JPH03189912A - Production of nonmagnetic substrate for magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a non-magnetic magnetic head substrate (Coo-NiO system) for depositing a metallic magnetic film, and particularly relates to a method for manufacturing a non-magnetic magnetic head substrate (Coo-NiO system) on which a metallic magnetic film is deposited. Or it relates to the rate of temperature increase in hot press.

Prior Art Conventionally, as a method for manufacturing a Coo-NiO-based nonmagnetic substrate for a magnetic head, the present inventors have already disclosed that a manufacturing method comprising the following steps is effective. (Application filed in 1986-
243995) That is, ■ a mixing process in which raw material powder is mixed and sieved; ■ a calcination process in which the CIP-formed mixed powder is calcined, pulverized, and then sieved; ■ a process in which the calcined powder is pulverized to 1 μm or less ,■ Finely ground powder to 20μm
2) Step of granulating into spherical shape, ■ Step of CIP molding the granulated powder, ■ Step of sintering the molded body, ■ Step of HI-Ping the sintered body.
This is a processing step. Furthermore, the molded body was sintered using normal pressure sintering or hot pressing at a temperature of 1000° C. or higher in an oxygen atmosphere.

Furthermore, in order to produce a sintered body with a crystal grain size of 5 μm or less, hot pressing is effective, and the processing temperature is 1150 µm or less.
~1300°C, and this was also disclosed. (
Application rate o1214207) In these manufacturing methods, there are no strict regulations regarding the temperature increase rate during sintering, and it is better to keep the temperature increase rate as slow as possible, but 1
The desired rate was approximately ℃/min. (Application filed 1986-2439
95) However, depending on the manufacturing conditions, there are parts where sintering is insufficient, and a uniform sintered body cannot be obtained.

Normally, when the heating rate is high, a temperature gradient occurs inside the sintered body during heating, which causes non-uniform sintering. That is,
This is because pores are rapidly removed near the surface, resulting in a difference in pore concentration.

Problems to be Solved by the Invention The present invention solves two drawbacks, specifically, regarding a method for sintering a molded body in a method for manufacturing a Coo-Ni0-based nonmagnetic substrate for a magnetic head. The purpose is to provide a method for obtaining a uniform sintered body by specifying the temperature increase rate.

Structure of the Invention That is, the present invention provides a method for pressureless sintering or hot pressing of a Coo-NiO-based nonmagnetic substrate for a magnetic head.
The present invention relates to a method of manufacturing a non-magnetic substrate for a magnetic head, characterized in that the temperature is raised from 0° C. to 950° C. at a rate of 0.5° C./min or less.

Means and Function for Solving the Problems The present inventors have been conducting research on Coo-Ni0 series ceramics, and as a result of detailed study on the method of sintering the molded body in the manufacturing method thereof, it was found that 900°C
It has been found that when the temperature is raised from 1 to 950° C. at a rate of 0.5° C./min or less, a uniform sintered body can be obtained without any unevenly sintered parts.

The present inventors investigated the sintering characteristics of COO-NiO ceramics and found that shrinkage begins and sintering begins in the range of 900 to 950°C. For this reason, it is more effective to slow down the temperature increase rate as much as possible in this temperature range.

Additionally, if the temperature increase rate exceeds 0.5°C/min in this temperature range, there will be a difference in pore concentration within the sintered body, and the pore concentration will be high in the center, making it impossible to obtain a uniform sintered body. I understand.

Furthermore, the equilibrium temperature of Coo, Go, O, in the atmosphere (
It was also found that the rate of temperature increase is irrelevant to sintering at temperatures below 700 to 800°C, so it is possible to increase the rate according to the specifications of the furnace used.

Based on these factors, it is desirable to divide the temperature increase rate into the following categories.

Up to 0700℃, speed up according to the specifications of the furnace used.Below 0700℃" -900℃: 0.5~b■900℃
0.5° C./min or less from 950° C. to 950° C. ■ 0.5 to b or less from 950° C. to processing temperature The overall manufacturing method will be described in detail.

Commercially available oxides are used as raw materials, weighed to give the desired composition, and mixed in a ball mill.

Mixing is carried out for example in a wet ball mill in ethanol for 10 to 30 minutes.
Do time.

After drying, CIP molding is performed, for example, 850'-! -1
Calcined at 100℃, then crushed using a coarse crusher,
Sieving is performed using a 0-200 μm sieve.

The calcined powder is further heated, for example, with ethanol at a medium temperature of 20%.
Treat for ~72 hours and pulverize to less than 1 μm.

After granulation, this is subjected to CIP molding, followed by pressureless sintering or hot press treatment in an oven.

The conditions for pressureless sintering are preferably +230-1400°C for 1-12 hours, and in hot press, Co○/Ni
At 1100-1300°C corresponding to 0 molar ratio, 100
~500 kg/crd, 1-8 hours is preferred.

It is desirable to divide the temperature increase rate into four ranges as shown below. It is preferable to increase the speed up to 0700°C depending on the specifications of the furnace used. 0.5 to 3°C/min up to 0900°C, 0.5°C/min or less from 0900°C to 950°C, ■
From then on, the sintered body is further subjected to HTP treatment at a temperature of 0.5 to 2. This is preferred to improve strength. The conditions are 800-1
200 kg/c, 1000~]250°C, 1 to 2 hours is preferable. The HTP treatment temperature is desirably lower than the sintering temperature.

It was confirmed that the sintered body obtained as in Example B was dense and had excellent uniformity.

Example An oxide represented by the compositional formula CoxNi, xo, (x=0.7) was prepared from Nip and Coo. Additives to this include AI, 0. 2. Ow and added %. The mixture is
It was treated with ethanol medium temperature polmir for 22 hours.

After drying, CIP molding and A r +41 ] 000°C
After calcining, the powder was pulverized to I 504 m or less.

The calcined powder was further treated in a wet ball mill in ethanol for 70 hours and pulverized to 1 fzm or less. After granulating this, C
IP molded, 0. Medium, hot press at 1250℃ 5
Sintered for hours.

The temperature increase rate was as follows.

0~700℃　　　　5℃/min 0700~900℃　1℃/min ~8 0900-950℃　0.3℃/min ■950~12508C1℃/min Table 1 shows the properties of this sintered body.

As a comparative example, when the temperature is raised at the same rate of 3°C/min in all temperature ranges up to 1250°C, that is, from 900°C to 9°C.
The characteristics of the sintered body when the temperature increase rate is fast in the temperature range up to 50°C are shown.

(2) As a result, the characteristics of the sintered body are uniform, and there is an advantage in economical efficiency such as yield rate during substrate processing.

Claims (1)

[Claims] (1) In pressureless sintering or hot pressing of a CoO-NiO-based nonmagnetic substrate for a magnetic head,
A method for manufacturing a non-magnetic substrate for a magnetic head, characterized by raising the temperature up to 50°C at a rate of 0.5°C/min or less