JPS5832066A - Tenacious zirconia sintered body - 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] Concerning a conia sintered body.

The biggest drawback of conventional ceramic materials is their low transverse rupture strength, but if this could be improved, they could be used to great effect in cutting tools, artificial aggregates, and still internal combustion engine parts. Therefore, many researchers have been working on this problem.

For example, Y.

ZrO2 partially stabilized with oxides such as Ca and Mg was published in JP-A-Sho! ! - 11107t. It is disclosed as No. 2 "Zirconia Cutting Tool Material" and it is reported that the total amount of tetragonal and equiaxed crystal systems is 10 to taj weight ratio.

Also, ZrOOlm and YOl. It was published in the United States that a high-strength ZrOx sintered body can be obtained by co-precipitating a mixture of ZrO2, calcining the powder, and sintering a fine powder of ZrO2 stabilized with Y, O. Ceramic Britain/Ta7
J, S., Vol. 6, p. 777.

Published by Reθd. However, none of these are satisfactory in terms of strength, and it is thought that the range of use can be greatly expanded if the strength is further increased. Therefore, as a result of intensive research, A1. By solidly dissolving and dispersing O in Zr01, the temperature at which the tetragonal ZrCh transforms to monoclinic is lowered, and the grain growth of Zr01 is suppressed. The present invention has been completed based on the discovery that it is possible to increase the slip resistance, increase the hardness, and approximately double the high-temperature strength. The gist of the patent is as set forth in the claims. A at this
l! If the content of os is less than 0% by weight of O,S (hereinafter, "electrical storage" is omitted), the addition effect is poor, and if it is more than t0, it is tough.
rO! content is low, resulting in unsatisfactory strength and toughness.

In addition, the crystal phase of zrO mushrooms requires a content ratio of tetragonal to cubic of o = 4 or more; if it is less than this, the toughness is low; If it is less than this, the toughness is insufficient. Further, the average crystal grain size of the sintered body must be 3 μ or less; if it exceeds 3 μ, the tetragonal system changes to a monoclinic system and the toughness decreases.

Alternatively, the total number of T101 including O and S is up to 3, and if it is more than this, the sinterability will be hindered and the toughness will be poor.

A more specific explanation will be given below with reference to Examples.

Example 1 To monoclinic Zr01 having the properties shown in Table 1, Ylos, CaO, and MgO were added as stabilizers in the proportions shown in Table 1, and fine particles of Al with average particle diameters o and iμ and varying purity were prepared.
Os was added to the proportions shown in Table 2, and after wet mixing, it was dried and powdered, press-molded, and heated in an electric furnace in the air to /≠O
It was baked at a temperature of 0 to lzzθ°C for about 1 hour. After firing, the sintered body was cut and polished to ≠XJ'XJ, is*, and the characteristics shown in Table 1 were measured.

The average crystal grain size was 3 μm or less in all cases, but when the firing temperature was increased beyond that shown in Table 2, the grain size grew to 3 μm or more, and the strength decreased in all cases. As is clear from Table 1, the addition of A and 1tOs suppresses the transition from tetragonal to monoclinic, increases the amount of remaining tetragonal, and improves strength and toughness. Several types of υ were selected from the samples in Table 1, and their hardness and high temperature transverse rupture strength were measured, and the results are shown in Table 3 and Figure 1. As can be seen, the hardness increases as Alton increases, and A3.3 containing tO% shows almost the same hardness as A1 Os porcelain, and the high temperature strength was also compared with the commercially available product. Compared to a partially stabilized zirconia made by Corning in the United States,
It has improved significantly.

Table l Table 3 Note l) Measurement method of various physical properties (1) Bending strength is measured by J Engineering S B4110≠, j
Shows the average value of the book.

0) Fracture toughness is determined according to ASTM Special Technical Publication A 1770, medium≠silk, thickness! Akebono, length, depth 0.3 sin on specimen of ztw, i) 0. A notch of /j- was inserted and the measurement was carried out by the three-point bending notch method with a span of 20 tlN. The measured value is the average value of each j pieces.

<3> Hardness i Measured using a Hallockwell Super Physical Hardness Meter under a load of ejtg.

(<') The crystal system is Geigerflex RA manufactured by Rigaku'α Machinery.
The analysis was carried out using the D-rA type by X-ray diffraction method. No selection, l
X-ray diffraction was performed on a specimen mirror-polished with jμ diamond paste, and the (/// ) plane and (///
) plane, and the sum of the integrated intensities of the [///) plane of tetragonal Zr0z and the [7773 plane of cubic ZrO2, Tt+
The amount of monoclinic ZrO was determined from the IC ratio.

The sintered body was then crushed to a 32J mesh, x gM diffracted under the same conditions, and monoclinic ZrO2
and the integrated intensity I'l11 and I'C of cubic ZrO2 were determined. At this time, it is thought that the residual tetragonal ZrO2 in the sintered body is subjected to mechanical stress by the crushing and is completely transformed into monoclinic ZrO2, so I'c/(I'm + I'c
), cubic Zr0m:t was determined, and then tetragonal ZrOs sweetness was also determined.

Note 2) Sample numbers with the suffix R are comparative examples.

Example - Mixing zirconium oxychloride and yttrium chloride as an aqueous solution, co-precipitating the mixture and calcining it in too 'c, and then measuring the ip and +j properties of the powder consisting of Zr01, y, o, and
Shown in the table. Using this, a sintered body was produced using the same method as in Example 1, and the results shown in Table J were obtained. The high temperature strength was also measured in the same manner as in Example 1 and is shown in FIG. As is clear from these results, even when coprecipitated Zr0t powder was used, the addition of A], 03 showed a great effect as in Example/.

[Brief explanation of drawings]

FIG. 1 is a graph showing the high-temperature strength of the Example/commercial product and the comparative commercial product, and AR is a comparative commercial product, partially stabilized zirconia manufactured by Corning. FIG. 2 is a graph showing the high temperature strength of the sample of Example 2. (/2) Seri 1 figure sparrow L ('C) Sparrow 5 grave strong (¥2 figure 5 supervision degree (0C) for salt strength

Claims (1)

[Claims] (1) A sintered body containing the following A component at ψO ~ 99.6% by weight, the remainder B component at o, z, to''ffXkk, and in some cases υC component. An X m-type zirconia sintered body characterized by an average crystal grain size of 3 μ or less. Component A: ZrO2 containing stabilizers such as Y2O9, CaO, MgO, etc., with 0 wt-1% or more of tetragonal crystals. Zr02 which is dominated by system or cubic system, and the ratio of tetragonal system to cubic system is 1:3 or more D component: A], 103 C component: Sigh of 3 times it% or less, 0.j times 'M ,%
The following Fe2O2 or 0.2% by weight or less of TiO body.