JP2014051424A - Member for heat treatment and vessel for heat treatment including the same - Google Patents

Abstract

The present invention provides a heat-treating member that hardly causes cracks in a corrosion-resistant layer even when heat treatment is repeated, and a heat-treating container including the heat-treating member.
A substrate 1a made of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite or cordierite, and magnesium oxide formed on at least a part of the surface of the substrate 1a as a main component. The heat-treating member 1 is provided with the corrosion-resistant layer 1b, and the average crystal grain size of the magnesium oxide crystal particles forming the corrosion-resistant layer 1b is smaller than the average pore size of the porous sintered body.
[Selection] Figure 1

Description

  The present invention relates to a heat treatment member used for firing an object to be fired, and a heat treatment container including the heat treatment member.

In a heat treatment of a positive electrode material (for example, LiMnO ₂ , LiCoO ₂ , LiNiO ₂ ) of a lithium ion secondary battery, a heat treatment container using a heat treatment member made of mullite-cordierite excellent in thermal shock resistance is widely used. ing.

  However, such a heat treatment container is eroded by a lithium compound or a transition metal (for example, Mn, Co, Ni) compound contained in the positive electrode material, and the heat treatment container deteriorates in a short period of time if it is used repeatedly. I had to.

  Therefore, in suppressing deterioration of the heat treatment container, in Patent Document 1, at least one part of the cordierite sintered body is covered with an intermediate buffer bonding layer and an electrofused magnesia layer for preventing reaction. An electronic component firing jig has been proposed. Such a jig for electronic component firing is used when the magnesium oxide crystal particles contained in the electrofused magnesia layer (corrosion-resistant layer) are larger than the average pore diameter of the cordierite sintered body (substrate). The crystal particles of the electrofused magnesia layer (corrosion-resistant layer) are present in a state in which a part of the crystal particles are fitted and fixed in the open pores on the surface of the cordierite sintered body (substrate). there were.

JP-A-1-176276

  However, when heat treatment is repeated using a jig for firing electronic parts in a state where some of the magnesium oxide crystal particles are fitted and fixed in the open pores of the cordierite sintered body (substrate), cordierite Volume change occurs in the sintered material (base), and in this case, the crystal particles of magnesium oxide crystal particles fixed to the cordierite-based sintered body (base material) and unfixed magnesium oxide crystal particles Since the magnitude of the force applied to each is different, cracks occur in the electrofused magnesia layer (corrosion-resistant layer) starting from the site where fixed magnesium oxide crystal particles and non-fixed magnesium oxide crystal particles are in contact There was a problem that it was easy.

  In view of such problems, the present invention provides a heat-treating member that hardly causes cracks in a corrosion-resistant layer even when heat treatment is repeated, and a heat-treating container equipped with the heat-treating member.

  The heat-treating member of the present invention mainly comprises a base composed of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite or cordierite, and magnesium oxide formed on at least a part of the surface of the base. A heat-treating member comprising a corrosion-resistant layer as a component, wherein the average crystal grain size of the magnesium oxide crystal particles forming the corrosion-resistant layer is smaller than the average pore size of the porous sintered body It is a feature.

The heat treatment container of the present invention is characterized by comprising the above heat treatment member.

  According to the heat-treating member of the present invention, a substrate made of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite or cordierite, and magnesium oxide formed on at least a part of the surface of the substrate. A corrosion-resistant layer as a main component, and the average crystal grain size of the magnesium oxide crystal particles forming the corrosion-resistant layer is smaller than the average pore size of the porous sintered body. The entire crystal particles are easily held in the open pores present on the surface of the substrate, and it is possible to avoid a part of the crystal particles being fitted and fixed in the pores. Therefore, even if the volume change of the substrate is caused by the heat treatment, since the force generated with the volume change of the substrate is easily uniformly applied to each crystal particle of magnesium oxide of the corrosion resistant layer, the corrosion resistant layer is hardly cracked. .

  In addition, according to the heat treatment container of the present invention, since the heat treatment member of the present invention is provided, it can be used for a long period of time.

It is a perspective view which shows an example of the container for heat processing of this embodiment. The other example of the container for heat processing of this embodiment is shown, (a) is a perspective view, (b) is sectional drawing in the A-A 'line | wire. Still another example of the heat treatment container of the present embodiment is shown, (a) and (b) are a perspective view and a plan view, respectively, and (c) is a cross-sectional view taken along line B-B '.

  Hereinafter, the heat treatment member of this embodiment will be described in detail.

  The heat treatment member of this embodiment can be used mainly when heat-treating a positive electrode material of a lithium ion secondary battery, and is a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite, or cordierite. And a corrosion-resistant layer mainly composed of magnesium oxide formed on at least a part of the surface of the substrate, and the average crystal grain size of the magnesium oxide crystal particles forming the corrosion-resistant layer is porous. It is important that it is smaller than the average pore size of the sintered body.

  With such a configuration, the entire magnesium oxide crystal particles of the corrosion-resistant layer are easily held in the open pores existing on the surface of the substrate, so that some of the crystal particles are fitted and fixed in the open pores. Can be avoided. Therefore, even if the volume change of the substrate is caused by the heat treatment, since the force generated with the volume change of the substrate is easily uniformly applied to each crystal particle of magnesium oxide of the corrosion resistant layer, the corrosion resistant layer is hardly cracked. . Therefore, erosion of the substrate due to penetration of a component (simply referred to as erosion component) constituting the positive electrode material of the lithium ion secondary battery from the crack is suppressed.

  The thickness of the corrosion-resistant layer is preferably 10 μm or more based on the surface of the substrate. If the thickness is within this range, it is difficult for stress to remain in the corrosion-resistant layer even if heat treatment is repeated. As a result, cracks are less likely to occur.

  Here, each main component of the substrate and the corrosion-resistant layer means a component having the largest content among the components constituting each, and the main component in the substrate and the corrosion-resistant layer is 60% by mass or more and 95% by mass or more, respectively. Is more preferred.

When the main component of the substrate is aluminum oxide, the components other than the main component can include, for example, magnesium oxide, calcium oxide, and silicon oxide.

  When the main component of the substrate is magnesium metalate, the component other than the main component can include, for example, magnesium oxide.

  When the main component of the substrate is mullite, the component other than the main component can include, for example, cordierite.

  In addition, when the main component of the substrate is cordierite, components other than the main component can include, for example, magnesium aluminate, mullite, silicon oxide, and aluminum oxide.

  Moreover, as components other than the main component of a corrosion-resistant layer, calcium, manganese, silicon, and zinc can be included, for example.

  The components of the substrate and the corrosion-resistant layer can be identified by using an X-ray diffraction method, and the amount of each element contained in the substrate or the corrosion-resistant layer can be determined by fluorescent X-ray analysis or ICP (Inductively Coupled Plasma). ) It can obtain | require by measuring content of each element by the emission spectroscopy analysis method.

Here, as magnesium metalate, for example, magnesium aluminate, magnesium titanate, magnesium tantalate, or magnesium tungstate can be used. In addition, the composition formula of magnesium aluminate is expressed as MgAl ₂ O ₄ , and the molar ratio of MgO and Al ₂ O ₃ is preferably a constant ratio of 1: 1, but MgO and Al ₂ O ₃ and For example, the molar ratio is in the range of 1: 0.8 to 1: 1.2. Further, the composition formula of magnesium titanate is expressed as MgTiO ₃ , and the molar ratio of MgO and TiO ₂ is preferably a constant ratio of 1: 1, but the molar ratio of MgO and TiO ₂ is, for example, 1: 0.8
If it is in the range of ˜1: 1.2, there is no problem. Further, the composition formula of magnesium tantalate is expressed as Mg ₄ Ta ₂ O ₉ and the molar ratio of MgO and Ta ₂ O ₅ is preferably a constant ratio of 4: 1, but MgO and Ta ₂ O For example, the molar ratio with ₅ is in the range of 4: 0.8 to 4: 1.2. Further, the composition formula of magnesium tungstate is expressed as MgWO ₃ , and the molar ratio of MgO and WO ₃ is preferably a constant ratio of 1: 1, but the molar ratio of MgO and WO ₃ is, for example, There is no problem as long as it is in the range of 1: 0.8 to 1: 1.2.

  Next, according to the heat treatment member of the present embodiment, the magnesium oxide crystal particles are preferably nanoparticles. When the magnesium oxide crystal particles are nanoparticles, the crystal particles are more easily arranged in the corrosion-resistant layer, and the corrosion-resistant layer in the open pores becomes denser. With such a configuration, each particle becomes minute and the stress is easily dispersed, and since the space between the particles is narrow, it is difficult for the erosion component to penetrate. Therefore, the heat treatment member repeats the heat treatment. However, cracks are less likely to occur in the corrosion-resistant layer, and the corrosion resistance tends to be higher.

  In addition, the particle diameter in this embodiment is 1 nm or more and 100 nm or less based on the definition described in JIS K 0216-2008.

  Whether the magnesium oxide crystal particles are nanoparticles can be determined by the following procedure. That is, a sample is prepared by embedding in a cold embedding resin such as a polyester resin so that a surface parallel to the surface of the corrosion-resistant layer becomes an observation surface, and the surface on the observation surface side of this sample is polished. This polishing is performed as long as the corrosion-resistant layer can be observed. Then, using a scanning electron microscope, the reflected electron composition image of the observation surface of the sample is obtained at a magnification of 25,000, for example.

Then, the components of the crystal particles observed in the reflected electron composition image are changed to EPMA (Electron Probe).
Identify using Micro Analyzer). And when the crystal particle reflected in the reflection electron composition image is identified as magnesium oxide, for example, the image analysis software “IMAGE-PRO PLUS” (registered trademark, manufactured by MEDIA BERBERTICS) is used for analysis. For the crystal particles, the number of samples is arbitrarily selected as 30, and the particle diameter of the selected sample is calculated as the equivalent circle diameter. If the value of these samples is in the range of 1 nm to 100 nm, the magnesium oxide crystal particles are It can be identified as a nanoparticle. The average particle diameter of each magnesium oxide crystal particle is preferably 40 nm or more and 60 nm or less.

Moreover, according to the member for heat treatment of this embodiment, it is preferable that magnesium oxide is present in the surface layer of the substrate on the corrosion-resistant layer side. With such a configuration, even if the corrosion-resistant layer deteriorates with time and the erosion component erodes the corrosion-resistant layer, the erosion rate of the substrate can be reduced because magnesium oxide exists on the surface of the substrate. The corrosion resistance of the heat treatment member can be maintained for a longer period. Here, the surface layer of the substrate is 100 μm inward with respect to the surface of the substrate.
It suffices to exist in the area up to. From the viewpoint of the mechanical strength of the substrate, if the magnesium oxide present in the surface layer of the substrate is present only in the region, the mechanical strength can be maintained high.

  The presence and distribution of magnesium oxide on the surface layer of the substrate can be determined by measuring the abundance of magnesium in a cross section where the substrate and the corrosion-resistant layer can be confirmed using secondary ion mass spectrometry or electron beam microanalyzer.

Further, according to the heat treatment member of this embodiment, when the corrosion-resistant layer contains zirconium oxide, if the heat treatment is repeated, the reason is unknown, but fine cracks are generated in the crystal grains of zirconium oxide. The fine cracks can suppress the progress of cracks from one main surface of the corrosion-resistant layer to the other main surface, which can occur during repeated heat treatment, and can improve thermal shock resistance. it can. Zirconium oxide preferably has a crystal structure of at least one of a tetragonal crystal and a cubic crystal, and such a crystal structure has high thermal shock resistance and is subjected to thermal shock by repeated heat treatment. Is not easily damaged. Zirconium oxide can be identified using thin film X-ray diffraction or X-ray photoelectron spectroscopy. In particular, the content of zirconium oxide is preferably 2% by mass or less and 12% by mass or less with respect to 100% by mass of the corrosion-resistant layer.

  In addition, the porous sintered body, which is a substrate constituting the heat treatment member of this embodiment, has a cumulative 75 volume% pore diameter (d75) with respect to a cumulative 25 volume% pore diameter (d25) in the cumulative distribution curve of pore diameter. The ratio (d75 / d25) (hereinafter simply referred to as the ratio (d75 / d25)) is preferably 1.1 or more and 1.5 or less.

  When the ratio (d75 / d25) is 1.1 or more and 1.5 or less, the variation in pore diameter is reduced, so that both the thermal shock resistance and the mechanical properties can be improved. It can be made hard to produce a crack in a sintered compact.

  The pore diameters (d25) and (d75) of the pores of the porous sintered body are obtained, for example, by calculating the pore diameter of the porous sintered body by the following equation (1), and accumulating 25% by volume in the cumulative distribution curve. And the pore diameter corresponding to 75% by volume may be obtained as the pore diameters (d25) and (d75), respectively. The pore size cumulative distribution curve is a curve showing the cumulative distribution of pore diameters, where the horizontal axis in the two-dimensional graph is the pore diameter and the vertical axis is the percentage of the cumulative pore volume of the pore diameter. It shows the distribution range of.

  The pore diameters (d25) and (d75) of the pores of this porous sintered body may be determined according to the mercury intrusion method. Specifically, first, a sample is cut out from the substrate so that the mass is 2 g or more and 3 g or less. Next, using a mercury intrusion porosimeter, mercury is injected into the pores of the sample, and the pressure applied to the mercury and the volume of mercury that has entered the pores are measured.

The volume of mercury is equal to the volume of pores, and the following formula (1) (Washburn's relational expression) is established for the pressure applied to mercury and the pore diameter.
d = −4σcos θ / P (1)
Where d: pore diameter (m)
P: Pressure applied to mercury (Pa)
σ: Surface tension of mercury (0.485N / m)
θ: Contact angle between mercury and pore surface (130 °)
From the equation (1), each pore diameter d for each pressure P is obtained, and distribution of each pore diameter d and cumulative pore volume can be derived. Then, the respective pore diameters (d25) and (d75) corresponding to the cumulative pore volume percentages of 25 volume% and 75 volume% may be obtained.

  Moreover, according to the member for heat treatment of this embodiment, it is preferable that the corrosion-resistant layer further includes at least one of lithium, cobalt, manganese, nickel, and phosphorus. When any one of these components is included, when the temperature of the positive electrode material for a lithium ion secondary battery is heat-treated, an oxide film containing the above components is formed on the surface of the heat-treating member, and the erosion component Since the diffusion rate of the heat treatment becomes slow, the member for heat treatment becomes difficult to be eroded. In particular, it is more preferable that each content of lithium, cobalt, manganese, nickel, and phosphorus is 3% by mass or more and 5% by mass or less. The content of these components can be determined by fluorescent X-ray analysis or ICP (Inductively Coupled Plasma) emission spectroscopy. The oxide film can be identified using thin film X-ray diffraction or X-ray photoelectron spectroscopy.

The main surface of the substrate constituting the heat treatment member of the present embodiment has arithmetic average roughness R _a , ten-point average roughness R _zJIS , skewness R _sk and kurtosis R _{ku of 2} to 6 μm, 14 to 22 μm, It is suitable that it is −1, 1, 2 to 5. In particular, the kurtosis R _ku is preferably 3 or more and 5 or less, and if it is within this range, the sharpness of the main surface is increased, so that the adhesion of the corrosion-resistant layer to the substrate is increased.

The arithmetic average roughness R _a , ten-point average roughness R _zJIS , skewness R _sk and kurtosis R _ku may be measured in accordance with JIS B 0601-2001, and the measurement length and cut-off value are 5 mm each. And 0.8 mm, when measuring using a stylus type surface roughness meter, for example, a stylus having a stylus tip radius of 2 μm is applied to the main surface of the substrate, and the scanning speed of the stylus is 0.5 What is necessary is just to calculate the average value of 5 places obtained by setting to mm / sec.

  Next, the heat treatment container of this embodiment will be described.

  The heat treatment container of the present embodiment preferably includes the heat treatment member of the present embodiment described above.

  FIG. 1 is a perspective view showing an example of the heat treatment container of the present embodiment.

The heat treatment container of the example shown in FIG. 1 is a heat treatment container 10 made of the heat treatment member 1 of this embodiment, and its shape is a mortar shape. The heat treatment member 1 is a base 1a made of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite or cordierite.
And a corrosion-resistant layer 1b mainly composed of magnesium oxide formed on at least a part of the inner surface of the base 1a. The shape of the heat treatment container 10 may be a bowl shape or a square shape other than a mortar shape, and is particularly limited as long as it has a shape of a bowl that can place a heat treatment object in the container. is not.

  2A and 2B show another example of the heat treatment container of the present embodiment, in which FIG. 2A is a perspective view and FIG. 2B is a cross-sectional view taken along line A-A ′.

  The heat treatment container 20 in the example shown in FIG. 2 includes a support body 2 made of the heat treatment member of the present embodiment and a frame body 3 placed on the support body 2, and is supported by the frame body 3. This is a container for placing an object to be heat-treated on the body 2. The support 2 includes a base 2a made of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite or cordierite, and magnesium oxide formed on at least a part of the inner surface of the base 2a. And a corrosion-resistant layer 2b as a main component. Moreover, the corrosion-resistant layer 4 which has a magnesium oxide as a main component can also be provided in the at least lower side surface of the inner surface side wall of the frame 3, and the example provided with this corrosion-resistant layer 4 in the container 20 for heat processing shown in FIG. ing.

  FIG. 3 shows still another example of the heat treatment container of the present embodiment, (a) and (b) are a perspective view and a plan view, respectively, and (c) is a cross-sectional view taken along the line BB ′. .

  The heat treatment container 30 of the example shown in FIG. 3 includes a support body 5 made of the heat treatment member of the present embodiment and a frame body 7 provided with a cavity portion 6 that accommodates the support body 5. A corrosion-resistant layer 8 mainly composed of magnesium oxide is provided on at least the lower side of the side wall. The frame 7 can be a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite or cordierite.

  Here, the support 5 includes a base 5a made of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite, or cordierite, and a surface of the base 5a on the side on which the heat-treated object is placed. And a corrosion-resistant layer 5b mainly composed of magnesium oxide formed at least in part.

  The heat treatment container 30 is arranged so that the frame 7 has a through-hole 9 connected to the cavity 6, one end is located in the through-hole 9 and the other end is located in the cavity 6. The stationary member 11 which is a triangular plate-like body for placing the support body 5 on the cavity portion 6 from above is provided. Since the other end of the stationary member 11 is positioned above the support body 5, the support body 5 can be placed so that the position does not shift even if the frame body 7 is reversed or moved. The stationary member 11 is not limited to a triangular shape, and may be, for example, a quadrangular shape.

  Further, on the bottom surface of the frame body 7, a gap member 12 for providing a space between the lower surface of the support body 5 and the bottom surface of the frame body 7 is provided. With such a configuration, even when the positive electrode material for a lithium ion secondary battery is heat-treated using the heat treatment container 30, for example, the support 5 Since the lower surface of the support body 5 is gradually cooled than when the bottom surface of the frame body 7 is in contact with the bottom surface of the frame body 7, it is less likely to receive a strong thermal shock. Therefore, it is preferable that a space is formed between the bottom surface of the frame body 7 and the lower surface of the support body 5 because the support body 5 is less likely to be damaged such as cracks even if heating and cooling are repeated. As the gap member 12, a member having the same component as that of the frame body 7 or the base body 5a is preferably used from the viewpoint of preventing cracks during heat treatment.

Here, in the heat treatment container 30, it is preferable that the stationary member 11 is made of ceramic, and the porosity of the base 5a is higher than the porosity of the gap member 12.

  When the porosity of the substrate 5a is higher than the porosity of the gap member 12, the strength of the gap member 12 can be made relatively higher than the strength of the substrate 5a. It is preferable because cracks are unlikely to occur in the gap member 12 even if the inversion is repeated. Moreover, since the mass of the support body 5 will become light if the porosity of the base | substrate 5a becomes relatively high, it is more suitable also at the point of handling.

  Note that the porosity of the support 5 and the stationary member 11 is preferably 30% by volume or less in order to have sufficient mechanical strength, and in order to make the generated cracks less likely to progress. It is suitable that it is 15 volume% or more.

Furthermore, the difference between the porosity of the support 5 and the porosity of the stationary member 11 is preferably 1% by volume or more and 5% by volume or less. If the difference between the porosity of the support 5 and the porosity of the stationary member 11 is within this range, the expansion and contraction behaviors of the support 5 and the stationary member 11 are substantially the same even when heating and cooling are repeated. The distance between the upper surface of the corrosion-resistant layer 5b and the lower surface of the stationary member 11 can be reduced. If this interval is narrow, the impact force applied to the stationary member 11 is small even if the frame body 7 is inverted to take out the object to be heat treated, so that the stationary member 11 is hardly cracked even if the frame body 7 is repeatedly inverted. Become. In addition, each porosity of the support body 5 and the stationary member 11 can be calculated | required based on the Archimedes method.

  Moreover, it is preferable that the main components of the base body 5a and the stationary member 11 are the same. In this case, the difference in shrinkage between the base body 5a and the stationary member 11 is reduced, so that the top surface of the corrosion-resistant layer 5b and the stationary member are The distance from the lower surface of 11 can be further reduced.

  Here, the main components of the corrosion-resistant layers 4 and 8 shown in FIGS. 2 and 3 are components having the largest content among the components constituting each, and the main components in the corrosion-resistant layers 4 and 8 are each 95 mass. % Or more is more preferable.

  The composition of the components contained in the corrosion-resistant layers 4 and 8 can be identified using an X-ray diffraction method. Moreover, the amount of each element contained in the corrosion-resistant layers 4 and 8 can be determined by fluorescent X-ray analysis or ICP (Inductively Coupled Plasma) emission spectroscopic analysis.

  The heat treatment containers 10, 20, and 30 shown in FIGS. 1 to 3 include the heat treatment members 1, 2, and 5 of the present embodiment that have high corrosion resistance over a long period of time. Can be used.

  Furthermore, since the corrosion resistant layers 4 and 8 are formed in the heat treatment containers 20 and 30 in the example shown in FIGS. 2 and 3, respectively, the corrosion resistance of the frames 3 and 7 is increased. Can be raised.

  The heat treatment containers 20 and 30 in the examples shown in FIGS. 2 and 3 are heat treatment containers in which the corrosion resistant layers 4 and 8 are formed, respectively, but the requirements for the corrosion resistance of the frames 3 and 7 are not strict. If the corrosion resistant layer is not formed, there is no problem.

  Further, the heat treatment member of the present embodiment described above may be preferably used as a member constituting a rotary retort furnace or a rotary heat treatment furnace other than the heat treatment container described above.

  Next, the manufacturing method of the member for heat processing and the container for heat processing of this embodiment is demonstrated.

First, a substrate made of a porous sintered body having aluminum oxide, magnesium metalate, mullite, or cordierite as a main component and having an average pore diameter of, for example, 90 μm or more and 100 μm or less is prepared.

On the surface of the substrate on which the object to be heat-treated is placed, a slurry containing 4% by mass or more and 6% by mass or less of a powder mainly composed of magnesium oxide and using ion-exchanged water as a solvent is applied by, for example, a brush coating method Apply and dry at room temperature. Here, in order for the magnesium oxide crystal particles forming the corrosion-resistant layer to be nanoparticles, a powder having a particle size of 1 nm to 100 nm may be used. In addition, by repeating the operations of applying a plurality of times of application, applying a slurry whose amount is appropriately adjusted, and drying, the magnesium oxide particles can easily penetrate into the inside of the substrate, and the amount of application and the number of times of application per time By appropriately adjusting, magnesium oxide can be present within the above range of the surface layer.

  And after the apply | coated slurry dries, the member for heat processing of this embodiment can be obtained by heat-processing with temperature and holding time being 1000 degreeC or more and 1200 degrees C or less and 2 hours or more and 3 hours or less, respectively.

  In addition to the above method, the substrate may be formed of a laminate. In this case, a layer to be a layer on the inner surface side of the laminate is prepared by containing magnesium oxide, and the other layers are layers not containing magnesium oxide, and these are sequentially laminated to form a laminate. Good.

  In order to obtain the heat treatment containers 10, 20 and 30 of the example shown in FIGS. 1 to 3, first, the slurry is applied to at least the lower side of the inner surface of the base 1 a and the inner surfaces of the side walls constituting the frames 3 and 7. For example, it is applied by a brush coating method and dried at room temperature.

  Then, after the applied slurry is dried, the base 1a and the frames 3 and 7 are heat-treated at a temperature and a holding time of 1000 ° C. or more and 1200 ° C. or less and 2 hours or more and 3 hours or less, respectively. , 8 are formed. Here, the heat treatment container 10 can be manufactured by the above manufacturing method.

  And the container 20 for heat processing can be obtained by mounting the frame 3 in which the corrosion-resistant layer 4 was formed on the member (support body) 2 for heat processing obtained by the method mentioned above.

  In addition, after the gap member 12 and the heat treatment member (support) 5 are sequentially placed on the bottom surface of the frame 8 on which the corrosion-resistant layer 5 is formed, the stationary member 11 is inserted into the penetrating portion 9, whereby the heat treatment container You can get 30.

  The heat treatment containers 10, 20, and 30 using the heat treatment members 1, 2, and 5 of the present embodiment produced by such a manufacturing method have excellent corrosion resistance and are used for a long period of time. be able to.

  In addition, although the member for heat processing of this embodiment can be used suitably for the heat processing of the positive electrode material of a lithium ion secondary battery, it contains a lithium compound and a transition metal (for example, Mn, Co, Ni) compound. Needless to say, it can be used for heat treatment of electronic components such as varistors, thermistors, piezoelectric elements or ceramic capacitors, or lithium compound or transition metal raw materials themselves.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

First, the content of aluminum oxide, magnesium metalate (magnesium aluminate and magnesium titanate), mullite and cordierite shown in Tables 1 and 2 is 90% by mass for cordierite, and 60% by mass for the other. Each substrate was prepared from a porous sintered body having a pore diameter of 95 μm. Then, on the surface of each of the substrates on the side on which the object to be heat-treated is placed, purity and average particle diameter (D ₅₀ ) of 99.98% by mass and 50 nm of magnesium oxide powder, purity and average particle diameter (D ₅₀ ) and a zirconium oxide powder of 98% by mass and 50 nm, respectively, were prepared by applying a slurry in which the content of zirconium oxide in the corrosion-resistant layer had the values shown in Tables 1 and 2, and applied to the substrate. Dried at room temperature. The content of magnesium oxide powder was 4% by mass with respect to the slurry. Moreover, ion-exchanged water was used as the solvent for the slurry.

  After the applied slurry is dried, the substrate is heat-treated at a temperature and holding time of 1100 ° C. for 2 hours, respectively, so that the main components are aluminum oxide, magnesium metalate, mullite and cordierite shown in Tables 1 and 2. Sample No. 2 was provided with a corrosion-resistant layer mainly composed of nano-sized magnesium oxide having a mean particle size of crystal grains smaller than the mean pore size of the substrate. 1-6, 8-13, 15-20, 22-27 and 29-34 were produced.

Sample No. except that the average crystal grain size of the magnesium oxide crystal particles was 100 μm.
. In the same manner as 6, 13, 20, 27, and 34, the crystalline particles were applied to a substrate made of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite and cordierite shown in Tables 1 and 2. Sample No. 1 provided with a corrosion-resistant layer mainly composed of magnesium oxide having an average crystal grain size larger than the average pore size of the substrate. 7, 14, 21, 28 and 35 were prepared.

  Magnesium oxide and zirconium oxide in the corrosion-resistant layer of each sample are identified by thin film X-ray diffraction, and the zirconium oxide content is determined by ICP (Inductively Coupled Plasma) emission spectroscopic analysis. Was converted to oxide.

  Next, thermal shock resistance evaluation of each sample was performed by the method shown below. Each sample was held at a high temperature for 5 hours in a firing furnace, then rapidly cooled outside the firing furnace, and the temperature difference between the temperature when the crack was first observed in the corrosion-resistant layer and the room temperature was defined as the thermal shock temperature ΔT. . The observation method was to observe the corrosion-resistant layer using an optical microscope at a magnification of 50 times. The contents of zirconium oxide and the thermal shock temperature ΔT are shown in Tables 1 and 2.

  In addition, for the corrosion resistance evaluation of each sample, first, a disk-shaped molded body (erosion component) made of a powder obtained by mixing each powder of lithium oxide and cobalt oxide was placed on the upper surface of each sample, The maximum temperature and holding time were kept at 1000 ° C for 10 hours in the firing furnace. And after completion | finish of holding | maintenance, it cooled to 400 degreeC with the temperature-fall rate of 150 degreeC / hour, and cooled to normal temperature after that.

  The mass change rate of each sample was calculated based on the following formula (2). The calculated mass change rate values are shown in Tables 1 and 2. It can be said that the smaller the mass change rate, the harder the sample is eroded by the erosion component.

(W ₁ −W ₀ ) / W ₀ × 100 (%) (2)
(W ₀ : Mass of sample before holding (g) W ₁ : Mass of sample after holding (g))

The main component of the substrate is the component shown in Table 1, and the average crystal particle size of the magnesium oxide crystal particles forming the corrosion-resistant layer is smaller than the average pore size of the porous sintered body as the substrate. 1-6, Sample No. 8-13, sample no. 15-20, Sample No. 22-27 and sample no. In all of 29 to 34, the thermal shock temperature ΔT is 900 ° C. or higher, and the average crystal grain size of the magnesium oxide crystal particles forming the corrosion-resistant layer is larger than the average pore size of the porous sintered body as the substrate. Sample no. 7, Sample No. 14, Sample No. 21, Sample No. 28 and Sample No. It can be said that the thermal shock resistance is better than 35. In other words, by making the average crystal grain size of the magnesium oxide crystal particles that form the corrosion resistant layer smaller than the average pore size of the porous sintered body that is the substrate, cracks occur in the corrosion resistant layer even when heat treatment is repeated. It can be said that it is difficult. Furthermore, sample no. 1-6, Sample No. 8-13, sample no. 15-20, Sample No. 22-27 and sample no. Nos. 29 to 34 have a mass change rate of 0.4% or less. 8, sample no. 15, Sample No. 22, Sample No. 29 and Sample No. Compared with 36, it can be said that it is hard to be eroded by the erosion component.

The main components of the base are aluminum oxide, magnesium metalate (magnesium aluminate and magnesium titanate), mullite and cordierite, respectively, and the average crystal grain size of the magnesium oxide crystal particles forming the corrosion-resistant layer is the base. Sample No. which is a sample smaller than the average pore diameter of the porous sintered body. 1-6, Sample No. 8-13, sample no. 15-20, Sample No. 22-27, sample no. In Nos. 29 to 34, the corrosion-resistant layer contains Sample Nos. 1 to 13% by mass of zirconium oxide. 1-5, Sample No. 8-12, sample no. 15-19, Sample No. 22-26, Sample No. Nos. 29 to 33 have a thermal shock temperature ΔT of 900 ° C. or higher, and have higher thermal shock resistance than Sample Nos. 6, 13, 20, 27, and 35 that do not contain zirconium oxide. It can be said that cracks are less likely to occur in the layer. Furthermore, sample No. 2 containing 2% by mass or more and 12% by mass or less of zirconium oxide. 2-4, Sample No. 9-11
, Sample No. 16-18, Sample No. 23-25, Sample No. 30 to 32 have a thermal shock temperature ΔT of 970
It was found that even when the heat treatment was repeated at a temperature of ℃ or higher, cracks were not easily generated in the corrosion-resistant layer, and the mass change rate was 0.3% or less, and the corrosion resistance was particularly good.

1: Heat treatment member 1a: base 2, 5: support (heat treatment member)
3, 7: Frames 1b, 2b, 4, 8, 5b: Corrosion resistant layer 6: Cavity portion 9: Through portion
11: Stationary member
12: Gap member
10, 20, 30: Container for heat treatment

Claims (6)

A substrate made of a porous sintered body mainly composed of aluminum oxide, magnesium metalate, mullite or cordierite;
A heat treatment member comprising a corrosion-resistant layer mainly composed of magnesium oxide formed on at least a part of the surface of the substrate,
A heat treatment member, wherein an average crystal grain size of magnesium oxide crystal particles forming the corrosion-resistant layer is smaller than an average pore size of the porous sintered body.   The heat-treating member according to claim 1, wherein the magnesium oxide crystal particles are nanoparticles.   3. The heat treatment member according to claim 1, wherein magnesium oxide is present in a surface layer on the corrosion-resistant layer side of the substrate.   The heat-treating member according to any one of claims 1 to 3, wherein the corrosion-resistant layer contains zirconium oxide.   The heat treatment member according to any one of claims 1 to 4, wherein the corrosion-resistant layer further contains at least one of lithium, cobalt, manganese, nickel, and phosphorus.   A heat treatment container comprising the heat treatment member according to any one of claims 1 to 5.

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