JPS6152101B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a porcelain device for a magnetic head stopper that supports a magnetic head that performs recording and reproduction using a magnetic material. Conventional configurations and their problems Conventionally, magnetic head holders that support magnetic heads that read information from or record information on magnetic materials have been made of porcelain such as alumina, forstellite, and stearite. Ta. However, since these porcelains have the same composition, their thermal expansion coefficients hardly change. Therefore, when used in combination with a ferrite element or a glassy material, it has been very difficult to select one because the thermal expansion coefficients of these elements are different. For example, when a magnetic head is brought into contact with a magnetic tape to perform recording and reproduction, the magnetic head stopper also comes into contact with the magnetic tape at the same time. However, since the magnetic head and the magnetic head stopper generally have different abrasive properties, a gap occurs between the ferrite and the magnetic tape, which adversely affects the magnetization of the magnetic tape. Furthermore, if the porcelain of the magnetic head stopper contains pores having a diameter of 60 .mu.m or more, they may damage the magnetic tape surface. In order to solve these problems, it is possible to freely change the coefficient of thermal expansion according to the purpose, have strong thermal shock resistance, high mechanical strength and Vickers hardness, and have abrasion resistance comparable to that of magnetic heads. Furthermore, it is necessary to develop porcelain for magnetic head fasteners with fewer pores. In particular, the hot press method and HIP (Hot
Porcelain for fasteners such as magnetic heads for electronic computers and video tape recorders, which uses polycrystalline ferrite made by the isostatic pressing method or single crystal ferrite, has a high mechanical strength, thermal spalling, and hardness. , has good ceramic pore distribution, and has a thermal expansion coefficient of +80 to +95×
Porcelain in the 10 ^-7 °C ^-1 range is strongly desired. Currently, there is a document on porcelain for magnetic head fasteners that solves some of these drawbacks.
−15528 Publication, Special Publication No. 51-42606, Special Publication Sho
There is a publication No. 52-29766. However, since the pore distribution of the devices described in these documents is not improved, there are many pores with a pore diameter of 60 μm or more, which damage the surface of the magnetic material on which recording and reproduction are performed. Furthermore, when the atmosphere in the furnace changes from an oxidizing atmosphere to a neutral or reducing atmosphere when firing porcelain for a magnetic head stopper, TiO ₂ is reduced and color unevenness occurs inside the porcelain. In addition, other documents have solved these drawbacks, but on the other hand, chipping is likely to occur during machining,
It has the disadvantage that precision machining is difficult. Purpose of the Invention The present invention eliminates the conventional drawbacks, is extremely stable in the firing atmosphere, has very few chippings during precision machining, and has strong thermal shock resistance during rapid heating and cooling. It also provides a method for manufacturing a magnetic head stopper in porcelain with reduced pores. Structure of the Invention In order to achieve the above object, the present invention replaces Mg with MgO
35-60% by weight in terms of _TiO2
35-60% by weight, 0.2-5.0% by weight of Zr converted to _ZrO2 , 0.02-5.0% of at least one rare earth element oxide
A porcelain for a magnetic head stopper containing 5.00% by weight was prepared. By changing the ingredient ratio within the above range,
Depending on the purpose, the thermal expansion coefficient value can be changed from +80 to +95×10 ^-7 ℃
^-1 can be selected freely, there is very little chipping during machining, there is no uneven color due to changes in the firing atmosphere, and the pore distribution is good.
It has the same level of abrasion resistance as ferrite for magnetic heads, has good thermal shock properties, and is stable without any cracks even when the ferrite element and porcelain for magnetic head stoppers are combined through glass. Moreover, it is possible to produce products with high reproducibility. DESCRIPTION OF EMBODIMENTS The present invention will be described below along with one embodiment. In the sample preparation process, industrial raw materials (purity 98
% or more) TiO ₂ , MgO, ZrO ₂ , Nd ₂ O ₃ ,
La ₂ O ₃ was used, and wet mixing was performed using a urethane-lined pot mill to prevent contamination with impurities. The order of sample preparation was as follows: raw materials were mixed to have the composition ratios shown in Table 1 below, and a mechanical press was used to mold samples of 50 x 150 x 15 mm. The main firing was carried out using an electric furnace at a temperature of 1300 to 1400°C. In other words, from Sample No. 1 to Sample No. 9, the porcelain for the magnetic head stopper is 35~
60% by weight, 35-60% by weight when Ti is converted to _TiO2 ,
The raw materials were mixed to have a composition ratio containing 0.2 to 5.0% by weight of Zr in terms of ZrO ₂ and 0.02 to 5.00% by weight of at least one rare earth element oxide, and from Sample No. 10 to Sample No. 13. The raw materials were mixed to have a composition ratio other than the above.

【table】

[Table] Table 2 shows various properties of the element body obtained from the composition ratios shown in Table 1 above.

[Table] In Table 2 above, the method for measuring the number of chippings is to cut a 10 x 10 x 100 mm sample in the length direction (100 mm) using a diamond high-speed rotary cutting machine, and measure the cut surface. The number of chips was counted using an optical microscope equipped with a micrometer.
The operating conditions of the diamond high-speed rotary cutting machine (diamond cutter rotation speed, sample feeding speed) are constant. In addition, 100 pieces were tested, and the number of chips was recorded as an average value per 10 cm ² of cutting cross-sectional area. Further, at the bottom, alumina, which has been conventionally used as a material for porcelain for magnetic head fasteners, is shown for comparison. As is clear from Table 2 above, samples from No. 1
Up to No. 9, the incidence of chipping during machining is extremely low, and exhibits excellent properties such as mechanical strength, pore distribution, and color unevenness. In addition, from sample No. 10 to sample No. 13, adverse effects such as chipping and pores appeared during machining. That is, when MgO was less than 35% by weight, color unevenness occurred due to the firing atmosphere, and the wear rate was higher than that of ferrite. Furthermore, when MgO exceeded 60% by weight, machinability decreased and the incidence of chipping increased. When TiO ₂ was less than 35% by weight, the degree of wear was lower than that of ferrite, and the sinterability was lowered. Furthermore, if TiO ₂ exceeds 60% by weight, abnormal grain growth occurs, pore distribution becomes poor, and mechanical strength also decreases. If ZrO ₂ is less than 0.2% by weight, abnormal grain growth cannot be suppressed, and if it exceeds 5% by weight, sinterability will decrease. Furthermore, if one or more rare earth element oxides are less than 0.02% by weight,
Segregation of the ZrO ₂ phase occurs, and when it exceeds 5% by weight, segregation of rare earth element oxides occurs and the chipping incidence increases. In addition, since porcelain for magnetic head fasteners is embedded in the porcelain (fastener) using a ferrite element and adhesive glass as a medium, the relationship between coefficient of thermal expansion, thermal shock resistance, mechanical strength, pore distribution, etc. is very important. As materials that satisfy these conditions, the porcelain bodies made from the compositions shown in Sample No. 1 to Sample No. 9 can have their thermal expansion coefficients freely controlled. In the examples, MgO was used as a raw material for obtaining the magnesium component, but MgCO ₃ , MgCl ₂ , Mg
(OH) ₂ may also be used, or as a neodymium component.
Although Nd ₂ O ₃ was used, good characteristics were also obtained using raw materials such as Nd ₂ (CO ₃ ) ₃ carbonate and oxalate. Furthermore, although Nd ₂ O ₃ and La ₂ O ₃ were used as rare earth element oxides, good characteristics were also obtained using SmO ₂ , Pr ₂ O ₃ CeO ₂ and the like. Effects of the Invention As described above, according to the present invention, Mg is 35 to 60% by weight in terms of MgO, and Ti is 35 to 60% in terms of _TiO2 .
It constitutes a porcelain for a magnetic head stopper having a composition containing 0.2 to 5.0 weight % of Zr (calculated as ZrO ₂ ) and 0.02 to 5.00 weight % of at least one kind of rare earth element oxide. The coefficient of thermal expansion can be changed freely according to the requirements, and it can provide wear resistance comparable to that of a magnetic head, and also has strong thermal shock resistance and high mechanical strength. Furthermore, color unevenness can be eliminated and pore distribution can be improved, which has great industrial value.

Claims (1)

[Claims] 1 35 to 60% by weight of Mg converted to MgO, Ti
A porcelain for a magnetic head stopper containing 35 to 60% by weight in terms of _TiO2 , 0.2 to 5.0% by weight of Zr in terms of _ZrO2 , and 0.02 to 5.00% by weight of at least one rare earth element oxide.