JP3454957B2 - Alumina sintered body - Google Patents
Alumina sintered bodyInfo
- Publication number
- JP3454957B2 JP3454957B2 JP03979395A JP3979395A JP3454957B2 JP 3454957 B2 JP3454957 B2 JP 3454957B2 JP 03979395 A JP03979395 A JP 03979395A JP 3979395 A JP3979395 A JP 3979395A JP 3454957 B2 JP3454957 B2 JP 3454957B2
- Authority
- JP
- Japan
- Prior art keywords
- alumina
- sintered body
- dielectric loss
- less
- cao
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Compositions Of Oxide Ceramics (AREA)
- Inorganic Insulating Materials (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、アルミナ質焼結体に関
するものであり、特に、例えば、通信用ＭＩＣ基板やＭ
ＩＣパッケージ、マイクロ波コンデンサ、マイクロ波通
信装置用部品、高エネルギー粒子加速装置のマイクロ波
透過窓等に用いることができる高周波低損失性のアルミ
ナ質焼結体に関する。
【０００２】
【従来技術】従来、例えば、通信用ＭＩＣ基板やＭＩＣ
パッケージ、マイクロ波コンデンサ、マイクロ波通信用
装置用部品、高エネルギー粒子加速装置のマイクロ波透
過窓に用いられるアルミナ質焼結体では、誘電損失は１
０ＧＨｚ程度のマイクロ波帯において１×１０-4以下で
あることが求められる。
【０００３】このようなアルミナ質焼結体としては、従
来、誘電損失を１×１０-4以下にするために、不純物の
含有量を元素基準のｐｐｍ単位で、Ｓｉを８０ｐｐｍ以
下、Ｍｇを６０ｐｐｍ以下、Ｓｉ／Ｍｇを１〜５、かつ
他の金属やアルカリ成分等を総量７０ｐｐｍ以下とした
アルミナ質焼結体が知られている（特開平１−２１３９
１０号公報）。
【０００４】また、特開平４−３５６９２２号公報で
は、マイクロ波透過窓として、マイクロ波を透過させる
性質を持たせるため、含有しているアルカリ金属（Ｎａ
2 Ｏ、Ｋ2 Ｏ）の総量を１５０ｐｐｍ以下に抑制し、マ
イクロ波帯の誘電損失を１×１０-3以下としたアルミナ
質焼結体が開示されている。
【０００５】
【発明が解決しようとする問題点】一般に、アルミナ質
焼結体の誘電損失の増加に粒界相のガラス質が大きく寄
与していると言われている。このため、低損失磁器を得
るためには、粒界相の生成を制御する必要がある。一般
に粒界相の生成を極力さける目的で、生成原因となる不
純物を避けるために、高純度の原料を用いて不純物の総
量を規制している。
【０００６】その中でも、ガラス相を形成しやすいアル
カリ成分は極力避ける必要がある。
【０００７】しかしながら、実際には高純度アルミナ原
料（純度９９．９９９％程度）を用いても、必ずしも誘
電損失が１×１０-4以下にならないという問題があっ
た。
【０００８】また、特開平１−２１３９１０号公報に開
示されるアルミナ質焼結体では、アルカリ金属酸化物以
外の不純物含有量も減少させ、全体的に磁器を高純度化
させる必要があるため、生産性が低下するという問題が
あった。さらに焼成温度が高くなりがちであった。
【０００９】さらに、特開平４−３５６９２２号公報に
開示されるアルミナ質焼結体では、低誘電損失化させる
ためアルカリ金属（Ｎａ2 Ｏ、Ｋ2 Ｏ）総量を抑制して
いるが、この場合でも必ずしも１×１０-4以下の誘電損
失を達成できるとは限らないという問題があった。
【００１０】本発明は、高純度アルミナ原料を用いるこ
となく、誘電損失を確実に１×１０-4以下とすることが
できるとともに、生産性および焼結性を向上することが
できるアルミナ質焼結体を提供することを目的とする。
【００１１】
【問題点を解決するための手段】本発明者は、上記問題
を解決すべく鋭意検討した結果、アルミナ質焼結体中に
生成する粒界相には様々な結晶相があり、そのすべてが
誘電損失を増加させているわけではなく、誘電損失増加
の原因としてはＮａ含有量だけでなく、粒界相中の析出
結晶相のうちＣａＯ・６Ａｌ2 Ｏ3 の存在も、アルミナ
質焼結体の誘電損失を増加させていることを見出した。
また、Ｃａはアルミナに殆ど固溶せず、粒界にＣａＯ・
６Ａｌ2 Ｏ3 として析出するため、アルミナ質焼結体の
誘電損失を低下させるためには、Ｃａ量を減少させ、粒
界相中におけるＣａＯ・６Ａｌ2 Ｏ3 の析出量を少なく
すれば良いことを見出した。さらに、ＭｇＯは、微量添
加（０．０３〜１０重量％）で粒界にＭｇＡｌ2 Ｏ4 を
生成し、アルミナの焼結性を促進する効果があることが
知られている。しかし、ＣａＯを添加せず、粒界にＣａ
Ｏ・６Ａｌ2 Ｏ3 が生成しないと、緻密化が阻害され、
焼成温度が高くなり生産上好ましくない。このため、ア
ルミナ焼結体の粒界相中にＭｇＡｌ2 Ｏ4 とＣａＯ・６
Ａｌ2 Ｏ3 を析出させるとともに、Ｎａ含有量を一定以
下に抑制することにより、アルミナ質焼結体の誘電損失
を確実に１×１０-4以下とすることができるとともに、
生産性および焼結性を向上することができることを見出
し、本発明に至った。
【００１２】即ち、本発明のアルミナ質焼結体は、主成
分としてのアルミナに、Ｎａ含有量がＮａ2Ｏ換算で７
０〜１００ｐｐｍ、ＣａがＣａＯ換算で０．０５〜０．
５重量％、ＭｇがＭｇＯ換算で０．０３〜１０重量％の
割合で含有し、かつ、粒界相をＸ線回折測定した場合
に、ＣａＯ・６Ａｌ2Ｏ3とＭｇＡｌ2Ｏ4のピークが存在
するとともに、測定周波数１４ＧＨｚにおける誘電損失
ｔａｎδが１×１０-4以下であることを特徴とすること
を特徴とするものである。
【００１３】本発明のアルミナ質焼結体では、Ｎａ含有
量をＮａ2Ｏ換算で１００ｐｐｍ以下としたのは、Ｎａ
含有量がＮａ2Ｏ換算で１００ｐｐｍよりも大きくなる
と、誘電損失が１×１０-4よりも大きくなるからであ
る。Ｎａ含有量は少ない方が良く、Ｎａを含む結晶相の
ピークは、Ｘ線回折測定ではピークが実質的に存在しな
いことが望ましいが、本発明によれば、Ｎａ量が７０ｐ
ｐｍ以上であっても誘電損失を低減することができる。
【００１４】また、ＣａをＣａＯ換算で０．５重量％以
下としたのは、０．５重量％よりも多い場合にはＣａＯ
・６Ａｌ2Ｏ3の析出量が多く、誘電損失が１×１０-4よ
りも大きくなるからである。ＣａはＣａＯ換算で０．０
５〜０．５重量％とする。
【００１５】さらに、ＭｇをＭｇＯ換算で０．０３重量
％以上としたのは、０．０３重量％よりも少ない場合に
は焼成温度が高くなり、誘電損失が１×１０-4以上とな
るからである。ＭｇはＭｇＯ換算で０．０３〜１０重量
％であることが誘電損失の点から必要である。
【００１６】そして、粒界相をＸ線回折測定した場合
に、ＣａＯ・６Ａｌ2 Ｏ3 とＭｇＡｌ2 Ｏ4 のピークを
存在させた理由は、上記したように誘電損失を１×１０
-4以下にし、さらにアルミナ質焼結体の焼結性を向上す
るためである。ＣａＯ・６Ａｌ2 Ｏ3 が多いと誘電損失
が高くなるため、なるべく少なくする必要がある。Ｘ線
回折測は、例えば、波長λ＝１．５４１８ÅのＣｕＫα
線により行う。
【００１７】本発明のアルミナ質焼結体は、例えば、高
純度アルミナ粉末にＭｇ（ＯＨ）2粉末およびＣａＣＯ
3 粉末を所定量添加し、イソプロピルアルコール（ＩＰ
Ａ）と混合し、アルミナボールで粉砕混合する。混合後
のスラリーを乾燥し、仮焼して得られた粉末を、例え
ば、金型プレスで成形し、焼結助剤によっても異なる
が、例えば、大気中において１５００〜１６００℃で
０．５〜４時間焼成することにより、本発明のアルミナ
質焼結体が得られる。
【００１８】
【作用】本発明のアルミナ質焼結体では、Ｎａ含有量が
Ｎａ2Ｏ換算で７０〜１００ｐｐｍであっても、Ｃａを
ＣａＯ換算で０．０５〜０．５重量％、ＭｇをＭｇＯ換
算で０．０３〜１０重量％とし、粒界相にＣａＯ・６Ａ
ｌ2Ｏ3とＭｇＡｌ2Ｏ4を存在させることにより、焼結体
の誘電損失を１×１０-4以下とすることが可能となる。
【００１９】また、本発明のアルミナ質焼結体では、高
純度のアルミナ原料を用いなくてもよく、アルミナ純度
９９．９％程度の汎用原料を用いても１×１０-4以下の
誘電損失が得られるため、適切な焼結助剤を用いて焼成
温度を低下させることが可能となり、焼結性および生産
性を向上することができる。
【００２０】
【実施例】Ｎａ2 Ｏ含有量の異なるアルミナ原料（純度
９９．９％）と、ＣａＣＯ3 及びＭｇ（ＯＨ）2 を、表
１の組成となるように秤量し、この混合粉末を、純度９
９．９％のアルミナボール、イソプロピルアルコール
（ＩＰＡ）と共に１リットルポリポットに投入し、４２
時間回転ミル台にて混合した。混合後のスラリーにバイ
ンダーとしてパラフィンワックスを６重量％加え混合攪
拌した。このスラリーを８０℃大気中にて乾燥し、評価
粉末得た。尚、表１では、ＣａＣＯ3 はＣａＯに換算
し、また、Ｍｇ（ＯＨ）2 はＭｇＯに換算して記載し
た。
【００２１】この粉末を金型プレスにて１０００ｋｇ／
ｃｍ2 で直径１２ｍｍ、厚み８ｍｍに成形した。成形体
は、大気中において４００℃で２時間脱脂を行い、その
後、表１に示す焼成温度で２時間保持して焼成した。焼
結体は、直径１０ｍｍ、厚み５ｍｍに加工研磨した。こ
の試料の高周波誘電損失を測定周波数１４ＧＨｚで測定
した。また、波長λ＝１．５４１８ÅのＣｕＫα線によ
るＸ線回折測により試料の結晶相を同定した。これらの
結果を表１に示す。
【００２２】
【表１】【００２３】この表１から、粒界相中にＣａＯ・６Ａｌ
2 Ｏ3 の他に、ＭｇＡｌ2 Ｏ4 が析出した本発明の試料
については、１×１０-4以下の低誘電損失を示すことが
判る（試料Ｎo.２〜５，８〜１１）。また、本発明の試
料では、焼成温度が１６００℃以下となっており、従来
よりも低温で焼成できることが判る。さらに、ＣａＯの
添加量が増加するにしたがって誘電損失が増加し、Ｍｇ
Ｏ添加量が増加するに伴い焼成温度が低下することが判
る。
【００２４】
【発明の効果】以上のように、本発明のアルミナ質焼結
体ではＮａ含有量をＮａ2 Ｏ換算で１００ｐｐｍ以下と
し、ＣａおよびＭｇを所定量含有させ、さらに、粒界相
にＣａＯ・６Ａｌ2 Ｏ3 とＭｇＡｌ2 Ｏ4 を存在させる
ことにより、焼結体の誘電損失を確実に１×１０-4以下
とすることができるとともに、高純度のアルミナ原料を
用いなくても、純度９９．９％程度の汎用原料を用いて
も１×１０-4以下の誘電損失を得ることができるため、
焼結性および生産性を向上することができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alumina sintered body, and more particularly to, for example, a communication MIC substrate and an MMIC.
The present invention relates to a high-frequency low-loss alumina sintered body that can be used for an IC package, a microwave capacitor, a component for a microwave communication device, a microwave transmission window of a high energy particle accelerator, and the like. 2. Description of the Related Art Conventionally, for example, a communication MIC board or MIC
The dielectric loss is 1 in the alumina sintered body used for the package, the microwave capacitor, the component for the microwave communication device, and the microwave transmission window of the high energy particle accelerator.
It is required to be 1 × 10 −4 or less in a microwave band of about 0 GHz. Conventionally, such an alumina-based sintered body has been designed so that the content of impurities is 80 ppm or less of Si and 60 ppm of Mg in terms of elemental ppm in order to reduce the dielectric loss to 1 × 10 −4 or less. Hereinafter, an alumina sintered body in which the content of Si / Mg is 1 to 5 and the total amount of other metals and alkali components is 70 ppm or less is known (Japanese Patent Laid-Open No. 1-2139).
No. 10). In Japanese Patent Application Laid-Open No. 4-356922, an alkali metal (Na) is contained as a microwave transmitting window in order to have a property of transmitting microwaves.
An alumina sintered body is disclosed in which the total amount of 2 O, K 2 O) is suppressed to 150 ppm or less and the dielectric loss in the microwave band is 1 × 10 −3 or less. [0005] Generally, it is said that the glassiness of the grain boundary phase greatly contributes to the increase in the dielectric loss of the alumina-based sintered body. Therefore, in order to obtain low-loss porcelain, it is necessary to control the generation of the grain boundary phase. Generally, for the purpose of minimizing the generation of the grain boundary phase, a high-purity raw material is used to regulate the total amount of impurities in order to avoid impurities that cause the generation. [0006] Among them, it is necessary to avoid an alkali component which easily forms a glass phase as much as possible. However, there is a problem that the dielectric loss does not always become 1 × 10 −4 or less even when a high-purity alumina raw material (purity of about 99.999%) is actually used. Further, in the alumina-based sintered body disclosed in Japanese Patent Application Laid-Open No. 1-213910, it is necessary to reduce the content of impurities other than the alkali metal oxide and to make the porcelain highly pure as a whole. There was a problem that productivity fell. Furthermore, the firing temperature tends to be high. Further, in the alumina-based sintered body disclosed in Japanese Patent Application Laid-Open No. 4-356922, the total amount of alkali metals (Na 2 O, K 2 O) is suppressed in order to reduce the dielectric loss. However, there is a problem that a dielectric loss of 1 × 10 −4 or less cannot always be achieved. According to the present invention, there is provided an alumina-based sintering method capable of reliably reducing dielectric loss to 1 × 10 -4 or less without using a high-purity alumina raw material and improving productivity and sinterability. The purpose is to provide the body. The present inventors have conducted intensive studies to solve the above problems, and as a result, there are various crystal phases in the grain boundary phase formed in the alumina-based sintered body. all are not necessarily have to increase the dielectric loss, the causes of the dielectric loss increases not only the Na content, existence of CaO · 6Al 2 O 3 of the precipitated crystal phases of grain boundary phase, aluminous It was found that the dielectric loss of the sintered body was increased.
In addition, Ca hardly dissolves in alumina and CaO.
Since it precipitates as 6Al 2 O 3 , the dielectric loss of the alumina-based sintered body can be reduced by reducing the amount of Ca and reducing the amount of CaO · 6Al 2 O 3 in the grain boundary phase. Was found. Furthermore, it is known that MgO generates MgAl 2 O 4 at the grain boundary when added in a small amount (0.03 to 10% by weight), and has an effect of promoting sinterability of alumina. However, without adding CaO, Ca
If O.6Al 2 O 3 is not generated, densification is hindered,
The firing temperature is increased, which is not preferable in production. Therefore, MgAl 2 O 4 and CaO · 6 are contained in the grain boundary phase of the alumina sintered body.
By precipitating Al 2 O 3 and suppressing the Na content to a certain level or less, the dielectric loss of the alumina-based sintered body can be reliably reduced to 1 × 10 −4 or less,
The present inventors have found that productivity and sinterability can be improved, and have reached the present invention. That is, in the alumina sintered body of the present invention, the alumina as a main component has a Na content of 7 in terms of Na 2 O.
0-100 ppm, Ca is 0.05-0.
5 wt%, Mg is contained in a proportion of 0.03 to 10 wt% in terms of MgO, and, if the grain boundary phase were measured X-ray diffraction peak of CaO · 6Al 2 O 3 and MgAl 2 O 4 is And a dielectric loss tan δ at a measurement frequency of 14 GHz is 1 × 10 −4 or less. In the alumina-based sintered body of the present invention, the Na content is set to 100 ppm or less in terms of Na 2 O because Na
If the content is greater than 100 ppm in terms of Na 2 O, the dielectric loss will be greater than 1 × 10 −4 . It is preferable that the Na content is small, and it is desirable that the peak of the Na-containing crystal phase has substantially no peak in the X-ray diffraction measurement.
Even if it is not less than pm, the dielectric loss can be reduced. The reason why the content of Ca is set to 0.5% by weight or less in terms of CaO is that if the content is more than 0.5% by weight, CaO
This is because the amount of 6Al 2 O 3 deposited is large, and the dielectric loss is larger than 1 × 10 −4 . Ca is 0.0 in CaO conversion
5 to 0.5% by weight. Further, the reason why Mg is made 0.03% by weight or more in terms of MgO is that if less than 0.03% by weight, the firing temperature becomes high and the dielectric loss becomes 1 × 10 -4 or more. It is. Mg is required to be 0.03 to 10% by weight in terms of MgO from the viewpoint of dielectric loss. When the grain boundary phase was measured by X-ray diffraction, the peaks of CaO.6Al 2 O 3 and MgAl 2 O 4 were present because the dielectric loss was 1 × 10
-4 or less to further improve the sinterability of the alumina-based sintered body. And since the dielectric loss is high CaO · 6Al 2 O 3 is large, it is necessary to as small as possible. X-ray diffraction measurement is performed, for example, using CuKα having a wavelength λ = 1.5418 °.
Perform by line. The alumina-based sintered body of the present invention is obtained, for example, by adding Mg (OH) 2 powder and CaCO 2 to high-purity alumina powder.
3 Add a predetermined amount of powder and add isopropyl alcohol (IP
A) and pulverized and mixed with alumina balls. The mixed slurry is dried, and the powder obtained by calcination is formed by, for example, a die press, and varies depending on the sintering aid. By calcining for 4 hours, the alumina sintered body of the present invention is obtained. In the alumina-based sintered body of the present invention, even if the Na content is 70 to 100 ppm in terms of Na 2 O, 0.05 to 0.5% by weight of Ca in terms of CaO and Mg 0.03 to 10% by weight in terms of MgO, and CaO.6A
The presence of l 2 O 3 and MgAl 2 O 4 makes it possible to reduce the dielectric loss of the sintered body to 1 × 10 −4 or less. Further, in the alumina sintered body of the present invention, it is not necessary to use a high-purity alumina raw material, and even if a general-purpose raw material having an alumina purity of about 99.9% is used, a dielectric loss of 1 × 10 −4 or less is used. Is obtained, the firing temperature can be lowered by using an appropriate sintering aid, and sinterability and productivity can be improved. EXAMPLE Alumina raw materials (purity 99.9%) having different Na 2 O contents, CaCO 3 and Mg (OH) 2 were weighed so as to have the composition shown in Table 1, and this mixed powder was weighed. , Purity 9
Put into a 1 liter polypot with 9.9% alumina balls and isopropyl alcohol (IPA),
The mixture was mixed on a rotary mill table for an hour. 6% by weight of paraffin wax was added as a binder to the mixed slurry, followed by mixing and stirring. This slurry was dried in the air at 80 ° C. to obtain an evaluation powder. In Table 1, CaCO 3 is converted to CaO, and Mg (OH) 2 is converted to MgO. This powder was pressed at 1000 kg /
It was molded to a diameter of 12 mm and a thickness of 8 mm in cm 2 . The molded body was degreased in the air at 400 ° C. for 2 hours, and then fired while maintaining the firing temperature shown in Table 1 for 2 hours. The sintered body was processed and polished to a diameter of 10 mm and a thickness of 5 mm. The high-frequency dielectric loss of this sample was measured at a measurement frequency of 14 GHz. Further, the crystal phase of the sample was identified by X-ray diffraction measurement using CuKα radiation having a wavelength λ = 1.5418 °. Table 1 shows the results. [Table 1] From Table 1, it can be seen that CaO.6Al is contained in the grain boundary phase.
It can be seen that the sample of the present invention, on which MgAl 2 O 4 was precipitated in addition to 2 O 3 , exhibited a low dielectric loss of 1 × 10 −4 or less (samples No. 2 to 5, 8 to 11). Further, in the sample of the present invention, the firing temperature is 1600 ° C. or lower, which indicates that firing can be performed at a lower temperature than in the past. Furthermore, as the addition amount of CaO increases, the dielectric loss increases, and Mg increases.
It can be seen that the firing temperature decreases as the amount of O added increases. As described above, in the alumina-based sintered body of the present invention, the Na content is reduced to 100 ppm or less in terms of Na 2 O, Ca and Mg are contained in predetermined amounts, and By the presence of CaO.6Al 2 O 3 and MgAl 2 O 4 , the dielectric loss of the sintered body can be reliably reduced to 1 × 10 −4 or less, and without using a high-purity alumina raw material. Even if a general-purpose material having a purity of about 99.9% is used, a dielectric loss of 1 × 10 −4 or less can be obtained.
Sinterability and productivity can be improved.
Claims (1)
Ｎａ2Ｏ換算で７０〜１００ｐｐｍ、ＣａがＣａＯ換算
で０．０５〜０．５重量％、ＭｇがＭｇＯ換算で０．０
３〜１０重量％の割合で含有し、かつ、粒界相をＸ線回
折測定した場合に、ＣａＯ・６Ａｌ2Ｏ3とＭｇＡｌ2Ｏ4
のピークが存在するとともに、測定周波数１４ＧＨｚに
おける誘電損失ｔａｎδが１×１０-4以下であることを
特徴とすることを特徴とするアルミナ質焼結体。(57) [Claims 1] An alumina as a main component has a Na content of 70 to 100 ppm in terms of Na 2 O, Ca is 0.05 to 0.5% by weight in terms of CaO, Mg Is 0.0 in MgO conversion
In a proportion of 3 to 10 wt%, and the grain boundary phase when measured X-ray diffraction, CaO · 6Al 2 O 3 and MgAl 2 O 4
Characterized in that the dielectric loss tan δ at a measurement frequency of 14 GHz is 1 × 10 −4 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03979395A JP3454957B2 (en) | 1995-02-28 | 1995-02-28 | Alumina sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03979395A JP3454957B2 (en) | 1995-02-28 | 1995-02-28 | Alumina sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08235933A JPH08235933A (en) | 1996-09-13 |
| JP3454957B2 true JP3454957B2 (en) | 2003-10-06 |
Family
ID=12562841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03979395A Expired - Fee Related JP3454957B2 (en) | 1995-02-28 | 1995-02-28 | Alumina sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3454957B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4530380B2 (en) * | 1999-11-29 | 2010-08-25 | 日本特殊陶業株式会社 | Spark plug insulator and spark plug including the same |
| JP4762168B2 (en) * | 2006-02-24 | 2011-08-31 | 京セラ株式会社 | Alumina sintered body, member for processing apparatus using the same, and processing apparatus |
| US8247337B2 (en) | 2007-11-28 | 2012-08-21 | Kyocera Corporation | Alumina sintered article |
| WO2009069770A1 (en) * | 2007-11-28 | 2009-06-04 | Kyocera Corporation | Aluminous sinter, process for producing the same, member for semiconductor production apparatus, member for liquid-crystal-panel production apparatus, and member for dielectric resonator |
| JP6352686B2 (en) * | 2014-01-30 | 2018-07-04 | 京セラ株式会社 | Alumina sintered body, semiconductor manufacturing apparatus member, and liquid crystal panel manufacturing apparatus member |
| JP6462449B2 (en) * | 2015-03-26 | 2019-01-30 | 京セラ株式会社 | High-frequency window member, semiconductor manufacturing device member, and flat panel display (FPD) manufacturing device member |
-
1995
- 1995-02-28 JP JP03979395A patent/JP3454957B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08235933A (en) | 1996-09-13 |
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