JPS6020342B2 - Low thermal expansion porcelain composition - Google Patents

Description

Detailed Description of the Invention The present invention uses lithium-containing materials such as betalite and clay raw materials that are comparable to ordinary porcelain in terms of mechanical strength, corrosion resistance, and plastic moldability, and have excellent properties in terms of heat resistance. The present invention relates to the improvement of low thermal expansion porcelain compositions, and in particular, to widen the firing temperature range to obtain industrially advantageous low thermal expansion porcelain.

The firing temperature range used here was a range in which the water absorption rate of the sintered body was approximately 0% and no increase in shrinkage or softening of the shape could be observed. Conventionally, the lithium material base material, which exhibits low thermal expansion and is used as heat-resistant porcelain, is usually blended with a lithium-containing material such as bayite and a clay material to improve plasticity.

However, this lithium-containing material base has a firing temperature range of 20
Considering the difficulty in controlling the firing temperature as kilns have become larger in recent years, industrial production has become difficult unless there is a firing temperature range of at least 40 oo. Various studies have been conducted to expand this firing temperature range, but this problem has not yet been solved by an industrially advantageous method. On the other hand, research is also progressing on yuzu medicine used in relatively low-temperature Hori Shogen porcelain such as cordierite base material, and the present inventor has proposed that this yuzu medicine can be used in 7 mountains 203.
・56. We have found that formulations containing alkali and alkali metal oxides such as $i02, Kitsune Nao, Mokke g0, and Xao are effective, and furthermore, we have discovered that this formulation contributes to expanding the firing temperature range mentioned above, and have published this book. I came up with an invention.

That is, in the present invention, 23.0% of feldspar, 31.5% of silica, and 15.4% of talc are added to the raw materials for low thermal expansion porcelain, which is composed of 30 to 60% of lithium-containing material and 20 to 60% of clay material.
%, limestone 4.0%, and kaolin 26.2% by 10 to 40%, and fired at 1220 to 1340q0, so that the firing temperature range can be considerably expanded to about 4000 to 60000. It is an industrially advantageous low thermal expansion porcelain composition.

In the present invention, the formulation containing alkali and alkali metal oxides to be added to expand the firing temperature range is 7AI.
203・56. $j02・Fox Nao・QMg○・Xa○
Something like this is good.

Next, as the raw materials to be blended, Betalite may be used as the raw material for the lithium-containing substance, and Frogme clay or Kibushi clay may be used as the clayey raw material.For a mixture containing an alkali and an alkali metal oxide, Katsuraite is the raw material for silica, kaolin is the raw material for alumina, limestone is the raw material for calcium oxide,
Talc or magnesite may be used as a raw material for magnesium oxide, and feldspar may be used as a raw material for potassium oxide and sodium oxide.

In addition, a formulation containing alkali and alkaline earth metal oxides is made by combining the above raw materials with 23.0% feldspar, 31.5% laurel, and 1 talc.
5.4%, limestone 4.0%, Korean kaolin 26.2% (
Wt. %), and this formulation can be expressed as Wt. It is sufficient to mix 10 to 40% of betalite with 30 to 60% of betalite and 20 to 60% of clay raw material.

Example 1 40% Betalite, 40% Frog-eye clay, 4.6 Inoue feldspar
%, stone 6.3%, talc 3.1%, limestone 0.8%, and Korean kaolin 5.24% (Wt.%), and the chemical composition is Si.

267.87%, N2031892%, Fe2030.
49%, Ti020. Spot%, Mg01.26%, Ca0
0.86%, K20 1.16%, Na00.75%, L
i201.74%, loss on ignition 665% (Wt.%), wet-mixed in a pot mill for 4 hours, dehydrated and adjusted to a tsubo soil with appropriate plasticity, and then mixed in a vacuum extruder at 170× A test bar of 17 h/m was prepared, dried, and then treated in an electric furnace with heating element heating element at a heating rate of 5°C/min and a maximum temperature holding time of 1 hour.After that, it was allowed to cool naturally in the furnace and physical tests were performed on it. By changing the maximum processing temperature in steps of 120,000 to 130 picoC, the degree of adjacency can be determined and the firing temperature range can be determined.

The test results are as follows. Table 1 As shown, the water absorption rate is almost 0 from 122 pi○ to 128 pi 0.
%, and there is no softening, and 60° C. can be said to be the range of complete magnetization during this period.

Next, we will show the water absorption rate, thermal tension coefficient, anaerobic range, and chemical composition for several parts of the ternary composition diagram.
The optimum range of ℃~60oo is shown.

The formulation herein refers to a formulation containing the alkali and alkali metal oxides described above, and the numbers correspond to the numbers in the ternary composition diagram. As shown in the ship's starch grade, if betalite is more than 60%, the dawning temperature will be high.For example, as shown in the figure (■), the temperature is high above 100%, and it softens above 1350%, so the sintering temperature range will eventually change. is extremely narrow at 10 qo.

On the other hand, if betalite is reduced to less than 30%, it becomes 10,1 in the figure.
As shown in Nos. 1 and 12, the coefficient of thermal expansion is large, 4×10-6 or more, making it unsuitable as a low thermal expansion porcelain, and the firing temperature range is narrow, at 2.0. Furthermore, even if the clay content is less than 20%, the braning temperature range is 1000~20q as shown in 5 and 9 in the figure.
0, making it difficult to use industrially. Similarly, if the mixture is less than 10% or more than 40%, 4 in the figure
, 10 or 9, 12, the firing temperature range is 1pi0 to 2pi0, which is the result of the same machine.

Striped betalite 30-60%, clay raw material 20-60%
, 2, 3, 6, 7 in the figure when the formulation is 10 to 40%.
, 8, the coefficient of thermal expansion is as low as 1 to 3.5 x 10-6, and the firing temperature range is approximately 40°C to 60qo, making it easy to control the kiln during production, making it an industrially advantageous low thermal expansion porcelain. A composition can be obtained.

[Brief explanation of drawings]

Figure 1 shows the temperature of the mackerel body of only the formulation blended in the present invention.
A graph of the coefficient of thermal expansion, and Figure 2 is an X-ray analysis diagram of the formulation.
Figure 3 is a three-component system composition diagram of betalite, viscosity, and a compound. 3 diagrams outside the diagram

Claims (1)

[Claims] 30-60% fine powder of lithium-containing materials such as petalite,
As additives to expand the firing temperature range, feldspar 23.0% and silica stone 3
Low thermal expansion porcelain made by blending 10 to 40% (wt%) of a formulation containing 1.5% talc, 15.4% limestone, and 26.2% kaolin and firing at 1220 to 1340°C. Composition.