JPS60183709A - Substrate for thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain a fine substrate which is mechanically strong and excellent in machining by adding specific quantity of a reducing oxide in a composition consisting of TiC-Al2O3. CONSTITUTION:A material consisting of 70-98% of the total weight TiC and Al2O3 and 30-2% of the total weight reducing oxide and the content of TiC being 5-50% of the total weight is used. If the content of TiC and AlO3 exceeds 98% of the total weight, the sintering temperature rises and cannot be sintered under a temperature of 1,700 deg.C and if the content is 70% or less of the total weight, the phases of TiC and Al2O3 are reduced and the Vickers hardness is lowered. If the content is 5% or less of the total weight, the resistance against abrasion is reduced. If the weight of the reducing oxide exceeds 30% of the total weight, rich phases of TiC and Al2O3 rapidly grow into grains and if the content is 2% or less of the total weight, holes increase rapidly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a substrate for a thin film magnetic head that has high hardness and excellent machinability.

Conventional Structure and Problems TiC-based ceramic materials have been widely used due to their high wear resistance. In particular, TiC--Al2O3-based ceramics have recently attracted particular attention as substrates for thin films. However, the mechanical strength of the TiC-Al2O3 substrate is so high that it is used as a cutting tool, and it is difficult to machine it. The cause of this is an intermediate phase existing between Tic and Al2O3 components (e.g. TiC-A mediated by TiCO3).
The properties of lO3 (compounds of oxide-based additives) are due to the coefficient of thermal expansion and mechanical strength.

OBJECTS OF THE INVENTION The present invention provides a substrate composition for a thin film magnetic head which eliminates the conventional drawbacks and has high wear resistance and excellent machinability.

Structure of the Invention In order to achieve the above object, the present invention provides TiC-Al2O
3. In the composition consisting of Al2O3 sintering aid, TiC-A
A reducing oxide capable of forming an intermediate phase between 12O3 is added.

Description of examples The present invention will be described below along with examples.

For the sample preparation process, commercially available industrial raw materials (99% purity) were used.
(above) TiC, Al2O2, MgO, SiO2, Ni
O, CoO, MnO2, Cr2O3, Nb2O5, Ou
Prepare O, high purity Al2O3 pot, high purity Al2O
After mixing and pulverizing for 48 hours using 3 balls, an acrylic binder was added and a granulated powder was produced using a spray dryer.

The granulated powder was molded into a rectangular shape of 50 mm x 50 mm x 10 mm with a pressing force of 1 ton/cm 2 , and after the binder was removed, it was fired in an Ar atmosphere at a temperature within the range of 1600° C. to 1700° C. for 2 hours.

The sintered body was hot isostatically pressed (H.I.P.) at 1400°C and 1000 atm in an Ar atmosphere, and then annealed at a temperature within the range of 1000°C to 1100°C in an Ar atmosphere. . Various characteristics of the substrate as shown in FIGS. 1 to 5 were investigated.

FIG. 1 shows the relationship between TiC and Al2O3 contents and Vickers hardness. TiC, Al2O3 content is 70
At ~98% by weight, the Vickers hardness is 1900 kg/m
m2 or more, the desired value for thin film magnetic head substrates (≧18
00kg/mm2).

When it exceeds 98% by weight, the sintering temperature increases to 1700℃.
It will not sinter below. If less than 70% by weight, TiC, Al
The Vickers hardness decreases because the 2O3 phase decreases.

Furthermore, if the TiC content exceeds 50% by weight, the sinterability decreases and the Vickers hardness decreases. If it is less than 5% by weight, wear resistance tends to decrease.

FIG. 2 shows the relationship between reducing oxides and average crystal particle size.

When the content of the reducing oxide exceeds 30% by weight, grains of TiC-rich phase and Al2O3-rich phase rapidly grow.

The order of components that cause grain growth is CuO>Nb2O5>Cr2O3>MnO2, NiO,
It is CoO. FIG. 2 uses the average value of the crystal particle diameters of these reducing oxides.

Figure 3 shows the average crystal grains of the Al2O3 rich phase when SiO2 and MgO are added to a composition of TiC (27 parts by weight) - Al2O3 (63 parts by weight) - MnO2 (8 parts by weight) - CuO (2 parts by weight). Shows the relationship between diameters.

When SiO2 and MgO exceed 10 parts by weight, both Al
Grain growth of 2O3 is promoted. When MgO is 10 parts by weight or less, grain growth of Al2O3 tends to be suppressed. Si
When O2 is added, liquid crystals are generated and the sintering temperature decreases, but
Since it tends to induce abnormal grain growth, it is necessary to add MgO and control it appropriately.

FIG. 4 shows the number of chippings that occurred when machining the product of the present invention and a commercially available TiC-Al2O3 thin film magnetic head substrate. It can be seen that the present invention has excellent machinability. The cutting was performed using a diamond peripheral blade high-speed cutting machine at a peripheral blade rotation speed of 3000 r. p. It was held at m.

Figure 3 shows that the weight ratio of Al2O3 and TiC is Al2O3/T.
Ni, which is a reducing oxide, is added to the composition where iC = 7/3.
O, CoO, MnO2, Cr2O3, Nb2O5, Cu
It shows the number of pores per unit area when O is added. It can be seen that the products of the present invention generally have fewer pores and are denser than conventional products. When the reducing oxide content is less than 2% by weight, the number of vacancies increases rapidly.

Listed in descending order of the number of vacancies among reducing oxides: CuO>Cr2O3>MnO2>CoO>NiO>Nb
2O5 It will look like this.

Although MgO was used here as the Al2O3-based sintering aid, similar results can be obtained using other alkaline earth oxides.

Effects of the Invention According to the present invention, it has become possible to obtain a dense substrate for a thin film magnetic head that has high mechanical strength and excellent machinability.

[Brief explanation of the drawing]

Figure 1 shows the relationship between TiC and Al2O3 contents and Vickers hardness, Figure 2 shows the relationship between reducing oxides and average crystal particle size, and Figure 3 shows the addition of sintering aid for Al2O3. Figure 4 shows the relationship between cutting speed and chipping number; Figure 5 shows the relationship between the amount of reducing oxide added and the number of pores. It is. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure TζG, /+1,03 t (Imperial measure Figure 2 Color original stock ridge wail amount (■〉) Figure 3 Figure 4 Figure F'J R1/i (Shi in mm7) Figure 5 4 notOs/ Tic ='A 1 ty*i original%'fI
I (H%>711111i (tii, %) Procedural Amendment 11: i, li 5 9 Il', 7 ノ'' Z
eye! I55. V, Director General 1, Title of invention for thin-film magnetic heads, I;, Provisional 3 Ura Masa, Vice-(1: ↓-Fraud 415!, Output 1: 't'
1 Personnel p'jr Oaza Kadoma, Kadoma City, Osaka Prefecture] 0o61
1'rjii'1 Lee J. (582) Matsucho Electric Industry ((
, Ceremony and 1st Generation・□・Ba 111 Lower 1 Boat Noe 4 Agent 〒571 Address Oaza Kadoma, Kadoma City, Osaka Prefecture] o No. 06, Electrical Appliance Industry System Company 6, Details of Amendment Ij, j'> ``The cause of this is from 1 to 17th line of the same page 131j.

Claims (4)

[Claims] (1) Tic whose total amount accounts for 70 to 98% by weight of the whole
and Al2O3, and 30 to 2% by weight of a reducing oxide based on the total weight, and the TiC content is 5 to 50% by weight based on the total weight of the TiC substrate. (2) The reducing oxide is NiO, CaO, MnO2, C
One or two of r2O3, Nb2O5, and CuO
The thin film magnetic head substrate according to claim 1, characterized in that the thin film magnetic head substrate comprises at least one species. (3) TiC whose total amount accounts for 70 to 98% by weight of the whole
and 100 parts by weight of a composition comprising Al2O3 and a reduced oxide of 30 to 2% by weight of the total, and the content of TiC in the total is 5 to 50% by weight, and 10 parts by weight or less of a sintering aid. A thin film magnetic head substrate made of a thin film magnetic head. (4) The substrate for a thin film magnetic head according to claim 3, wherein the sintering aid comprises one or more of alkaline earth oxides and SiO2.