JPS61106455A - Zirconia ceramics - 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 The present invention relates to the composition of zirconia ceramics suitable for use in substrates of various electronic devices, such as sliders of thin-film magnetic heads and substrates of magnetic recording disks, as well as heat insulating materials. It is something.

Ceramics used in such applications are first required to have excellent machinability. That is, it is required that there is little cutting resistance during machining and that there is no clogging of the cutting blade or the like. Further, during processing, crystal grains may fall off in the processed portion, but it is desirable that this falling off portion be as small as possible. for that purpose,
It is desirable that the crystal grains be small.

In addition, in these applications, it is necessary to have sliding properties, but the previously proposed At=o,, T
The iO, 1% ceramic had poor sliding properties.

Therefore, the present invention proposes zirconia-based ceramics that have good processability and are also highly slidable.

The zirconia ceramic of the present invention has periodic table IV&,
VIL, carbide of at least one starch element selected from the Ma group, α4~,2&3wt%, alumina, α34/
It is characterized in that it contains V2 & 5 wt%, and the remainder consists essentially of zirconia. Preferably, the amount of carbide is 0.
7M, 2wt%, containing an alumina amount of 08~&1wt%.

It is believed that by dispersing fine carbide particles, particularly TiG fine particles, and fine alumina particles in the zirconia phase, the growth of crystal grains in the zirconia phase is prevented, and (ma) the IJ lux crystal grains are made finer. Although it is possible to contain 5ins and 7@moa, which are generally acceptable levels as impurities, it is desirable that the amount of 1hs OB is not more than α1wt%. There is no problem with the amount of $10 up to 5wt%. In addition, Y*Os% OaOll, which is usually considered to be solid solution in the zirconia phase
Go etc. may partially precipitate and become dispersed particles, or may be dispersed in the zirconia phase as fine particles bonded or reacted with added TiO, d-103, etc., but this is not a problem. As mentioned above, At, 03 and TiO are dispersed in the zirconia phase to prevent coarsening of crystal grains, or at the same time, when cutting zirconia ceramics, high hardness carbide acts as a dressing. The zirconia phase that prevents clogging of the diamond blade is preferably a stabilized zirconia phase, that is, cubic zirconia.

Cubic zirconia has excellent sliding properties.

To stabilize the zirconia phase, Y* Oa % Mg
Add a stabilizer such as 0s OaO. Zirconia to which these stabilizers are not added becomes monoclinic (m-phase) at high temperatures (above 400°C) and vertically (below 400°C). Therefore, when the amount of stabilizer is extremely small, zirconia becomes m-phase at room temperature, but when the amount of stabilizer is increased, t-phase exists at room temperature, and even more stabilizer is added. If you increase , it will exist in the 〇-phase even at room temperature.

Therefore, in the zirconia ceramic of the present invention, it is desirable that the zirconia phase contains a stabilizer sufficient to exist as cubic zirconia even at room temperature. In the case of Y, O, 5 to 20 m in the zirconia phase
It is desirable that ZrO be present in an amount of 0.000%, with the remainder being substantially ZrO. However, there is no problem even if mackerel and 0 (Ten) are also included at the time of rotation.

If such a stabilizer is included in excess, ZrO*-
A YmOs compound precipitates, leading to deterioration of sliding properties and a decrease in strength. Therefore, it is not acceptable to contain 20 mot% or more of Y, O, or more. As mentioned above, when the amount of stabilizer decreases, a phase and an m phase are also formed.If an m phase is formed at room temperature, volumetric expansion is accompanied at that time.

If the m-phase is generated due to heating or cooling up to several hundred degrees Celsius during film deposition or patterning on the substrate, there is a risk that the substrate will warp or the pattern will shift. Therefore, the lower limit of the stabilizer for making stabilized Zirphere is about 5πoL%. Y
The content of , O, is preferably 5 mot % or more and as small as possible, and a more suitable amount is about 5 to about 10 mot %.

It is desirable that the crystal grain size of the zirconia phase is 12 μm or less. More preferably, it is 10 μm or less.

The crystal grain size of tetragonal zirconia is usually 15 μm, but by reducing it to 12 μm or less, machinability can be improved and the size of chipping can be reduced.

Further, it is desirable that the relative density (compared to the theoretical density) of the zirconia ceramic of the present invention is 99% or more, and the number of bores is extremely small.

Since it has such a high density, its sliding properties are poor.

To produce the zirconia ceramics of the present invention, Zr
O@fine powder, YmOs powder, lTh5 Va % M'
Group element carbides (e.g. IfTiOlZrO, HfO, V
'O, NbOlTaOlwo) powder and AA105 powder are blended in a predetermined ratio, thoroughly mixed, and dried.
Add a small amount of binder and granulate. This granulated powder is preformed into a molded body using a press machine having a cavity of the desired shape. This molded body was heated to 1400°C to 1600°C in a vacuum.
A zirconia ceramic is obtained as a sintered body by hot pressing at a temperature of °C.

The temperature at which this hot pressing is carried out is necessary to achieve the desired temperature. However, if the temperature exceeds 1600°C, the crystal grains of stabilized zirconia will grow significantly.
It is desirable to hot press at 0°C or lower.

Zirconia ceramics obtained by hot pressing are cut with a diamond blade into the required shape according to the application.
Finish with a grinder, etc. It is used with a magnetic core, signal coil, and insulating film attached as necessary. As this insulating film, A210a sputtered to a thickness of several 10.1 m is used.The insulating film is as high as 0° and has almost no bore.

Furthermore, since the material has good machinability, fine processing can be performed.

Examples of the zirconia ceramics of the present invention are shown below.

Example 1 Zr0i fine powder with an average particle size α0311m, Y, O, powder, and carbides of typical IVa, Va, Ma group transition elements (T10, Zr0w01vO1NbO1'raa)
, wo) powder and At1Oa powder were blended in the proportions shown in Table 1, and mixed for 24 hours in an alumina ball mill using pure water as a solvent. Dry the mixed solution, add 10% fan solution, granulate it with a sieve machine, and then 80φ at a pressure of 1 ton/cyP.
It was pre-molded into a molded body of ×6 to 7. Next, put this in vacuum 1
Hot pressed under the conditions of 450°C x 300 x 9/(1!jl chicken xlh).

The density of the sintered body was measured by the underwater turtle conversion method, and the relative density was determined by dividing the theoretical density. The bending strength test was carried out by cutting the sintered body with a diamond blade.
A test piece of m+11 was used and was bent at 1184 points for measurement. Boa 11 again! Festival, Vickers hardness measurement (charged 200
g) was performed by mirror polishing a part of the specimen. The specific resistance was measured using a 1α square specimen using the rose method, which is a type of four-terminal method. When the specific resistance was high, silver paste was applied to both sides to determine the insulation resistance. In addition, a wear test was conducted, the amount of wear was measured, and a relative comparison was made when the amount of wear of zirconia was set as 100. Machinability was evaluated by making grooves on mirror-polished specimens using a diamond blade and comparing the size of chipping that occurred on both the lapping surface and the cutting direction. In addition, the sliding properties were compared by cutting a sintered body into the shape of an actual thin-film magnetic head, bringing it into contact with a magnetic disk, and rotating the disk. The above measurement results are shown in Table 1.

zirconia ceramics. In both cases, 2 wt % of At205 was added as an auxiliary agent. In addition, the A edge was hot-pressed at 1650° C. with α5wt% of - added as an auxiliary agent.

Relative WAj is 99 for all except Altos TiO
% or more, and almost no bores were observed even when observing the bores on the mirror surface, indicating that the substrate satisfies the condition of having no bores on the surface, which is a basic characteristic of the substrate. This is a matrix where Zr01 is At, 0. This seems to be due to the fact that the sinterability is originally better than that of the sintered steel, and that it is sintered under pressure.

The Vickers hardness of ZrO2 is higher than that of Ateg Q5 TiO.
is smaller, but by adding carbide, Hv becomes 14
00-1550 and rises by about 100-200. Therefore, the bending strength, which also improves wear resistance, is strongly influenced by the strength of the matrix, so compared to A7, which has more residual tetragonal crystals,
ZrOll and Zr01-carbide systems have low strength, but are strong enough to be used as a substrate material. Also, the specific resistance is 30v
When a 1% carbide is composited, although there are large differences depending on the average particle size and distribution state of the carbide particles, the conductivity is still significantly improved compared to the matrix IRO 1, and it is a preferable choice in terms of antistatic properties. Give the volume.

As for chipping during grooving, adding carbide reduced the amount and size of chipping and improved workability. In terms of sliding properties, Y0s-TiO is not very desirable as a substrate material because it scratches the disk in a short period of time.
Stabilized zirconia containing a sufficient amount of Os can withstand long-time disk rotation and has good sliding properties.

Example 2 Zirconia ceramics having the composition shown in Table 2 were produced under the same manufacturing conditions as Example 1. Process this and wrap it to a mirror surface? It was made into a wafer of diameter. Regarding this sample, the crystal diameter S chipping resistance 1 cutting resistance workability, texture of the cut surface, and sliding properties were measured.

The chipping resistance was measured by the size of chipping that occurs during machining with a dicer (indicated by the maximum chipping depth in the table) and chipping of the alumina group. The alumina film is formed on a ceramic substrate by sputtering to a thickness of approximately 40 μm, and when the alumina film is chipped together with the substrate when a droplet is placed on it using a dicer, the width of the chip is 0. The stress applied to the slicer was measured using a piezoelectric element.

The sliding characteristics were determined by an O8S test in which a magnetic disk was rotated and a zirconia ceramic was slid in contact with the magnetic disk.

In the case of A12 and A14 zirconia to which AJaOa and TiO were not added, the cutting resistance was very large and the texture of the cut surface was not good. The chipping depth was either small in A12, which has a small grain size, or became large in Grave 14, where there were many coarse cubic crystals due to increased yosm. TiO, AJ! , *
In A1+5.16, in which Oa was added alone, the crystal grains were refined to some extent, so the chipping depth was reduced to some extent, but the size of the texture of the cut surface was not improved.

On the other hand, A1 with TiO and Al-m0a added simultaneously
In the case of 3 and Todoroki 17 to 25, the amount of chipping was reduced to about b compared to 414.The cutting resistance was small and the texture of the cut surface was good, and even after machining 90 sliders, the cut surface remained the same as before. Not much has changed. In addition, chips in the alumina film are also very small.

A25 is a case in which a very large amount of TiO is added at 40 VoL%, and although the chipping cutting resistance is small, the sliding properties are poor.

As is clear from the above experiments, zirconia ceramics exhibits a sliding property of 1°, but carbide
If added in excess of oL%, the sliding properties will deteriorate slightly. Still, O zirconia ceramics, which are superior to At and 03-'l'lQ yarns with carbide and alumina dispersed in them, have excellent wear resistance.

Even in the case of O-phase zirconia, when ALiOa and TiO are dispersed, the crystal grain size becomes smaller and the amount of chipping becomes smaller. This improves workability.

Claims (1)

[Claims] 1. 0.4 to 26.3 wt% of carbide of at least one element selected from groups IVa, Va, and VIa of the periodic table, and 0.34 to 22.5 wt% of alumina. zirconia ceramics, the remainder being substantially composed of a zirconia portion. 2. The zirconia ceramic according to claim 1, wherein the zirconia portion is substantially cubic zirconia. 3. The zirconia ceramic according to claim 2, wherein the carbide of an element in groups IVa, Va, or VIa of the periodic table is titanium carbide. 4. The zirconia part contains 5 to 20 mo of yttrium oxide.
3. The zirconia ceramic according to claim 3, wherein the remaining 1% is substantially zirconium oxide. 5. The zirconia ceramic according to claim 4, which is hot-pressed to a density of 99% or more of the theoretical density.