JP2012066370A - Cerium-based abrasive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cerium-based abrasive high in an abrasion speed and capable of achieving a polished surface in which the occurrence of abrasion flaws is reduced as much as possible.SOLUTION: The cerium-based abrasive contains F, an rare earth element Ce, and one kind of rare earth element (RE) selected from 14 kinds of rare earth elements Y, La, ..., other than Ce. The contained amount of F in the abrasive is 5.0-15.0 mass%. The percentage of the mass of cerium oxide occupying in the total rare earth oxide-equivalent mass is 48-90 mass%. The percentage of the mass of the oxide of REoccupying in the total rare earth oxide-equivalent mass is 8-50 mass%. The percentage of the total mass of CeOand the oxide of REoccupying in the total rare earth oxide-equivalent mass is 98 mass% or more. The contained amount of a rare earth element selected from 13 kinds excluding the rare earth element REfrom the 14 kinds of Y, La, ..., is 0.5 mass% or less in the percentage of the mass of each oxide in the 13 kinds of ORE occupying in the total rare earth oxide-equivalent mass.

Description

  The present invention relates to a cerium-based abrasive containing cerium oxide as a main component, and particularly to a cerium-based abrasive containing a rare earth oxide containing F as a main component.

The cerium-based abrasive is produced, for example, by pulverizing, roasting, and classifying as necessary, raw materials such as bastonite concentrate containing abundant rare earth elements including cerium. The produced cerium-based abrasive is mainly composed of cerium oxide (CeO ₂ or the like), and additionally contains oxides of rare earth elements other than cerium such as lanthanum oxide (La ₂ O ₃ or the like). Yes. Moreover, there is a cerium-based abrasive containing fluorine (F) as an abrasive capable of obtaining a higher polishing rate (see Patent Document 1).

The cerium-based abrasive containing fluorine in Patent Document 1 contains fluorine (F) and cerium (Ce), lanthanum (La), praseodymium (Pr), and neodymium (Nd) as rare earth elements, and F is 0.1. The ratio of the weight of neodymium oxide (Nd ₂ O ₃ / TREO) in the total rare earth oxide equivalent weight (hereinafter referred to as TREO) is 5% to 10% by weight, 0.001% to 5% by weight, and TREO The proportion of lanthanum oxide occupying (La ₂ O ₃ / TREO) is 2 wt% to 45 wt%, or the proportion of praseodymium oxide occupying TREO (Pr ₆ O ₁₁ / TREO) is 0.1 wt% to 10 wt%. percent by weight, and the weight ratio of cerium oxide to total TREO _(CeO 2 / TREO) is preferable to be 50% to 90% by weight To have. It has been proposed that the ratio of the total weight of rare earth oxides of cerium, lanthanum, praseodymium and neodymium in TREO is 97% by weight or more.

  Also known is a cerium-based abrasive that focuses on the peak obtained by X-ray diffraction of rare earth oxides using Cu-Kα ray or Cu-Kα1 ray as a cerium-based abrasive with high polishing speed and few polishing scratches. (See Patent Document 2). In Patent Document 2, half of the peak a based on the (111) plane among the peaks obtained by X-ray diffraction using a Cu—Kα ray or a Cu—Kα1 ray of a rare earth oxide containing the rare earth element Ce as a main component. A cerium-based abrasive having a value width of 0.10 to 1.00 ° at 2θ has been proposed.

  These cerium-based abrasives in the prior art have a relatively high polishing rate, and the generation of abrasive scratches is suppressed to some extent. However, recently, there has been a demand for a cerium-based abrasive capable of finishing a highly accurate polished surface, that is, a polished surface in which the generation of polishing scratches is reduced as much as possible.

Table 2004-0922297 JP 2007-106890 A

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a cerium-based abrasive capable of realizing a polished surface that not only has a high polishing speed but also reduces the occurrence of polishing scratches as much as possible. And

  The inventors of the present invention have examined the influence of rare earth elements other than Ce (cerium) on the polishing rate and the generation of abrasion scratches of cerium-based abrasives, and control the oxide ratio of rare earth elements other than Ce. Thus, the inventors have found that not only the polishing speed is increased, but also the generation of polishing scratches can be suppressed as much as possible, and the present invention has been conceived.

The present invention includes F (fluorine), Ce (cerium) as a rare earth element, and Y (yttrium), La (lanthanum), Pr (praseodymium), Nd (neodymium), Sm as rare earth elements other than Ce. (Samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium) 14 In the cerium-based abrasive containing a rare earth element selected from seeds (referred to as RE ^* ) as a main component, the content of F in the cerium-based abrasive is 5.0-15. 0 wt%, cerium oxide in the total rare earth oxide in terms of weight (TREO) ratio of the mass of _{(CeO 2) (CeO 2 /} TREO) 48% to 90% by weight, the total rare earth oxide in terms of weight (TREO), the ratio of the mass of the oxides of rare earth elements kind other than cerium ^{(RE * O) (RE *} O / TREO) is 8 mass % To 50% by mass, and the ratio of the total mass of cerium oxide and an oxide of a rare earth element other than cerium (RE ^* O) in the total rare earth oxide equivalent mass (TREO) ((CeO ₂ + RE ^* O) / TREO) is 98% by mass or more, excluding rare earth elements RE ^* from 14 types of Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. The ratio of the mass of each oxide (each OREO) in each of the thirteen types of ORE, where the rare earth element selected from 13 types (referred to as ORE) occupies the total rare earth oxide equivalent mass (TREO) ((each OREO) / T EO), characterized in that more than 0.5 wt%.

The cerium-based abrasive according to the present invention substantially consists of two types of RE ^* other than Ce and Ce as rare earth elements, and the content of F is 5.0 to 15.0% by mass. The cerium-based abrasive has a high polishing speed equivalent to that of the cerium-based abrasive in the prior art, and the generation of abrasive scratches is extremely suppressed.

RE ^* in the present invention is a kind selected from 14 kinds of rare earth elements other than Ce, such as Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Of rare earth elements. These rare earth elements may be contained in the raw material of the abrasive. However, the rare earth element Pm (promethium) is excluded because it is a radioactive element that does not exist in nature. Usually, cerium-based abrasives often contain La, Pr, or Nd as rare earth elements other than Ce, and may also contain Sm. RE ^* in the present invention is preferably any one of La and Nd, and La is particularly preferable because of its high ability to retain F. This is because, when it is La or Nd, the effect of suppressing the occurrence of abrasive scratches is great. When RE ^* is one of La and Pr, the binary component material of Ce-La or Ce-Pr can be easily separated and purified by solvent extraction. When RE ^* is a rare earth oxide other than La or Pr, it is necessary to separate and purify RE ^* and Ce by solvent extraction, respectively, and remain in a liquid state or be mixed after precipitation.

And RE ^* O in the present invention is selected from 14 types of rare earth elements other than Ce, Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Specifically, Y ₂ O ₃ , La ₂ O ₃ , Pr ₆ O ₁₁ , Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ It is a kind selected from O ₃ , Tb ₄ O ₇ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , and Lu ₂ O ₃ .

In the present invention, ORE refers to 14 types of Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, excluding the rare earth element RE ^*. The selected rare earth element.

Then, the OREO in the present _{invention, Y 2 O 3, La 2} O 3, Pr 6 O 11, Nd 2 O 3, Sm 2 O 3, Eu 2 O 3, Gd 2 O 3, Tb 4 O 7, Dy A rare earth oxide obtained by removing RE ^* O from 14 types of ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , and Lu ₂ O ₃ .

In the present invention, the ratio of the mass of cerium oxide (CeO ₂ ) to the total rare earth oxide equivalent mass (TREO) (CeO ₂ / TREO) is 48 mass% to 90 mass%. CeO ₂ / TREO is preferably 50% by mass to 90% by mass, more preferably 55% by mass to 85% by mass, and further preferably 60% by mass to 80% by mass. When CeO ₂ / TREO is less than 50% by mass, the polishing rate tends to decrease, and when it exceeds 90% by mass, the generation of abrasive scratches tends to increase.

In the present invention, the ratio (RE ^* O / TREO) of the oxide of one kind of rare earth element other than cerium (RE ^* O) in the total rare earth oxide equivalent mass (TREO) is 8% by mass to 50%. % By mass. RE ^* O / TREO is preferably 10% by mass to 50% by mass, more preferably 15% by mass to 45% by mass, and still more preferably 20% by mass to 40% by mass. When RE ^* O / TREO is less than 10% by mass, the occurrence of polishing scratches tends to increase, and when it exceeds 50% by mass, the polishing rate tends to decrease.

In the present invention, the total mass ratio ((CeO ₂ + RE ^* O) / TREO) of cerium oxide and one kind of rare earth element oxide (RE ^* O) other than cerium is 98% by mass or more. (CeO ₂ + RE ^* O) / TREO is preferably 99% by mass or more, and more preferably 99.5% by mass or more. When (CeO ₂ + RE ^* O) / TREO is less than 98% by mass, abrasive scratches tend to increase. The (CeO ₂ + RE ^* O) / TREO may be 100% by mass.

Furthermore, in this invention, it selects from 13 types remove ^| excluding rare earth elements RE ^* from 14 types of Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. The ratio of the mass of each oxide (each OREO) in the 13 kinds of ORE ((each OREO) / TREO) in the total rare earth oxide equivalent mass (TREO) is 0.5% by mass or less. is there. The fact that (each OREO) / TREO is 0.5% by mass or less means that each OREO, that is, Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu Among all the 13 types of rare earth elements excluding the rare earth element RE ^* from the 14 types, all 13 types of oxides are targeted. Specifically, when RE ^* is La, Y ₂ O ₃ , Pr ₆ O ₁₁ , Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₄ O ₇ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , and Lu ₂ O ₃ oxides (each OREO) are targeted. When (each OREO) / TREO exceeds 0.5 mass%, the number of abrasive scratches tends to increase. Preferably, (each OREO) / TREO) is less than 0.1% by mass, and more preferably 0.05% by mass or less.

Even if this (each OREO) / TREO is 0.01% by mass or less, or 0.001% by mass or less, there is substantially no problem. The normal mixed rare earth-based cerium-based abrasive hardly contains any rare earth elements other than La, Ce, Pr, Nd, and Sm, contains the most Ce, and then contains the most La ^. Is La (where RE ^* O is La ₂ O ₃ ), the mass ratio of the respective oxides for Pr ₆ O ₁₁ , Nd ₂ O ₃ , and Sm ₂ O ₃ is 0.5% by mass or less. It can be estimated that the other OREOs are each 0.5% by mass or less. Similarly, for Pr ₆ O ₁₁ , Nd ₂ O ₃ and Sm ₂ O ₃ , if it is confirmed that the mass ratio of each oxide is less than 0.1% by mass, the other OLEO is also set to 0. If it can be estimated that it is less than 1% by mass, and the mass ratio of each of Pr ₆ O ₁₁ , Nd ₂ O ₃ , and Sm ₂ O ₃ is 0.05% by mass or less, other OLEO Each can be estimated to be less than 0.05% by mass.

  In addition, in the present invention, the content of F in the cerium-based abrasive is 5.0 to 15.0 mass%. The F content is preferably 5.0% by mass to 12.0% by mass, and more preferably 5.0% by mass to 10.0% by mass. When the content of F is less than 5.0% by mass, the polishing rate tends to decrease, and when it exceeds 15% by mass, the polishing rate increases, but it tends to easily cause polishing scratches.

The cerium-based abrasive according to the present invention has a CeO in the vicinity of 2θ (diffraction angle) = 28 deg when X-ray peak intensity is measured by an X-ray diffraction method using Cu—Kα ray or Cu—Kα1 ray as an X-ray source. It is preferable that the half width of the peak of the rare earth oxide containing ₂ as a main component is 0.1 to 1.0 deg at 2θ. The half width of this peak is more preferably 0.15 to 0.9 deg, and particularly preferably 0.2 to 0.8 deg. When the half width is less than 0.1 deg, the cerium-based abrasive tends to be easily damaged, and when it exceeds 1.0 deg, the cerium-based abrasive tends to have a low polishing rate.

Further, the cerium-based abrasive according to the present invention, 2 [Theta] (diffraction angle) when measured with X-ray peak intensity by X-ray diffractometry using Cu-K [alpha rays or Cu-K [alpha ₁ line as an X-ray source = 28Deg The intensity ratio (B / A) of the peak intensity (B) of the rare earth oxyfluoride near 2θ (diffraction angle) = 26.5 deg to the peak intensity (A) of the rare earth oxide containing CeO ₂ as a main component in the vicinity. It is preferable that it is 0.05-1.0. The intensity ratio B / A of this peak is more preferably from 0.1 to 0.8, and even more preferably from 0.15 to 0.7. If the peak intensity ratio B / A is less than 0.05, the polishing rate tends to be a cerium-based abrasive, and if it exceeds 1.0, it tends to be a cerium-based abrasive that tends to cause scratches. is there.

The cerium-based abrasive according to the present invention preferably has an average particle size D _{50 of} 50% cumulative volume from the small particle size side in the laser diffraction / scattering particle size distribution measurement of 0.2 to 3.5 μm. . More preferably the average particle diameter _{D 50} is 0.3 to 3.0 [mu] m, more preferably 0.4～2.5Myuemu. When the average particle diameter D ₅₀ is less than 0.2 μm, the polishing speed decreases, and when it exceeds 3.5 μm, the number of polishing flaws tends to increase.

  The cerium-based abrasive according to the present invention is preferably used as a cerium-based abrasive slurry using an aqueous liquid. The aqueous liquid in this case refers to water or a mixture of water and at least one organic solvent having solubility in water within the solubility range, and includes water containing at least 1%. And as an organic solvent, alcohol, a ketone, etc. are mentioned.

  Examples of alcohols that can be used in the present invention include methanol (methyl alcohol), ethanol (ethyl alcohol), 1-propanol (n-propyl alcohol), 2-propanol (iso-propyl alcohol, IPA), 2-methyl-1- Examples include propanol (iso-butyl alcohol), 2-methyl-2-propanol (tert-butyl alcohol), 1-butanol (n-butyl alcohol), 2-butanol (sec-butyl alcohol), and the like. Polyhydric alcohols include 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol), 1,3-propanediol (trimethylene glycol), 1,2,3-propanetriol. (Glycerin).

  Examples of the ketone that can be used in the present invention include propanone (acetone) and 2-butanone (methyl ethyl ketone, MEK). In addition, tetrahydrofuran (THF), N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), 1,4-dioxane and the like can also be used.

  When used as a cerium-based abrasive slurry using the cerium-based abrasive and the aqueous liquid according to the present invention, the cerium-based abrasive content is preferably 0.1% by mass to 50% by mass, and 0.5% by mass. It is more preferable to set it to -40 mass%, and it is further more preferable to set it as 1 mass%-30 mass%.

  The cerium-based abrasive according to the present invention can be generally produced as follows. FIG. 1 shows a schematic flow of the manufacturing process. In FIG. 1, the steps enclosed in parentheses are optional steps.

  First, raw materials will be described. The raw material of the abrasive is one or more of carbonate, monooxy carbonate, hydroxide carbonate, oxalate, hydroxide, oxide (less than 1.0% loss on ignition). Can be used. And what baked 1 or more types of carbonate, monooxy carbonate, hydroxide carbonate, and oxalate, and adjusted the ignition loss (1000 degreeC, 1 hr) to 1.0 to 20% can be used. . As the raw material having an oxide form, one having an ignition loss (1000 ° C., 1 hr) of less than 1.0% can be used. The composition of the raw material is a rare earth element composition similar to the composition of the target cerium-based abrasive, and the composition amount is the same as that of the cerium-based abrasive as an oxide equivalent amount. The F content of the raw material is not particularly limited, but since the raw material may contain moisture, carbonate radicals, etc., when viewed as the ratio of the mass of F to the total rare earth oxide equivalent mass (TREO) (F / TREO) , 0.5 mass% or less, and usually 0.1 mass% in many cases.

  As a manufacturing method for the above-mentioned raw materials, for example, Ce-containing rare earth concentrates such as bastonite concentrate, monazite concentrate, and Chinese complex ore concentrate are treated by sulfuric acid decomposition method or alkali decomposition method, fractional precipitation, After fractional dissolution and the like, F, U, Th and other rare earth elements are reduced, followed by separation and purification by solvent extraction.

In the raw material production method, generally, a Ce solution (purity CeO ₂ / TREO is 99.9 mass% or more, more preferably 99.99 mass% or more) obtained by separation / purification by solvent extraction, and RE ^* After obtaining a liquid (purity REO / TREO of 99.9% by mass or more, more preferably 99.99% by mass or more), the Ce solution and the RE ^* solution are made to have the composition of the target cerium-based abrasive. So that the Ce solution and the RE ^* solution are separately mixed with the precipitating agent to obtain precipitates, and the respective precipitates have the desired cerium-based abrasive composition. Mix.

When RE ^* is La, a Ce-La solution composed of Ce and La can be obtained by almost completely removing the rare earth element having a larger atomic number than Y, Pr and Pr by solvent extraction. However, when adjusting the ratio of Ce and La, a part of Ce or a part of La can be removed.

  As a precipitant, ammonium carbonate, ammonium carbonate, sodium carbonate, sodium hydrogen carbonate, urea, guanidine carbonate, etc. can be used when producing carbonate raw materials, and when producing oxalate, There are acid salts, ammonium oxalate, sodium oxalate and the like, and ammonia or the like can be used when producing hydroxide.

  When the carbonate raw material is produced, part or all of the carbonate raw material may be obtained as monooxy carbonate and / or hydroxide carbonate depending on the production conditions. For example, when an excessive precipitant is present by producing carbonate, or when re-pulping the filtered carbonate with water and then heating to 60 to 100 ° C. (immersion heat treatment), monooxy carbonate and It tends to be a raw material for hydroxide carbonate. Moreover, in the case of a raw material whose ignition loss is adjusted to 1 to 20%, one or more of carbonate, monooxy carbonate, hydroxide carbonate and oxalate is baked at 300 ° C to 700 ° C to adjust the ignition loss. Can be produced. Furthermore, in the case of an oxide raw material, one or more of carbonate, monooxy carbonate, hydroxide carbonate, and oxalate can be fired at 750 ° C. to 1100 ° C. to produce the oxide raw material.

Grinding in schematic flow of FIG. 1, it is preferred that the average particle diameter D ₅₀ of the cumulative volume of 50% from the smaller particle size side in a laser diffraction scattering method particle size distribution measurement is to 0.2 to 3.0 [mu] m, 0. It is more preferable that it is 3-2.5 micrometers, and it is further more preferable that it is 0.4-2.0 micrometers. A known method can be used for this pulverization treatment.

The fluorination treatment in the schematic flow of FIG. 1 can be used with any one of ammonium fluoride, hydrogen fluoride, ammonium hydrogen fluoride, or rare earth fluoride, or a combination of two or more. The fluorine content after the fluorination treatment is preferably 5.5% by mass to 16% by mass in F / TREO, more preferably 5.5% by mass to 13% by mass, and more preferably 5.5% by mass to 11% by mass. Particularly preferred. In this fluorination treatment, if the content of the preferred range described above is deviated, the fluorine content of the resulting cerium-based abrasive may deviate from the scope of the present invention. In addition, it is preferable to perform a washing process and a solid-liquid separation process after the fluorination treatment. However, since the rare earth fluoride is a solid that does not dissolve in water, it is preferably used after pulverizing until the average particle diameter D ₅₀ is about the same as the raw material pulverized before use. In addition, the pulverization treatment and the fluorination treatment can be performed simultaneously by mixing the rare earth fluoride fluoride with the raw material during the pulverization treatment.

  The firing in the schematic flow of FIG. 1 is preferably performed before the firing. Although there is no restriction | limiting in particular in this drying method, For example, when baking with a rotary kiln, a drying process can achieve energy saving by using the rotary dryer using the waste heat of a rotary kiln. When a lump is contained after the drying treatment, it is preferable to crush, and heat can be uniformly applied if the lump is broken. As a calcination temperature, 750-1150 degreeC is preferable, 800-1100 degreeC is more preferable, 850-1050 degreeC is especially preferable. The firing time is preferably 0.5 to 48 hours, more preferably 1 to 36 hours, and particularly preferably 2 to 24 hours.

  Although the crushing in the schematic flow of FIG. 1 is an optional step, it is preferably performed in order to improve the classification efficiency in the subsequent step. It is preferable to perform dry crushing when the subsequent classification is dry, and wet crushing when wet classification.

  Classification in the schematic flow of FIG. 1 is performed in order to remove coarse particles. In some cases, not only coarse particles but also fine particles can be removed. This classification treatment can be performed dry or wet. When wet classification is performed, a drying process is required to obtain a powdered cerium-based abrasive.

  When the cerium-based abrasive of the present invention obtained by the above production method is used as a cerium-based abrasive slurry, the cerium-based abrasive according to the present invention and an aqueous liquid are mixed or wet pulverized to mix the slurry. Become. Or in the manufacturing method of the above-mentioned cerium-based abrasive of the present invention, a fired product before classification or a product obtained by pulverizing a fired product can be used as a slurry as it is. And in the manufacturing method of the cerium type abrasive | polishing material of this invention mentioned above, what performed wet classification can also be used as a slurry as it is.

  ADVANTAGE OF THE INVENTION According to this invention, the cerium type abrasive | polishing material which can implement | achieve the grinding | polishing surface which reduced not only the grinding | polishing speed | rate but also reduced the generation | occurrence | production of an abrasion scratch as much as possible can be provided.

Schematic flow diagram of cerium-based abrasive production. The schematic flowchart of the abrasives manufacturing process in embodiment. The process schematic of a solvent extraction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to examples and comparative examples.

  First, the manufacturing method of the cerium type abrasive | polishing material regarding embodiment of this invention is demonstrated. FIG. 2 shows a schematic flow of the manufacturing process in the present embodiment.

According to the production process shown in FIG. 2, a cerium-based abrasive was produced using a carbonate raw material. As shown in Table 1, the raw materials of Example 1 are cerium carbonate (TREO 45.2 mass%, CeO _{2 /} TREO 99.99 mass%), lanthanum carbonate (TREO 43.0 mass%, La ₂ O _{3 /} TREO 99.99). Mass%), praseodymium carbonate (TREO 44.6 mass%, Pr ₆ O _{11 /} TREO 99.99 mass%), neodymium carbonate (TREO 43.3 mass%, Nd ₂ O _{3 /} TREO 99.99 mass%), samarium carbonate (TREO 44) 2 mass%, Sm ₂ O _{3 /} TREO 99.99 mass%). Table 1 shows the raw materials used in each Example and each Comparative Example (excluding Example 36 and Comparative Example 1), where ◎ is a raw material as a supply of cerium, ● is RE ^* , and other than Ce A raw material as a supply of one kind of rare earth element, ○ is ORE, rare earth element RE from 14 kinds of Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu It is a raw material for supplying rare earth elements selected from 13 types excluding ^* , and-indicates a carbonate rare earth that is not used.

  And the raw material of this Example 1 was used as a raw material the carbonic acid rare earth which weighed and mixed so that it might become the composition of the cerium type abrasive | polishing material of Example 1 shown in Table 3. The cerium-based abrasive produced from the raw material adjusted by such mixing has the same raw material composition.

The raw material for the rare earth carbonate was first calcined at 450 ° C. for 12 hours. Then, wet pulverization was performed by an attritor (manufactured by Nippon Coke Industries Co., Ltd.). As a grinding medium, a stainless ball having a diameter of 5 mm was used for grinding. The average particle diameter D ₅₀ of the raw material after the wet grinding process was measured to be 1.22 .mu.m.

  After the wet pulverization treatment, fluorination treatment was performed using a 55% hydrogen fluoride solution. By this fluorination treatment, the fluorine concentration of the raw material was adjusted to 7.0 mass% with F / TREO. After the fluorination treatment, filtration treatment was performed using a filter press. After the filtration treatment, it was dried in an air atmosphere at 150 ° C. for 24 hours, and crushed by a roll mill.

  After the pulverization treatment, a calcination treatment was performed at 950 ° C. for 10 hours, and then the pulverization treatment was performed using a sample mill (manufactured by Fuji Powder Co., Ltd.). Finally, using a precision air classifier (Turbo Classifier TC-25N: manufactured by Nissin Engineering Co., Ltd.), it was subjected to a dry classification process and dropped under the sieve. Obtained as a material.

For cerium-of Example 1, composition, X-rays diffraction, it was investigated average particle diameter D _50, were polished assessment polishing rate and polishing scratches (Table 2). Measurement conditions and the like will be described below.

Composition: About the obtained cerium-based abrasive, total oxidized rare earth (TREO), fluorine content, and rare earth oxide content were measured. The total oxidized rare earth (TREO) of the cerium-based abrasive was measured by oxalate precipitation / firing / gravimetry (unit solid: mass%, liquid: g / L). As a pretreatment, a solid (abrasive material or abrasive) was dissolved in perchloric acid and hydrogen peroxide and boiled. When the measurement object was a liquid, it was boiled as it was. For CeO ₂ / TREO, a TREO sample obtained by performing the above-mentioned total oxidation rare earth (TREO) measurement was dissolved in perchloric acid and hydrogen peroxide, and measured by the ICP-AES method (Y ₂ O ₃ / TREO, La ₂ O ₃ / TREO, Pr ₆ O ₁₁ / TREO, Nd ₂ O ₃ / TREO, Sm ₂ O ₃ / TREO, Eu ₂ O ₃ / TREO, Gd ₂ O ₃ / TREO, Tb ₄ O ₇ / TREO, Dy ₂ O ₃ / TREO, Ho ₂ O ₃ / TREO, Er ₂ O ₃ / TREO, Tm ₂ O ₃ / TREO, Yb ₂ O ₃ / TREO, and Lu ₂ O ₃ / TREO). In addition, the fluorine (F) content is determined by measuring the F concentration of the solution by the fluoride ion electrode method after making the solid (abrasive) to be measured into a solution by alkali melting / hot water extraction and measuring the F concentration in the solid. The content (% by mass) was calculated. In this composition survey, RE ^* O and OREO were calculated based on the analysis results obtained. _{Incidentally,} CeO 2 / TREO and ^RE * O / TREO (Example 34 _Nd 2 _O 3 / TREO, Example 35 _Y 2 _O 3 / TREO, others _La 2 _O 3 / TREO) measurements for all These examples and comparative examples were carried out. However, except for Example 36 and Comparative Example 1 described below, the values of CeO ₂ / TREO and RE ^* O / TREO of each Example and each Comparative Example in Tables 3 to 6 are the instructions at the time of mixing raw materials. The values (abrasive target composition values of each example and each comparative example) are described.

X-ray diffraction measurement: X-ray diffraction analysis was performed on the cerium-based abrasive using an X-ray diffractometer (manufactured by Mac Science Co., Ltd., MXP18), and the diffracted X-ray intensity was measured. In this measurement, a copper (Cu) target was used, and a peak appearing in a diffraction X-ray pattern by Cu-Kα ₁ line obtained by irradiation with Cu-Kα ray was analyzed. Other measurement conditions were a tube voltage of 40 kV, a tube current of 150 mA, a measurement range 2θ = 5 to 80 deg, a sampling width of 0.02 deg, and a scanning speed of 4 deg / min. Further, read from the X-ray diffraction measurement result of the cerium-based abrasive, the half-value width of the peak of rare earth oxide mainly composed of CeO ₂ in the vicinity of 2θ (diffraction angle) = 28 deg, 2θ (diffraction angle) in the vicinity of 28 deg. The intensity ratio (B / A) of the peak intensity (B) of the rare earth oxyfluoride near 2θ (diffraction angle) = 26.5 deg to the peak intensity (A) of the rare earth oxide containing CeO ₂ as the main component was measured.

Measurement of the average particle diameter D _50: laser diffraction scattering method particle size distribution measuring apparatus (manufactured by HORIBA, Ltd.: LA-920) using the measurement of particle size distribution of the cerium-based abrasive, the average particle diameter D ₅₀ ( The particle size at a cumulative volume of 50% from the small particle size side) was determined.

Polishing evaluation: A polishing test was performed using the obtained cerium-based abrasive, and the polishing speed and the scratches on the resulting polished surface were investigated. In the polishing test, first, a powdered cerium-based abrasive powder and pure water were mixed to prepare an abrasive slurry having a solid content concentration of 15% by weight. Using this polishing material slurry, the surface of the glass for 65 mmφ flat panel was polished by a polishing tester (HSP-2I type, manufactured by Taito Seiki Co., Ltd.). After the polishing, the flat panel glass was washed with pure water and dried in a dust-free state. In this polishing tester, the surface to be polished is polished with a polishing pad while supplying an abrasive slurry to the surface to be polished, and a polishing pad made of polyurethane was used. The pressure of the polishing pad against the polishing surface was 5.9 kPa (60 g / cm ² ). The rotational speed of the polishing tester was set to 100 rpm. The supply amount of the abrasive slurry was 5 liters / minute.

Polishing speed: The weight of glass before and after polishing was measured to determine the amount of reduction in glass weight by polishing, and the polishing value was determined based on this value. In this polishing test, the polishing rate was evaluated using this polishing value. In the present embodiment, the polishing value when polishing is performed using the cerium-based abrasive obtained in Comparative Example 1 described later is used as the reference (100).

Abrasion scratches: After polishing, scratches were evaluated on polished surfaces that were washed with pure water and dried in a dust-free state. The scratch evaluation was performed by visually observing the glass surface by a reflection method using a 300,000 lux halogen lamp as a light source and counting scratches of 2 mm or more. If more than 50 scratches are confirmed, this abrasive scratch is an indicator that it is not practical as a cerium-based abrasive. Moreover, 20 or less is preferable for precision polishing, and 10 or less is particularly preferable.

  Various conditions were changed in the same procedure as the manufacturing process of Example 1 described above, and cerium-based abrasives of Examples 2-36 were manufactured.

Regarding the raw materials of Examples 2 to 35, as shown in Table 1, cerium carbonate (TREO 45.2% by mass, CeO _{2 /} TREO 99.99% by mass), lanthanum carbonate (TREO 43.0% by mass, La ₂ O ₃ / TREO 99.99 mass%), praseodymium carbonate (TREO 44.6 mass%, Pr ₆ O _{11 /} TREO 99.99 mass%), neodymium carbonate (TREO 43.3 mass%, Nd ₂ O _{3 /} TREO 99.99 mass%), The raw material is a rare earth carbonate mixed with yttrium carbonate (TREO 36.0 mass%, La ₂ O _{3 /} TREO 99.99 mass%) and weighed and mixed so as to have the composition of each cerium-based abrasive shown in Tables 3-6. Used as. The cerium-based abrasive produced from the raw material adjusted by such mixing has the same raw material composition.

Each raw material was first subjected to calcination treatment at 450 ° C. for 12 hours. Then, wet pulverization was performed by an attritor (manufactured by Nippon Coke Industries Co., Ltd.). As a grinding medium, a stainless ball having a diameter of 5 mm was used for grinding. The wet pulverization treatment was performed with the average particle size D ₅₀ shown in Table 2 as a target.

  And each cerium type abrasive was manufactured according to the process flow shown in FIG. 2 using the rare earth carbonate raw material of each composition. In addition, Table 2 shows the production conditions for the cerium-based abrasive of each Example.

Differences in manufacturing conditions between the embodiments will be described. In Examples 1 to 6, the content of OREO / TREO is changed. Then, the ratio of CeO ₂ and RE ^* O (La ₂ O ₃ ) is CeO ₂ : RE ^* O = 7: 3. In Examples 7 to 11, since the content of the rare earth oxide was made constant and the fluorine content was changed, the firing temperature was adjusted so as to have substantially the same average particle diameter. In Examples 12 to 17, in order to change the rare earth oxide content (RE ^* O) so as to have almost the same fluorine content, the addition amount of hydrogen fluoride is made constant and the average particle diameter becomes almost the same. In this way, the firing temperature is adjusted. In Examples 18 to 25, the firing temperature was changed in order to change the half width of the peak of the rare earth oxide mainly composed of CeO ₂ of the obtained cerium-based abrasive. When the firing temperature was high, fluorine was used. Since it is easy to volatilize, the amount of hydrogen fluoride used is also adjusted. In Examples 26 to 33, the average particle size was adjusted by changing the wet pulverization time after the calcination treatment. In Examples 34 and 35, those that are not La (La ₂ O ₃ ) are used as RE ^* (RE ^* O), and Example 34 is Nd (Nd ₂ O ₃ ) and Example 35 is Y (Y ₂ O ₃ ).

Example 36 is the raw material of Comparative Example 1 shown below (China acid rare earth (TREO 45% by mass, CeO _{2 /} TREO 62.5% by mass, La ₂ O _{3 /} TREO 31.6% by mass, which is a general abrasive raw material). %, Pr ₆ O ₁₁ / TREO 5.3% by mass, Nd ₂ O ₃ / TREO 0.6% by mass, F / TREO <0.1% by mass)) by the following procedure: did.

  Solvent extraction separation purification shown in FIG. 3 was performed using the above-described dissolved Chinese carbonated earth dissolved in hydrochloric acid and using a filtrate obtained by vacuum filtration. In FIG. 3, the process schematic of the solvent extraction is shown. In this solvent extraction, a 50-stage mixer settler was used. In the first stage, the solvent was used at 2.0 L / min. As the extractant, a commercially available product PC-88A (manufactured by Daihachi Chemical Industry Co., Ltd.) was used, and as the diluent, a commercially available product IP solvent 2028 (manufactured by Idemitsu Kosan Co., Ltd.) was used. The mixing ratio of this extractant and diluent was such that the extractant was 30 vol%. In the 20th stage, a dissolved filtrate (TREO 100 g / L) was used at 1.0 L / min. In the 40th stage, 1 mol / L hydrochloric acid is used at 0.2 L / min, in the 50th stage, 4 mol / L hydrochloric acid is used at 0.5 L / min, and in the 5th and 10th stages, 1 mol / L aqueous ammonia was used at 0.2 L / min. From the first stage, Ce-La liquid is produced, and from the 41st stage, Pr-Nd liquid is produced. The solvent produced from the 50th stage was returned to the service tank and used in the first stage.

Then, the obtained purified solution (Ce-La solution) is diluted with water so that TREO becomes 50 g / L, and heated until the solution temperature reaches 50 ° C., and an aqueous solution of ammonium bicarbonate having a concentration of 50 g / L is adjusted to pH 7 The mixture was added over about 1 hour until it became 0.0, and stirring was continued for 10 minutes after the addition was completed. Thereafter, vacuum filtration was performed, followed by washing with water, so that the rare earth carbonate material of Example 36 (TREO 45 mass%, CeO _{2 /} TREO 66.1 mass%, La ₂ O _{3 /} TREO 33.9 mass%). After this calcined rare earth material was calcined at 400 ° C. for 12 hours, a cerium-based abrasive of Example 36 was produced under the conditions shown in Table 2.

For comparison, cerium-based abrasives of Comparative Examples 1 to 13 were produced. Comparative Example 1 is a Chinese acid carbonate rare earth (TREO 45 mass%, CeO _{2 /} TREO 62.5 mass%, La ₂ O ₃ / TREO 31.6 mass%, Pr ₆ O ₁₁ / TREO 5. 3% by mass, Nd ₂ O ₃ / TREO 0.6% by mass, F / TREO <0.1% by mass)) were used after calcining at 400 ° C. for 12 hours. The production conditions for Comparative Example 1 are shown in Table 2.

  In Comparative Examples 2 to 13, the raw materials shown in Table 1 were used, and in the same manner as described in Examples 2 to 35, a rare carbonate carbonate having the same composition as the cerium-based abrasives of Comparative Examples shown in Tables 3 to 5 was used. Soil raw materials were used. After the calcined rare earth material of each composition was calcined at 400 ° C. for 12 hours, the cerium-based abrasives of Comparative Examples 2 to 13 were produced according to the process flow shown in FIG. 2 (the cerium-based abrasives of the respective comparative examples) The production conditions are shown in Table 2).

Differences in manufacturing conditions between Comparative Examples 1 to 13 will be described. In Comparative Examples 1 to 5, the content of OREO / TREO was changed as in Examples 1 to 6. Comparative Examples 6 and 7 were the same as in Examples 7 to 11, and the content of rare earth oxide was kept constant and the fluorine content was changed. Therefore, the firing temperature was adjusted so that the average particle diameter was almost the same. It is. Comparative Examples 8 and 9 are the same as Examples 12 to 17, and the content of rare earth oxide (RE ^* O) is changed to make the fluorine content almost the same, so that the amount of hydrogen fluoride added is constant. At the same time, the firing temperature is adjusted so that the average particle diameter is substantially the same. Comparative Examples 10 and 11 were the same as in Examples 18 to 25, and the firing temperature was changed in order to change the half width of the peak of the rare earth oxide mainly composed of CeO ₂ of the obtained cerium-based abrasive. When the firing temperature is high, fluorine easily volatilizes, so the amount of hydrogen fluoride used is also adjusted. Comparative Examples 12 and 13 are the same as in Examples 26 to 33, and the average particle size is adjusted by changing the wet pulverization time after the calcination treatment.

Example 1-36, the cerium-based abrasive of Comparative Examples 1 to 13, composition, X-rays diffraction, the result of the examination of the average particle diameter D _50, the abrasive evaluation results of polishing rate and polishing scratches in Tables 3 6 Show. In addition, about Example 6, it described in several places in a table | surface as a data comparison reference | standard.

From the results of Tables 3 to 6, the following was found. If each OREO / TREO is 0.5% by mass or less and the total is 2% by mass or less ((CeO ₂ + RE ^* ) / TREO is 98% or more), the generation of abrasive scratches is small. When each OREO / TREO is small, the generation of abrasive scratches is small (Examples 1-6, Comparative Examples 1-5).
As for Comparative Example 5, each OREO / TREO is 0.5% by mass or less, but (CeO ₂ + RE ^* ) / TREO is less than 98%. became.

  About F content, it turned out that 5-15 mass% has few generation | occurrence | production of an abrasion wound, and 5-10 mass% is especially preferable.

The CeO ₂ / TREO, when terms the occurrence of polishing scratches can be suppressed, preferably 50 to 90 wt%, more preferably 55 to 85 wt%, has been found to be particularly preferred 60 to 80 wt% (embodiment Examples 12-17, comparative examples 8, 9). About RE ^* O / TREO, it turned out that 10-50 mass% is preferable from the point that generation | occurrence | production of an abrasion wound can be suppressed, 15-45 mass% is further more preferable, and 20-40 mass% is especially preferable ( Examples 12 to 17, Comparative Examples 8 and 9).

Next, the half width of the peak of the rare earth oxide mainly composed of CeO ₂ in the X-ray diffraction measurement is preferably 0.10 deg or more, and preferably 0.15 deg or more, from the viewpoint of suppressing the occurrence of abrasive scratches. Further, it has been found that 0.20 deg or more is particularly preferable. Further, from the viewpoint of high polishing speed, it was found that 1.0 deg or less is preferable, 0.90 deg or less is more preferable, and 0.80 deg or less is particularly preferable (Examples 18 to 25, Comparative Examples 10 and 11). .

The average particle diameter _{D 50} is, from the viewpoint of polishing rate is large, is preferably at least 0.2 [mu] m, still more preferably at least 0.3 [mu] m, more 0.4μm have been found to be particularly preferred (Example 26 to 33, Comparative Examples 12 and 13). From the viewpoint of occurrence of abrasive scratches, it has been found that 3.5 μm or less is more preferable, 3.0 μm or less is more preferable, and 2.5 μm or less is particularly preferable.

Regarding RE ^* O, it was found from the results of Examples 34, 35, and Example 6 that other than La ₂ O ₃ can be used. However, La ₂ O ₃ was the most preferable from the viewpoint of suppressing the occurrence of abrasive scratches.

  From the results of Example 36, it was confirmed that the same raw material can be produced by performing separation and purification by solvent extraction without mixing a plurality of high-purity rare earth carbonates. In the case of the Ce-La system, manufacturing by solvent extraction is particularly easy, and low cost can be realized. And since the raw material of Comparative Example 1 is also produced by separation and purification by solvent extraction at the raw material supply site, the purified solution is subjected to the same solvent extraction as Example 36 without making carbonate. Can be separated and purified. Incidentally, the cerium-based abrasive of Comparative Example 1 using a Chinese carbonated rare earth, which is a commonly available raw material, has a larger number of abrasive scratches than the cerium-based abrasive of each Example. However, when the accuracy is not particularly required, it is a polishing speed and a polishing scratch level that can be practically used.

  ADVANTAGE OF THE INVENTION According to this invention, the cerium type abrasive | polishing material which can implement | achieve the grinding | polishing surface which not only has high grinding | polishing speed but reduced the generation | occurrence | production of the grinding | polishing damage as much as possible can be provided. Therefore, it is possible to finish a polished surface with higher accuracy, that is, a polished surface in which the generation of abrasive scratches is reduced as much as possible.

Claims (7)

Containing F,
Ce as a rare earth element;
A kind of rare earth element selected from 14 kinds of rare earth elements other than Ce, such as Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (referred to as RE ^* ) In a cerium-based abrasive containing a rare earth oxide as a main component,
The content of F in the cerium-based abrasive is 5.0 to 15.0% by mass,
The ratio of the mass of cerium oxide (CeO ₂ ) to the total rare earth oxide equivalent mass (TREO) (CeO ₂ / TREO) is 48 mass% to 90 mass%, and the cerium accounts for the total rare earth oxide equivalent mass (TREO). The ratio of the mass (RE ^* O / TREO) of the rare earth element oxide (RE ^* O) other than 1% to 50% by mass is cerium oxide, which accounts for the total rare earth oxide equivalent mass (TREO). The total mass ratio ((CeO ₂ + RE ^* O) / TREO) with one kind of rare earth element oxide (RE ^* O) other than cerium is 98% by mass or more,
Rare earth elements selected as 13 kinds of Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, excluding rare earth elements RE ^*. ) Is a ratio of the mass of each oxide (each OREO) in the 13 kinds of ORE to the total rare earth oxide equivalent mass (TREO) ((each OREO) / TREO) is 0.5% by mass or less. A cerium-based abrasive characterized by When the X-ray peak intensity is measured by an X-ray diffraction method using Cu—Kα ray or Cu—Kα1 ray as an X-ray source, a rare earth oxide mainly composed of CeO ₂ in the vicinity of 2θ (diffraction angle) = 28 deg. The cerium-based abrasive according to claim 1, wherein the peak half-value width is 0.1 to 1.0 deg at 2θ. 3. The cerium-based abrasive according to claim 1, wherein an average particle diameter D ₅₀ of 50% cumulative volume from the small particle diameter side in the laser diffraction / scattering particle size distribution measurement is 0.2 to 3.5 μm. RE ^* is La, The cerium type abrasive | polishing material as described in any one of Claims 1-3. (Each OREO) / TREO is less than 0.1 mass%, The cerium type abrasive | polishing material as described in any one of Claims 1-4. When the X-ray peak intensity is measured by an X-ray diffraction method using Cu—Kα ray or Cu—Kα1 ray as an X-ray source, a rare earth oxide mainly composed of CeO ₂ in the vicinity of 2θ (diffraction angle) = 28 deg. The intensity ratio (B / A) of the peak intensity (B) of the rare earth oxyfluoride near 2θ (diffraction angle) = 26.5 deg to the peak intensity (A) is 0.05 to 1.0. The cerium-based abrasive according to claim 5. A cerium-based abrasive slurry comprising the cerium-based abrasive according to any one of claims 1 to 6 and an aqueous liquid.

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