a function capable of performing the crystal structure analysis.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

In a preferred embodiment of the conductive paste preparation condition evaluation system disclosed herein, the firing means uses a firing temperature as at least one parameter, and the plurality of mixed samples are fired by changing the parameter. The means for evaluating the preparation conditions is configured to include the above parameters as preparation conditions for the two or more types of conductive paste. . According to such a configuration, not only the composition of the fired body sample but also the firing conditions including the firing temperature can be evaluated for the preparation conditions of the conductive paste.
Moreover, the evaluation method of the preparation conditions of the electrically conductive paste using this preparation condition evaluation system of an electrically conductive paste is also provided.

It is the conceptual diagram which showed the structure of the preparation condition evaluation system of the electrically conductive paste which concerns on one Embodiment of this invention. It is the figure which showed an example of the flow at the time of evaluating the preparation conditions of an electrically conductive paste with the preparation condition evaluation system of the electrically conductive paste of this invention. It is the figure which showed an example of the structure of the electrical conductivity measuring apparatus which can be used for the preparation condition evaluation system of the electrically conductive paste of this invention. (A) (b) is the figure which illustrated the structure of the electrical conductivity measurement function with which an electrical conductivity measuring apparatus is equipped.

  Hereinafter, preferred embodiments of the present invention will be described. It should be noted that matters other than matters specifically mentioned in the present specification (for example, characteristics of each element for constructing a conductive paste preparation condition evaluation system) and matters necessary for carrying out the present invention (for example, evaluation) A manufacturing method, an operation method, an operation condition, and the like of each component constituting the apparatus can be grasped as a design matter of a person skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

FIG. 1 conceptually shows the configuration of the conductive paste preparation condition evaluation system disclosed herein. Moreover, FIG. 2 is a figure which showed an example of the flow at the time of evaluating the preparation conditions of an electrically conductive paste by this evaluation system. Hereinafter, the evaluation system disclosed herein will be described in detail along the flow shown in FIG.
The evaluation system 500 generally includes a control unit 100, a sample adjustment unit 200, and a measurement unit 300, and main components of the evaluation system are disposed in each unit. In this example, the control unit 100 includes the evaluation unit 40 together with the input unit 10, the sample preparation unit 200 includes the combinatorial sample preparation unit 20 and the baking unit 22, and the measurement unit 300 measures the electrical conductivity. Means (hereinafter simply referred to as electrical conductivity measuring means) 30 and means for performing composition analysis (hereinafter simply referred to as composition analyzing means) 32 are provided. The evaluation system is not limited to such a configuration. For example, the input unit 10 and the evaluation unit 40 are disposed in the sample preparation unit 200 and the measurement unit 300, respectively, so that data can be transmitted and received between them. Various aspects such as the aspect and the firing unit 22 in the sample preparation unit 200 may play a part of the function of the test / analysis unit in the measurement unit 300 may be considered.

The above evaluation system evaluates the blending ratio of two or more types of paste samples so that the conductive film, which is a fired body obtained by mixing and baking two or more types of paste samples, has a desired function. It is.
The paste sample used here is a paste-like material (including slurry-like and ink-like) that is the basis for constituting the conductive paste, and the desired function can be obtained by mixing this paste sample. And constructing a conductive paste exhibiting properties. The configuration and characteristics of the paste sample are not particularly limited, and for example, can be configured from a part of the configuration of the target conductive paste. Such sample paste basically includes conductive particles, a binder, and a solvent. The configuration of the paste sample will be described below by exemplifying typical examples.

The conductive particles are a substance responsible for the conductivity of a fired body (typically a conductive film) obtained after firing the conductive paste. There is no restriction | limiting in particular about the kind etc. of this electroconductive particle, The various electroconductive particle conventionally used for the target electroconductive paste can be especially used without a restriction | limiting. The target conductive paste may be various conductive pastes for electrode formation, printed circuit, bonding, resistor, anisotropic conductive ink, etc., as an example of such conductive particles, Gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), iridium (Ir), osmium (Os), nickel (Ni) and Metals such as aluminum (Al) and alloys thereof, carbonaceous materials such as carbon black, LaSrCoFeO ₃ -based oxides (eg LaSrCoFeO ₃ ), LaMnO ₃ -based oxides (eg LaSrGaMgO ₃ ), LaFeO ₃ -based oxides (eg LaSrFeOO) _3), a transition metal perovskite acids represented as LaCoO ₃ type oxide (e.g., LaSrCoO ₃₎ or the like Conductive ceramics typified by the object is illustrated.
There are no strict restrictions on the shape and particle diameter of the particles, and typically, for example, the average particle diameter is selected from a range of several nm to several μm, for example, about 10 nm to 10 μm, depending on the application. Particles having an average particle size can be used. In the present specification, the “average particle size” means an integrated value of 50% in the particle size distribution measured by a particle size distribution measuring apparatus based on the laser scattering / diffraction method in the range where the average particle size is approximately 0.5 μm or more. In the range where the average particle diameter is about 0.5 μm or less, it can be obtained by observation means such as an electron microscope. It can be determined as the particle diameter at an integrated value of 50% in the particle size distribution created based on the equivalent circle diameter of a plurality of particles in the observed image to be observed. Note that there is no strict criticality in the particle size range to which these average particle size calculation methods are applied, and the calculation method can be appropriately selected according to the accuracy of the apparatus to be employed.

As another component of the conductive paste, there is a medium called a vehicle in which the conductive particles are dispersed. Such a medium is typically composed of a binder and a solvent. Any vehicle can be used as long as it can disperse the conductive particles appropriately, and those used in conventional conductor pastes can be used without particular limitation.
Examples of the binder include those based on acrylic resin, epoxy resin, phenol resin, alkyd resin, cellulosic polymer, polyvinyl alcohol, polyvinyl butyral, and the like. Further, a glass frit may be included as a component responsible for the ability of the conductive paste to adhere to the substrate (binder function) or as a component responsible for other functions such as adhesion and durability.

Examples of the solvent include cellulose polymers such as ethyl cellulose, ethylene glycol and diethylene glycol derivatives, high-boiling organic solvents such as toluene, xylene, mineral spirits, butyl carbitol, and terpineol, or combinations of two or more thereof. An organic vehicle can be used.
In addition, the paste sample contains various additives that can give desired properties such as good viscosity and ability to form a coating film (attached film to the base material) to constitute the conductive paste, if necessary. May be. Examples of such additives include surfactants, antifoaming agents, plasticizers, thickeners, antioxidants, dispersants, various photopolymerizable compounds and photopolymerization initiators, polymerization inhibitors, and ceramic groups. Various coupling agents such as silicon-based, titanate-based, and aluminum-based materials for the purpose of improving adhesion to the material can be mentioned.

  The above paste sample can have, for example, the same composition as the target conductive paste or a part of the composition. Specifically, for example, when the composition of the paste sample is the same as that of the conductive paste, for example, it is possible to prepare paste samples having two or more kinds of concentrations by appropriately changing the concentration. When the composition of the paste sample is different from that of the conductive paste, for example, the constituents of the target conductive paste can be divided into two or more parts, and two or more types of paste samples including the parts can be prepared.

These paste samples are viscoplastic fluids that exhibit non-Bingham flow and can be adjusted to high viscosity. Such viscosity cannot be uniquely indicated because of the performance of the combinatorial sample preparation means 20 to be used, but can be, for example, 10 Pa · s or more. In the evaluation system disclosed herein, the viscosity is preferable because the effect can be clearly obtained by applying it to a paste sample having a relatively high viscosity of about 10 Pa · s to 2000 Pa · s. More specifically, the viscosity of the paste sample is preferably about 50 Pa · s to 1500 Pa · s, for example, about 100 Pa · s to 1000 Pa · s.
The viscosity of the conductive paste can be measured with a viscometer or rheometer capable of measuring the viscosity of the viscoplastic fluid. The viscosity in the present specification is a value measured using a Brookfield viscometer of the HBT type under the condition of 10 rpm at 25 ° C.

In the evaluation system of this embodiment, first, as shown in step S <b> 10, the operating conditions of the combinatorial sample preparation unit 20 and the baking unit 22 are set in the input unit 10.
As a setting of the combinatorial sample preparation means 20, a condition necessary for sample preparation is input based on a combinatorial technique. For example, the blending ratio of two or more basic paste samples is determined. Such a blending ratio is determined so that a necessary number and composition range of mixed pastes can be prepared. Here, for example, the blending ratio of one paste sample is set as at least one parameter, and the ratio is continuously or discretely changed, whereby the blending ratio of the remaining paste sample (the total of the remaining basic paste samples is calculated). It may be a blending ratio). When there are a plurality of remaining basic paste samples, their blending ratio can be further set. For example, only the proportion of some paste samples may be changed and the proportion of the remaining part of paste samples may be constant, or the proportion of all paste samples may be changed comprehensively. good. The number of conductive pastes to be prepared (that is, the number of blending ratios and the number of conductive paste compositions) is not particularly limited, but is preferably 5 or more, for example, 8 or more. Is more preferable. For example, it is possible to use 10 or more types, 30 or more types, and the like.

As the setting of the firing means 22, for example, conditions such as a heating rate in firing, a firing temperature, a firing time, and a firing atmosphere can be set. Such firing conditions may be changed based on a combinatorial method, or may be set to constant conditions for all conductive pastes. Furthermore, in addition to baking of the conductive paste, it may be set to additionally perform a heat cycle.
As such an input means 10, a computer, a personal computer (PC) or the like having a predetermined information input / output function and an arithmetic processing function can be suitably used. The information input in the input means 10 is sent to the combinatorial sample preparation means 20 and the baking means 22 of the sample preparation unit 200. Transmission and reception of information (including various signals; the same shall apply hereinafter) in this evaluation system may be performed by wired communication or wireless communication (hereinafter the same).

  In the sample preparation unit 200, as shown in step S20, based on information such as the preparation conditions input in the input means 10, a plurality of blending ratios (that is, a plurality of compositions) from two or more types of conductive pastes. A mixed paste is prepared on a substrate. Thereafter, as shown in step S30, the mixed paste on the substrate is fired to form a fired body. The fired body formed by the sample preparation unit 200 becomes a conductor (typically a conductive film) that is an object to be evaluated.

  The combinatorial sample preparation means 20 prepares a plurality of mixed samples having different compositions based on a combinatorial technique. In the evaluation system disclosed herein, a plurality of mixed pastes having different compositions are prepared by mixing two or more basic paste samples having different electrical conductivities. Specifically, the blending ratio of two or more basic paste samples is set as at least one parameter, and this parameter is continuously or discretely changed to mix the basic paste samples. A mixed paste having a different composition is prepared. The mixed paste is uniformly mixed at a predetermined sample position on the substrate or in a predetermined mixing container, and is placed at a predetermined sample position on the substrate.

As the substrate, a flat library plate having a predetermined sample arrangement position can be used. Such a substrate may be one having a smooth surface on which the sample is disposed, or may be one in which a depression is provided at the sample disposition position. There is no particular limitation on the material of the substrate, for example, a material that does not react with the conductive paste, a material that causes a desired reaction with the conductive paste, or an object to which such a conductive paste is applied. Any material can be used.
Here, it is preferable that the combinatorial sample preparation means 20 be prepared so that, for example, the preparation amount of the mixed paste is 10 g or less (for example, 1 g or less). Although this evaluation system will be described in detail later, even if there is an error or variation in sampling, the blending ratio can be corrected, so even if the amount of one mixed paste is as small as 10 g or less, it is sufficiently accurate The conditions for preparing the conductive paste can be evaluated well. Further, only a necessary amount of the mixed paste is prepared without considering the sampling accuracy, and the disposal loss of the conductive paste can be reduced.

  Such combinatorial sample preparation means 20 can be realized, for example, by using various automatic wet sample preparation apparatuses, sampling apparatuses and the like that can perform sampling based on a combinatorial technique. As an automatic wet sample preparation device and a sampling device, if it can handle a liquid or slurry wet sample and can physically sample the paste sample having the above viscosity, its sampling accuracy and The configuration and the like are not particularly limited, and various types can be used. A preferable example of such an apparatus is one that performs sampling by sucking and discharging a paste sample by a pipette and a syringe pump connected to the pipette. Specifically, for example, a weighing and mixing device and a chemical reaction processing device disclosed in Patent Document 6 can be exemplified.

The firing means 22 fires the mixed paste prepared above and forms a fired body at a predetermined position on the substrate. Such firing means 22 can be realized by using various known heating devices. Specific examples of the heating device include a muffle furnace using a high frequency induction coil, a tunnel heating furnace, a laser heating device, a local heating device, and the like. In order to adjust the firing conditions of all the mixed pastes on the substrate and accurately control the firing atmosphere and firing temperature, it is preferable to use a closed heating apparatus such as a muffle furnace. In addition, it is preferable to employ a tunnel-type heating furnace or the like because a large number of substrates can be continuously heated and the heating temperature history and the like are easily changed. Furthermore, when changing the heating conditions of the mixed paste on the same substrate, for example, it is considered to employ a heating device that enables local heating by a laser heating device or a ceramic heating element.
The fired bodies having different compositions prepared in this way are also different in electrical conductivity.

  Thereafter, in the measurement unit 300, as shown in steps S30 to S36, for the fired bodies having different compositions formed as described above, for example, based on information from the control unit 100, a test for desired functions and characteristics is automatically performed.・ Analysis can be performed. In the case of the evaluation system 500 illustrated in FIG. 1, for example, the measurement unit 300 includes the electrical conductivity measurement unit 30, the composition analysis unit 32, the crystal structure analysis unit 34, and the thermal expansion coefficient measurement unit 36. Measurement and analysis of electrical conductivity (resistivity), composition, crystallinity, coefficient of thermal expansion, and the like can be performed. This test and analysis can be performed while transmitting / receiving information to / from the input means 10 and the evaluation means 40 as necessary.

  The electrical conductivity measuring means 30 can automatically measure the electrical conductivity (resistivity) of the plurality of fired bodies (conductive films) prepared above based on information from the control unit 100, for example. That is, a plurality of fired bodies (conductive films) sent to the electrical conductivity measuring means 30 are installed at a predetermined measurement position together with the substrate, for example, and the electrical conductivity (resistivity) of each fired body is measured. The measurement of electric conductivity can be realized by an apparatus having a function of measuring electric conductivity by, for example, a four-probe method, a two-terminal method, a four-terminal method, or the like. In the measurement of electrical conductivity, a plurality of fired bodies may be measured one by one in order.For example, the electrical conductivity of all the fired bodies formed on the substrate is measured at a time. More preferably.

  In order to measure the electrical conductivity of the plurality of fired bodies at a time, for example, as shown in FIG. 3, a plurality of electrical conductivity measurement functions 30B ( In FIG. 3, a part of the electrical conductivity measurement function 30B is omitted, and the electrical conductivity measurement device 30A provided with the electrical conductivity measurement function 30B is shown as a preferred example. The electric conductivity measurement function 30B, for example, a four-probe probe is used, so that the electric conductivity of all the samples formed on the substrate can be obtained even if the fired body is in the form of a fine thin film. Simultaneous and instantaneous measurement is possible. Further, for example, the tips of the four probes (probes) in each electrical conductivity measurement function 30B are movable in the direction of the respective needle axes, so that the four-probe probe is only pressed against the sample. Thus, the unevenness of the sample surface and the difference in surface height of each sample can be absorbed by the movement of the probe, and the electrical conductivity of all the samples can be measured simultaneously and instantaneously. For example, as shown in FIGS. 4 (a) and 4 (b), the movement of the tip of the probe is specifically performed by, for example, (a) sliding in the needle axis direction, or (b) the probe. It can be realized by a minute curvature. Furthermore, this electrical conductivity measuring means 30 is provided with a function that enables control of the temperature and measurement atmosphere of a muffle furnace or the like, so that, for example, electrical conductivity can be measured in a high temperature environment. Information on the electrical conductivity measured by the electrical conductivity measuring device 30 is sent to the evaluation means 40.

  The composition analysis unit 32 can automatically measure the chemical composition of the plurality of fired bodies (conductive films) prepared above based on information from the control unit 100, for example. Analysis of chemical composition is, for example, analysis capable of non-destructive composition analysis of solid inorganic substances such as X-ray fluorescence analyzers having an analysis function by X-ray fluorescence analysis, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, etc. An analysis apparatus or the like based on a technique can be preferably employed. As the fluorescent X-ray analyzer, for example, either an energy dispersion type or a wavelength dispersion type may be used. In composition analysis, for example, a substrate on which a plurality of fired bodies are formed is moved in the horizontal direction so that the fired body to be measured is moved to the measurement position, and all the fired bodies are automatically and sequentially analyzed. May be performed. Note that, depending on the configuration of the composition analysis means 32 to be used, the composition analysis procedure and method are not limited to this example. The result of the composition analysis in the composition analysis means 32 is sent to the evaluation means 40.

  The crystal structure analyzing means 34 can automatically analyze information on the crystal structures of the plurality of fired bodies (conductive films) prepared above based on information from the control unit 100, for example. The analysis of the crystal structure can be suitably realized by using, for example, an X-ray diffraction analyzer having an analysis function by an X-ray diffraction analysis method. In such X-ray diffraction analysis, for example, the substrate on which a plurality of fired bodies are formed is moved in the horizontal direction so that the fired body to be measured is moved to the measurement position. The composition analysis can be performed. Note that, depending on the configuration of the crystal structure analysis means 34 to be used, the composition analysis procedure and method are not limited to such examples. The result of the composition analysis in the crystal structure analysis means 34 is sent to the evaluation means 40.

  The thermal expansion coefficient measuring unit 36 can automatically measure the thermal expansion coefficients of the plurality of fired bodies (conductive films) prepared above based on information from the control unit 100, for example. The thermal expansion coefficient may be either a linear thermal expansion coefficient or a volume thermal expansion coefficient. Such a coefficient of thermal expansion measurement means 36 can be suitably realized, for example, by employing a device having a measurement function based on a precise absolute measurement method such as an optical interference method, an X-ray diffraction method, a telephotometry method, or the like. It is desirable that such measurement can be performed in a predetermined measurement atmosphere within a predetermined temperature range, for example. For example, two types of measurement atmospheres, an oxidizing atmosphere and a reducing atmosphere, are measured, and a thermal expansion coefficient in a desired measurement temperature range from room temperature to about 500 ° C. or more in each measurement atmosphere is measured. It can be calculated by the evaluation means 40 described later. The reductive expansion coefficient can be calculated by, for example, the above equation (1). For example, when an X-ray diffraction analyzer is employed as the thermal expansion coefficient measuring means 36, the same X-ray diffraction analyzer may be used as the thermal expansion coefficient measuring means 36 and the crystal structure analyzing means 34. . The measurement of the coefficient of thermal expansion by the X-ray diffraction method is to calculate the coefficient of thermal expansion by reading the temperature change of the lattice spacing (that is, the lattice constant) of the crystal lattice as the change of the X-ray diffraction angle. In addition, since the X-ray diffraction method can measure even a very small amount of sample that is difficult to measure with other measurement methods if it is a crystalline sample, the thermal expansion of the fired body produced by such a combinatorial method It is preferable to apply to the measurement of rate. The result of the thermal expansion coefficient in the thermal expansion coefficient measuring unit 36 is sent to the evaluation unit 40.

  The evaluation unit 40 can evaluate the preparation conditions of the conductive paste based on the information sent from the measurement unit 300 as described above and the information set by the input unit 10. Specifically, the evaluation means 40 analyzes the relationship between the composition of the conductive paste and the function or characteristic tested and analyzed above, and the composition of the conductive paste that can realize the desired function or characteristic. Is calculated. Such analysis can be performed using known analysis software. For example, it may be analysis software attached to each test / analysis apparatus. In the present invention, when this analysis is performed, the blending ratio of the actual paste sample is calculated based on the result of the composition analysis sent from the composition analyzing means 32, and the calculated value is set in the input means 10. Instead of the ratio, it is used for analysis. Hereinafter, the calculated value of the blending ratio calculated from the result of the composition analysis may be simply referred to as “correction value”. This is because in the preparation of the conductive paste, it is considered that the accuracy of the composition analysis of the conductive paste by the composition analysis means 32 is higher than the accuracy of the preparation of the conductive paste by the combinatorial sample preparation means 20. Then, by analyzing the relationship between the corrected conductive paste composition and the function or characteristic tested and analyzed above, a more accurate composition of the conductive paste that can realize the desired function or characteristic ( Alternatively, the composition range) can be calculated and evaluated. The introduction of the correction value into the analysis may be always reflected in the evaluation. For example, the difference between the mixing ratio of the basic paste sample set by the input means 10 and the correction value is set in advance. If it is larger than the threshold value, the blending ratio set in advance in the input means 10 may be replaced with a correction value for correction.

The information regarding the function (which may be a characteristic) of the fired body sent from the measurement unit 300 includes, for example, the electrical conductivity (resistivity), crystallinity, thermal expansion coefficient, reduction expansion coefficient, and the like of the fired body. Although a threshold is set for each of these functions in advance, a fired body within the range indicated by this threshold is evaluated as “OK”, and a fired body outside the range indicated by this threshold is evaluated as “impossible”. This is exemplified. Such evaluation is not limited to two stages of “permitted” and “impossible”, and can be performed in more detail by providing a plurality of stages. Then, the evaluation result and the blending ratio of the fired body can be correlated to determine the blending ratio of the conductive paste capable of forming a fired body having more desirable characteristics.
The relationship between the evaluation results of the above functions and the blending ratio of the fired body can be expressed, for example, on a composition map. For example, it is possible to create a map showing the relationship between the glass composition and the contact angle. Thereby, the relationship between the blending ratio of the conductive paste and the function of the fired body achieved by the blending ratio can be visually and clearly evaluated.

The functional evaluation of the fired body is not limited to the function tests and analyzes exemplified above, and may be other known or various measuring means that will be developed in the future. Further, a measurement unit in which a plurality of measurement functions are combined into one measurement unit may be provided. Examples of the evaluation and analysis means for various functions and characteristics provided in the measurement unit 300 include a dielectric constant measurement means for measuring a dielectric constant of a fired body, a laser Raman analysis means including a laser Raman spectrophotometer, and the like. Evaluation of the dielectric constant and molecular structure of each fired body can be taken into consideration in determining the blending ratio.
In addition, between the plurality of measurement and / or analysis means provided in the measurement unit 300, a transfer means that can automatically transfer the fired body (sample) together with the substrate can be provided. Examples of such transfer means include vertical transfer means capable of transferring a transfer object such as a lift and a robot arm in the vertical direction, horizontal transfer means capable of transferring a transfer object such as a roller conveyor and a belt conveyor in the horizontal direction, and transfer. Various well-known transport systems including a control unit that controls the operation of these transfer units based on the movement of the object can be employed. However, since a relatively large space is required for installation of the transfer means that can be automatically transferred, in some cases, such a transfer means is not necessarily automatically (mechanically) implemented, You may make it utilize the transfer by a human hand.
EXAMPLES Examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the following examples.

[Embodiment 1]
Using a conductive paste preparation condition evaluation system described below, a paste sample A for preparing a resistive paste having a predetermined resistivity from two types of paste samples A and B having different electrical conductivities, and The optimum blending ratio of B was examined. The conductive paste preparation condition evaluation system used in this embodiment includes a combinatorial sample preparation means for preparing a sample library by preparing a mixed paste prepared by mixing paste samples A and B at a predetermined mixing ratio on a substrate, and a preparation An automatic firing furnace for firing the mixed paste together with the library under predetermined firing conditions, means for measuring the resistivity (electrical conductivity) of the fired bodies after firing, means for analyzing the composition of the fired bodies, And means for evaluating the blending ratio of paste samples A and B from the information received from each means.

[Combinatorial sample preparation means]
As the combinatorial sample preparation means, an automatic sample preparation device that can collect a plurality of liquid samples by a predetermined amount, mix them, and place them at a predetermined sample position based on a combinatorial method was used. In this embodiment, the blending ratio of paste samples A and B was used as a parameter, and this parameter was changed at a constant ratio to prepare a mixed sample with the nine blends shown in Table 1 below.

The paste samples A and B are pastes for forming resistors for electronic devices, in which conductive ruthenium oxide (RuO ₂ ) powder and glass powder as a binder are dispersed in terpineol as a solvent. I prepared something. Paste sample A and paste sample B are prepared to have different resistivities in advance by adjusting the composition of RuO ₂ powder and glass powder. The viscosity of these paste samples A and B was measured and found to be 100 Pa · s and 120 Pa · s at 25 ° C. and 10 rpm, respectively. As the substrate, a substrate made of alumina and provided with a dish-like depression at a predetermined sample position on the surface of the flat substrate was used.
In the automatic sample preparation device, about 50 mg to 100 mg each of paste sample A and paste sample B are automatically collected with a pipette and discharged to a mixing ampoule. The paste in the mixing ampoule is stirred by applying ultrasonic waves and vibration. The stirred mixed paste is collected again by a pipette, and a predetermined amount of, for example, about 10 mg to 20 mg is supplied to a predetermined position on the substrate. In this example, sample positions are set on the substrate in a 6 × 6 lattice pattern, and the samples are arranged in a predetermined order at the predetermined sample positions. Thus, it took about 10 minutes to prepare nine kinds of mixed pastes from the two types of resistance pastes on the substrate. The prepared mixed paste is sent to the baking means together with the substrate.

[Baking means]
As a firing means, a firing furnace capable of automatically controlling all firing conditions was used. In this embodiment, nine types of mixed paste were fired at 800 ° C. together with the substrate in an air atmosphere to obtain a resistor sample having nine compositions as a fired body. The obtained resistor sample is sent to a means for performing composition analysis after air cooling.

[Composition analysis means]
As the composition analysis means, an energy dispersive microscopic X-ray fluorescence spectrometer equipped with a substrate holder capable of automatically moving the substrate to a predetermined measurement position was used. In the present embodiment, the concentration (mass%) of ruthenium (Ru) in the resistor sample was examined using this fluorescent X-ray analyzer. Information on the Ru concentration of each resistor sample is sent to the evaluation means. For reference, the measurement results of the Ru concentration of each resistor sample are shown in Table 1. The resistor sample for which the composition analysis has been completed is sent to the electrical conductivity (volume resistivity) measuring means together with the substrate.

[Electric conductivity measurement means]
As the electrical conductivity measuring means, an electrical conductivity measuring device in which a plurality of (in this case, 36) electrical conductivity measuring devices are arranged so as to correspond to the sample positions on the substrate is used. This electrical conductivity measurement device can simultaneously measure the resistivity (electrical conductivity) of all samples formed on a substrate, even with a small thin film sample, etc., using a four-probe probe. it can. In addition, each of the four probes (probes) can be moved in the direction of the needle axis. By simply pressing the four-probe method probe against the sample, unevenness of the sample surface, difference in surface height for each sample, etc. This makes it possible to instantly measure an accurate resistivity (electrical conductivity). Furthermore, the measurement part is installed in the muffle furnace, and can measure the electrical conductivity at a high temperature of about 1400 ° C. at the maximum. With this electrical conductivity measuring device, the volume resistivity of the resistor sample at 25 ° C. is measured, and the information is sent to the evaluation means. For reference, the measurement results of the volume resistivity of each resistor sample are shown in Table 1. In the table, the blending ratios of paste sample A and paste sample B are shown in the columns of paste A and paste B, respectively.

[Evaluation means]
As described above, the relationship between the composition of the prepared mixed paste and the volume resistivity of the obtained electrode film sample was determined from the measurement results sent from the composition analysis means and the electrical conductivity measurement means. The relationship between the two theoretically shows a linear relationship, but it is extremely rare that an electrode film actually manufactured shows perfect linearity. Therefore, the blending ratio of the prepared mixed paste was corrected. In the present embodiment, from the volume resistivity of the known paste samples A and B and the above measured values (volume resistivity, Ru content), the blending ratio as shown in the correction value column of Table 1 is actually It was calculated to be a conductive paste formulation. Therefore, a more reliable evaluation can be performed by replacing the blending ratio as the setting condition with the blending ratio (correction value) calculated from the Ru content and evaluating the relationship with the volume resistivity. .
Further, the above measurement results also change delicately under the influence of the weather and the like on the day of conducting the evaluation of the preparation conditions of the conductive paste, so that the preparation for each day is indispensable. From this relationship between the corrected blending ratio and volume resistivity, for example, to prepare a resistance paste having a volume resistivity of 1.20 Ω · cm on this day, paste sample A and paste sample B are prepared as (A) 53 .8: (B) It was found that mixing at a ratio of 46.2 was sufficient.
Table 2 below shows the time required for each process when this system is used. For reference, Table 2 also shows the time required for evaluating the conventional resistance paste preparation conditions.

  As described above, if the conductive paste preparation condition evaluation system disclosed herein is used, conventionally, the optimization evaluation of the conductive paste preparation conditions is performed by film-forming one sample at a time or by analyzing or testing each sample. It was confirmed that the time required can be greatly shortened by depositing multiple samples at the same time and analyzing or testing multiple samples simultaneously or continuously. In addition, the basic paste used for sample preparation must be used only in an amount that can be prepared with small errors such as weighing and mixing by human hands. According to such a system, it is possible to produce a sample with a small amount of error even with a small amount, and to reduce waste loss. Thereby, for example, the enormous test time and cost for optimizing the daily preparation conditions of the conductive paste can be reduced.

In this example, Ru-type resistive pastes are used as the two types of conductive pastes. However, as the conductive pastes, those having different components and compositions of conductive particles may be used. As described above, for example, three or four kinds of conductive pastes may be blended.
Moreover, the evaluation content of the formed multiple types of resistors is not limited to composition analysis and resistivity measurement, and other evaluations may be performed.

[Embodiment 2]
Using the conductive paste preparation condition evaluation system described below, two types of conductive pastes C and D having different electrical conductivities have predetermined characteristics (electrical conductivity, crystal structure, reduction expansion coefficient). The blending ratio of pastes C and D for preparing a conductive paste was examined. The conductive paste preparation condition evaluation system used in this embodiment includes the same combinatorial sample preparation means as used in Embodiment 1 above, and a firing means for firing the prepared mixed sample together with the library under predetermined firing conditions. The means for measuring the electrical conductivity of the fired bodies after firing, the means for measuring the reduction expansion coefficient of the fired bodies, and the ratio of the conductive pastes C and D evaluated from the information received from each means Means to do.

[Combinatorial sample preparation means]
As the combinatorial sample preparation means, the same automatic sample preparation apparatus as in the first embodiment was used. In this embodiment, the blending ratio of the conductive pastes C and D was used as a parameter, and by changing this parameter at a constant ratio, a mixed sample was prepared with the nine blends shown in Table 2 below.

As the conductive paste C and D, a paste for electrode formation in the solid oxide fuel cell, the paste C includes LaSrCoFeO ₃ as the conductive oxide, the paste D LaSrTiFeO ₃ as conductive oxide In addition, a glass powder as a binder and dispersed in terpineol as a solvent were used. The conductive paste C and the conductive paste D are prepared in advance with different electrical conductivities. When the viscosity of these conductive pastes C and D was measured, they were 130 Pa · s and 150 Pa · s, respectively. As the substrate, a substrate made of 8 mol% yttria-stabilized zirconia (8YSZ) and having a dish-like recess at a predetermined sample position on the surface of the flat substrate was used.

  In the automatic sample preparation device, about 50 mg to 100 mg of conductive paste C and conductive paste D are each automatically collected by a pipette and discharged to a mixing ampoule. The paste in the mixing ampoule is stirred by applying ultrasonic waves and vibration. The stirred mixed paste is collected again by a pipette, and a predetermined amount of, for example, about 10 mg to 20 mg is supplied to a predetermined position on the substrate. In this example, sample positions are set on the substrate in a 6 × 6 lattice pattern, and the samples are arranged in a predetermined order at the predetermined sample positions. Thus, it took about 10 minutes to prepare nine kinds of mixed pastes from the two kinds of conductive pastes on the substrate. The prepared mixed paste is sent to the baking means together with the substrate.

[Baking means]
As a firing means, a firing furnace capable of automatically controlling all firing conditions was used. In this embodiment, nine kinds of mixed pastes were baked at 1000 ° C. in the air atmosphere together with the substrate, thereby obtaining electrode film samples having nine kinds of compositions as a fired body. The obtained fired body is air-cooled and then sent to a means for measuring the reduction expansion coefficient.

[Composition analysis means]
As the composition analysis means, an energy dispersive microscopic X-ray fluorescence spectrometer equipped with a substrate holder capable of automatically moving the substrate to a predetermined measurement position was used. In the present embodiment, the concentration (mass%) of cobalt (Co) in the electrode film sample was examined by this fluorescent X-ray analyzer. Information on the Co concentration of the electrode film sample is sent to the evaluation means. For reference, the measurement results of the Co concentration of the electrode film sample are shown in Table 3. The electrode film sample that has been subjected to the composition analysis is sent to the reduction expansion coefficient measuring means together with the substrate.

[Measurement of reduction expansion coefficient]
The reduction expansion coefficient measuring means includes a substrate holder that can automatically move the substrate to a predetermined measurement position, and can perform X-ray diffraction analysis of a plurality of electrode film samples continuously under desired atmospheric conditions. A line diffraction analyzer was used. In this embodiment, the unit crystal lattice size (that is, crystal lattice constant a, b, c) of the electrode film sample at room temperature and 1273 K is obtained by this X-ray diffractometer, and calculated from these values. The volume thermal expansion coefficient from room temperature to 1273K is determined from the volume change of the unit cell. Further, the volume thermal expansion coefficient is obtained in both the oxidizing (air) atmosphere and the reducing atmosphere, and the increase in the thermal expansion coefficient volume in the reducing atmosphere when the thermal expansion volume in the oxidizing (air) atmosphere is used as a reference, The reduction expansion coefficient was used. That is, this reduction expansion coefficient is expressed by the above equation (2). Information on the room temperature of the electrode film sample and the lattice constant at 1273K measured in an oxidizing (atmospheric) atmosphere and a reducing atmosphere is sent to the evaluation means. For reference, the measurement results of the lattice constant of each electrode film sample are shown in Table 3. The electrode film sample that has been subjected to the X-ray diffraction analysis is sent to the electrical conductivity measuring means together with the substrate.

[Electric conductivity measurement means]
As the electrical conductivity measuring means, the same electrical conductivity measuring device as that used in the first embodiment was used. In this embodiment, the high-temperature electrical conductivity of the electrode film sample at 800 ° C. was measured by such an electrical conductivity measurement device, and the information was sent to the evaluation means. For reference, the measurement results of the high-temperature electrical conductivity of each electrode film sample are shown in Table 3. In the table, the blending ratios of the conductive paste C and the conductive paste D in the electrode film sample are shown in the columns of paste C and paste D, respectively.

[Evaluation means]
As described above, the relationship between the composition of the prepared conductive paste and the high-temperature electrical conductivity of the obtained electrode film sample was determined from the measurement results sent from the composition analysis means and the electrical conductivity measurement means. The relationship between the two theoretically shows a linear relationship, but it is extremely rare that an electrode film actually manufactured shows perfect linearity. Therefore, the blending of the prepared conductive paste was corrected. In this embodiment, from the high-temperature electrical conductivity of known conductive pastes C and D and the above measurement results (high-temperature electrical conductivity, Co content), the blending ratio as shown in the column of correction values in Table 3 is The actual conductive paste composition was calculated. Therefore, various characteristics are evaluated based on this blending ratio. That is, it is possible to perform a more reliable evaluation by replacing the blending ratio which is the setting condition with a blending ratio (correction value) calculated from the Co content and evaluating the relationship with the high temperature electrical conductivity. it can.
As described above, the reduction expansion coefficient was calculated from the lattice constant data sent from the reduction expansion coefficient measuring means, and the relationship between the reduction expansion coefficient and the high temperature conductivity was obtained. As the characteristics of the electrode film, it is preferable that the electrical conductivity at high temperature is high, but it is preferable that the reduction expansion coefficient is small. From the results of Table 3, for example, in order to prepare a conductive paste having a high-temperature conductivity of 100 S / cm or more and a reduction expansion coefficient of 0.1% or less, paste C and paste D are (C) 44.6 :( D) 55.9 to (C) 58.4: (D) It was found to be mixed in the range of 40.6.
Table 4 below shows the time required for each process when this system is used. For reference, Table 4 also shows the time required for evaluating the conditions for preparing a conductive paste by a conventional manual operation.

[Evaluation means]
Further, the above measurement results also change delicately under the influence of the weather and the like on the day of conducting the evaluation of the preparation conditions of the conductive paste, so that the preparation for each day is indispensable. From this relationship between the corrected blending ratio and the high temperature conductivity, for example, in order to prepare a resistance paste having a high temperature conductivity of 120 S / cm on this day, paste sample C and paste sample D are (C) 55 :( D) It has been found that mixing at a ratio of 45 is sufficient.
Table 4 below shows the time required for each process when this system is used. For reference, Table 4 also shows the time required for evaluation of the conventional preparation conditions of the resistance paste.

  As described above, if the conductive paste preparation condition evaluation system disclosed herein is used, conventionally, the optimization evaluation of the conductive paste preparation conditions is performed by film-forming one sample at a time or by analyzing or testing each sample. Where time was spent, multiple samples were deposited simultaneously, and multiple samples were analyzed or tested simultaneously or continuously, so the time required could be greatly reduced. It was confirmed that the measurement of the reduction expansion coefficient can be performed with high accuracy even with a very small sample by using an X-ray diffraction analyzer. In addition, the basic paste used for sample preparation has conventionally had to be prepared in a certain amount in order to minimize errors such as weighing and mixing by human hands, resulting in a large amount of waste loss. According to such a system, it is possible to produce a sample with a small amount of error even with a small amount, and to reduce waste loss. Thereby, for example, the enormous test time and cost for optimizing the daily preparation conditions of the conductive paste can be reduced.

As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible. For example, the evaluation target of the conductive paste preparation condition evaluation system disclosed herein is not limited to the SOFC electrode material and the resistance material of the electronic device as exemplified above. Applicable to evaluation of preparation conditions for electrode paste and conductive adhesives for printed wiring in electro-mechanical systems (MEMS) and multilayer ceramic capacitors (MLCC) Can do. Further, in this evaluation system, the conductive particles contained in the conductive paste to be evaluated are not limited to the above-mentioned RuO ₂ or transition metal perovskite type oxides, and conductive particles composed of various other components. It can be applied to a conductive paste containing particles. Moreover, it is not limited to mix | blending two types as a conductive paste, For example, you may make it evaluate the mixing | blending ratio of three types or four or more types of conductive paste. In order to evaluate the formed conductive film, it goes without saying that other test, analysis or evaluation means other than the analysis means specifically disclosed above may be provided.

DESCRIPTION OF SYMBOLS 10 Input means 20 Combinatorial sample preparation means 22 Baking means 30 Electrical conductivity measurement means 30A Electrical conductivity measurement apparatus 30B Electrical conductivity measurement function 32 Composition analysis means 34 Crystal structure analysis means 36 Thermal expansion coefficient measurement means 40 Evaluation means 100 Control part 200 Sample Preparation Unit 300 Measuring Unit 500 Conductive Paste Preparation Condition Evaluation System

Claims (10)

A system for evaluating preparation conditions of a conductive paste for producing a conductive substance,
A plurality of conductive pastes having different compositions by mixing the two or more types of paste samples with at least one parameter as a blending ratio of two or more types of paste samples for constituting the conductive paste Combinatorial sample preparation means for preparing a predetermined position on the substrate;
Firing means for firing the plurality of conductive pastes to form a plurality of fired bodies;
Means for measuring the electrical conductivity of the plurality of fired bodies;
Means for performing composition analysis of the plurality of fired bodies;
For each of the fired bodies, the blending ratio of the two or more types of paste samples is corrected based on the result of the composition analysis, and the relationship between the blending ratio after the correction and the measurement result of the electric conductivity Means for evaluating the preparation conditions of the conductive paste,
A conductive paste preparation condition evaluation system comprising: The paste sample includes conductive particles, a binder, and a solvent,
2. The conductive paste preparation condition evaluation system according to claim 1, wherein the viscosity at 25 ° C. and 10 rpm is 10 Pa · s to 2000 Pa · s.   3. The conductive paste preparation condition evaluation system according to claim 1, wherein the combinatorial sample preparation unit is configured to be able to prepare each of the plurality of conductive pastes in an amount of 10 g or less.   4. The conductive paste according to claim 1, wherein the means for measuring the electrical conductivity is configured to be able to simultaneously measure the plurality of fired bodies by a single measurement operation. 5. Preparation condition evaluation system.   5. The conductive paste according to claim 1, wherein the means for measuring the electrical conductivity is configured to be able to measure the electrical conductivity of the plurality of fired bodies at a high temperature of 500 ° C. or higher. Preparation condition evaluation system. Furthermore, a means for measuring the thermal expansion coefficient of a plurality of fired bodies is provided,
The means for evaluating the preparation conditions is configured to be capable of evaluating the preparation conditions of the plurality of conductive pastes including the measurement result of the coefficient of thermal expansion. Preparation condition evaluation system for conductive paste. The means for measuring the coefficient of thermal expansion has a function of measuring the coefficient of thermal expansion of the fired body in an oxidizing atmosphere and a reducing atmosphere.
The means for evaluating the preparation conditions is expressed by the following formula (1) from the measurement result of the coefficient of thermal expansion of the fired body in an oxidizing atmosphere and a reducing atmosphere.

It is possible to calculate the reduction expansion coefficient defined by
The conductive paste preparation condition evaluation system according to claim 6, wherein the preparation conditions of the plurality of conductive pastes including the reduction expansion coefficient can be evaluated. The means for measuring the coefficient of thermal expansion is capable of controlling the measurement atmosphere, and has a function capable of crystal structure analysis in a region from at least room temperature to 1200 ° C.,
The means for evaluating the preparation conditions calculates the reduction expansion coefficient based on a change in lattice constant in a measurement temperature range,
The conductive paste preparation condition evaluation system according to claim 7, wherein the preparation conditions of the plurality of conductive pastes including the reduction expansion coefficient can be evaluated.   9. The conductive paste preparation condition evaluation system according to claim 8, wherein the function capable of crystal structure analysis is an X-ray diffraction analyzer. The firing means is configured to be able to form a plurality of fired bodies by firing the plurality of mixed samples by changing the parameter with a firing temperature as at least one parameter,
The means for evaluating the preparation conditions is configured to be able to be evaluated including the parameters as preparation conditions for the plurality of conductive pastes. The preparation of the conductive paste according to any one of claims 1 to 9 Condition evaluation system.

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