JPS6158426B2 - - Google Patents
Info
- Publication number
- JPS6158426B2 JPS6158426B2 JP58062719A JP6271983A JPS6158426B2 JP S6158426 B2 JPS6158426 B2 JP S6158426B2 JP 58062719 A JP58062719 A JP 58062719A JP 6271983 A JP6271983 A JP 6271983A JP S6158426 B2 JPS6158426 B2 JP S6158426B2
- Authority
- JP
- Japan
- Prior art keywords
- tio
- thermal expansion
- magnetic
- cao
- ferrite
- 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
Links
- 239000000203 mixture Substances 0.000 claims description 18
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 16
- 229910052573 porcelain Inorganic materials 0.000 claims description 11
- 239000000463 material Substances 0.000 description 13
- 229910000859 α-Fe Inorganic materials 0.000 description 11
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- 229910018605 Ni—Zn Inorganic materials 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- 239000011162 core material Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000001513 hot isostatic pressing Methods 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- -1 CaCO 3 Inorganic materials 0.000 description 1
- 229910002971 CaTiO3 Inorganic materials 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910001035 Soft ferrite Inorganic materials 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000009770 conventional sintering Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000006247 magnetic powder Substances 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
Landscapes
- Magnetic Heads (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
Description
この発明は、磁気ヘツドの構造部品に用いる非
磁性材料に係り、コンピユータ等の各種磁気ヘツ
ド、特にフロツピイデイスク用フエライト磁気ヘ
ツドの構成に不可欠のスライダーあるいはスペー
サーに使用する磁気ヘツド用磁器組成物に関す
る。
一般に磁気ヘツドは、Mn―Znフエライト、Ni
―Znフエライトの磁性材料からなるコアと非磁
性材料からなる構造部品とをガラス溶着して組立
てられており、特にデジタル用磁気ヘツドには磁
性材料として、高周波特性及び耐摩耗性のすぐれ
たNi―Znフエライトが使用され、非磁性構造部
品材料には熱膨張係数が同等のTiO2―CaO系磁
器が使用されている。
すなわち、コア材と、非磁性構造部品との熱膨
張係数が異なると、これらをガラス溶着する際
に、歪を生じ、磁気特性の劣化が起こるだけでな
く、ひび、剥離等を生じて磁気ヘツドの組立上大
きな問題となつている。
さらに、この非磁性構造部品材料に気孔が多く
存在すると、磁気ヘツドと記録媒体との接触走行
時に、記録媒体にコーテイングされた磁性粉が上
記気孔に付着したり、チツピングを生じて磁気ヘ
ツドや記録媒体を損傷するため、気孔率の低い高
密度化された非磁性磁器組成物が切望されてい
る。
従来のTiO2―CaO系磁器組成物は、CaO・
TiO2とTiO2の２相混合組織の範囲内において、
CaO・TiO2の量とともに熱膨張係数が直線的に
大きくなることが知られており、上述したコア材
のNi―Znフエライトの熱膨張係数は要求される
電磁気特性によつて定まる組成により固定される
が、90〜100×10-7／℃であるため、非磁性構造
部品材料の熱膨張係数をフエライトの方に合せる
必要があり、熱膨張係数の差を２×10-7／℃以下
に抑えるべく、TiO277〜86wt％、CaO14〜23wt
％の組成からなる磁器組成物が使用されていた。
一方、磁器組成物の気孔を低減する方法とし
て、上記組成の磁器組成物に、Al2O3、SiO2、
MgO、SrO、CdO、ZrO2等の焼結補助剤を少な
くとも１種以上で4wt％以下添加し、焼結密度を
改善する方法が知られているが、大気中焼結では
１〜３％の気孔が残存し、とくにZrO2の添加量
が2wt％以下の場合は、成形体の寸法が40mm×20
mm×20mmと大きくなると通常の焼結法では焼結体
の内部が還元されて黒色化する問題があつた。
また、気孔率を低減する方法として、熱間静水
圧プレス処理が知られており、極めて有効ではあ
るが、この処理が通常アルゴン雰囲気中で行なわ
れるため、被処理材表面が還元されて黒色化する
問題があり、酸素雰囲気中で再び熱処理を施して
も、完全に脱色することが困難で材料内部まで均
一に回復させることができなかつた。
この発明は、上述の問題点に鑑み、Ni―Znフ
エライトと同時の熱膨張係数を有し、結晶組織が
非常に緻密であり、熱間静水圧プレス処理を施す
ことなく、通常の焼結処理で熱間静水圧プレス処
理と同等の0.2％以下の気孔率を有するTiO2―
CaO系磁器組成物を提案するものである。
すなわち、この発明は、TiO277〜86wt％、
CaO14〜23wt％からなり、TiO2、CaOの合計を
100として、ZrO25〜15wt％を含有し、CaTiO3、
TiO2、ZrTiO4の３相からなり、気孔率0.2％以下
に高密度化したことを要旨とする磁気ヘツド用磁
器組成物である。
この発明による磁器組成物は、CaTiO3、
TiO2、ZrTiO4の３相からなることを特徴とし、
熱間静水圧プレス処理材料の気孔率と同程度に高
密度化できるとともに、熱膨張係数90〜100×
10-7／℃の範囲に精度よく調整することができ、
ZrO2の含有により従来の焼結温度より低温で焼
結できるため、緻密で孔が少なく欠陥のない材料
で耐摩耗性が良く、結晶粒径も十分に小さく加工
性も良い。
この発明による磁器組成物におけるZrTiO4相
を、Ｘ線マイクロアナライザーにより観察する
と、ZrTiO4相はほとんど粒界に生成されてお
り、同相が増加すると結晶中にZrTiO4相を通じ
てO2の流入が可能になると思われ、焼結体内部
の黒色化防止に有効になる。
この発明による磁器組成物の成分を限定した理
由は以下のとおりである。
TiO277wt％の含有では、熱膨張係数が100×
10-7／℃を越えてしまい、TiO2が86wt％を超え
る含有であると、熱膨張係数が90×10-7／℃未満
となり、Ni―Znフエライトとのガラス溶着の相
手材料として不適であり、Ni―Znフエライトの
熱膨張係数90〜100×10-7／℃と同じ熱膨張係数
を保持させるため、TiO277〜86wt％の含有とす
る。
CaOが23wt％を超える含有では、熱膨張係数
が100×10-7／℃を越えてしまい、CaOが14wt％
未満の含有であると、熱膨張係数が90×10-7／℃
未満となり、Ni―Znフエライトとのガラス溶着
の相手材料として不適であり、Ni―Znフエライ
トの熱膨張係数90〜100×10-7／℃と同じ熱膨張
係数を保持させるため、CaO14〜23wt％の含有
とする。
ZrO2はTiO2―CaO系の気孔率を改善するため
に添加するものであるが、その含有がTiO2、
CaOの合計を100として、5wt％末満では磁器組
成物焼結体の気孔率が1.0％以上になり、組織が
CaTiO3、TiO2、ZrO2の３相となり、焼結体内部
は還元されやすくなり黒色化するため好ましくな
い。また15wt％を超える含有では焼結体の気孔
率が0.2％以上となり、加工性も悪化するためソ
フトフエライトの相手材料として不適となるた
め、５〜15wt％の添加とする。
以下に、この発明を実施例に基づいて説明す
る。
市販されているTiO2、CaCO3、ZrO2を用い
て、第１表に示す如く、焼結後の組成がこの発明
による組成化（No.1〜６）ならびにこの発明の
範囲外の組成比（No.7〜９）となるよう秤量
し、ボールミルで混合し、乾燥した後、空気中で
900℃、２時間の仮焼を行つた。さらに仮焼した
原料を再びボールミルで平均粒度1.3μｍになる
まで、微粉砕し、次に結合剤としてポリビニルア
ルコールを1.5wt％加えて造粒した。造粒後に、
2000Kg／cm2の成形圧で40×20×20mmの寸法に成形
し、空気中で1200℃、２時間の焼結を行つた。
得られた磁器について、密度、熱膨張係数、ビ
ツカース硬度等の特性を調べ、第２表に測定結果
を示している。また、表中の加工性は、同一の加
工機を使用しその主軸モータの電力増加量をワツ
ト単位で表わし評価している。
第１表、第２表から明らかな如く、試料No.7
〜９の比較例はその熱膨張係数がNi―Znフエラ
イトの熱膨張係数90〜100×10-7／℃に合致する
が気孔率が悪いのに対し、この発明の実施例（試
料No.1〜６）は、熱膨張係数を90〜100×10-7／
℃の間にコントロールすることができ、機械的強
度、加工性等もすぐれた特性を示しており、特
に、熱間静水圧プレス処理した材料と同等に緻密
化され、結晶粒径が小さくなり、孔が少なく加工
性の良好なる磁器が得られているため、耐摩耗性
にすぐれ、記録媒体が摺動する磁気ヘツド構造部
品用材料に最適であることがわかる。
The present invention relates to non-magnetic materials used for structural parts of magnetic heads, and in particular to ceramic compositions for magnetic heads used for sliders or spacers essential to the construction of various magnetic heads such as computers, especially ferrite magnetic heads for floppy disks. Regarding. Generally, magnetic heads are made of Mn-Zn ferrite, Ni
-A core made of Zn ferrite magnetic material and structural parts made of non-magnetic material are assembled by glass welding.Ni- Zn ferrite is used, and TiO 2 -CaO-based porcelain with the same coefficient of thermal expansion is used as the non-magnetic structural component material. In other words, if the core material and non-magnetic structural components have different coefficients of thermal expansion, distortion will occur when they are welded to glass, which will not only cause deterioration of magnetic properties, but also cause cracks, peeling, etc., and damage the magnetic head. This has become a major problem in assembly. Furthermore, if there are many pores in this non-magnetic structural component material, when the magnetic head and the recording medium come into contact with each other, the magnetic powder coated on the recording medium may adhere to the pores or cause chipping, which may cause the magnetic head or recording medium to run in contact with each other. Due to media damage, densified non-magnetic porcelain compositions with low porosity are desired. Conventional TiO 2 -CaO based porcelain compositions
Within the range of the two-phase mixed structure of TiO 2 and TiO 2 ,
It is known that the coefficient of thermal expansion increases linearly with the amount of CaO/ TiO2 , and the coefficient of thermal expansion of the Ni-Zn ferrite core material mentioned above is fixed by the composition determined by the required electromagnetic properties. However, since it is 90 to 100×10 -7 /℃, it is necessary to match the thermal expansion coefficient of the non-magnetic structural component material to that of ferrite, and the difference in thermal expansion coefficient should be kept below 2×10 -7 /℃. To suppress TiO2 77-86wt%, CaO14-23wt
A porcelain composition consisting of a composition of % was used. On the other hand, as a method for reducing pores in a ceramic composition, Al 2 O 3 , SiO 2 ,
A known method is to improve the sintered density by adding at least one kind of sintering aid such as MgO, SrO, CdO, or ZrO 2 up to 4wt%. If pores remain, especially if the amount of ZrO 2 added is less than 2wt%, the size of the molded product may be 40mm x 20mm.
When the size is as large as mm x 20 mm, the problem with normal sintering methods is that the inside of the sintered body is reduced and becomes black. In addition, hot isostatic pressing is a known method for reducing porosity, and although it is extremely effective, since this treatment is usually performed in an argon atmosphere, the surface of the treated material is reduced and becomes black. Even if heat treatment is performed again in an oxygen atmosphere, it is difficult to completely decolorize the material, and it is not possible to uniformly restore the color to the inside of the material. In view of the above-mentioned problems, this invention has the same thermal expansion coefficient as Ni-Zn ferrite, has a very dense crystal structure, and can be processed by normal sintering without hot isostatic pressing. TiO2 with a porosity of less than 0.2%, which is equivalent to hot isostatic pressing treatment.
We propose a CaO-based porcelain composition. That is, this invention contains TiO 2 77-86wt%,
Consists of 14-23wt% CaO, the total of TiO 2 and CaO
100, containing 5-15wt% of ZrO2 , CaTiO3 ,
This ceramic composition for magnetic heads consists of three phases of TiO 2 and ZrTiO 4 and has a high density with a porosity of 0.2% or less. The porcelain composition according to the present invention includes CaTiO 3 ,
It is characterized by consisting of three phases: TiO 2 and ZrTiO 4 ,
It can be made as dense as the porosity of hot isostatically pressed materials, and has a thermal expansion coefficient of 90 to 100×.
It can be adjusted accurately within the range of 10 -7 /℃,
Because it contains ZrO 2 , it can be sintered at a lower temperature than conventional sintering temperatures, so it is a dense material with few pores and no defects, has good wear resistance, and has a sufficiently small crystal grain size and good workability. When the ZrTiO 4 phase in the ceramic composition according to the present invention is observed using an X-ray microanalyzer, it is found that most of the ZrTiO 4 phase is generated at grain boundaries, and as the number of ZrTiO 4 phases increases, O 2 can flow into the crystal through the ZrTiO 4 phase. This is thought to be effective in preventing blackening inside the sintered body. The reasons for limiting the components of the porcelain composition according to the present invention are as follows. When TiO 2 content is 77wt%, the thermal expansion coefficient is 100×
10 -7 /℃, and if the TiO 2 content exceeds 86wt%, the thermal expansion coefficient will be less than 90 × 10 -7 /℃, making it unsuitable as a partner material for glass welding with Ni-Zn ferrite. In order to maintain the same thermal expansion coefficient as that of Ni--Zn ferrite, 90 to 100 x 10 -7 /°C, the TiO 2 content is 77 to 86 wt%. If the CaO content exceeds 23wt%, the thermal expansion coefficient will exceed 100×10 -7 /℃, and the CaO content will exceed 14wt%.
If the content is less than 90×10 -7 /℃, the thermal expansion coefficient will be
CaO is less than 14 to 23 wt%, making it unsuitable as a partner material for glass welding with Ni-Zn ferrite. Contains. ZrO 2 is added to improve the porosity of the TiO 2 -CaO system;
When the total amount of CaO is 100, the porosity of the porcelain composition sintered body becomes 1.0% or more at the end of 5wt%, and the structure changes.
Three phases of CaTiO 3 , TiO 2 , and ZrO 2 are formed, and the inside of the sintered body is easily reduced and becomes black, which is not preferable. Further, if the content exceeds 15 wt%, the porosity of the sintered body will be 0.2% or more, and the workability will deteriorate, making it unsuitable as a mating material for soft ferrite. Therefore, the addition should be from 5 to 15 wt%. The present invention will be explained below based on examples. Using commercially available TiO 2 , CaCO 3 , and ZrO 2 , as shown in Table 1, the composition after sintering was the composition according to the present invention (Nos. 1 to 6) and the composition ratio outside the scope of the present invention. (No. 7 to 9), mix in a ball mill, dry, and then leave in the air.
Calcining was performed at 900°C for 2 hours. Furthermore, the calcined raw material was again finely ground in a ball mill until the average particle size was 1.3 μm, and then 1.5 wt % of polyvinyl alcohol was added as a binder and granulated. After granulation,
It was molded into a size of 40 x 20 x 20 mm under a molding pressure of 2000 Kg/cm 2 and sintered in air at 1200°C for 2 hours. The obtained porcelain was examined for properties such as density, coefficient of thermal expansion, and Vickers hardness, and the measurement results are shown in Table 2. Furthermore, the workability in the table is evaluated by using the same processing machine and expressing the increase in power of the spindle motor in watts. As is clear from Tables 1 and 2, sample No. 7
Comparative examples No. 9 to 9 have thermal expansion coefficients that match those of Ni-Zn ferrite, 90 to 100×10 -7 /°C, but have poor porosity, whereas Examples of the present invention (Sample No. 1) have poor porosity. ~6) is a thermal expansion coefficient of 90~100×10 -7 /
℃, and exhibits excellent properties such as mechanical strength and workability. In particular, it is densified to the same degree as hot isostatically pressed materials, and its grain size is reduced. Since the porcelain has few holes and has good workability, it has excellent wear resistance and is found to be optimal as a material for magnetic head structural parts on which the recording medium slides.
【表】【table】
【表】【table】
Claims (1)
り、TiO2、CaOの合計を100として、ZrO25〜
15wt％を含有し、気孔率0.2％以下に高密度化し
たことを特徴とする磁気ヘツド用磁器組成物。1 Consisting of TiO 2 77-86wt% and CaO 14-23wt%, taking the total of TiO 2 and CaO as 100, ZrO 2 5-
A porcelain composition for a magnetic head, characterized in that it contains 15 wt% and has a high density with a porosity of 0.2% or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58062719A JPS59190261A (en) | 1983-04-09 | 1983-04-09 | Ceramic composition for magnetic head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58062719A JPS59190261A (en) | 1983-04-09 | 1983-04-09 | Ceramic composition for magnetic head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59190261A JPS59190261A (en) | 1984-10-29 |
| JPS6158426B2 true JPS6158426B2 (en) | 1986-12-11 |
Family
ID=13208432
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58062719A Granted JPS59190261A (en) | 1983-04-09 | 1983-04-09 | Ceramic composition for magnetic head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59190261A (en) |
-
1983
- 1983-04-09 JP JP58062719A patent/JPS59190261A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59190261A (en) | 1984-10-29 |
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