JP2016056215A - Method for producing abrasive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an abrasive material, by which an amount of use of cerium oxide can be suppressed, a high speed of polishing for harder glass substrate can be obtained, and surface roughness of a material to be polished can be reduced.SOLUTION: The method for producing an abrasive material containing a core-shell type inorganic particle is provided that comprises a calcination step in which a precursor of the core-shell type inorganic particle is calcined at a temperature of 500 to 1200°C for 1 to 5 hours, the precursor comprising: a core containing at least salts of at least one element selected from yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd), and terbium (Tb); and a shell 2 containing salts of at least one element selected from the aforementioned eight elements and a salt of cerium (Ce).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing an abrasive. More specifically, the present invention relates to a method for producing an abrasive containing core-shell type inorganic particles containing a salt of an element such as yttrium in a core and a salt of an element such as yttrium and a cerium salt in a shell.

  As an abrasive that precisely polishes optical glass and semiconductor devices in the finishing process, a rare earth element oxide, which is mainly composed of cerium oxide and lanthanum oxide, neodymium oxide, praseodymium oxide, etc., has been used. . Other abrasives include diamond, iron oxide, aluminum oxide, zirconium oxide, colloidal silica, etc., but when compared in terms of polishing rate and surface roughness of the polished object, cerium oxide Is known to be effective and is used extensively.

  However, cerium oxide is unevenly distributed worldwide, and it cannot be said that the supply is stable. Therefore, establishment of a manufacturing method of an abrasive that can polish glass with high accuracy while reducing the amount of cerium oxide used is required.

  For example, Patent Document 1 describes a method in which a cerium-based abrasive having a crystallite diameter of 20 to 40 nm (200 to 400 mm) obtained by firing at a temperature of 850 to 1100 ° C. for 1 to 10 hours is described. In this method, a cerium-based abrasive is obtained by mixing and grinding a mixed rare earth oxide and a mixed rare earth fluoride.

  However, since the cerium-based abrasive obtained by the method of Patent Document 1 has a low cerium concentration on the outermost surface of the particles, a sufficient polishing rate cannot be obtained.

  In addition, as a specific example of the object to be polished, for example, a glass substrate for hard disk can be mentioned, but in order to increase the recording density, the glass substrate for hard disk can be obtained by reducing the surface roughness of the glass substrate. There is a tendency to shorten the distance to the magnetic head.

  However, if the average particle size of the particles contained in the abrasive is reduced in order to reduce the surface roughness, there is a problem that the polishing rate is lowered and the productivity is also lowered.

  In addition, demands for improvement in mechanical characteristics, in particular, hardness and rigidity, are increasing year by year for glass substrates for hard disks in order to suppress disk shake when rotating at high speed. In order to satisfy these mechanical property requirements, a tempered glass substrate mainly composed of aminosilicate and a crystallized glass substrate mainly composed of lithium silicate have been used.

  However, these glass substrates have excellent chemical resistance and are hard, so that workability is poor, and the polishing rate becomes extremely slower than when a conventional glass substrate is polished. Moreover, since these glass substrates are harder than the conventional glass substrate, there exists a problem that a board | substrate is easily damaged by applying a high pressure compared with the case where the conventional glass substrate is grind | polished.

JP 2006-97014 A

  The problem of the present invention has been made in view of the above problems / situations, and the problem to be solved is that the amount of cerium used can be suppressed and a higher polishing rate can be obtained for a harder glass substrate. An object of the present invention is to provide a method for producing an abrasive that can reduce the surface roughness of an abrasive.

In order to solve the above problems, the present inventor, in the process of examining the cause of the above problems, yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium ( Eu), a core containing a salt of at least one element selected from gadolinium (Gd) and terbium (Tb), a salt of at least one element selected from the eight elements, and a salt of cerium (Ce) The present inventors have found that it is effective to calcine a precursor of core-shell type inorganic particles having a shell within a specific temperature range for a specific time.
That is, the said subject which concerns on this invention is solved by the following means.

1. A method for producing an abrasive containing core-shell type inorganic particles,
Contains a salt of at least one element selected from yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd) and terbium (Tb) A core-shell type inorganic particle precursor having a core containing a shell containing at least one elemental salt selected from the eight elements and a cerium (Ce) salt within a range of 500 to 1200 ° C. The manufacturing method of the abrasive | polishing material characterized by having the baking process which bakes within the range of 1 to 5 hours at temperature.

2. Producing the precursor of the core-shell type inorganic particles through at least a core-forming step, a shell-forming step, and a solid-liquid separation step of separating the precursor from the reaction solution,
2. The precursor is calcined within a range of 300 to 490 ° C. for 1 to 5 hours after the solid-liquid separation step and before the calcining step. Manufacturing method for abrasives.

  3. 2. The method for producing an abrasive according to item 1, wherein the temperature increase rate of the firing temperature in the firing step is in the range of 20 to 50 ° C./min.

  4). 3. The method for producing an abrasive according to claim 1 or 2, wherein a temperature decreasing rate for cooling the precursor is within a range of 1 to 20 ° C./min after the firing step.

  5. The method for producing an abrasive according to any one of claims 1 to 4, wherein a firing apparatus for firing the precursor in the firing step is a roller hearth kiln or a rotary kiln.

6). The core formation step forms a basic carbonate of at least one element selected from yttrium, titanium, strontium, barium, samarium, europium, gadolinium and terbium by adding a urea compound, Forming a core of the precursor as a main component,
In the shell forming step, an aqueous solution prepared from nitrate of at least one element selected from the eight elements and nitrate of cerium is added, and at least one selected from the eight elements is outside the core. The abrasive according to any one of items 2 to 5, which is a step of forming a shell of the precursor containing an elemental basic carbonate and a cerium basic carbonate. Manufacturing method.

By the above means of the present invention, the amount of cerium used can be suppressed, a high polishing rate can be obtained for a harder glass substrate, and the surface roughness of the object to be polished can be reduced.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
By setting the firing temperature in the firing step within the range of 500 to 1200 ° C. and the firing time within the range of 1 to 5 hours, particles having a crystallite size suitable as an abrasive grow and are sufficient for polishing. It is considered that an abrasive containing core-shell type inorganic particles having hardness is obtained.

Schematic diagram showing the flow of the abrasive manufacturing process Schematic diagram showing particle crystallites and particle size The graph which shows the temperature change in a temporary baking and a baking process typically Schematic diagram showing the structure of the core-shell type inorganic particles contained in the abrasive

  The method for producing an abrasive of the present invention is a method for producing an abrasive containing core-shell type inorganic particles, and includes yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium ( Sm), europium (Eu), gadolinium (Gd), a core containing a salt of at least one element selected from terbium (Tb), a salt of at least one element selected from the eight elements, and cerium (Ce) The precursor of the core-shell type inorganic particles having a shell containing a salt of the above is calcined at a temperature in the range of 500 to 1200 ° C. for 1 to 5 hours. . This feature is a technical feature common to the inventions according to claims 1 to 6.

  As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, at least the core / shell type inorganic particle precursor is separated from the reaction solution by at least the core forming step, the shell forming step and the reaction solution. Preferably, the precursor is manufactured through a separation step, and after the solid-liquid separation step and before the baking step, the precursor is pre-fired within a range of 300 to 490 ° C. for 1 to 5 hours. . Thereby, it is considered that an abrasive containing core-shell type inorganic particles having sufficient durability against pressure during polishing is obtained by sufficiently growing crystallites forming the core.

  Moreover, it is preferable that the temperature increase rate of the baking temperature in the said baking process exists in the range of 20-50 degrees C / min. Thereby, it is thought that the crystallite of the shell containing many cerium salts grows stably.

  Moreover, it is preferable that the temperature decreasing rate of the temperature which cools the said precursor after the said baking process exists in the range of 1-20 degrees C / min. This makes it possible to suppress the generation of minute cracks between the core and the shell, and since the bonding between layers becomes stronger, the core / shell type is resistant to pressure during polishing and has less unevenness on the outermost surface. It is thought that inorganic particles can be formed.

  Moreover, it is preferable that the baking apparatus which bakes the said precursor at the said baking process is a roller hearth kiln or a rotary kiln. Thereby, heat is uniformly applied to the precursor of the core / shell type inorganic particles contained in the abrasive, which is preferable.

  Further, the core forming step forms a basic carbonate of at least one element selected from yttrium, titanium, strontium, barium, samarium, europium, gadolinium and terbium by adding a urea compound, A step of forming a core of the precursor having a salt as a main component, wherein the shell forming step comprises adding an aqueous solution prepared from a nitrate of at least one element selected from the eight elements and a nitrate of cerium. It is preferable that the step of forming a shell of the precursor containing a basic carbonate of at least one element selected from the eight elements and a basic carbonate of cerium outside the core. As a result, it is possible to produce an abrasive containing core-shell type inorganic particles exhibiting monodispersity suitable for an abrasive with few impurities.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<Outline of manufacturing method of abrasive>
The method for producing an abrasive of the present invention is a method for producing an abrasive containing core-shell type inorganic particles, and includes yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium ( Sm), europium (Eu), gadolinium (Gd), a core containing a salt of at least one element selected from terbium (Tb), a salt of at least one element selected from the eight elements, and cerium (Ce) The precursor of the core-shell type inorganic particles having a shell containing a salt of the above is calcined at a temperature in the range of 500 to 1200 ° C. for 1 to 5 hours. .

Common abrasives include those made by dispersing abrasive particles such as bengara (αFe ₂ O ₃ ), cerium oxide, aluminum oxide, manganese oxide, zirconium oxide, colloidal silica in water or oil to form a slurry. is there.

  The present invention is a chemical mechanical polishing method for polishing semiconductor devices and glass, in which polishing is performed by both physical action and chemical action in order to obtain a sufficient polishing rate while maintaining flatness with high accuracy. This is a method for producing an abrasive containing core-shell type inorganic particles containing cerium capable of being subjected to (CMP; Chemical Mechanical Polishing), and will be described in detail below.

<Abrasive manufacturing method>
Below, the manufacturing method of the abrasive | polishing material containing the core-shell type inorganic particle (refer FIG. 4) which consists of the core 1 and the shell 2 is shown.
As shown in FIG. 1, the method for producing abrasive particles of the present invention is preferably a production method of an aspect comprising four steps of a core formation step, a shell formation step, a solid-liquid separation step, and a firing step.

1. Core formation step The core formation step is selected from yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd) and terbium (Tb). An embodiment is preferred in which a salt of at least one element is formed, and the core 1 of a precursor of abrasive particles mainly containing the salt is formed. In addition, Ce, Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, The core 1 may be formed using a salt of at least one element selected from the group consisting of Th and an alkaline earth metal.

Specifically, in the core forming step, for example, a yttrium salt and a precipitant are dissolved in water to prepare a solution having a predetermined concentration. The seed crystal of the core 1 is produced by heating and stirring the solution at 80 ° C. or higher. In the core formation step, a solution prepared with a yttrium salt is further added to the prepared solution, and the mixture is heated and stirred at 80 ° C. or higher. Thereby, the core forming step forms a basic carbonate insoluble in water, for example, yttrium basic carbonate (Y (OH) CO ₃ or Y (OH) CO ₃ .xH ₂ O, x = 1, etc.). Then, by growing yttrium basic carbonate on the outside of the seed crystal, it becomes the core 1 of the precursor of the abrasive particles. In the following description, a solution that has started heating and stirring is referred to as a reaction solution.

  From yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd) and terbium (Tb) dissolved in water in the core formation step A salt of at least one element selected and Ce, Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Dy, Ho, which may be used in combination As the salt of at least one element selected from the group consisting of Er, Tm, Yb, Lu, W, Bi, Th and alkaline earth metals, nitrates, hydrochlorides, sulfates, etc. can be used. Nitrates with low impurities (for example, yttrium nitrate, titanium nitrate, strontium nitrate, barium nitrate, samarium nitrate, europium nitrate, Acid gadolinium, it is preferable to use the terbium nitrate, etc.).

  The precipitating agent may be any alkaline compound that produces a basic carbonate when mixed with water with the element salt and heated, and urea compounds, ammonium carbonate, ammonium hydrogen carbonate, and the like are preferable.

  Examples of urea compounds include urea salts (for example, nitrates and hydrochlorides), N, N′-dimethylacetylurea, N, N′-dibenzoylurea, benzenesulfonylurea, p-toluenesulfonylurea, trimethylurea, tetraethylurea. , Tetramethylurea, triphenylurea, tetraphenylurea, N-benzoylurea, methylisourea, ethylisourea and the like, and urea is also included. Among urea compounds, urea is particularly preferable in that it gradually hydrolyzes to form a precipitate slowly and a uniform precipitate is obtained.

  Further, by forming a basic carbonate insoluble in water, for example, a basic carbonate of yttrium, the deposited precipitate can be dispersed in a monodispersed state. Furthermore, since a basic carbonate of cerium is also formed in the shell formation step described later, a continuous layer structure of basic carbonate can be formed.

  In the following examples, the aqueous solution prepared from the yttrium salt added to the reaction solution in the core formation step and the shell formation step is an aqueous solution of yttrium nitrate prepared by dissolving yttrium nitrate in water. Show. Moreover, although the case where urea is used as a urea compound is shown, it is an example and the present invention is not limited to this.

In the core formation step, for example, the addition rate of an aqueous solution containing a salt of yttrium is preferably 0.003 mol / L to 5.5 mol / L per minute, and is added to the reaction solution while heating and stirring at 80 ° C. or higher. Is preferred. This is because by setting the addition rate within the above range, spherical abrasive particles having excellent monodispersibility are easily formed. This is because when the heating is performed at 80 ° C. or higher, the added urea is easily decomposed. The urea concentration to be added is preferably 5 to 50 times the yttrium ion concentration. This is because it is possible to synthesize spherical abrasive particles exhibiting monodispersity by setting the ion concentration and urea concentration in the aqueous solution of yttrium within the ranges.
If sufficient stirring efficiency is obtained during heating and stirring, the shape of the stirrer is not specified, but a rotor / stator type axial flow stirrer is used to obtain higher stirring efficiency. It is preferable to do.

2. Shell forming step The shell forming step includes yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd) and terbium formed by the core forming step. Prepared from an aqueous solution prepared from a salt of at least one element selected from the above eight elements and a salt of cerium (Ce) in a reaction solution in which a basic carbonate of at least one element selected from (Tb) is dispersed. An embodiment in which a mixed solution of an aqueous solution is added at a constant rate for a predetermined time is preferable. Specifically, when yttrium is used as at least one element selected from the above eight elements, a basic carbonate of yttrium such as yttrium basic carbonate (Y (OH) CO ₃ or Y (OH) CO ₃ .xH ₂ O, x = 1, etc.) and cerium basic carbonates, such as cerium basic carbonates (Ce (OH) CO ₃ or Ce (OH) CO ₃ .xH ₂ O, and a precursor shell 2 of abrasive particles containing x = 1) is formed.
Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th and The shell 2 may be formed using a salt of at least one element selected from the group consisting of alkaline earth metals.

  In addition, as the cerium salt used for the preparation of the aqueous solution, it is preferable to use a nitrate with a small amount of impurities in the product, so the case where cerium nitrate is used has been shown. Sulfates and the like can be used.

  The addition rate of the aqueous solution added in the shell forming step is preferably 0.003 mol / L to 5.5 mol / L per minute. This is because by setting the addition rate within the above range, spherical abrasive particles having excellent monodispersibility are easily formed.

  Moreover, it is preferable that the ratio of the density | concentration of the cerium which the aqueous solution to add contains is 90 mol% or less. This is because when the ratio of the concentration of cerium in the aqueous solution to be added is larger than 90 mol%, when the addition is performed for the same addition time as in the case of adding an aqueous solution prepared to 90 mol% or less, the formed abrasive particles This is because it does not exhibit monodispersibility and aggregates in a plate shape.

  The reaction solution is preferably heated and stirred at 80 ° C. or higher while the aqueous solution is added at the addition rate. This is because when heated and stirred at 80 ° C. or higher, decomposition of urea added in the core forming step easily proceeds.

3. Solid-liquid separation step The solid-liquid separation step separates the precursor of the core-shell type inorganic particles, in which the shell 2 is formed by the shell formation step, from the reaction solution. In the solid-liquid separation step, the obtained core / shell type inorganic particle precursor may be dried and then transferred to the firing step, if necessary.

4). Firing step In the firing step, the precursor of the core / shell type inorganic particles obtained in the solid-liquid separation step is fired in air or in an oxidizing atmosphere within a range of 500 to 1200 ° C. for 1 to 5 hours. . Since the precursor of the core-shell type inorganic particles is calcined to release carbon dioxide, the basic carbonate is converted into an oxide, and the target core-shell type inorganic particles are obtained.

  By firing within the temperature range and the time range, particles having a crystallite size suitable as an abrasive grow, and core-shell type inorganic particles having sufficient hardness during polishing can be obtained. It is considered a thing. Here, the crystallite means the maximum region that can be regarded as a single crystal. Specifically, as shown in FIG. 2, one particle is formed of a plurality of crystallites. Since the growth rate of the crystallite changes depending on the firing temperature and time, a core having a crystallite diameter suitable as an abrasive is obtained by firing within a range of 500 to 1200 ° C. for 1 to 5 hours. It is considered that an abrasive containing shell-type inorganic particles can be produced.

As a specific baking apparatus for baking the precursor of the core-shell type inorganic particles, a known roller hearth kiln or rotary kiln is preferable. Thereby, heat is uniformly applied to the precursor of the core / shell type inorganic particles contained in the abrasive, which is preferable.
As a general roller hearth kiln, for example, a plurality of rollers are installed in the furnace, and the raw material is carried on the roller, so that the area in the furnace can be adjusted according to the temperature such as pre-baking, baking, cooling. it can. Moreover, as a general rotary kiln, for example, it is substantially cylindrical, and the raw material is gradually fed while slowly rotating in the kiln.

Moreover, it is preferable to perform temporary baking after the solid-liquid separation process and before the baking process. Specifically, the pre-baking is preferably performed within the range of 300 to 490 ° C. and 1 to 5 hours. By performing preliminary firing under the conditions, it is considered that the crystallites forming the core 1 are sufficiently grown and an abrasive containing core-shell type inorganic particles having high durability against pressure during polishing can be obtained. . In particular, it is preferable to perform temporary firing within a range of 300 to 400 ° C. and within a range of 2 to 3 hours from the viewpoint of sufficient growth of crystallites.
In addition, also in temporary baking, a well-known roller hearth kiln or rotary kiln can be used similarly to a baking process.

  Furthermore, it is preferable to raise the temperature in the firing step at a rate of temperature rise in the range of 20 to 50 ° C./min. Thereby, it is considered that the crystallites of the shell 2 containing a large amount of cerium grow stably.

  Further, after the firing step, it is preferable to lower the temperature from 500 ° C. to room temperature (25 ° C.) at a temperature lowering rate within the range of 1 to 20 ° C./min. As a result, the generation of minute cracks between the core 1 and the shell 2 can be suppressed, and the bonding between the layers becomes stronger, so that the core is resistant to pressure during polishing and has less unevenness on the outermost surface. It is considered that shell-type inorganic particles can be formed.

  FIG. 3 shows a graph schematically showing temperature changes in the pre-baking and baking steps. As shown in FIG. 3, the precursor of the core-shell type inorganic particles is calcined within the range of 1 to 5 hours within the range of 300 to 490 ° C. before the firing step, and then the range of 500 to 1200 ° C. It is preferable to bake within the range of 1 to 5 hours at the inner temperature. Here, in the present application, the firing in the firing step means firing at a temperature in the range of 500 to 1200 ° C. for 1 to 5 hours. Moreover, temporary baking before a baking process means pre-baking within the range of 1 to 5 hours within the range of 300-490 degreeC before a baking process. The firing step may be a temperature change that does not include the holding time for maintaining a constant temperature in the firing time, and the same applies to the temporary firing.

  In addition, the temporary temperature in the following examples is the maximum temperature before the baking step when there is no temporary baking or the maximum temperature during temporary baking when there is temporary baking. The pre-baking time is a time for performing pre-baking within a range of 300 to 490 ° C. The temporary holding time is the time for which the temporary temperature is held in the temporary baking. Similarly, the temperature is the highest temperature in the firing process. The firing time is the time for firing within the range of 500 to 1200 ° C. in the firing step. The holding time is the time during which the maximum temperature is held in the firing process.

  The rate of temperature increase represents the rate at which the temperature is increased from 500 ° C. to the maximum temperature in the firing step. A cooling rate represents the rate which cools temperature from 500 degreeC to room temperature (25 degreeC) after a baking process.

<Structure of core / shell type inorganic particles>
The “core-shell type inorganic particles” according to the present invention refers to the core (also referred to as “core portion” or “inner core portion”) constituting the inside including the central portion of the inorganic crystal particles, and the innermost of the inorganic crystal particles. An inorganic crystal particle having a crystal structure composed of a shell (also referred to as “shell layer”) constituting an outer shell (also referred to as “outermost layer”).
The core may have a structure having a plurality of layers. Moreover, even if the boundary line which becomes the interface of the said core and shell is clear, the structural component of a core and the structural component of a shell may be mixed near a boundary, and a boundary line may be unclear.
As a method for confirming the shape of the core-shell structure of the inorganic particles according to the present invention, for example, there is a method of visually confirming a boundary line that becomes an interface between the core and the shell using a transmission electron microscope (TEM).
Specifically, for example, first, inorganic particles according to the present invention are sufficiently dispersed in a room temperature curable epoxy resin, embedded, and then dispersed in a styrene fine powder having a particle size of about 100 nm, followed by pressurization. Mold. After the necessary block was dyed together with ruthenium tetroxide or osmium tetroxide, a flaky sample was cut out using a microtome equipped with diamond teeth, and the inorganic material was examined using a transmission electron microscope. A photograph is taken at a magnification (approximately 10000 times) that allows the cross section of one particle to be viewed. Next, in the said photograph, the boundary line used as the interface of a core and a shell is confirmed visually.
Specifically, as the core-shell type inorganic particles according to the present invention, as shown in FIG. 4, a two-layer structure having a core 1 including a center and a shell 2 outside the core 1 is preferable.

  The core 1 is at least one element selected from yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd), and terbium (Tb). Salt, for example, yttrium oxide is contained as a main component (60 mol% or more). This is because a salt such as yttrium oxide is less likely to break than cerium oxide against stress applied during polishing. The seed crystal formed in the core forming step and the basic carbonate formed outside thereof are combined to make the core 1.

  The core 1 is made of Ce, Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Dy, Ho, Er, Tm, Yb, Lu, A salt of at least one element selected from the group consisting of W, Bi, Th, and alkaline earth metal may be used in combination.

  The shell 2 is at least one element selected from yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd), and terbium (Tb). Salts such as yttrium oxide and cerium (Ce) salts such as cerium oxide.

  The shell 2 is at least selected from yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd), and terbium (Tb). In addition to a kind of element salt and cerium (Ce) salt, Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Dy, Ho, At least one element selected from the group consisting of Er, Tm, Yb, Lu, W, Bi, Th, and alkaline earth metal may be used in combination.

  The concentration distribution of the shell 2 may be uniform, but an embodiment in which the composition of cerium oxide continuously increases from the center of the core-shell type inorganic particle toward the surface is preferable. Specifically, the composition of the portion close to the core 1 on the center side of the core-shell type inorganic particles in the shell 2 occupies a large proportion of yttrium oxide. Then, as the core-shell type inorganic particles move from the center side to the surface side, the ratio of the cerium oxide in the composition of the shell 2 continuously increases.

  In addition, about the composition change of the shell 2, it is an example, Comprising: The ratio for which cerium oxide occupies may increase continuously from the core 1 side, and the predetermined area | region on the outermost surface side may become a fixed ratio. The shape of the core-shell type inorganic particles is not limited to a spherical shape, and may be a substantially elliptical shape.

<Shape of core / shell type inorganic particles>
The particle diameter of the core 1 is preferably in the range of 0.015 to 1.1 μm. By setting it within this range, it is possible to maintain high durability against pressure applied during polishing.

  The thickness of the shell 2 is preferably in the range of 0.0025 to 0.45 μm. By setting it within this range, it is possible to produce core / shell type inorganic particles exhibiting monodispersity and excellent in polishing rate and durability.

  The abrasive particles contained in the abrasive differ in the required level for the particle diameter depending on the use application, but as the finished surface accuracy after polishing becomes higher, the abrasive particles contained in the used abrasive particles become finer. I need it. For example, the average particle size needs to be 2.0 μm or less for use in the manufacturing process of a semiconductor device.

  The smaller the particle size of the abrasive, the higher the finished surface accuracy after polishing. On the other hand, the smaller the particle size, the slower the polishing rate. The superiority that the polishing rate of the material is faster than that of an abrasive such as colloidal silica is lost.

  Therefore, the average particle diameter of the core-shell type inorganic particles is preferably in the range of 0.02 to 2.0 μm, and more preferably in the range of 0.05 to 1.5 μm.

  Further, in order to improve the planar accuracy after the polishing process, it is desirable to use an abrasive having the same particle diameter as possible and a small particle diameter distribution variation coefficient.

<Using abrasives and deterioration of abrasives>
Taking a glass substrate as an example, a method of using an abrasive will be described.
1. Preparation of Abrasive Slurry Abrasive powder using core / shell type inorganic particles is added to a solvent such as water to prepare an abrasive slurry. By adding a dispersant or the like to the abrasive slurry, aggregation is prevented, and the slurry is constantly stirred using a stirrer or the like to maintain a dispersed state. The abrasive slurry is circulated and supplied to the polishing machine using a supply pump.

2. Polishing process The glass substrate is brought into contact with the upper and lower surface plates of the polishing machine to which the polishing pad (polishing cloth) is applied, and the pad and the glass are moved relative to each other under pressure while supplying the abrasive slurry to the contact surface. It is polished by that.

3. Abrasive Material Degradation The abrasive material is used under pressure as in the polishing step. For this reason, the core-shell type inorganic particles contained in the abrasive gradually collapse and become finer as the polishing time elapses. Since miniaturization of the core-shell type inorganic particles causes a reduction in the polishing rate, core-shell type inorganic particles having a small change in particle size distribution before and after polishing are desired.

  Hereinafter, although an example and a comparative example are given and explained concretely, the present invention is not limited to these.

  In addition, the baking in a baking process means baking within the range for 1 to 5 hours at the temperature within the range of 500-1200 degreeC. Moreover, temporary baking before a baking process means pre-baking within the range of 1 to 5 hours within the range of 300-490 degreeC before a baking process. The provisional temperature in the table is the highest temperature in provisional firing. The pre-baking time is a time for performing pre-baking within a range of 300 to 490 ° C. The temporary holding time is the time for which the temporary temperature is held in the temporary baking. Similarly, the temperature is the highest temperature in the firing process. The firing time is the time for firing within the range of 500 to 1200 ° C. in the firing step. The holding time is the time during which the maximum temperature is held in the firing process.

  The rate of temperature increase represents the rate at which the temperature is increased from 500 ° C. to the maximum temperature in the firing step. The temperature decreasing rate represents the rate of cooling the temperature from 500 ° C. to room temperature (25 ° C.) after the firing step.

[Example 1]
<Abrasive Material 1: Examples>
(1) Prepare 2 L of 0.02 mol / L yttrium nitrate (III) aqueous solution (hereinafter, simply referred to as “yttrium nitrate aqueous solution”), and then mix it with this aqueous solution so that urea is 0.60 mol / L. The seed crystal was produced by heating and stirring at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) The reaction solution obtained in (2) above is mixed with a 0.48 mol / L yttrium nitrate aqueous solution and a 1.12 mol / L cerium nitrate (III) aqueous solution (hereinafter simply referred to as an aqueous cerium nitrate solution). The liquid was added with heating and stirring at 90 ° C. for 65 minutes at an addition rate of 1 mL / min to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 500 ° C. and fired for 1 hour (of which 1 hour was retained) to obtain core / shell type inorganic particles.

<Abrasive Material 2: Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) was heated to 500 ° C. and fired for 5 hours (of which 5 hours were maintained) to obtain core-shell type inorganic particles.

<Abrasive Material 3: Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 800 ° C. and calcined for 3 hours (retention time 0 hour) to obtain core / shell type inorganic particles.

<Abrasive Material 4: Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Abrasive Material 5: Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 1200 ° C. and fired for 1 hour (of which 0.5 hour was maintained) to obtain core / shell type inorganic particles.

<Abrasive 6: Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 1200 ° C. and fired for 5 hours (retention time 0 hour) to obtain core-shell type inorganic particles.

<Abrasive 7: Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 1200 ° C. and fired for 5 hours (of which 1 hour was maintained) to obtain core-shell type inorganic particles.

<Abrasive Material 8: Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 1200 ° C. and fired for 5 hours (of which 4 hours were maintained) to obtain core / shell type inorganic particles.

<Abrasive Material 9: Comparative Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) was heated to 300 ° C. and held for 5 hours to obtain core / shell type inorganic particles.

<Abrasive Material 10: Comparative Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 300 ° C. and held for 8 hours to obtain core / shell type inorganic particles.

<Abrasive Material 11: Comparative Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 500 ° C. and calcined for 0.8 hours (of which 0.8 hours were maintained) to obtain core / shell type inorganic particles.

<Abrasive 12: Comparative Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 500 ° C. and fired for 6 hours (of which 6 hours were maintained) to obtain core / shell type inorganic particles.

<Abrasive Material 13: Comparative Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) was heated to 1200 ° C. and calcined for 0.8 hours (of which 0.1 hour was maintained) to obtain core-shell type inorganic particles.

<Abrasive 14: Comparative Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 1200 ° C. and fired for 0.8 hours (of which 0.5 hour was maintained) to obtain core / shell type inorganic particles.

<Abrasive 15: Comparative Example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) was heated to 1200 ° C. and fired for 6 hours (of which 1 hour was maintained) to obtain core-shell type inorganic particles.

<Abrasive material 16: Comparative example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 1500 ° C. and baked for 1 hour, and held for 8 hours at 1500 ° C. to obtain core-shell type inorganic particles.

<Abrasive material 17: Comparative example>
(1) 2 L of a 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C. to prepare a seed crystal. .
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes at 90 ° C. Was added with heating and stirring to form shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 1500 ° C. and baked for 5 hours, and 0.5 hours was maintained at 1500 ° C. to obtain core-shell type inorganic particles.

<Evaluation of abrasive>
For abrasives 1 to 17, the polishing rate and the surface roughness after polishing were evaluated according to the following methods.

1. Polishing speed The polishing machine used for the polishing process is a surface to be polished while supplying an abrasive slurry in which a powder of an abrasive using core / shell type inorganic particles is dispersed in a solvent such as water to the surface to be polished. Is polished with a polishing cloth.

  The abrasive slurry had a dispersion medium of only water and a concentration of 100 g / L. In the polishing test, polishing was performed by circulatingly supplying an abrasive slurry at a flow rate of 5 L / min. A glass substrate made of crystallized glass of 65 mmΦ was used as an object to be polished, and a polyurethane cloth was used as the polishing cloth.

The polishing pressure on the polished surface was 9.8 kPa (100 g / cm ² ), the rotation speed of the polishing tester was set to 100 min ⁻¹ (rpm), and polishing was performed for 30 minutes. The thickness before and after polishing was measured with Nikon Digimicro (MF501), and the polishing amount per minute (μm) was calculated from the thickness displacement, and was used as the polishing rate.

2. Surface State after Polishing Regarding the surface state (surface roughness Ra) of the glass substrate surface, a glass substrate that had been polished for 30 minutes in the measurement of “1. Polishing speed” was used as a light wave interference type surface roughness meter (Zygo Surface roughness evaluation was performed using a Dual-channel ZeMapper manufactured by the company. Ra represents the arithmetic average roughness in JIS B0601-2001.

<Evaluation method>
Polishing rate A: Faster than 1.0 μm / min
○: Within the range of 0.3 to 1.0 μm / min
×: Less than 0.3 μm / min Surface state ◎: Surface roughness Ra is less than 0.15 μm
A: Surface roughness Ra is in the range of 0.15 μm or more and less than 0.3 μm.
○: Surface roughness Ra is in the range of 0.3 to 0.5 μm
X: Surface roughness Ra is rougher than 0.5 μm

<Evaluation of abrasive>
The results obtained from the above experimental conditions and evaluation are summarized in Table 1.

  As can be seen from Table 1, the abrasives 1 to 8 as examples of the present invention have a surface roughness Ra as the surface state of the object to be polished within a polishing rate of 0.3 to 1.0 μm / min. 0.5 μm or less. Therefore, it turned out that it is favorable on production as an abrasive and is suitable for using an object to be polished as a hard disk device (HDD).

  On the other hand, the polishing materials 9 to 17 as comparative examples had a polishing rate of less than 0.3 μm / min, and a result that the surface roughness Ra was rougher than 0.5 μm as the surface state of the object to be polished. Thereby, the firing temperature in the firing step is in the range of 500 to 1200 ° C., and the embodiment in which the firing time is fired within the range of 1 to 5 hours is higher than the polishing rate and the surface of the object to be polished. The condition was found to be good.

[Example 2]
<Abrasive 18: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 200 ° C. and temporarily held for 1 hour, and then heated to 800 ° C. and fired for 3 hours (of which 1 hour was held). Shell-type inorganic particles were obtained.

<Abrasive Material 19: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 300 ° C. and pre-baked for 1 hour (of which 1 hour was temporarily held), and then heated to 800 ° C. and burned for 3 hours (of which 1 hour) To obtain core / shell type inorganic particles.

<Abrasive 20: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above is heated to 300 ° C. and pre-baked for 5 hours (of which 5 hours are temporarily held), and then heated to 800 ° C. for 3 hours (of which 1 hour) To obtain core / shell type inorganic particles.

<Abrasive Material 21: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in the above (4) was heated to 490 ° C. and pre-baked for 1 hour (of which 0.5 hour was temporarily held), and then heated to 800 ° C. for 3 hours (of which For 1 hour) to obtain core / shell type inorganic particles.

<Abrasive 22: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 490 ° C. and pre-baked for 5 hours (of which 4 hours were temporarily held), and then heated to 800 ° C. and burned for 3 hours (of which 1 hour) To obtain core / shell type inorganic particles.

<Abrasive Material 23: Comparative Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 300 ° C. and pre-baked for 1 hour (of which 1 hour was temporarily held), then heated to 450 ° C. and held for 1 hour to hold the core -Shell-type inorganic particles were obtained.

<Evaluation of abrasive>
The results obtained from the above experimental conditions and evaluation are summarized in Table 2. The evaluation method is the same as in Example 1.

  As can be seen from Table 2, the abrasives 19 to 22 which are examples of the present invention have a surface roughness Ra of less than 0.15 μm, and are better than the abrasives 4 and 18, which are less likely to be scratched. It turned out to be an abrasive. This is because by performing preliminary firing at 300 to 490 ° C., crystallites forming the core 1 are sufficiently grown, and core-shell type inorganic particles having high durability against pressure during polishing are obtained, and the surface state It is considered that good results were obtained.

  On the other hand, the abrasive 23 as a comparative example was pre-baked at 300 ° C. for 1 hour. However, since the baking temperature in the baking process was 450 ° C., the core-shell type inorganic particles did not grow sufficiently, and the abrasive It is considered that a sufficient polishing rate and surface state could not be obtained.

[Example 3]
<Abrasive Material 24: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) In the firing step, the precursor obtained in (4) above is heated from 500 ° C. to 800 ° C. at a temperature rising rate of 20 ° C./min, and fired for 3 hours (of which 1 hour is maintained), The core / shell type inorganic particles were obtained by cooling from 500 ° C. to room temperature (25 ° C.) at a temperature lowering rate of 30 ° C./min.

<Abrasive 25: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) In the firing step, the precursor obtained in the above (4) is heated from 500 ° C. to 800 ° C. at a rate of temperature rise of 50 ° C./min, and fired for 3 hours (of which 1 hour is held). -Shell-type inorganic particles were obtained.

<Evaluation of abrasive>
The results obtained from the above experimental conditions and evaluation are summarized in Table 3. The evaluation method is the same as in Example 1.

  As can be seen from Table 3, the abrasives 24 and 25, which are examples of the present invention, are abrasives having a polishing rate faster than 1.0 μm / min and superior to the abrasive 4 in terms of production efficiency. It was found to be a better abrasive that can reduce the amount of abrasive used because it is high. This is because the crystallite of the shell 2 containing a large amount of cerium is stably grown by setting the temperature rising rate in the firing step to 20 to 50 ° C./min, so that an excellent abrasive with a higher polishing rate is obtained. It is thought that it was done.

[Example 4]
<Abrasive Material 26: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above is heated from 500 ° C. to 800 ° C. at a rate of temperature increase of 20 ° C./min, fired for 3 hours (of which 1 hour is held), and the temperature decrease rate is 1 ° C. / It cooled from 500 degreeC to room temperature (25 degreeC) by min, and obtained the core-shell type inorganic particle.

<Abrasive material 27: Example>
(1) 2 L of 0.02 mol / L yttrium nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of yttrium nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. A core 1 made of salt was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L yttrium nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution was added at a rate of 1 mL / min for 65 minutes, 90 minutes. Addition with heating and stirring at 0 ° C. formed shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above is heated from 500 ° C. to 800 ° C. at a temperature rising rate of 20 ° C./min, fired for 3 hours (of which 1 hour is held), and the temperature decreasing rate is 20 ° C. / It cooled from 500 degreeC to room temperature (25 degreeC) by min, and obtained the core-shell type inorganic particle.

<Evaluation of abrasive>
The results obtained from the above experimental conditions and evaluation are summarized in Table 4. The evaluation method is the same as in Example 1.

  As can be seen from Table 4, it was found that the abrasives 26 and 27 according to the examples of the present invention are abrasives having a surface state superior to that of the abrasive 24. It is possible to suppress the generation of minute cracks between the core 1 and the shell 2 by setting the temperature lowering rate during cooling after the firing step within the range of 1 to 20 ° C./min. It is considered that an abrasive containing core-shell type inorganic particles that is strong against pressure at the time of polishing and has few irregularities on the outermost surface is obtained by strengthening the bond.

[Example 5]
<Abrasive 28: Example>
(1) 2 L of a 0.02 mol / L titanium nitrate (IV) aqueous solution was prepared, and then mixed with the aqueous solution so that urea was 0.60 mol / L, followed by heating and stirring at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of titanium nitrate (IV) having a concentration of 1.6 mol / L was added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. Core 1 consisting of basic carbonate was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L titanium nitrate (IV) aqueous solution and 1.12 mol / L cerium nitrate aqueous solution is added at a rate of 1 mL / min for 65 minutes. Was added at 90 ° C. with heating and stirring to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Abrasive 29: Example>
(1) 2 L of a 0.02 mol / L strontium (II) nitrate aqueous solution was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, followed by heating and stirring at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of strontium nitrate (II) having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C., Core 1 consisting of basic carbonate was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L strontium nitrate (II) aqueous solution and 1.12 mol / L cerium nitrate aqueous solution is added at a rate of 1 mL / min for 65 minutes. Was added at 90 ° C. with heating and stirring to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Abrasive 30: Example>
(1) A 0.02 mol / L barium (II) nitrate aqueous solution (2 L) was prepared, and then mixed with the aqueous solution so that urea was 0.60 mol / L, followed by heating and stirring at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of barium (II) nitrate having a concentration of 1.6 mol / L was added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. Core 1 consisting of basic carbonate was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L barium nitrate (II) aqueous solution and 1.12 mol / L cerium nitrate aqueous solution is added at a rate of 1 mL / min for 65 minutes. Was added at 90 ° C. with heating and stirring to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Abrasive material 31: Example>
(1) A 2 L aqueous solution of 0.02 mol / L samarium (III) nitrate was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, and heated and stirred at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of samarium (III) nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C., Core 1 consisting of basic carbonate was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L samarium (III) nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution is added at a rate of 1 mL / min for 65 minutes. Was added at 90 ° C. with heating and stirring to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Abrasive material 32: Example>
(1) A 0.02 mol / L aqueous solution of europium (III) nitrate (2 L) was prepared, and then mixed with this aqueous solution so that urea was 0.60 mol / L, followed by heating and stirring at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of europium (III) nitrate having a concentration of 1.6 mol / L is added with heating and stirring at 90 ° C. for 65 minutes at an addition rate of 1 mL / min, Core 1 consisting of basic carbonate was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L europium (III) nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution is added at a rate of 1 mL / min for 65 minutes. Was added at 90 ° C. with heating and stirring to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Abrasive material 33: Example>
(1) A 2 L aqueous solution of 0.02 mol / L gadolinium (III) nitrate was prepared, and then mixed with the aqueous solution so that urea was 0.60 mol / L, followed by heating and stirring at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of gadolinium (III) nitrate having a concentration of 1.6 mol / L is added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. Core 1 consisting of basic carbonate was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L gadolinium (III) nitrate aqueous solution and 1.12 mol / L cerium nitrate aqueous solution is added at a rate of 1 mL / min for 65 minutes. Was added at 90 ° C. with heating and stirring to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Abrasive Material 34: Example>
(1) A 0.02 mol / L aqueous terbium (III) nitrate solution (2 L) was prepared, and then mixed with the aqueous solution so that urea was 0.60 mol / L, followed by heating and stirring at 90 ° C.
(2) To the reaction solution obtained in (1) above, an aqueous solution of terbium (III) nitrate having a concentration of 1.6 mol / L was added at a rate of 1 mL / min for 65 minutes with heating and stirring at 90 ° C. Core 1 consisting of basic carbonate was formed.
(3) To the reaction solution obtained in (2) above, a mixed solution of 0.48 mol / L terbium nitrate (III) aqueous solution and 1.12 mol / L cerium nitrate aqueous solution is added at a rate of 1 mL / min for 65 minutes. Was added at 90 ° C. with heating and stirring to form a shell 2.
(4) The precursor of the core / shell type inorganic particles precipitated from the reaction solution obtained in the above (3) was separated by a membrane filter.
(5) The precursor obtained in (4) above was heated to 100 ° C. and held for 1 hour, then heated to 800 ° C. at a heating rate of 10 ° C./min and calcined for 3 hours (of which 1 hour was And core / shell type inorganic particles were obtained.

<Evaluation of abrasive>
The results obtained by the above experimental conditions and evaluation are summarized in Table 5. The evaluation method is the same as in Example 1.

  As can be seen from Table 5, it was found that the abrasives 28 to 34 according to the examples of the present invention are excellent abrasives similarly to the abrasive 4. This is because the elements used in the abrasives 28 to 34 are resistant to the high pressure applied to the core 1 when polishing, like yttrium, and the shell 2 is contained together with cerium so that it is contained in the shell and between the core and shell. This is thought to be due to the increased binding power.

1 Core 2 Shell

Claims (6)

A method for producing an abrasive containing core-shell type inorganic particles,
Contains a salt of at least one element selected from yttrium (Y), titanium (Ti), strontium (Sr), barium (Ba), samarium (Sm), europium (Eu), gadolinium (Gd) and terbium (Tb) A core-shell type inorganic particle precursor having a core containing a shell containing at least one elemental salt selected from the eight elements and a cerium (Ce) salt within a range of 500 to 1200 ° C. The manufacturing method of the abrasive | polishing material characterized by having the baking process which bakes within the range of 1 to 5 hours at temperature. Producing the precursor of the core-shell type inorganic particles through at least a core-forming step, a shell-forming step, and a solid-liquid separation step of separating the precursor from the reaction solution,
The precursor is calcined within a range of 300 to 490 ° C. for 1 to 5 hours after the solid-liquid separation step and before the calcining step. Manufacturing method for abrasives.   The method for producing an abrasive according to claim 1, wherein a temperature increase rate of the firing temperature in the firing step is in a range of 20 to 50 ° C./min.   The method for producing an abrasive according to claim 1 or 2, wherein the temperature lowering rate of the temperature for cooling the precursor is within a range of 1 to 20 ° C / min after the firing step.   The method for producing an abrasive according to any one of claims 1 to 4, wherein a firing apparatus for firing the precursor in the firing step is a roller hearth kiln or a rotary kiln. The core formation step forms a basic carbonate of at least one element selected from yttrium, titanium, strontium, barium, samarium, europium, gadolinium and terbium by adding a urea compound, Forming a core of the precursor as a main component,
In the shell forming step, an aqueous solution prepared from nitrate of at least one element selected from the eight elements and nitrate of cerium is added, and at least one selected from the eight elements is outside the core. The abrasive according to any one of claims 2 to 5, which is a step of forming a shell of the precursor containing an elemental basic carbonate and a cerium basic carbonate. Manufacturing method.

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