JPS59111976A - 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 Field of Industrial Application The present invention relates to zirconia porcelain that can be used for bearings, cutting tools, and the like.

Structure of conventional examples and their problems Stabilized zirconia porcelain, which is made by mixing zirconia with stabilizers such as yttoria, calcia, and magnesia and firing it at high temperatures, has been attracting attention as a high-strength ceramic material. There is. Furthermore, recently, partially stabilized porcelain, which requires a smaller amount of stabilizer added and has higher strength than the above-mentioned stabilized zirconia porcelain, has been recognized as one of the most suitable high-strength ceramic materials. It is attracting attention.

However, this partially stabilized zirconia porcelain has major drawbacks. It is under certain temperature conditions, for example 200~
Holding at 360'C or room temperature and high temperature (1000'C)
When the temperature changes repeatedly between 2000 and 2000, spontaneous destruction of the porcelain occurs. The reason for this is that during high-temperature firing, partially stabilized zirconia porcelain, which is a porcelain with two coexisting phases of cubic and tetragonal crystals, has one crystalline phase, tetragonal, which is a high-temperature phase, and monoclinic, a low-temperature phase. The reason for this is that a large volumetric expansion occurs due to the change in .

OBJECT OF THE INVENTION The object of the invention is to provide a material that is thermally stable over a wide temperature range;
Another object of the present invention is to provide zirconia porcelain having a high tensile modulus.

Structure of the Invention The zirconia porcelain of the present invention has ZrO2 as a main component and Y
Add 3~emot% of 2O5, and further add 1~6wt% of Aβ2 and add 006~0% of SiO2.
．． 3 wt%, 0.05 to 0.3 wt% of CaO, and 0.05 to 0.3 wt% of -MgO, and using the resulting composite additive effect, the By suppressing the phase transition from the tetragonal phase to the monoclinic phase, we have achieved porcelain that does not cause porcelain fracture.

Description of examples Examples of the present invention will be described in detail below.

Acid flower zirconium ZrO2 and inotrium oxide Y2O
Partially stabilized zirconia porcelain raw material powder was prepared by uniformly mixing 6 and 6 at a ratio of 95:5 in terms of moA%. As an additive to this, k120s.

SiO2, Cab, and MgO are added alone or in combination, and only 54 wt% of Al2O is added, 5iO2
Added only 0.1wt%, CaOo, 1wt
% only, MgOo, 1wt% only, and Aβ2034wt%, 5iO2
0.1 wt% added in combination), A120
54wt%, 5iO20, 1wt%.

Composite addition of 0.1 wt% MgO, Aβ205
4W Hanawa 5iO2o, 1wt%, CaOO, 1wt%,
Eight types of zirconia porcelain powders were prepared, including one to which 0.1 wt% of MgO was added in combination and one containing no additive at all (containing 5tsrnot% of Y2O).

Using these powders, form them into a plate shape using a hydraulic press, and
Baked at 650℃, width 10mm x thickness 2mm x length 35m
In plate-shaped zirconia porcelain was created.

The thus prepared sample was left in a constant temperature bath kept at a temperature of 250°C for a long time (up to 6000 hours). This promoted a phase change in the crystalline phase. The samples left in the thermostatic bath were taken out at regular intervals, and the bending strength was measured by a known three-point bending test, and the state of deterioration of the porcelain was determined from the results.

The results are shown in the drawing. In the figure, 1 is a sample of an embodiment of the present invention in which a combination of four types of additives is added, 2 is a sample containing no additives, and 3 to 6 are A12'3°SiO2, Ca, respectively.
b, Sample where MgO was added alone, 7: Sample where Al2O5 and 5i02 were added in combination, 8: Al2O5゜SiO
2. This is a sample with combined addition of MgO.

Samples 2 to 8 of these have a thermal knee zinc time of approximately 1
The bending strength tends to become extremely low within 1,000 hours. This phenomenon is a porcelain destruction phenomenon due to crystal phase transition of partially stabilized zirconia porcelain.

Furthermore, it can be seen that when no additives are added, when only one type of additive is added, or when up to three types of additives are added, the additives do not have a sufficient effect to prevent porcelain destruction. However, it can be seen that in sample 1, in which four types of additives were added in combination, the bending strength did not change at all from the initial value even after 5000 hours of thermal aging. That is, k1203. By adding SiO2, Cab, and HgO in combination, a clear additive effect appears.

Next, the amount of Y2O6 and the additive k1203°S
The same study as above was conducted on sasseta dinonconia porcelain in which the amounts of iO2, Cab, and MgO added were varied. The results are shown in the table below.

(Margin below) Rice Comparative Example In the above table, samples Nα1.2, 3, 22°23 are Y
These are samples with varying amounts of 2O5, among which sample Nα
1 with a low Y2O3 content (2 mot%), the initial bending strength was as high as 47 f/-, but porcelain fracture was observed in the heat aging test (260' (:, -5000 hours). , sample N123 has a large amount of Y2O3 (ym
o7%) 1, no porcelain fracture was observed in the heat aging test, but the initial bending strength was low. on the other hand,
It can be seen that in sample Nα2, 3.22, no porcelain fracture was observed in the heat aging test, and the initial bending strength was high.

In addition, for samples Nα4 to 21, the addition amount of Y20g was s m
Fixed to ot%, N[14~Bkej, 1203(7)
Amount added.

NrL9-13 is the amount of SiO2 added, N1114-17
are samples in which the added amounts of aO and N [118 to 21 are MgC1] were changed, but as can be understood from the table, the Nα4 sample with the least amount of k120s was subjected to the thermal aging test. porcelain destruction was observed.

Similarly, 5102 samples with a small amount of Nαg, Nα14 with a small amount of CaO, and Nα18 with a small amount of MgO conversely, N[L8゜1 with a large amount of these additives added.
In the sample No. 3.1 and No. 21, no porcelain fracture was observed in the heat aging test, but the initial bending strength was low.

On the other hand, sample N (Al2O5 amount of 15-7 is 1-6 wt%
The amount of SiO2 is in the range of Nα1o to 12. ,06
~0.3 wt% (7), NIL 15
~1 enoca.

The amount ranges from 0.05 to 0.3 wt% and Nα
It can be seen that in samples No. 19 to 20 with an MgO content in the range of 0.05 to 0.3 wt%, no porcelain fracture was observed in the heat aging test, and the initial bending strength was high.

In addition, for the sample in which no porcelain destruction was observed in the above-mentioned aging test at 250°C, the heating and cooling speed was 300°C/300°C in the temperature range expected to be actually used (RT ~ 600'C). n, thermal aging test with repeated temperature changes with a holding time of 6 hours.

Although the test was carried out for several hours, no porcelain fracture was observed in any of the samples, and they had high strength.

Effects of the Invention As is clear from the above explanation, the zirconia porcelain of the present invention contains ZrO2 as a main component and Y2O3 in an amount of 3 to 6 moz.
%, and to this, 1 to 6 w of A12o5 was added.
t%, SiO2 0.05-0.3 w, t%,
CaO 0.05-0.3 wt%, MgO 0.0
6 to 0.3 wt%t%, and the combined addition effect of these additives overcomes the porcelain destruction phenomenon caused by thermal aging at 200°C to 350°C humidity, which was a drawback of zirconia porcelain. Therefore, its practical value is great.

[Brief explanation of drawings]

The drawing is a characteristic diagram showing the results of a thermal aging test at 25.0'c of the zirconia porcelain of the present invention. Name of agent: Patent attorney Toshio Nakao and 1 other person-4
(

Claims (1)

[Claims] The main component is ZrO2, 3~6m01% of Y2O is added, and 1~ewt% of A4205 is added.
SiO2 0.05-0.3 wt%, CaO 0
．． 05-0.3 wt% and 0.05-0.3 MgO
Zirconia porcelain characterized by wt% addition.