JPH0373044B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a substrate material for a magnetic head incorporated in a floppy disk device or a hard disk device that is a peripheral device of a computer, and particularly relates to a nonmagnetic substrate material for a thin film magnetic head. [Prior Art] Magnetic heads for computers, VTRs, or audio devices are generally constructed by glass-bonding ferrite, which is a magnetic material, and ceramic, which is a non-magnetic material. On the other hand, in the case of a thin film magnetic head, a magnetic thin film such as sendust or permalloy is formed on a magnetic or non-magnetic ceramic substrate by plating, vapor deposition or sputtering. Generally, Al ₂ O ₃ -TiC ceramics are used as the substrate material for thin-film magnetic heads.The reasons for this are that they have superior wear resistance compared to other materials, and that Examples include good wettability with the magnetic film being deposited.
In recent years, digital magnetic recording heads have been required to be smaller, have narrower gaps, and have higher reliability as technology advances toward higher recording densities. For this reason, substrate materials for thin-film magnetic heads are required to have high density, few pores, excellent wear resistance, and excellent workability. Specifically, a relative density of 99.95% or more of the theoretical density is required, and in terms of wear resistance, it is necessary to have a relative density of 99.95% or more of the theoretical density.
Hardness of 2500 or higher is required. However, it is generally used as a substrate material for thin-film magnetic heads.
Al ₂ O ₃ -TiC ceramics has poor sinterability due to poor wettability between Al ₂ O ₃ and TiC, and has many residual pores. Furthermore, the workability is extremely poor and it cannot meet the demand for miniaturization. By the way, the currently used manufacturing method for Al ₂ O ₃ −TiC ceramics is
One example uses the HIP (hot isostatic pressing) method, but in order to obtain the densification effect of HIP treatment, it is necessary to obtain a sintered body with a relative density of 95% or more as a pretreatment. Become. However, since Al ₂ O ₃ -TiC ceramics have poor sinterability, a relative density of 95% or higher cannot be obtained unless sintering is performed at a high temperature of 1850°C to 1900°C. Furthermore, due to exposure to such high temperatures, Al ₂ O ₃ ,
Significant grain growth of the TiC particles occurred, resulting in a decrease in mechanical strength, resulting in a decrease in workability.Workability was also poor due to high-temperature treatment, and there were also problems from the perspective of energy conservation. For this reason, attempts have been made to add subcomponents to the main components of Al ₂ O ₃ and TiC.
140068, Japanese Patent Application Laid-open No. 57-205372, etc. As a result of research to solve the above problems, the present invention has made it possible to obtain a good substrate by simultaneously adding an additive that promotes sintering and an additive that inhibits grain growth. It is something. [Object of the Invention] In view of the above-mentioned problems, the present invention provides a substrate material for a thin film magnetic head that has excellent sinterability, has high density, has few pores, has excellent wear resistance, and has good processing characteristics. It provides: [Summary of the Invention] As a result of various experiments, the present inventor found that TiC15~
By adding 1 to 10 wt% of one or more of _{La 2 O 3 ,} CeO ₂ , and Sm ₂ O ₃ to 100 wt % of the main component consisting of 60 wt % and the remainder Al 2 O 3 , Al ₂ O ₃ and Because the wettability with TiC is improved, sinterability is improved, and there are few remaining pores and the relative density is 99.95% or more.
It also contains 1 to 5 wt% of Cr ₂ O ₃ , TiO ₂ , and NiO, which are additives that have excellent wear resistance and exhibit grain growth suppressing effects.
By adding this, it is possible to easily produce a thin film magnetic head substrate material with a small grain size structure and excellent workability. The present invention will be described in detail below with reference to Examples. [Example] Al ₂ O ₃ with an average particle size of 0.1 to 0.2 μm and a purity of 99% or more,
TiC, La ₂ O ₃ , CeO ₂ , Sm ₂ O ₃ , Cr ₂ O ₃ , TiO ₂ ,
Each powder raw material of NiO was weighed so as to have the composition ratio shown in Table 1, and samples No. 1 to No. 16 were prepared. In addition
The weighed values of La ₂ O ₃ , CeO ₂ , and Sm ₂ O ₃ (Additive B) and the weighed values of Cr ₂ O ₃ , TiO ₂ , and NiO (Additive C) are based on Al ₂ O ₃ and TiC. This is the ratio to the main components, with a total of 100wt%. Also, sample No. 8 to 16
is for comparison. After weighing each sample as described above, using ethanol as a solvent, mixing in a ball mill for 20 to 40 hours, filtering and drying, adding an organic binder,
It was pressure molded into a block body measuring mm x 30 mm x 10 mm. Furthermore, this was heated at 1700℃ in an Ar gas atmosphere for 2 hours.
After sintering for a period of time, hot isostatic pressing (HIP) treatment was performed using Ar gas as a pressure medium at a pressure of 1000 Kg/cm ² , a temperature of 1600° C., and a holding time of 2 hours. After cutting out a 5 mm x 5 mm x 20 mm square prism from each sample obtained through the above steps, the two adjacent 5 mm x 20 mm sides of the prism were processed into a mirror surface, and the ridges of 2 x 2 μm or more were formed. The number of chips was counted using an optical microscope with a magnification of 1000 times, and converted to the chipping incidence rate per 1 cm.
The evaluation item was workability. The size of the chipping is determined by its length: 2-10μm, 11-50μm, 51μm.
Classified above. Furthermore, on the fracture surface of each sample, the diameters of 50 to 100 particles were measured using a scanning electron microscope, and the average value was taken as the particle diameter of each sample. Furthermore, as evaluation items for mechanical strength, Bitkers hardness Hv (load: 1 kg) and bending strength F were measured. Furthermore, the density of each sample was measured using the Archimedes method, and the relative density with respect to the theoretical density was calculated. The above results are shown in Table-1.

【table】

〔Effect of the invention〕

As is clear from the above results, the present invention has excellent wear resistance, which has been difficult to manufacture in the past.
We were able to easily produce a high-density ceramic substrate material for thin-film magnetic heads that has few pores and good machinability.

Claims (1)

[Claims] 1 Contains 15 to 60 wt% of TiC, and the remainder is Al ₂ O ₃ for 100 parts by weight of the main component, and further contains La ₂ O ₃ , CeO ₂ ,
1 to 10 wt% of one or more types of Sm ₂ O ₃ ,
One or more of Cr ₂ O ₃ , TiO ₂ , NiO
Substrate material for thin film magnetic heads, characterized by the addition of 5wt%.