JP2663191B2 - Method for producing polycrystalline alumina sintered body - Google Patents
Method for producing polycrystalline alumina sintered bodyInfo
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- JP2663191B2 JP2663191B2 JP2056645A JP5664590A JP2663191B2 JP 2663191 B2 JP2663191 B2 JP 2663191B2 JP 2056645 A JP2056645 A JP 2056645A JP 5664590 A JP5664590 A JP 5664590A JP 2663191 B2 JP2663191 B2 JP 2663191B2
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- sintered body
- hip
- particle diameter
- polycrystalline alumina
- temperature
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Description
【発明の詳細な説明】 産業上の利用分野 この発明は、ナトリウムランプ外管等に使用される光
透過率の高い多結晶アルミナの焼結体に関するものであ
る。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered body of polycrystalline alumina having a high light transmittance used for a sodium lamp outer tube and the like.
従来の技術 従来の透光性の多結晶アルミナの焼結体は、アルミナ
粉末を成形して、水素還元雰囲気下で1800℃程度で常圧
焼結していた。2. Description of the Related Art Conventionally, a sintered body of translucent polycrystalline alumina is formed by molding an alumina powder and sintering it at about 1800 ° C. under normal pressure under a hydrogen reducing atmosphere.
この多結晶アルミナ焼結体の透光性を高めるための要
件、すなわち光の散乱を少なくして光透過率を高めるた
めの要件は、次のとおりである。The requirements for increasing the translucency of this polycrystalline alumina sintered body, that is, the requirements for reducing the scattering of light and increasing the light transmittance are as follows.
（１）不純物量を減少させる （２）粒界に存在する気孔を減少させる このうち（２）については、結晶粒子径を大きくする
ことにより、気孔を（粒界を）減少させていた。(1) Reducing the amount of impurities (2) Reducing the porosity present at the grain boundaries Regarding (2), the pores (the grain boundaries) were reduced by increasing the crystal particle diameter.
発明が解決しようとする課題 結晶粒子径が大きいことから３点曲げ強さが280〜300
Mpaと低く、応力集中を起こしやすい複雑形状品には使
用できなかった。Problems to be Solved by the Invention Since the crystal grain size is large, the three-point bending strength is 280 to 300.
It could not be used for products with complex shapes that are low in Mpa and easily cause stress concentration.
発明の目的 この発明は、透光性を高くできしかも高強度の多結晶
アルミナの焼結体を提供することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to provide a sintered body of polycrystalline alumina which can have high translucency and high strength.
発明の要旨 本発明は、高純度Al2O3の原料粉末を用いて、原料粉
末を分散処理してスラリーを得て、このスラリーをスリ
ップキャスティング法によって成形し、バインダーを含
まない成形体を得る工程と、成形体を乾燥してから、予
備焼結して、予備焼結体を得る工程と、予備焼結体を12
00℃〜1400℃の温度でHIP処理して、多結晶アルミナ焼
結体を得るとともに、その1mm厚さにおけるハロゲンラ
ンプの直線透過率を30％以上にし、平均結晶粒子径を0.
5μｍ〜20μｍにし、３点曲げ強度を650MPa以上にする
工程とを含むことを特徴とする多結晶アルミナ焼結体の
製造方法を要旨としている。SUMMARY OF THE INVENTION The present invention uses a raw material powder of high purity Al 2 O 3 to obtain a slurry by subjecting the raw material powder to a dispersion treatment, and molding the slurry by a slip casting method to obtain a molded body containing no binder. Drying the compact, pre-sintering it to obtain a pre-sintered body,
HIP treatment is performed at a temperature of 00 ° C. to 1400 ° C. to obtain a polycrystalline alumina sintered body, a linear transmittance of a halogen lamp at a thickness of 1 mm is set to 30% or more, and an average crystal grain diameter is 0.1 mm.
A method of producing a polycrystalline alumina sintered body, characterized by comprising a step of setting the three-point bending strength to 5 μm to 20 μm and a 650 MPa or more three-point bending strength.
課題を解決するための手段 高い透光性、すなわち直線透過率が30％以上である多
結晶アルミナの焼結体について、この焼結体の平均結晶
粒子径が0.5μｍ以上20μｍ以下である。平均結晶粒子
径をこのように制御することにより曲げ強さを高めるこ
とができ、つまり応力集中の起しやすい複雑形状品に使
用できる。特に好ましくは1.5μｍ以上10μｍ以下であ
る。直線透過率が30％より小さいとナトリウム外管や容
器などの用途に不適切である。Means for Solving the Problems For a sintered body of polycrystalline alumina having a high translucency, that is, a linear transmittance of 30% or more, the average crystal grain size of the sintered body is 0.5 μm or more and 20 μm or less. By controlling the average crystal grain size in this way, the bending strength can be increased, that is, it can be used for a product having a complicated shape in which stress concentration easily occurs. Particularly preferably, it is 1.5 μm or more and 10 μm or less. If the linear transmittance is less than 30%, it is unsuitable for applications such as sodium outer tubes and containers.
平均粒子径が0.5μｍより小さいと、直縁透過率の低
下が著くなるためよくない。また20μｍより大きいと、
平均曲げ強さが低くなるためよくない。If the average particle diameter is smaller than 0.5 μm, the decrease in the transmittance at the direct edge becomes remarkable, which is not preferable. If it is larger than 20 μm,
Not good because the average bending strength is low.
熱処理は、好ましくは熱間静水圧プレス（以下HIPと
いう）処理である。HIP処理温度は、好ましくは1200℃
〜1400℃である。1200℃より低いと、直線透過率の低下
が著くなるためよくない。1400℃より高いと、３点曲げ
強さが低くなるためよくない。The heat treatment is preferably a hot isostatic pressing (HIP) treatment. HIP processing temperature is preferably 1200 ° C
~ 1400 ° C. If the temperature is lower than 1200 ° C., the linear transmittance is remarkably reduced, which is not preferable. If the temperature is higher than 1400 ° C., the three-point bending strength decreases, which is not good.
直線透過率を高めるためには、1300℃以上の処理温度
で処理するのが好ましい。たとえば1350℃や1400℃の熱
処理温度の焼結体では、40％以上の直線透過率が得られ
る。In order to increase the linear transmittance, the treatment is preferably performed at a treatment temperature of 1300 ° C. or more. For example, in a sintered body at a heat treatment temperature of 1350 ° C. or 1400 ° C., a linear transmittance of 40% or more can be obtained.
本発明の多結晶アルミナの焼結体は、焼結助剤、たと
えばMgOが無添加でも直線透過率30％以上のものが得ら
れる。The sintered body of polycrystalline alumina of the present invention has a linear transmittance of 30% or more even without adding a sintering aid such as MgO.
HIP処理はArのような不活性ガス雰囲気下で行う。 The HIP treatment is performed in an inert gas atmosphere such as Ar.
一例として1250℃で予備焼結後、1300℃でHIP処理を
行った多結晶アルミナの焼結体は、直線透過率が40％、
平均３点曲げ強さが760MPa、ビッカース硬度〔Hv〕が1
9.4GPa、ワイブル係数が14と高透光性、高強度の特質が
得られている。As an example, after pre-sintering at 1250 ° C, the sintered body of polycrystalline alumina subjected to HIP treatment at 1300 ° C has a linear transmittance of 40%,
Average 3 point bending strength is 760MPa, Vickers hardness [Hv] is 1
9.4 GPa, Weibull coefficient of 14, high translucency and high strength are obtained.
実 施 例 実験例１〜５ A.多結晶アルミナの焼結体の製造 （１）［原料］ 原料は高純度Al2O3である。高純度Al2O3は、アンモニ
ュウムドーソナイト（NH4Al（OH）2CO3）を出発原料と
して、これを仮焼、粉砕して得られた粉末である。高純
度Al2O3の粉末試料の特性を後掲の表−１に示す。また
高純度Al2O3の粒度径分布を第１図に示す。Implementation Examples Experimental Examples 1 to 5 A. polycrystalline production of a sintered body of alumina (1) [raw] raw material of high purity Al 2 O 3. High-purity Al 2 O 3 is a powder obtained by calcining and pulverizing ammonium dawsonite (NH 4 Al (OH) 2 CO 3 ) as a starting material. The properties of the powder sample of high purity Al 2 O 3 are shown in Table 1 below. FIG. 1 shows the particle size distribution of high-purity Al 2 O 3 .
（２）［成形］ 本発明の高純度Al2O3の粉末試料は、スリップキャス
ティング成形法によって成形を行った。(2) [Molding] The powder sample of the high-purity Al 2 O 3 of the present invention was formed by a slip casting method.
分散処理は予め所定量の蒸溜水に分散剤を含む有機助
剤を溶解させた後、原料と同材質のアルミナボールおよ
びアルミナポットを用いて約16時間混合を行った。In the dispersion treatment, after dissolving an organic auxiliary agent containing a dispersant in a predetermined amount of distilled water in advance, mixing was performed for about 16 hours using alumina balls and alumina pots of the same material as the raw materials.
こうして得られたスラリーは、真空・加圧鋳込装置を
用いて約20分間の脱泡処理を行った後、合成樹脂製の型
を用いて約6kg f/cm2の圧力で板状の成形体を製作し
た。成形体の大きさは60mm×80mm×6mmである。The slurry thus obtained, after the degassing treatment from about 20 minutes using a vacuum-pressure-cast apparatus, the molding plate at a pressure of about 6 kg f / cm 2 by using a mold made of synthetic resin Made a body. The size of the molded body is 60 mm × 80 mm × 6 mm.
（３）［予備焼結］ 得られた成形体は、室温、40℃及び100℃で十分乾燥
を行った後、電気炉で大気中において昇温速度40℃／時
間で昇温した後、1250℃で２時間予備焼結を行った。こ
のように得られた予備焼結体の特性値を表−２に示す。(3) [Preliminary sintering] The obtained compact was sufficiently dried at room temperature, 40 ° C and 100 ° C, and then heated in air at a heating rate of 40 ° C / hour in an electric furnace. Pre-sintering was performed at 2 ° C. for 2 hours. Table 2 shows the characteristic values of the pre-sintered body thus obtained.
（４）［HIP処理］ 予備焼結体は次にHIP処理をする。第２図にHIP処理の
スケジュールを示す。HIPはAr雰囲気で約150MPaの圧力
下、1050〜1400℃の温度範囲で処理を行った。処理温度
を変化させることにより結晶体の結晶粒子径を制御し
た。その関係を第８図に示す。(4) [HIP treatment] Next, the pre-sintered body is subjected to HIP treatment. FIG. 2 shows the schedule of the HIP processing. The HIP was processed in an Ar atmosphere at a pressure of about 150 MPa and a temperature range of 1050 to 1400 ° C. The crystal grain size of the crystal was controlled by changing the treatment temperature. FIG. 8 shows the relationship.
第３図には予備焼結体試料の位置を示す。 FIG. 3 shows the position of the pre-sintered sample.
圧力容器10内には熱電対11、グラファイトのヒータ1
2、グラファイトルツボ13があり、このルツボ13内には
予備焼結体試料14が配置されている。試料14はグラファ
イトルツボ中に入れ、拭粉として試料と同材質の仮焼粉
体を用いた。Thermocouple 11 and graphite heater 1 in pressure vessel 10
2. There is a graphite crucible 13 in which a pre-sintered body sample 14 is placed. Sample 14 was placed in a graphite crucible, and calcined powder of the same material as the sample was used as the wiping powder.
B.評価 HIP処理の試料（以下HIP焼結体という）については、
結晶体結晶粒子径（平均結晶粒子径、組織観察）、光学
的特性（直線透過率）、機械的特性（３点曲げ強さ、ビ
ッカース硬度、破壊靭性）について測定を行った。B. Evaluation Regarding the sample of HIP treatment (hereinafter referred to as HIP sintered body),
The crystal grain size (average crystal grain size, structure observation), optical properties (linear transmittance), and mechanical properties (three-point bending strength, Vickers hardness, fracture toughness) were measured.
平均結晶粒子径の測定 結晶粒子径 平均結晶粒子径を求めるためにまず、すでに第10図で
示した結晶粒子罫を求める。Measurement of Average Crystal Particle Diameter Crystal Particle Diameter In order to obtain the average crystal particle diameter, first, the crystal particle rule shown in FIG. 10 is obtained.
結晶粒子径測定面の研摩 ＃400,＃800、＃1500および３μｍのダイヤモンドペ
ーストを用い、最終的に１μｍのダイヤモンドペースト
で仕上げる。この仕上げた面を観察する。Polishing of crystal particle diameter measurement surface Use # 400, # 800, # 1500 and 3 μm diamond paste, and finally finish with 1 μm diamond paste. Observe the finished surface.
サーマルエッチング処理 HIP処理温度より50℃低い温度で、約１〜２時間処理
する。これにより結晶粒界面が明らかになる。Thermal etching treatment A treatment is performed at a temperature 50 ° C. lower than the HIP processing temperature for about 1 to 2 hours. This reveals the grain boundaries.
SEM観察 測定面画像のアウトプットをする。 SEM observation Outputs the measurement plane image.
画像解析により結晶粒子径の測定 １）焼結体結晶粒子の面積の測定をする。つまり、第４
図（ａ）のような連続トレース方式あるいは第４図
（ｂ）のような不連続点による面積測定をする。Measurement of crystal particle diameter by image analysis 1) Measure the area of crystal particles of the sintered body. That is, the fourth
The area is measured by a continuous trace method as shown in FIG. 4A or a discontinuous point as shown in FIG. 4B.
２）等価円への変換（面積等価円）と、等価円の直径測
定をする。2) Convert to equivalent circle (area equivalent circle) and measure the diameter of equivalent circle.
すなわち第５図に示すように、焼結体結晶粒子Ｐを直
径Ｄの等価円Ｃの変換するのである。つまり焼結体結晶
粒子Ｐの面積と等価円の面積は一致する。That is, as shown in FIG. 5, the sintered body crystal particles P are converted into an equivalent circle C having a diameter D. That is, the area of the sintered body crystal particles P and the area of the equivalent circle coincide.
データの解析 測定データの集計と、平均化を行い、平均結晶粒子径
を得る。Data analysis Aggregation and averaging of measured data to obtain the average crystal particle size.
このようにして得られた本発明でいう平均結晶粒子径
とは、測定面における焼結体結晶粒子Ｐの断面積を等価
円に変換した等価円Ｃの直径Ｄの平均をいうのである。The average crystal particle diameter thus obtained in the present invention means the average of the diameter D of the equivalent circle C obtained by converting the cross-sectional area of the sintered body crystal particles P on the measurement surface into an equivalent circle.
直線透過率の測定 この直線透過率は、次のように測定する。第６図は測
定装置の原理図であり、第７図は実際の測定装置を示し
ている。ランプ40から出た光をレンズ41で直進光に変光
し、スリット42を通った光が、測定試料43を通過する。
そして通過した光をスリット44に通してフォトセル45に
受光させる。この光の強度をフォトセル45によって測定
する。式に表すと、 となる。多結晶セラミックスは、結晶粒界を光が通過す
ると屈折し、セラミックスを通り抜けた時は、散乱状態
にある。この中で、直進光がどのくらいの比率かを示し
たものが、直線透過率である。したがって、測定試料の
厚み、及び表面状態で直線透過率は変化する。Measurement of linear transmittance The linear transmittance is measured as follows. FIG. 6 is a principle diagram of the measuring device, and FIG. 7 shows an actual measuring device. The light emitted from the lamp 40 is changed to straight light by the lens 41, and the light passing through the slit 42 passes through the measurement sample 43.
Then, the transmitted light passes through the slit 44 and is received by the photocell 45. The intensity of this light is measured by the photocell 45. In terms of the formula, Becomes Polycrystalline ceramics are refracted when light passes through the crystal grain boundaries, and are in a scattering state when passing through the ceramics. Among them, the linear transmittance indicates the ratio of the straight light. Therefore, the linear transmittance changes depending on the thickness and surface state of the measurement sample.
第７図の実際の測定装置では、レンズ41とスリット42
の代わりに光ファイバ51、プリズム52が用いられ、スリ
ット44の代わりに採光路53が用いられている。In the actual measuring device shown in FIG.
, An optical fiber 51 and a prism 52 are used, and instead of the slit 44, a lighting path 53 is used.
本発明における測定方法は次のとおりである。測定試
料43の厚さを1mmにし、１μｍのダイヤモンドペースト
で最終研摩した後、熱ホウ砂により化学研摩する。ハロ
ゲンランプ40の光を光ファイバ51で集め、測定試料43近
くまで光を送る。この光をプリズム52で反射させ、フォ
トセル45で光強度を測定する。なお、光を点燈しない時
の光強度を０に調整し、光を点燈しない時の光強度を０
に調整し、光を点燈し、試料43をセットしない時の光強
度を100に調整した後各試料をセットし光強度を測定す
る。The measuring method in the present invention is as follows. The thickness of the measurement sample 43 is set to 1 mm, and the sample is finally polished with a 1 μm diamond paste, and then chemically polished with hot borax. The light from the halogen lamp 40 is collected by the optical fiber 51, and is sent to the vicinity of the measurement sample 43. This light is reflected by the prism 52, and the light intensity is measured by the photocell 45. In addition, the light intensity when the light is not turned on is adjusted to 0, and the light intensity when the light is not turned on is set to 0.
, Light is turned on, the light intensity when the sample 43 is not set is adjusted to 100, and then each sample is set and the light intensity is measured.
３点曲げ強さの測定 ３点曲げ強さはJIS−R1601に規定されている方法によ
り測定を行う。Measurement of three-point bending strength The three-point bending strength is measured by the method specified in JIS-R1601.
比較例１〜４ A.多結晶アルミナの結晶体の製造 （１）〔原料〕 原料は高純度Al2O3である。その特性を後掲の表−１
に示す。Comparative Example 1 to 4 A. preparation of crystal of polycrystalline alumina (1) [raw] material is a high purity Al 2 O 3. The characteristics are shown in Table 1 below.
Shown in
（２）〔成形〕 試料は等方性静水圧プレス成形によって成形を行っ
た。成形に際し予め所定の粒度に調整した造粒体をゴム
型に均一に充填し、1000kg f/cm2の圧力で実施例と同形
状に成形した。(2) [Molding] The sample was formed by isotropic isostatic pressing. At the time of molding, the granules which had been adjusted to a predetermined particle size in advance were uniformly filled in a rubber mold, and molded at the pressure of 1000 kgf / cm 2 into the same shape as in the example.
（３）〔焼結〕 得られた成形体は水素還元雰囲気中において1800℃の
温度で焼結を行った。焼結時間を変化させることによ
り、焼結体の結晶粒子径を制御した。(3) [Sintering] The obtained compact was sintered at a temperature of 1800 ° C. in a hydrogen reducing atmosphere. The crystal grain size of the sintered body was controlled by changing the sintering time.
B.評価 各試料についてそれぞれ実験例と同一の方法により、
焼結体結晶粒子径（平均結晶粒子径）、光学的特性（直
線透過率）、機械的特性（３点曲げ強さ）について測定
を行った。B.Evaluation For each sample, use the same method as in the experimental example.
Measurements were made on the sintered body crystal particle diameter (average crystal particle diameter), optical characteristics (linear transmittance), and mechanical characteristics (three-point bending strength).
比較例５〜７ A.多結晶アルミナの結晶体の製造 （１）〔原料〕 実験例と同様のものを用いた。Comparative Examples 5 to 7 A. Production of Crystalline Polycrystalline Alumina (1) [Raw Materials] The same ones as in the experimental examples were used.
（２）〔成形〕 実験例と同様の方法により、実験例と同形状に形成し
た。(2) [Molding] The same shape as in the experimental example was formed by the same method as in the experimental example.
（３）〔焼結〕 得られた成形体は室温、40℃及び100℃で十分に乾燥
を行った後、電気炉で大気中において昇温速度40℃／時
間で昇温した後、大気圧下にて1250℃〜1350℃の温度範
囲で、２時間焼結を行った。焼結温度を変化させること
により焼結体の結晶粒子径を制御した。その関係を第８
図に示す。(3) [Sintering] The obtained compact was sufficiently dried at room temperature, 40 ° C. and 100 ° C., and then heated in an electric furnace at a heating rate of 40 ° C./hour in the atmosphere. The sintering was performed under a temperature range of 1250 ° C. to 1350 ° C. for 2 hours. The crystal grain size of the sintered body was controlled by changing the sintering temperature. Eighth relationship
Shown in the figure.
B.評価 各試料についてそれぞれ実験例と同一の方法により、
焼結体結晶粒子径（平均結晶粒子径）、光学的特性（直
線透過率）、機械的特性（３点曲げ強さ）について測定
を行った。B.Evaluation For each sample, use the same method as in the experimental example.
Measurements were made on the sintered body crystal particle diameter (average crystal particle diameter), optical characteristics (linear transmittance), and mechanical characteristics (three-point bending strength).
実施結果 （１）焼結体結晶粒子径 第８図に実験例におけるHIP処理温度と焼結体結晶粒
子径との関係及び比較例５〜７における焼結温度と焼結
体結晶粒子径との関係を示す。Results (1) Sintered Crystal Particle Diameter FIG. 8 shows the relationship between the HIP treatment temperature and the sintered body crystal particle diameter in the experimental example and the sintering temperature and the sintered body crystal particle diameter in Comparative Examples 5 to 7. Show the relationship.
第９図（ａ）〜（ｈ）は、HIP焼結体（実験例１〜
５）と常圧焼結体（比較例５〜７）の走査型電子顕微鏡
（SEM）写真を示す。FIGS. 9A to 9H show HIP sintered bodies (Experimental Examples 1 to 9).
5) and a scanning electron microscope (SEM) photograph of the normal pressure sintered body (Comparative Examples 5 to 7) are shown.
第９図（ａ）は1200℃におけるHIP焼結体（実験例
１）のサーマルエッチングされた表面を示す。FIG. 9 (a) shows the thermally etched surface of the HIP sintered body at 1200 ° C. (Experimental Example 1).
第９図（ｂ）は1250℃におけるHIP焼結体（実験例
２）のサーマルエッチングされた表面を示す。FIG. 9 (b) shows the thermally etched surface of the HIP sintered body at 1250 ° C. (Experimental Example 2).
第９図（ｃ）は1300℃におけるHIP焼結体（実験例
３）のサーマルエッチングされた表面を示す。FIG. 9 (c) shows the thermally etched surface of the HIP sintered body at 1300 ° C. (Experimental Example 3).
第９図（ｄ）は1350℃におけるHIP焼結体（実験例
４）のサーマルエッチングされた表面を示す。FIG. 9 (d) shows the thermally etched surface of the HIP sintered body at 1350 ° C. (Example 4).
第９図（ｅ）は1400℃におけるHIP焼結体（実験例
５）のサーマルエッチングされた表面を示す。FIG. 9 (e) shows the thermally etched surface of the HIP sintered body at 1400 ° C. (Experimental Example 5).
第９図（ｆ）は1250℃で常圧焼結体（比較例１）のサ
ーマルエッチングされた表面を示す。FIG. 9 (f) shows the surface of the sintered body under normal pressure (Comparative Example 1) at 1250 ° C.
第９図（ｇ）は1300℃で常圧焼結体（比較例２）のサ
ーマルエッチングされた表面を示す。FIG. 9 (g) shows the thermally etched surface of the normal pressure sintered body (Comparative Example 2) at 1300 ° C.
第９図（ｈ）は1350℃で常圧焼結体（比較例３）のサ
ーマルエッチングされた表面を示す。FIG. 9 (h) shows the surface of the normal pressure sintered body (Comparative Example 3) which was subjected to the thermal etching at 1350 ° C.
第９図（ａ）〜（ｅ）に示すようにHIP焼結体につい
ては、処理温度の上昇と共に結晶粒の成長が促進されて
おり、第９図（ｅ）の1400℃処理では約10μｍ以上の結
晶粒に成長している。As shown in FIGS. 9 (a) to 9 (e), in the HIP sintered body, the growth of crystal grains is promoted with an increase in the processing temperature, and the treatment at 1400 ° C. in FIG. 9 (e) is about 10 μm or more. Growing into crystal grains.
又、同じ処理温度の常圧焼結体と比較した場合に、HI
P焼結体の方が結晶粒子径が大きく、圧力をかけたこと
の効果が認められる。たとえば第９図（ｂ）のHIP焼結
体と第９図（ｆ）の常圧焼結体である。Also, when compared with a normal pressure sintered body at the same processing temperature, HI
The P sintered body has a larger crystal particle diameter, and the effect of applying pressure is recognized. For example, the HIP sintered body of FIG. 9B and the normal pressure sintered body of FIG. 9F are shown.
（２）光学的特性 第３表に核実験例及び比較例の直線透過率を示す。(2) Optical characteristics Table 3 shows the linear transmittances of the nuclear test examples and the comparative examples.
実験例は、いずれも直線透過率が30％よりも大きい。
比較例１は実験例５と同等の平均結晶粒子径であるが、
直線透過率は10％以下と低い。また比較例３、４は直線
透過率が40％と高いが平均結晶粒子径は実験例よりも大
きい。比較例５〜７は透光性がほとんどない。In each of the experimental examples, the linear transmittance is greater than 30%.
Comparative Example 1 has the same average crystal particle diameter as Experimental Example 5, but
The linear transmittance is as low as 10% or less. In Comparative Examples 3 and 4, the linear transmittance is as high as 40%, but the average crystal particle diameter is larger than that in the experimental examples. Comparative Examples 5 to 7 have almost no translucency.
機械的特性 第10図にHIP処理温度と相対密度との関係を示す。常
圧焼結体、すなわち（比較例５〜７）を比較として示し
ている。Mechanical Properties FIG. 10 shows the relationship between the HIP processing temperature and the relative density. A normal pressure sintered body, that is, (Comparative Examples 5 to 7) is shown for comparison.
相対密度はHIP処理温度1200℃以上においてほぼ100％
に達している。このため、密度に対するHIP処理温度の
効果は大きいと考えられる。Relative density is almost 100% at HIP processing temperature over 1200 ℃
Has been reached. Therefore, it is considered that the effect of the HIP processing temperature on the density is large.
第11図にHIP処理温度と３点曲げ強さとの関係を示
す。FIG. 11 shows the relationship between the HIP processing temperature and the three-point bending strength.
HIP処理した本発明の実験例の３点曲げ強さは1250℃
処理が最も高く、約790MPaであった。又、1250℃以上の
処理温度では、処理温度が高くなるにつれて強度は低く
なる。しかし、実験例の３点曲げ強さは650MPa以上であ
り、従来の透光性の多結晶体アルミナ、つまり比較例
３、４に比べ２倍以上の値を示す。The three-point bending strength of the HIP-treated experimental example of the present invention is 1250 ° C.
The highest treatment was at about 790 MPa. At a processing temperature of 1250 ° C. or higher, the strength decreases as the processing temperature increases. However, the three-point bending strength of the experimental example is 650 MPa or more, which is twice or more the value of the conventional translucent polycrystalline alumina, that is, Comparative Examples 3 and 4.
第12図にHIP処理温度と、破壊靭性〔Klc〕及びビッカ
ース硬度〔Hv〕との関係について示す。ビッカース硬度
は第10図の相対密度と良く対応している。ビッカース硬
度は第10図の相対密度がほぼ100％近くなる温度（1250
℃）で約19.5GPa値を示し、その後処理温度が高くなっ
てもこのビッカース硬度はほぼ一定である。破壊靭性に
ついては、処理温度が高くなるにつれて値が減少する傾
向が見られる。FIG. 12 shows the relationship between the HIP treatment temperature and the fracture toughness [Klc] and Vickers hardness [Hv]. The Vickers hardness corresponds well with the relative density in FIG. The Vickers hardness is the temperature (1250) at which the relative density in Fig. 10 becomes almost 100%.
C), and the Vickers hardness is almost constant even when the processing temperature is increased thereafter. As for the fracture toughness, there is a tendency that the value decreases as the processing temperature increases.
機械的特性と焼結体結晶粒子径との関係について考察
する。第３表に平均結晶粒子径と３点曲げ強さを示す。
HIP処理温度の上昇による３点曲げ強さの低下は第11図
に示されているが、つまり粒成長に伴う粒界のトータル
破壊エネルギーの低下に起因するものであると考えられ
る。The relationship between the mechanical properties and the crystal grain size of the sintered body will be considered. Table 3 shows the average crystal grain size and the three-point bending strength.
The decrease in the three-point bending strength due to the increase in the HIP treatment temperature is shown in FIG. 11, which is considered to be caused by the decrease in the total fracture energy of the grain boundary accompanying the grain growth.
さらに、第11図のように常圧焼結体の３点曲げ強さの
最大値が1300℃であることに比べ、HIP焼結体では1250
℃と低くなっている。しかし、1300℃で常圧焼結体と12
50℃でのHIP焼結体の結晶粒子サイズは第９図（ｇ）と
（ｂ）に示すようによく一致しており、焼結体強度は結
晶粒子サイズに大きく依存していることが分る。Further, as shown in FIG. 11, the maximum value of the three-point bending strength of the normal pressure sintered body was 1300 ° C., whereas the maximum value of the HIP sintered body was 1250 ° C.
° C. However, at 1300 ℃, normal pressure sintered body and 12
The crystal grain size of the HIP sintered body at 50 ° C. is in good agreement as shown in FIGS. 9 (g) and 9 (b), indicating that the strength of the sintered body greatly depends on the crystal grain size. You.
光学的特性と焼結体結晶粒子径との関係について考察
する。The relationship between the optical characteristics and the crystal grain size of the sintered body will be considered.
本発明の実験例と比較例１〜４とは、結晶粒子径が大
きくなると直線透過率が上がる。本発明の実験例では、
比較例１〜４に比べて結晶粒子径が大幅に小さいにもか
かわらず、高い直線透過率が得られる。このことから本
発明の実験例は、比較例１〜４に比べ結晶粒子径が小さ
いにもかかわらず直線透過率を大きくとれることが判
り、しかも結晶粒子径が小さいため強度が高いことか
ら、複雑な形状のものを作ることができるのである。In the experimental examples of the present invention and Comparative Examples 1 to 4, the linear transmittance increases as the crystal particle diameter increases. In the experimental example of the present invention,
Although the crystal particle diameter is significantly smaller than Comparative Examples 1 to 4, high linear transmittance is obtained. From this, it is understood that the experimental example of the present invention can obtain a large linear transmittance even though the crystal particle diameter is small as compared with Comparative Examples 1 to 4, and since the crystal particle diameter is small and the strength is high, the experimental example is complicated. We can make things of various shapes.
本発明の多結晶アルミナの焼結体を作るのにHIPを用
いれば、従来の常圧焼結温度1800℃に比べて約500℃程
度低い温度で透過性の良好な焼結体が得られる。しかも
高強度である。If HIP is used to make the sintered body of polycrystalline alumina of the present invention, a sintered body having good permeability can be obtained at a temperature lower by about 500 ° C. than the conventional normal pressure sintering temperature of 1800 ° C. Moreover, it has high strength.
実際1350℃でHIP処理した本発明の焼結体が最も直線
透過率が良かった。In fact, the sintered body of the present invention that had been HIPed at 1350 ° C. had the best linear transmittance.
本発明の多結晶アルミナの焼結体は高圧ナトリウムラ
ンプ用発光管や容器などに使用できる。The sintered body of polycrystalline alumina of the present invention can be used for arc tubes and containers for high-pressure sodium lamps.
発明の効果 以上説明したようにこの発明によれば、結晶粒子径が
小さくても透光性が高く、結晶粒子径が小さいので高強
度で複雑な形状の焼結体を得ることができる。Advantageous Effects of the Invention As described above, according to the present invention, even if the crystal particle diameter is small, the light-transmitting property is high, and since the crystal particle diameter is small, a sintered body having a high strength and a complicated shape can be obtained.
【図面の簡単な説明】 第１図は本発明の実験例の高純度アルミナ粉末試料の粒
子径分布を示す図である。 第２図はHIP焼結体作製用のHIP処理スケジュールを示す
図である。 第３図はHIP処理装置の例を示す図である。 第４図と第５図は焼結体の結晶粒子径を測定するための
原理を示す図である。 第６図は直線透過率の測定原理を示す図である。 第７図は直線透過率の測定装置の一例を示す図である。 第８図は処理温度と結晶粒子径の関係を示す図である。 第９図（ａ）〜（ｈ）は各温度におけるHIP焼結体と常
圧焼結体のサーマルエッチングされた表面の粒子構造を
示す写真である。 第10図は本発明のHIP処理と常圧焼結の処理温度と、相
対密度の関係を示す図である。 第11図は本発明のHIP焼結と常圧焼結の処理温度と、３
点曲げ強度との関係を示す図である。 第12図は処理温度とビッカース硬度と破壊靭性の関係を
示す図である。 14……試料 40……ランプ 41……レンズ 42,44……スリット 43……測定試料 51……光ファイバ 52……プリズム 53……採光路 Ｐ……焼結体結晶粒子 Ｃ……等価円 Ｄ……直径BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a particle size distribution of a high-purity alumina powder sample of an experimental example of the present invention. FIG. 2 is a diagram showing a HIP processing schedule for producing a HIP sintered body. FIG. 3 is a diagram showing an example of the HIP processing device. 4 and 5 are diagrams showing the principle for measuring the crystal grain size of the sintered body. FIG. 6 is a diagram showing the principle of measuring the linear transmittance. FIG. 7 is a diagram showing an example of a linear transmittance measuring device. FIG. 8 is a diagram showing the relationship between the processing temperature and the crystal particle diameter. 9 (a) to 9 (h) are photographs showing the particle structure of the thermally etched surface of the HIP sintered body and the normal pressure sintered body at each temperature. FIG. 10 is a diagram showing the relationship between the processing temperature of the HIP processing and the normal pressure sintering of the present invention and the relative density. FIG. 11 shows the processing temperature of HIP sintering and atmospheric sintering of the present invention,
It is a figure which shows the relationship with point bending strength. FIG. 12 is a diagram showing the relationship between the processing temperature, Vickers hardness, and fracture toughness. 14 ... Sample 40 ... Lamp 41 ... Lens 42,44 ... Slit 43 ... Measurement sample 51 ... Optical fiber 52 ... Prism 53 ... Sampling path P ... Sintered crystal grains C ... Equivalent circle D ... Diameter
───────────────────────────────────────────────────── フロントページの続き (72)発明者 深谷 孝洋 愛知県刈谷市熊野町２―１―５ 審査官 米田 健志 (56)参考文献 特開 昭63−242964（ＪＰ，Ａ) 特開 昭63−236757（ＪＰ，Ａ) 特開 昭62−72554（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Takahiro Fukaya 2-1-5 Kumano-cho, Kariya-shi, Aichi Examiner Kenshi Yoneda (56) References JP-A-63-242964 (JP, A) JP-A-63- 236757 (JP, A) JP-A-62-72554 (JP, A)
Claims (1)
末を分散処理してスラリーを得て、このスラリーをスリ
ップキャスティング法によって成形し、バインダーを含
まない成形体を得る工程と、 成形体を乾燥してから、予備焼結して、予備焼結体を得
る工程と、 予備焼結体を1200℃〜1400℃の温度でHIP処理して、多
結晶アルミナ焼結体を得るとともに、その1mm厚さにお
けるハロゲンランプの直線透過率を30％以上にし、平均
結晶粒子径を0.5μｍ〜20μｍにし、３点曲げ強度を650
MPa以上にする工程と、 を含むことを特徴とする多結晶アルミナ焼結体の製造方
法。A step of dispersing the raw material powder using a high-purity Al 2 O 3 raw material powder to obtain a slurry, and forming the slurry by a slip casting method to obtain a molded body containing no binder; Drying the compact and pre-sintering it to obtain a pre-sintered body; and subjecting the pre-sintered body to HIP treatment at a temperature of 1200 ° C to 1400 ° C to obtain a polycrystalline alumina sintered body. At the same time, the linear transmittance of the halogen lamp at a thickness of 1 mm is set to 30% or more, the average crystal particle diameter is set to 0.5 to 20 μm, and the three-point bending strength is set to 650.
A method for producing a polycrystalline alumina sintered body, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2056645A JP2663191B2 (en) | 1990-03-09 | 1990-03-09 | Method for producing polycrystalline alumina sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2056645A JP2663191B2 (en) | 1990-03-09 | 1990-03-09 | Method for producing polycrystalline alumina sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03261648A JPH03261648A (en) | 1991-11-21 |
| JP2663191B2 true JP2663191B2 (en) | 1997-10-15 |
Family
ID=13033084
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2056645A Expired - Lifetime JP2663191B2 (en) | 1990-03-09 | 1990-03-09 | Method for producing polycrystalline alumina sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2663191B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006087915A (en) * | 2004-08-27 | 2006-04-06 | Tosoh Corp | Orthodontic bracket and manufacturing method thereof |
| JP2009519761A (en) * | 2005-12-14 | 2009-05-21 | スリーエム イノベイティブ プロパティズ カンパニー | Orthodontic articles coated with zirconium oxide |
| US8133051B2 (en) | 2004-08-27 | 2012-03-13 | Tosoh Corporation | Orthodontic bracket and process for producing the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2308933C (en) | 1999-05-19 | 2008-07-22 | Ngk Spark Plug Co., Ltd. | Translucent polycrystalline ceramic and method for making same |
| JP4910750B2 (en) * | 2007-02-14 | 2012-04-04 | 東ソー株式会社 | Translucent alumina sintered body and method for producing the same |
| JP4983545B2 (en) | 2007-10-30 | 2012-07-25 | 東ソー株式会社 | High-toughness translucent alumina sintered body, manufacturing method and use thereof |
| EP2808313B1 (en) | 2008-11-18 | 2018-05-02 | Tosoh Corporation | Colored alumina sintered body of high toughness and high translucency, and its production method and its uses |
| JP2012238654A (en) * | 2011-05-10 | 2012-12-06 | Ngk Insulators Ltd | Translucent wiring board and method for manufacturing the same |
| JP6364257B2 (en) * | 2013-11-20 | 2018-07-25 | 日本碍子株式会社 | Optical components |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6272554A (en) * | 1985-09-25 | 1987-04-03 | 三菱鉱業セメント株式会社 | Manufacture of fine polycrystal al2o3 sintered body |
| JPH0688832B2 (en) * | 1987-03-26 | 1994-11-09 | 東陶機器株式会社 | Polycrystalline ceramic product and manufacturing method thereof |
| JPS63242964A (en) * | 1987-03-31 | 1988-10-07 | 日本碍子株式会社 | Alumina ceramics and manufacture |
-
1990
- 1990-03-09 JP JP2056645A patent/JP2663191B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006087915A (en) * | 2004-08-27 | 2006-04-06 | Tosoh Corp | Orthodontic bracket and manufacturing method thereof |
| US8133051B2 (en) | 2004-08-27 | 2012-03-13 | Tosoh Corporation | Orthodontic bracket and process for producing the same |
| US8215019B2 (en) | 2004-08-27 | 2012-07-10 | Tosoh Corporation | Process for producing an orthodontic bracket |
| JP2009519761A (en) * | 2005-12-14 | 2009-05-21 | スリーエム イノベイティブ プロパティズ カンパニー | Orthodontic articles coated with zirconium oxide |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03261648A (en) | 1991-11-21 |
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