JP2001158660A - Optically transmitting rare earth-aluminum garnet sintered product and production method therefor - Google Patents
Optically transmitting rare earth-aluminum garnet sintered product and production method thereforInfo
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- JP2001158660A JP2001158660A JP34289199A JP34289199A JP2001158660A JP 2001158660 A JP2001158660 A JP 2001158660A JP 34289199 A JP34289199 A JP 34289199A JP 34289199 A JP34289199 A JP 34289199A JP 2001158660 A JP2001158660 A JP 2001158660A
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- sintered body
- rare earth
- pores
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- aluminum
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Abstract
Description
【０００１】[0001]
【発明の利用分野】本発明は、一般式Ｒ3Ａｌ5Ｏ12（Ｒ
はＹ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕのうちいず
れか１種の希土類元素）で表されるガーネット構造を有
する、透光性焼結体及びその製造方法に関する。本発明
の焼結体は、例えばサファイヤ代替窓材、偏光板、放電
ランプ用エンベロープ、半導体製造装置等の耐食部材、
装飾品等に好適に用いられる。The present invention relates to a compound represented by the general formula R3Al5O12 (R
The present invention relates to a translucent sintered body having a garnet structure represented by one of Y, Dy, Ho, Er, Tm, Yb, and Lu). The sintered body of the present invention is, for example, a sapphire substitute window material, a polarizing plate, an envelope for a discharge lamp, a corrosion-resistant member such as a semiconductor manufacturing apparatus,
It is suitably used for decorative articles and the like.
【０００２】[0002]
【従来技術】一般式Ｒ3Ａｌ5Ｏ12（ＲはＹ，Ｄｙ，Ｈ
ｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕのうちいずれか１種の希土
類元素）で表される希土類アルミニウムガーネット化合
物は、その結晶構造が立方晶であり、透光性や耐熱性に
優れた焼結体が得られるため、様々な用途への適用がで
きる。特に、光の散乱源である気孔や異相を完全に除去
することにより、多結晶体でありながら単結晶に匹敵す
る透明度が得られるため、各種光学材料への適用が期待
されている。2. Description of the Related Art A general formula R3Al5O12 (R is Y, Dy, H
The rare earth aluminum garnet compound represented by any one of o, Er, Tm, Yb, and Lu) is a sintered body having a cubic crystal structure and excellent translucency and heat resistance. Is obtained, so that it can be applied to various uses. In particular, by completely removing pores and foreign phases, which are light scattering sources, transparency comparable to that of a single crystal can be obtained despite being a polycrystal, and thus application to various optical materials is expected.
【０００３】中でもイットリウムアルミニウムガーネッ
ト（Ｙ3Ａｌ5Ｏ12：ＹＡＧ）セラミックスは可視部から
赤外領域までの広範囲に渡り優れた透光性を示すため、
セラミックスの利点である強度、耐熱性及び形状自由度
を期待して、サファイヤ代替窓材、放電ランプ用発光管
材料、耐食部材等への適用が検討されている。一方、イ
ットリウム以外の希土類元素を用いた透光性希土類アル
ミニウムガーネット焼結体は、希土類元素が比較的高価
であること、さらに特定の用途が見出せないことから、
製造条件がＹＡＧセラミックスの場合とほぼ同様である
にもかかわらず、製造方法に関する報告はほとんど見当
たらない。[0003] Among them, yttrium aluminum garnet (Y3Al5O12: YAG) ceramics exhibit excellent translucency over a wide range from the visible region to the infrared region.
In view of the strength, heat resistance, and freedom of shape that are the advantages of ceramics, application to sapphire alternative window materials, arc tube materials for discharge lamps, corrosion-resistant members, and the like is being studied. On the other hand, a translucent rare earth aluminum garnet sintered body using a rare earth element other than yttrium is relatively expensive, because a rare earth element cannot be found in a specific use.
Despite the fact that the production conditions are almost the same as for YAG ceramics, there are few reports on production methods.
【０００４】従来より盛んに研究が行われている透光性
ＹＡＧセラミックスの製造方法として、ホットプレス法
によるもの（米国特許：３７６７，７４５）や、酸化物
微粉末のボールミル混合・ＣＩＰ成形による直接焼結法
（特開平３−２１８９６３号）等が知られている。ホッ
トプレス法は、セラミックスの特徴の１つである複雑形
状品の製造を困難にする。酸化物微粉末混合法では、透
光性の良い焼結体が得られるものの、反応性を増すと共
に混合時の比重差に基づくイットリアとアルミナの分離
を抑制するため、イットリアの超微粉体を用いる。この
ため、イットリアとアルミナを別々に製造する必要があ
る上、超微粉体を用いるため、成形密度が低くなる傾向
がある。成形密度が低いと、焼結時の収縮が大きく、寸
法精度が要求される用途には適用が困難である。さらに
充分な透光性を示す焼結体を得るためには、焼結助剤と
してＳｉＯ2を添加し、数十時間焼成を行う必要があ
る。また単一相ＹＡＧ微粉末を用いて透光性焼結体を得
る方法（特開平２−９２８１７号）も開示されている
が、原料粉末の焼結性が乏しいことから、ＳｉＯ2等の
焼結助剤を必要とする。[0004] As methods for producing translucent YAG ceramics, which have been extensively studied, a hot press method (US Pat. No. 3,767,745) and a ball mill mixing of oxide fine powder and CIP molding have been employed. A sintering method (Japanese Unexamined Patent Publication No. Hei 3-218963) and the like are known. The hot pressing method makes it difficult to manufacture a complex-shaped product, which is one of the characteristics of ceramics. In the oxide fine powder mixing method, although a sintered body with good translucency can be obtained, in order to increase the reactivity and suppress the separation of yttria and alumina based on the specific gravity difference at the time of mixing, ultrafine yttria powder is used. Used. For this reason, it is necessary to produce yttria and alumina separately, and since an ultrafine powder is used, the molding density tends to be low. If the molding density is low, the shrinkage during sintering is large, and it is difficult to apply to applications requiring dimensional accuracy. In order to obtain a sintered body having a sufficient translucency, it is necessary to add SiO2 as a sintering aid and perform sintering for several tens of hours. Also, a method of obtaining a light-transmitting sintered body using a single-phase YAG fine powder (Japanese Patent Application Laid-Open No. 2-92817) is disclosed. Requires auxiliary agents.
【０００５】一般に結晶構造が立方晶からなるセラミッ
クス中の光の散乱源は、気孔及び異相であり、透光性に
優れた焼結体を得るには、これらを完全に除去する必要
がある。希土類アルミニウムガーネット焼結体の様な２
成分系の酸化物では、組成を厳密に制御することによ
り、異相の発生を抑制できる。気孔の存在は、透光性を
低下させるのみならず、破壊源とも成り得るため好まし
くない。従って透光性に優れ、また機械的にも信頼性の
高い焼結体を得るには、気孔を如何に除去するかが課題
となる。[0005] Generally, light scattering sources in ceramics having a cubic crystal structure are pores and heterophases, and these must be completely removed in order to obtain a sintered body having excellent translucency. Rare earth aluminum garnet sintered body 2
In a component-based oxide, the generation of a foreign phase can be suppressed by strictly controlling the composition. The presence of the pores is not preferable because it not only reduces the light transmittance, but also can be a source of destruction. Therefore, in order to obtain a sintered body having excellent translucency and high mechanical reliability, the problem is how to remove pores.
【０００６】従来法では、焼結助剤及び焼成条件により
緻密化及び粒成長速度を制御し、粒成長による体積拡散
により結晶粒界を通して気孔の排出を行っている。しか
しながら、通常の原料粉末ならびに機械成形法を用いた
セラミックスの製造では、原料粒子の均一なパッキング
は不可能であり、多かれ少なかれ通常の焼結では取り除
けない大きさの空孔が生じる。従って、一般的に緻密体
といわれている透光性セラミックスでも、焼結体内部に
は数１００volppm以上の気孔が残存しており、単結晶と
同一の光学特性を示す多結晶体を得ることは困難であ
る。例えばジャーナルオブマテリアルサイエンス(Journ
al of Materials Science)34(1999)1189-1195では、真
空焼結法により得られたＮｄ添加ＹＡＧセラミックス内
部に気孔は最低でも１５０volppm存在していると報告
し、この値は単結晶のそれと比較して極めて多い。In the conventional method, densification and grain growth rate are controlled by a sintering aid and firing conditions, and pores are discharged through crystal grain boundaries by volume diffusion due to grain growth. However, in the production of ceramics using ordinary raw material powders and mechanical molding methods, uniform packing of the raw material particles is not possible, and pores of a size more or less cannot be removed by ordinary sintering. Therefore, even in a translucent ceramic generally called a dense body, pores of several hundred volppm or more remain inside the sintered body, and it is not possible to obtain a polycrystalline body having the same optical characteristics as a single crystal. Have difficulty. For example, Journal of Material Science (Journ
al of Materials Science) 34 (1999) 1189-1195 reported that at least 150 volppm of pores existed in Nd-doped YAG ceramics obtained by the vacuum sintering method. Very much.
【０００７】ところで、透光性アルミナの作製では熱間
等方圧加圧（Hot Isostatic Press:ＨＩＰ)により、気
孔を含まない焼結体が得られることが開示されている
（特開平８−３０１６６６号）。ＨＩＰでは、高温下に
て試料に数百kgf/cm2以上の高圧を等方的に加え、塑性
変形によってセラミックス内の気孔を除去する。一方Ｙ
ＡＧセラミックスにＨＩＰを適用し、無気孔焼結体を作
製しようとした例として、ジャーナルオブアメリカンセ
ラミックスソサイエティ（J.Am.Ceram.Soc)79[7]1927-3
3(1996)が報告されている。しかしながらこの報告で
は、圧力媒体であるＡｒガスが焼結体内部に気孔として
残存するため、無気孔ＹＡＧ焼結体を作製することは不
可能であるとされている。以上に述べたように、従来法
ではＹＡＧをはじめとする希土類アルミニウムガーネッ
トの無気孔焼結体は、知られていない。By the way, in the production of translucent alumina, it is disclosed that a sintered body having no pores can be obtained by hot isostatic pressing (HIP) (Japanese Patent Laid-Open No. 8-301666). issue). In HIP, a high pressure of several hundred kgf / cm2 or more is applied to a sample isotropically at a high temperature, and pores in ceramics are removed by plastic deformation. On the other hand, Y
Journal of American Ceramics Society (J. Am. Ceram. Soc) 79 [7] 1927-3 is an example of applying HIP to AG ceramics to produce a nonporous sintered body.
3 (1996) has been reported. However, according to this report, it is impossible to produce a nonporous YAG sintered body because Ar gas as a pressure medium remains as pores inside the sintered body. As described above, a poreless sintered body of rare earth aluminum garnet including YAG is not known in the conventional method.
【０００８】[0008]
【発明の課題】本発明の目的は、光透過率に優れた希土
類アルミニウムガーネット焼結体、及びその製造方法を
提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a rare earth aluminum garnet sintered body excellent in light transmittance and a method for producing the same.
【０００９】[0009]
【発明の構成】本発明の透光性希土類アルミニウムガー
ネット焼結体は、結晶構造が一般式Ｒ3Ａｌ5Ｏ12（Ｒは
Ｙ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕのうちいずれ
か１種の希土類元素）で表されるガーネット構造を有す
る焼結体であって、焼結体中の気孔が１００volppm以下
で、かつ可視から赤外領域に渡って特異吸収波長以外で
の光直線透過率が５mm厚みで８３％以上であることを特
徴とする。なお気孔の量はvolppm単位で表し、不純物量
はwtppm単位で表すものとする。The translucent rare earth aluminum garnet sintered body of the present invention has a crystal structure represented by a general formula R3Al5O12 (R is one of rare earth elements of Y, Dy, Ho, Er, Tm, Yb, Lu). A) a sintered body having a garnet structure represented by the following formula, wherein the pores in the sintered body are 100 volppm or less, and the light linear transmittance at a wavelength other than the specific absorption wavelength in the visible to infrared region is 5 mm thick. 83% or more. The amount of pores is expressed in units of volppm, and the amount of impurities is expressed in units of wtppm.
【００１０】モル換算で希土類元素とアルミニウムとの
比が０.５９９≦Ｒ／Ａｌ≦０.６０１であり、希土類元
素とアルミニウムとの比が０.５９９≦Ｒ／Ａｌ≦０.６
００で、焼結体中のＳｉが１５wtppm以下であり、希土
類元素とアルミニウムとの比が０.６００＜Ｒ／Ａｌ≦
０.６０１で、焼結体中のＳｉがＳｉ(wtppm)≦１５００
０×（Ｒ／Ａｌ）−８９８５である。The molar ratio of the rare earth element to aluminum is 0.599 ≦ R / Al ≦ 0.601, and the ratio of the rare earth element to aluminum is 0.599 ≦ R / Al ≦ 0.6.
00, the content of Si in the sintered body was 15 wtppm or less, and the ratio of rare earth element to aluminum was 0.600 <R / Al ≦
0.601, the Si in the sintered body is Si (wtppm) ≦ 1500
0 × (R / Al) −8985.
【００１１】本発明の透光性希土類アルミニウムガーネ
ット焼結体の製造方法は、比表面積が３〜１５ｍ2／ｇ
で、３μｍを超える凝集粒子が重量分率で５％以下の原
料粉末を用いて作製された一般式Ｒ3Ａｌ5Ｏ12（Ｒは
Ｙ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕのうちいずれ
か１種の希土類元素）で表されるセラミックス成形体を
１次焼成して、平均粒径３μｍ以下、理論密度比９４％
以上に緻密化し、この１次焼結体に熱間等方圧加圧を施
すことにより、焼結体中の気孔が１００volppm以下で、
可視から赤外領域に渡って特異吸収波長以外での光直線
透過率が５mm厚みで８３％以上の焼結体とすることを特
徴とする。The method for producing a translucent rare earth aluminum garnet sintered body according to the present invention has a specific surface area of 3 to 15 m 2 / g.
And a general formula R3Al5O12 (R is any one of Y, Dy, Ho, Er, Tm, Yb, and Lu) prepared by using a raw material powder in which agglomerated particles exceeding 3 μm have a weight fraction of 5% or less. Primary firing of a ceramic molded body represented by a rare earth element) has an average particle diameter of 3 μm or less and a theoretical density ratio of 94%.
By densifying as above and subjecting this primary sintered body to hot isostatic pressing, the pores in the sintered body are 100 volppm or less,
The sintered body is characterized in that the sintered body has a thickness of 5 mm and a linear transmittance of light of 83% or more at wavelengths other than the specific absorption wavelength in the visible to infrared region.
【００１２】１次焼成は１４５０℃以上１７００℃以下
で行うことが好ましい。またＨＩＰは、１４００℃以上
１８００℃以下で、Ａｒ等の雰囲気を用いて、８００kg
f/cm2以上２０００kgf/cm2以下で行うことが好ましい。The primary firing is preferably performed at 1450 ° C. or more and 1700 ° C. or less. The HIP is performed at a temperature of 1400 ° C. or more and 1800 ° C. or less and 800 kg using an atmosphere such as Ar.
It is preferable to carry out at a rate of f / cm2 or more and 2000 kgf / cm2 or less.
【００１３】[0013]
【発明の作用と効果】本発明者は、気孔が１００volppm
以下であって可視から赤外領域に渡って特異吸収波長以
外での光直線透過率が５mm厚みで８３％以上の希土類ア
ルミニウムガーネット焼結体を作製できることを見出し
た。そのためには例えば、希土類元素とアルミニウムと
の組成比、Ｓｉ含有量、１次粒子径及び２次凝集粒子径
を管理した易焼結性の原料粉末を高密度に成形した後
に、平均粒子径３μｍ以下、理論密度比９４％以上に１
次焼成し、ＨＩＰを施せば良い。The present inventors have found that the pores are 100 volppm.
It has been found that a rare earth aluminum garnet sintered body having a thickness of 5 mm and a luminous linear transmittance of 83% or more in the visible to infrared region other than the specific absorption wavelength can be produced. For this purpose, for example, after forming a high-density easily sinterable raw material powder in which the composition ratio of a rare earth element and aluminum, the Si content, the primary particle diameter, and the secondary aggregated particle diameter are controlled, the average particle diameter is 3 μm. Hereinafter, 1 for the theoretical density ratio of 94% or more
Next baking and HIP may be performed.
【００１４】モル換算で希土類元素とアルミニウムとの
モル比を０.５９９≦Ｒ／Ａｌ≦０.６０１とし、Ｓｉの
上限含有量はこのモル比に応じて変化させる。このモル
比が０.５９９〜０.６０１の範囲がＳｉ濃度が低い際の
透明化域であり、Ｓｉ濃度が上限含有量以下であること
が、粒界での液相の形成を防止する条件であり、このこ
とはＨＩＰ処理でのガスの侵入を防止して、気孔の生成
を阻止するための条件である。The molar ratio between the rare earth element and aluminum is 0.599 ≦ R / Al ≦ 0.601 on a molar basis, and the upper limit content of Si is changed according to this molar ratio. This molar ratio in the range of 0.599 to 0.601 is a transparent region when the Si concentration is low, and the condition that the Si concentration is not more than the upper limit content is a condition for preventing the formation of a liquid phase at the grain boundary. This is a condition for preventing gas from entering in the HIP process and preventing generation of pores.
【００１５】気孔は、例えば高温下において試料を高圧
で等方的に加圧しながら焼成して、粒成長により気孔を
排出すると共に、塑性変形により気孔の排出を加速する
ことにより除去する。従来法が粒成長による体積拡散効
果のみによって気孔を排出しているのに対し、本発明で
は塑性変形効果も加わる事により、通常では除去不可能
な大きさの気孔まで除去できる。ＨＩＰを用いても、焼
結助剤等のＳｉＯ2が上限濃度を超過して存在すると、
高温高圧下において粒界に偏析し、圧力媒体のＡｒ等が
潜り込み、ＨＩＰ後のアニールによって膨張する。この
ため気孔は除去できない。The pores are removed, for example, by baking the sample at a high temperature while isotropically applying a high pressure to discharge the pores by grain growth and accelerate the discharge of the pores by plastic deformation. In contrast to the conventional method in which pores are discharged only by the volume diffusion effect due to grain growth, in the present invention, by adding a plastic deformation effect, pores of a size which cannot be removed normally can be removed. Even when HIP is used, if SiO2 such as a sintering aid exists in excess of the upper limit concentration,
Under high temperature and high pressure, segregation occurs at the grain boundary, and Ar or the like of the pressure medium enters and expands by annealing after HIP. For this reason, pores cannot be removed.
【００１６】[0016]
【実施例】高純度希土類アルミニウムガーネット原料粉
末を、鋳込み成形法により成形する。ここで使用する原
料粉末中のＳｉ量はＲ／Ａｌが０.５９９≦Ｒ／Ａｌ≦
０.６００の範囲では１５ppm以下、０.６００＜Ｒ／Ａ
ｌ≦０.６０１の範囲ではＳｉ(ppm)≦１５０００×（Ｒ
／Ａｌ）−８９８５とする。いずれの場合も、Ｓｉ量は
より好ましくは５ppm以下とする。EXAMPLE A high purity rare earth aluminum garnet raw material powder is formed by a casting method. The amount of Si in the raw material powder used here is such that R / Al is 0.599 ≦ R / Al ≦
In the range of 0.600, 15 ppm or less, 0.600 <R / A
In the range of 1 ≦ 0.601, Si (ppm) ≦ 15000 × (R
/ Al) -8985. In any case, the amount of Si is more preferably 5 ppm or less.
【００１７】正規組成よりもアルミニウム過剰の場合、
Ｓｉは過剰分のアルミニウムと共に液相を生成し粒界に
偏析する。偏析した粒界相を通してＡｒ等のガスが焼結
体内部に潜り込み充分なＨＩＰ効果が生じなくなる。こ
れに対して正規組成よりも希土類過剰の場合、Ｓｉは過
剰分の希土類元素と共に、例えばＹＡＧではＹＡＰやＹ
ＡＭを形成し、多結晶ＹＡＧの三重点に局在化する。ア
ルミニウム過剰側で液相を形成するＳｉの限界量は１５
ppmで、イットリウム過剰側では三重点にＳｉが局在化
されるため、粒界に液相を形成するＳｉ量はイットリウ
ムの過剰量に伴い増加する。従ってＳｉ量を制限すれ
ば、粒界へのＡｒの流入経路は形成されず、有効なＨＩ
Ｐ効果が生じる。When the aluminum content is higher than the normal composition,
Si forms a liquid phase together with excess aluminum and segregates at the grain boundaries. A gas such as Ar penetrates into the sintered body through the segregated grain boundary phase, and a sufficient HIP effect is not generated. On the other hand, when the rare earth is more than the normal composition, Si is added together with the excess rare earth element, for example, YAP or YAP in YAG.
AM is formed and localized at the triple point of polycrystalline YAG. The limit amount of Si that forms a liquid phase on the aluminum excess side is 15
At ppm, since Si is localized at the triple point on the yttrium excess side, the amount of Si forming a liquid phase at the grain boundary increases with the excess amount of yttrium. Therefore, if the amount of Si is limited, an inflow route of Ar to the grain boundary is not formed, and the effective HI
The P effect occurs.
【００１８】原料組成は、得られる焼結体の光学特性を
大きく左右する。発明者等は、Ｓｉが先に述べたよう
に、粒成長を促進すると共に、多結晶体の透明化組成域
を広げることを見出した。従来法では、焼結助剤として
ＳｉＯ2を数百ppm以上添加しており、透明化組成域はそ
れほど厳密ではない。発明者等は、Ｓｉが１００ppm存
在する場合、ＹＡＧセラミックスの透明化組成域は０.
５９４≦Ｒ／Ａｌ≦０.６０６であることを見出してい
る。しかしながらＳｉ量を減少させると、透明化組成域
も変化し、Ｓｉ無添加の場合、正規組成よりもアルミニ
ウム過剰になると異常粒成長が生じ、逆に希土類過剰に
なると屈折率の全く異なる異相が生じる。従って充分な
透明体を得るために、より厳密に組成制御を行い、０.
５９９≦Ｒ／Ａｌ≦０.６０１とする。The raw material composition largely affects the optical characteristics of the obtained sintered body. The present inventors have found that Si promotes grain growth and expands the transparent composition region of the polycrystal as described above. In the conventional method, several hundred ppm or more of SiO2 is added as a sintering aid, and the transparent composition range is not so strict. The present inventors have found that when 100 ppm of Si is present, the transparent composition range of YAG ceramics is 0.1%.
It has been found that 594 ≦ R / Al ≦ 0.606. However, when the amount of Si is reduced, the transparent composition range also changes. In the case of no addition of Si, abnormal grain growth occurs when the aluminum content exceeds the normal composition and conversely, a heterogeneous phase having a completely different refractive index occurs when the rare earth content becomes excessive. . Therefore, in order to obtain a sufficient transparent body, the composition is more strictly controlled, and the composition is controlled to 0.1.
599 ≦ R / Al ≦ 0.601.
【００１９】なお必要に応じ、Ｃａ，Ｍｇ等の粒成長抑
制剤を添加しても問題ない。但し、必要以上に添加する
と粒界に偏析し、光の散乱源となるのみならず、Ｓｉの
場合と同様、ＨＩＰ効果を充分発揮することが困難とな
る。従ってその添加量は必要最小量に止め、合計で８０
ppm以下とすることが好ましい。これら助剤の添加方法
及び時期は特に限定するものではないが、成形体中に均
一に添加する必要がある。There is no problem if a grain growth inhibitor such as Ca and Mg is added as required. However, if it is added more than necessary, it segregates at the grain boundaries and becomes not only a light scattering source, but also it is difficult to sufficiently exhibit the HIP effect as in the case of Si. Therefore, the amount of addition should be kept to the minimum necessary amount, and a total of 80
It is preferable that the content be not more than ppm. The method and timing for adding these auxiliaries are not particularly limited, but they need to be uniformly added to the molded body.
【００２０】使用原料粉末は易焼結性とし、比表面積を
３〜１５ｍ2／ｇとすると共に、３μｍを超える２次凝
集粒子が重量分率で５％以下の、均一な粒度分布の原料
を使用する。焼結性は原料粉末の粒子径に依存し、微粉
末を使用するほど焼結性は良くなるが、比表面積が３ｍ
2／ｇ以下では、低温で緻密化させることは容易でな
い。また１５ｍ2／ｇ以上の場合には微粉末過ぎて、ハ
ンドリングが容易ではなく、成形密度を高くすることは
困難である。従って、焼結性、パッキング性及びハンド
リング性の容易さの観点から、使用原料の比表面積は３
〜１５ｍ2／ｇとする。また比表面積を調製するだけで
なく、原料粉末の２次凝集粒子の大きさも問題となる。
２次凝集粒子内ないし２次凝集粒子間には、一般の成形
によって生成するよりも大きな、数μｍにもなる空隙が
存在する。この空隙は１次焼成及びＨＩＰ処理では消滅
させることが出来ないため、３μｍを超える２次凝集粒
子が重量分率で５％以下の原料粉末を用いる。The raw material powder used is easy to sinter, has a specific surface area of 3 to 15 m 2 / g, and has a uniform particle size distribution of secondary aggregated particles exceeding 3 μm having a weight fraction of 5% or less. I do. The sinterability depends on the particle diameter of the raw material powder, and the sinterability improves as the fine powder is used, but the specific surface area is 3 m.
If it is less than 2 / g, it is not easy to densify at low temperature. If it is more than 15 m 2 / g, the powder is too fine, handling is not easy, and it is difficult to increase the molding density. Therefore, from the viewpoint of sinterability, packing property, and ease of handling, the specific surface area of the raw material used is preferably 3%.
１５15 m 2 / g. In addition to adjusting the specific surface area, the size of the secondary aggregated particles of the raw material powder also becomes a problem.
Between the secondary aggregated particles and between the secondary aggregated particles, there are voids as large as several μm, which are larger than those generated by general molding. Since these voids cannot be eliminated by the primary firing and the HIP treatment, a raw material powder containing secondary aggregated particles exceeding 3 μm in a weight fraction of 5% or less is used.
【００２１】成形法としては、セラミックスの製造に一
般に用いられている押出し成形、射出成形、プレス成形
等いずれでも良いが、歩留まり良く緻密な焼結体を得る
ため鋳込み成形法が好ましい。ＨＩＰにより除去可能な
気孔の大きさはサブミクロン以下であり、成形時のパッ
キング不良により生じた数ミクロン以上の欠陥を除去す
ることは、１次焼成及びＨＩＰ処理では不可能である。
押出し成形や射出成形では、原料粉末を大量のバインダ
ーと混合し、粘性の高いコンパウンド状とした後、成形
するため、数μｍから数十μｍの気泡が入りやすい。ま
たプレス成形では、一般に粉体のハンドリング性を改善
するため、一旦原料粉末を顆粒とした後、成形する。こ
の際、顆粒間、特に周辺の顆粒との間で形成される３重
点に、数μｍの空隙が生じやすい。これに対して鋳込み
成形では、数μｍにも及ぶ大きな欠陥が生じるのは鋳込
みスリップ中に気泡が入った場合のみであり、このよう
な気泡は超音波や真空により簡単に取り除くことができ
る。従って成形は鋳込み成形法で行い、成形密度を５９
％以上にしておくのが好ましい。As the molding method, any of extrusion molding, injection molding, press molding and the like generally used in the production of ceramics may be used, but a cast molding method is preferred for obtaining a dense sintered body with good yield. The size of pores that can be removed by HIP is submicron or less, and it is impossible to remove defects of several microns or more caused by poor packing during molding by primary firing and HIP processing.
In extrusion molding or injection molding, since a raw material powder is mixed with a large amount of a binder to form a highly viscous compound and then molded, air bubbles of several μm to several tens μm are likely to enter. In press molding, generally, in order to improve powder handling properties, the raw material powder is once granulated and then molded. At this time, a gap of several μm is likely to be generated at the triple point formed between the granules, particularly between the granules in the vicinity. On the other hand, in casting, large defects as large as several μm occur only when bubbles enter the casting slip, and such bubbles can be easily removed by ultrasonic waves or vacuum. Therefore, molding is performed by a casting method, and the molding density is 59%.
% Is preferable.
【００２２】得られた成形体は、熱分解による脱バイン
ダー処理を行う。この際の処理温度、時間、雰囲気は、
添加した成形助剤の種類により異なるが、試料が閉空孔
化してしまうと脱バインダーが困難となるため、焼結の
始まらない温度以下で充分時間をかけて行う。雰囲気は
酸素雰囲気が最も一般的で、必要に応じ加湿水素やＡ
ｒ、もしくは減圧下で行う。The obtained molded body is subjected to a binder removal treatment by thermal decomposition. At this time, the processing temperature, time, and atmosphere
Although it depends on the type of the molding aid added, if the sample becomes closed voids, it becomes difficult to remove the binder. Therefore, the sintering is performed for a sufficient time at a temperature at which sintering does not start. The atmosphere is most commonly an oxygen atmosphere, and if necessary, humidified hydrogen or A
r or under reduced pressure.
【００２３】脱バインダー終了後、試料を真空、大気、
水素等の雰囲気中で１次焼成し、平均粒径３μｍ以下、
理論密度比９４％以上に緻密化させる。ＨＩＰ処理の
際、１次焼成体の平均粒子径が大きすぎると、塑性変形
が生じないため、気孔の除去が困難となる。塑性変形に
より気孔を押し潰すためには、試料の平均粒径が３μｍ
以下であることが必要で、１μｍ以下であることがより
好ましい。平均粒径が３μｍ以下の場合でも、ある程度
緻密化していないと、気孔の除去が難しい。従って１次
焼成体を理論密度の９４％以上まで緻密化させるのが好
ましく、９６％以上であることがより好ましい。After the debinding, the sample is evacuated to vacuum, air,
First firing in an atmosphere such as hydrogen, the average particle size is 3 μm or less,
Densify to a theoretical density ratio of 94% or more. At the time of the HIP treatment, if the average particle diameter of the primary fired body is too large, plastic deformation does not occur, so that it is difficult to remove pores. In order to crush the pores by plastic deformation, the average particle size of the sample is 3 μm.
It is necessary that the thickness be less than or equal to 1 μm. Even if the average particle size is 3 μm or less, it is difficult to remove pores if the particles are not densified to some extent. Therefore, the primary fired body is preferably densified to 94% or more of the theoretical density, more preferably 96% or more.
【００２４】１次焼成温度が低すぎると、充分に緻密化
させることが困難であり、逆に高すぎると粒成長が進行
し、いずれの場合でもＨＩＰ処理によりで気孔を除去す
ることが困難となる。従って、好ましくは１４５０℃以
上１７００℃以下の温度で焼成を行う。例えば焼結助剤
を用いない場合には１５００℃から１６５０℃、Ｃａ，
Ｍｇ等の粒成長抑制剤を８０ppm以下添加した場合には
１６００℃から１７００℃の温度範囲で焼成することが
好ましい。また保持時間は、短すぎると表面組織が充分
に閉空孔化されないため、３０分以上が必要である。試
料厚みが厚い場合には２時間以上保持し、表面と内部を
均一にするが、例えば３mm以下の試料であれば１時間程
度の保持で充分である。If the primary firing temperature is too low, it is difficult to sufficiently densify, and if it is too high, grain growth proceeds, and in any case, it is difficult to remove pores by HIP treatment. Become. Therefore, firing is preferably performed at a temperature of 1450 ° C. or more and 1700 ° C. or less. For example, when a sintering aid is not used, 1500 ° C to 1650 ° C, Ca,
When a grain growth inhibitor such as Mg is added in an amount of 80 ppm or less, it is preferable to perform firing in a temperature range of 1600 ° C. to 1700 ° C. When the holding time is too short, the surface structure is not sufficiently closed and the pores are not sufficiently closed. When the thickness of the sample is large, the sample is held for at least 2 hours to make the surface and the inside uniform, but for a sample of 3 mm or less, holding for about 1 hour is sufficient.
【００２５】得られた１次焼結体中の気孔を除去するた
めに、ＨＩＰ処理を行う。ＨＩＰ処理による気孔の除去
は、高温高圧下での塑性変形によるものであり、処理温
度が低い場合、物質移動が生じないため塑性変形は起こ
らない。逆に処理温度が高すぎる場合、昇温途中に試料
が粒成長してしまうため、やはり塑性変形は起こらな
い。従ってＨＩＰ温度は１４００℃以上１８００℃以下
が好ましく、１５５０℃〜１６５０℃が特に好ましい。
さらにＨＩＰ温度が一次焼結温度と比較して１００℃以
上高い場合、粒成長が促進され、セラミックスの機械的
強度が低下するため、高強度焼結体を得るには、ＨＩＰ
温度を一次焼結温度±５０℃の範囲とすることが好まし
い。In order to remove pores in the obtained primary sintered body, HIP processing is performed. The removal of pores by the HIP treatment is due to plastic deformation under high temperature and high pressure. When the processing temperature is low, mass transfer does not occur, so that plastic deformation does not occur. Conversely, if the treatment temperature is too high, the sample grows during the temperature rise, so that no plastic deformation occurs. Therefore, the HIP temperature is preferably from 1400 ° C to 1800 ° C, and particularly preferably from 1550 ° C to 1650 ° C.
Further, when the HIP temperature is higher than the primary sintering temperature by 100 ° C. or more, the grain growth is promoted and the mechanical strength of the ceramics is reduced.
Preferably, the temperature is in the range of the primary sintering temperature ± 50 ° C.
【００２６】ＨＩＰ圧力の選定も重要であり、温度の最
適化を行っても圧力不足の場合には、気孔を除去するこ
とは困難でる。１４００℃以上の温度で気孔を押し潰す
ためには、８００kgf/cm2以上の圧力が好ましく、特に
試料厚みが５mm以上の場合、１０００kgf/cm2以上が好
ましい。ＨＩＰ圧力が２０００kgf/cm2を超える場合、
高圧容器の維持、管理が容易ではなく、さらに冷却時の
減圧を上手く行わなければ圧力容器内に結露が発生する
等の問題があり、好ましくない。従って、ＨＩＰ圧力は
８００kgf/cm2以上２０００kgf/cm2以下が好ましい。It is also important to select the HIP pressure, and it is difficult to remove pores if the pressure is insufficient even if the temperature is optimized. In order to crush pores at a temperature of 1400 ° C. or more, a pressure of 800 kgf / cm 2 or more is preferable, and particularly, when a sample thickness is 5 mm or more, a pressure of 1000 kgf / cm 2 or more is preferable. If the HIP pressure exceeds 2000kgf / cm2,
Maintenance and management of the high-pressure vessel is not easy, and if pressure reduction during cooling is not performed properly, there is a problem that dew condensation occurs in the pressure vessel, which is not preferable. Therefore, the HIP pressure is preferably 800 kgf / cm2 or more and 2000 kgf / cm2 or less.
【００２７】[0027]
【試験例１】０.５mol/Lの硝酸イットリウム水溶液１５
リッターと０.５mol/Lの硝酸アルミニウム水溶液２５リ
ッターを混合し、ＹＡＧ組成の混合溶液とした。アンモ
ニア水を加えてｐＨ８.０とした２Ｍの炭酸アンモニウ
ム水溶液４０リッター中に、この溶液を１.５リッター
／分の速度で滴下した。この際、ＹＡＧ組成の混合溶液
と、炭酸水素アンモニウム水溶液は共に３０℃に維持し
た。滴下の途中でのｐＨの最小値は７.０で、滴下終了
後３時間程度でｐＨは一定値の７.８に達した。滴下終
了後、３０℃で４８時間養生した後、濾過、水洗を６回
繰り返し、ＹＡＧ前駆体を得た。前駆体製造工程の全て
において超純水（導電率１８ＭΩ・ｃｍ）を使用した。Test Example 1 0.5 mol / L yttrium nitrate aqueous solution 15
The liter and 25 liter of a 0.5 mol / L aqueous solution of aluminum nitrate were mixed to obtain a mixed solution having a YAG composition. This solution was added dropwise at a rate of 1.5 liter / min into 40 liters of a 2M aqueous solution of ammonium carbonate adjusted to pH 8.0 by adding aqueous ammonia. At this time, the mixed solution of the YAG composition and the aqueous solution of ammonium hydrogen carbonate were both maintained at 30 ° C. The minimum value of the pH during the dropping was 7.0, and the pH reached a constant value of 7.8 in about 3 hours after the completion of the dropping. After completion of the dropwise addition, the mixture was cured at 30 ° C. for 48 hours, and then filtered and washed with water six times to obtain a YAG precursor. Ultrapure water (conductivity: 18 MΩ · cm) was used in all of the precursor production steps.
【００２８】得られたＹＡＧ前駆体を大気中１３００℃
で５時間仮焼し、一次粒子径０.４μｍのＹＡＧ原料粉
末を作製した。ＩＣＰを用いて原料粉末の純度分析を行
い、純度９９.９５％以上、Ｓｉは３ppm、Ｙ／Ａｌのモ
ル比は０.６００であることが判明した。また３μｍを
超える凝集粒子の重量分率は１％以下であった。The obtained YAG precursor is heated at 1300 ° C. in air.
For 5 hours to prepare a YAG raw material powder having a primary particle size of 0.4 μm. The purity of the raw material powder was analyzed using ICP, and it was found that the purity was 99.95% or more, the content of Si was 3 ppm, and the molar ratio of Y / Al was 0.600. The weight fraction of the aggregated particles exceeding 3 μm was 1% or less.
【００２９】得られたＹＡＧ原料粉末２００ｇに、解膠
剤として共栄社化学製フローレンＧ−７００を４.２ｇ
添加し、さらにバインダーとして積水化学製ＰＶＢ−Ｂ
Ｌ１を１ｇ添加して、エタノール５０ｇを加え、ナイロ
ンポット及びナイロンボールを用いて１２時間混合し、
アルコールスラリーとした。このスラリーを石膏型に流
し込み、５０mm×５０mm×１０mmの成形体を得た。この
成形体を、酸素気流中１０℃／ｈｒで昇温し、酸素中７
５０℃で１００時間脱脂し、脱脂処理後の成形体密度は
６０.７％であった。次にこの成形体を、真空炉で１５
００℃の温度で２時間１次焼成した。この際、昇温速度
は４００℃／ｈｒ、圧力は１０−３Torr以下とした。１
次焼成体の理論密度比をアルキメデス法により求めた結
果、９６.４％であった。また焼結体内部の微構造を光
学顕微鏡で観察した結果、焼結体平均粒子径は１.２μ
ｍであった。To 200 g of the obtained YAG raw material powder, 4.2 g of Kyoeisha Chemical Floren G-700 was used as a deflocculant.
Sekisui Chemical PVB-B as a binder
1 g of L1 was added, 50 g of ethanol was added, and mixed for 12 hours using a nylon pot and a nylon ball.
An alcohol slurry was obtained. This slurry was poured into a gypsum mold to obtain a molded body of 50 mm × 50 mm × 10 mm. The temperature of this molded body was raised at 10 ° C./hr in an oxygen stream,
Degreasing was performed at 50 ° C. for 100 hours, and the density of the molded body after the degreasing treatment was 60.7%. Next, the molded body is placed in a vacuum furnace for 15 minutes.
Primary firing was performed at a temperature of 00 ° C. for 2 hours. At this time, the temperature raising rate was 400 ° C./hr, and the pressure was 10 −3 Torr or less. 1
The theoretical density ratio of the next fired body was found to be 96.4% by Archimedes' method. As a result of observing the microstructure inside the sintered body with an optical microscope, the average particle diameter of the sintered body was 1.2 μm.
m.
【００３０】この１次焼成体を、５００℃／ｈｒで１５
５０℃まで昇温し、Ａｒ中１２５０kgf/cm2の圧力で２
時間ＨＩＰを行った。得られた焼結体から、略４０×８
×０．５mmの試料を１０枚切り出し両面をダイヤモンド
スラリーで鏡面研磨し、透過顕微鏡を用いて全試料中の
気孔を観察した。気孔数ならびに気孔径を観察し体積換
算した結果、気孔の量は７volppmであった。また、５．
０mm厚に切り出し両面を鏡面研磨したのち分光光度計で
直線透過率を測定した結果、波長５００nmで８４％であ
った。The primary fired body is heated at 500 ° C./hr for 15 hours.
The temperature was raised to 50 ° C., and the pressure was increased to 1250 kgf / cm 2 in Ar.
HIP was performed for hours. From the obtained sintered body, approximately 40 × 8
Ten samples of × 0.5 mm were cut out and both surfaces were mirror-polished with diamond slurry, and the pores in all the samples were observed using a transmission microscope. As a result of observing the number of pores and the pore diameter and converting the volume, the amount of pores was 7 volppm. Also, 5.
After being cut to a thickness of 0 mm and mirror-polished on both sides, the linear transmittance was measured by a spectrophotometer. As a result, it was 84% at a wavelength of 500 nm.
【００３１】[0031]
【試験例２〜９】試験例１と同様にして作製した高純度
ルテチュウムアルミニウムガーネット（Ｌｕ3Ａl5O12：
LuAGと略す）原料粉末にＳｉＯ2を添加し、試験例１と
同様にして焼結体を作製した（試験例２〜９）。焼結体
中のＳｉ量と気孔率の関係を表１に示す。なおこの試料
のＬｕとアルミニウムとのモル比はＬｕ／Ａｌ＝０.５
９９であった。表１から、焼結体中の気孔率を１００vo
lppm以下にするためには、焼結体中のＳｉを１５ppm以
下にする必要があることが判る。Test Examples 2 to 9 High-purity lutetium aluminum garnet (Lu3Al5O12:
LuAG) SiO2 was added to the raw material powder, and a sintered body was produced in the same manner as in Test Example 1 (Test Examples 2 to 9). Table 1 shows the relationship between the amount of Si in the sintered body and the porosity. The molar ratio between Lu and aluminum in this sample was Lu / Al = 0.5.
99. From Table 1, the porosity in the sintered body was 100 vo
It can be seen that in order to make it less than lppm, it is necessary to make Si in the sintered body less than 15ppm.
【００３２】[0032]
【表１】 焼結体中のＳｉと気孔率の関係 Ｓｉ／ppm 気孔率／volppm 光直線透過率（５００nm／５mm厚） 試験例２ ３ ３ ８４ 試験例３ ８ ４３ ８４ 試験例４ １４ ７２ ８３ 試験例５ １７ １１０ ８０ 試験例６ ２２ ２４０ ７７ 試験例７ ５０ ６００ ７２ 試験例８ １２０ ９５０ ６５ 試験例９ ５００ １３５０ ６０ Table 1 Relationship between Si and porosity in sintered body Si / ppm Porosity / volppm Linear light transmittance (500 nm / 5 mm thickness) Test Example 2 3 3 84 Test Example 3 8 43 84 Test Example 4 14 72 83 Test Example 5 17 110 80 Test Example 6 22 240 77 Test Example 7 50 600 72 Test Example 8 120 950 65 Test Example 9 500 1350 60
【００３３】[0033]
【試験例１０〜１４】試験例１と同様にして、組成の異
なる高純度ＬｕＡＧ原料粉末を作製し、ＳｉＯ2を添加
し、試験例１と同様にして焼結体を作製した。焼結体の
組成、Ｓｉ含有量及び気孔率の関係を表２に示す。表２
より、Ｌｕ／Ａｌ＝０.６０１の場合、 Ｓｉが３０ppm
までは気孔率が１００volppm以下であるが、Ｓｉがそれ
以上になると急激に気孔率が増加することが判る。また
試験例１３，１４より、Ｓｉ量が少ない場合でも、僅か
の組成ずれでも気孔が充分除去できないことが判る。Test Examples 10 to 14 In the same manner as in Test Example 1, high-purity LuAG raw material powders having different compositions were prepared, SiO2 was added, and a sintered body was prepared in the same manner as in Test Example 1. Table 2 shows the relationship among the composition, the Si content, and the porosity of the sintered body. Table 2
Therefore, when Lu / Al = 0.601, Si is 30 ppm
Until the porosity is 100 volppm or less, it can be seen that the porosity sharply increases when the Si content is more than 100 volppm. Test Examples 13 and 14 also show that even when the amount of Si is small, pores cannot be sufficiently removed even with a slight composition deviation.
【００３４】[0034]
【表２】 試験例１０〜１４ Ｌｕ／Ａｌ Ｓｉ／ppm 気孔率／volppm 試験例１０ ０.６０１ ３ ３ 試験例１１ ０.６０１ ２８ ８１ 試験例１２ ０.６０１ ３５ ２７０ 試験例１３ ０.５９８ ３ １４００ 試験例１４ ０.６０３ ３ ２２０ Table 2 Test Examples 10 to 14 Lu / Al Si / ppm Porosity / volppm Test Example 10 0.601 3 3 Test Example 11 0.601 28 81 Test Example 12 0.601 35 270 Test Example 13 0.5983 1400 Test Example 14 0.603 3 220
【００３５】[0035]
【試験例１５〜２４】試験例１と同様にして高純度イッ
テッルビウムアルミニウムガーネット（Ｙｂ3Ａｌ5O1
2：YbAGと略す）前駆体を作製し、仮焼時の温度及び時
間を種々に変更して、１次粒子径及び凝集度合いの異な
る高純度ＹｂＡＧ原料粉末を作製した。原料組成はＲ／
Ａｌ＝０.６００であり、ＩＣＰにより純度分析を行っ
た結果、全ての場合においてその純度は９９.９５％以
上、Ｓｉは３ppm以下であった。これら原料粉末を用
い、試験例１と同様にして成形体を作製し、脱バインダ
ー処理を行った後に、真空炉で１５７５℃で平均結晶粒
子径３μｍ以下、理論密度比９４％以上となるように一
次焼成を行った。この１次焼結体をＡｒ中２０００kgf/
cm2、１６００℃でＨＩＰを施した。原料粉末のＢＥＴ
表面積値、３μｍ以上の凝集粒子の重量分率、及び得ら
れた焼結体内部に含まれる気孔率を表３に示す。試験例
１５〜１９により、焼結体の気孔率は出発原料粉末中の
３μｍ以上の凝集粒子の重量分率に依存し、その割合が
多いほど気孔率が増加することが判る。Test Examples 15 to 24 In the same manner as in Test Example 1, high-purity ytterbium aluminum garnet (Yb3Al5O1
2: Abbreviated as YbAG) A precursor was produced, and the temperature and time during calcination were variously changed to produce high-purity YbAG raw material powders having different primary particle diameters and agglomeration degrees. The raw material composition is R /
Al was 0.600, and the purity was analyzed by ICP. As a result, in all cases, the purity was 99.95% or more and the content of Si was 3 ppm or less. Using these raw material powders, a molded body was prepared in the same manner as in Test Example 1, and after performing a binder removal treatment, the average crystal particle diameter was 3 μm or less at 1575 ° C. in a vacuum furnace, and the theoretical density ratio was 94% or more. Primary firing was performed. 2000 kgf /
HIP was performed at 1600 ° C. in cm 2. BET of raw material powder
Table 3 shows the surface area value, the weight fraction of the aggregated particles having a size of 3 μm or more, and the porosity contained in the obtained sintered body. Test Examples 15 to 19 show that the porosity of the sintered body depends on the weight fraction of the aggregated particles of 3 μm or more in the starting material powder, and the porosity increases as the ratio increases.
【００３６】[0036]
【表３】 試験例１５〜２４ ＢＥＴ(cm2/g) ３μｍ以上凝集粒子(wt%) 気孔率(ppm) 試験例１５ ３.４ ４.１ ５７ 試験例１６ ５.８ ２.２ ２１ 試験例１７ ８.４ １.０ ３ 試験例１８ １１.０ ３.３ ９ 試験例１９ １４.６ ４.６ ３４ 試験例２０ ２.７ ４.６ １１０ 試験例２１ ３.５ ６.２ １８５ 試験例２２ ６.８ １０.８ ６３０ 試験例２３ １２.３ ８.５ ５６５ 試験例２４ １６.７ ４.８ ２５０ Table 3 Test Examples 15 to 24 BET (cm2 / g) 3 μm or more agglomerated particles (wt%) Porosity (ppm) Test Example 15 3.4 4.1 57 Test Example 16 5.8 2.2 21 Test Example 17 8.4 1.0 3 Test Example 18 11.0 3.3 9 Test Example 19 14.6 4.6 34 Test Example 20 2.7 4.6 110 Test Example 21 3.5 6.2 185 Test Example 22 6.8 10.8 630 Test Example 23 12.3 8.5 565 Test Example 24 16.7 4.8 250
【００３７】試験例１と同様にして、各種希土類アルミ
ニウムガーネット焼結体を作製し、ＪＩＳ１６０１に基
づき室温での３点曲げ強度を測定した。焼成条件と気孔
率、３点曲げ強度及びワイブル係数を下表に示す。気孔
率の低いものほど高い強度を示しており、全ての場合に
おいて３点曲げ強度は３５０ＭＰａ以上であった。Various rare earth aluminum garnet sintered bodies were prepared in the same manner as in Test Example 1, and the three-point bending strength at room temperature was measured in accordance with JIS1601. The firing conditions, porosity, three-point bending strength and Weibull coefficient are shown in the table below. The lower the porosity, the higher the strength, and in all cases, the three-point bending strength was 350 MPa or more.
【００３８】[0038]
【表４】 各種素材の気孔率と３点曲げ強度 素材 １次焼成 ＨＩＰ温度 圧力 気孔率 3点曲げ強度 ワイフ゛ル係数 (℃×hr) (℃×hr) (kgf/cm2) (ppm) (MPa) Y3Al5O12 1550×2 1550×2 1250 7 430 7 Dy3Al5O12 1500×2 1525×3 1500 25 410 6 Ho3Al5O12 1550×2 1600×3 1000 68 365 7 Er3Al5O12 1600×3 1650×2 800 92 350 6 Tm3Al5O12 1650×5 1700×5 1800 35 395 7 Yb3Al5O12 1575×3 1600×2 800 50 380 7 Lu3Al5O12 1525×3 1550×2 1250 3 450 8 [Table 4] Porosity of various materials and 3-point bending strength material Primary firing HIP temperature Pressure porosity 3-point bending strength Wiper coefficient (℃ × hr) (℃ × hr) (kgf / cm2) (ppm) (MPa) Y3Al5O12 1550 × 2 1550 × 2 1250 7 430 7 Dy3Al5O12 1500 × 2 1525 × 3 1500 25 410 6 Ho3Al5O12 1550 × 2 1600 × 3 1000 68 365 7 Er3Al5O12 1600 × 3 1650 × 2 800 92 350 6 Tm3Al5O12 1650 × 5 1700 × 5 1800 35 395 7 Yb3Al5O12 1575 × 3 1600 × 2 800 50 380 7 Lu3Al5O12 1525 × 3 1550 × 2 1250 3 450 8
【００３９】表１〜表４から、気孔率が１００ppm以下
であることが、５００nmで５mm厚の試料で、直線透過率
を８３％以上とする条件であることが判る。そしてＳｉ
は気孔率を増加させ、気孔率とＳｉ濃度の関係は希土類
過剰かアルミニウム過剰かで異なることが判る。さら
に、出発原料中の３μｍ以上の凝集粒子も気孔率を増加
させ、出発原料のＢＥＴ表面積は３〜１５ｍ２／ｇが好
ましく、気孔率の増加は高圧放電灯等に必要な機械的強
度の点でも好ましくないことが判る。From Tables 1 to 4, it can be seen that a porosity of 100 ppm or less is a condition for a sample having a thickness of 5 mm at 500 nm and a linear transmittance of 83% or more. And Si
Increases the porosity, and it can be seen that the relationship between the porosity and the Si concentration is different depending on whether the rare earth is excessive or the aluminum is excessive. Further, agglomerated particles of 3 μm or more in the starting material also increase the porosity, the BET surface area of the starting material is preferably 3 to 15 m 2 / g, and the increase in the porosity is not sufficient in terms of mechanical strength required for high pressure discharge lamps and the like. It turns out to be undesirable.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 今川 盛輝 大阪市中央区高麗橋４丁目２番７号 神島 化学工業株式会社内 (72)発明者 山崎 裕生 大阪市中央区高麗橋４丁目２番７号 神島 化学工業株式会社内 Ｆターム(参考） 4G031 AA07 AA29 BA15 BA20 CA07 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Seiki Imagawa 4-4-7 Koraibashi, Chuo-ku, Osaka Inside Kamishima Chemical Industry Co., Ltd. (72) Inventor Hiroki Yamazaki 4-2-7 Koraibashi, Chuo-ku, Osaka-shi K-jima Chemical Industry Co., Ltd. F-term (reference) 4G031 AA07 AA29 BA15 BA20 CA07
Claims (3)
Ｙ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕのうちいずれ
か１種の希土類元素）で表されるガーネット構造を有す
る焼結体であって、焼結体中の気孔が１００volppm以下
で、かつ可視から赤外領域に渡って特異吸収波長以外で
の光直線透過率が５mm厚みで８３％以上であることを特
徴とする透光性希土類アルミニウムガーネット焼結体。1. A sintered body having a garnet structure having a crystal structure represented by a general formula R3Al5O12 (R is any one of rare earth elements of Y, Dy, Ho, Er, Tm, Yb, and Lu). Characterized in that the sintered body has pores of 100 volppm or less, and has a linear light transmittance other than the specific absorption wavelength of at least 83% at a thickness of 5 mm over the visible to infrared region. Aluminum garnet sintered body.
の比が０.５９９≦Ｒ／Ａｌ≦０.６０１であり、 希土類元素とアルミニウムとの比が０.５９９≦Ｒ／Ａ
ｌ≦０.６００で、焼結体中のＳｉが１５wtppm以下であ
り、 希土類元素とアルミニウムとの比が０.６００＜Ｒ／Ａ
ｌ≦０.６０１で、焼結体中のＳｉがＳｉ(wtppm)≦１５
０００×（Ｒ／Ａｌ）−８９８５である、ことを特徴と
する請求項１の透光性希土類アルミニウムガーネット焼
結体。2. The molar ratio of the rare earth element to aluminum is 0.599 ≦ R / Al ≦ 0.601, and the ratio of the rare earth element to aluminum is 0.599 ≦ R / A.
1 ≦ 0.600, Si in the sintered body is 15 wtppm or less, and the ratio of rare earth element to aluminum is 0.600 <R / A
When l ≦ 0.601, Si in the sintered body is Si (wtppm) ≦ 15
The translucent rare earth aluminum garnet sintered body according to claim 1, wherein 000 × (R / Al) −8985.
を超える凝集粒子が重量分率で５％以下の原料粉末を用
いて作製された一般式Ｒ3Ａｌ5Ｏ12（ＲはＹ，Ｄｙ，Ｈ
ｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕのうちいずれか１種の希土
類元素）で表されるセラミックス成形体を１次焼成し
て、平均粒径３μｍ以下、理論密度比９４％以上に緻密
化し、 この１次焼結体に熱間等方圧加圧を施すことにより、焼
結体中の気孔が１００volppm以下で、可視から赤外領域
に渡って特異吸収波長以外での光直線透過率が５mm厚み
で８３％以上の焼結体とすることを特徴とする、透光性
希土類アルミニウムガーネット焼結体の製造方法。3. The resin having a specific surface area of 3 to 15 m 2 / g and a thickness of 3 μm
R3Al5O12 (R is Y, Dy, H
o, Er, Tm, Yb, or Lu), a ceramic molded body represented by one of the following rare earth elements is subjected to primary firing to be densified to an average particle diameter of 3 μm or less and a theoretical density ratio of 94% or more. By subjecting the primary sintered body to hot isostatic pressing, the pores in the sintered body are 100 volppm or less, and the light linear transmittance at a wavelength other than the specific absorption wavelength in the visible to infrared region is 5 mm. A method for producing a sintered body of a translucent rare earth aluminum garnet, wherein the sintered body is 83% or more.
Priority Applications (1)
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|---|---|---|---|
| JP34289199A JP2001158660A (en) | 1999-12-02 | 1999-12-02 | Optically transmitting rare earth-aluminum garnet sintered product and production method therefor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34289199A JP2001158660A (en) | 1999-12-02 | 1999-12-02 | Optically transmitting rare earth-aluminum garnet sintered product and production method therefor |
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| Publication Number | Publication Date |
|---|---|
| JP2001158660A true JP2001158660A (en) | 2001-06-12 |
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ID=18357323
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|---|---|---|---|
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