JPS63251202A - How to grind ceramic powder - 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 the Invention The present invention relates to a method for wet-pulverizing ceramic powder into fine particles.

Conventional technology Conventionally, the method for pulverizing ceramic powder into fine particles is to disperse the ceramic powder in a liquid such as water, ethanol, or trichloroethane, and then stir this together with cobblestones such as agate, zirconia porcelain, or alumina porcelain. There is a way to crush it. It has been reported that using this method with small diameter boulders (diameter in mm) can shorten the grinding time compared to using large boulders (Tanaka et al., "Materials" Vol. 35, p. 54-58. ).

Problems to be Solved by the Invention However, in the conventional method, it takes a long time to grind ceramic powder into fine particles, especially submicron particle size. BaT i (h
In order to reduce the particle size of the calcined powder to about 0.6 μm or less, more than 100 hours are required even if 2-1 cobblestones are used.

Means for Solving the Problems In a method of wet-pulverizing at least one type of ceramic powder using cobblestone as a medium, the volume of the liquid is set to less than four times the true volume of the ceramic powder, and a dispersant is used. Add and further crush using a boulder with a diameter of 5 or less.

Function The ceramic powder pulverization method of the present invention reduces the volume of the liquid to several times that of the conventional method, adds a dispersant, and further pulverizes using cobblestones with a diameter of 5 mm or less. It can be pulverized into fine particles and easily pulverized into submicron particle diameters.

Example Examples are shown below.

Example 1 Ceramic powder with Pbz 04 and ZnO1Snos+
, NbzOs, TiO2, zr02 (the average particle size of these powders is in the range of 0.3 to 2 μ■)
These were converted into pb(Zntzs NbIIt2) using
o, os(Snt, 2Nb2t3')O9Q9TiO-
The weight (
After about 220 g), pure water with a volume of 0.75 to 9 times the true volume of these ceramic powders, and polycarbonate with a weight of 0.1 to 2 wt, $ (solid content equivalent) of the ceramic powders. Acid-type dispersant (Ceramo 013 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
4) was placed in a polyethylene pot (140 rpm, 100 cc of zirconia cobbles) with an internal volume of 60 liters and pulverized and mixed for 20 hours.

A certain amount of the slurry obtained in this way is placed in a test tube.
This was placed in a centrifuge to sediment the ceramic powder and the sedimentation volume was measured.The particle size of the obtained powder was measured using a sedimentation type particle size distribution analyzer (Sedigraph 5 manufactured by Shimadzu Corporation).
000).

Note that the size of the sedimentation volume is a measure of the dispersibility of the powder; if the sedimentation volume is small, it is fine (it is dispersed, and conversely, if it is large, the particles are agglomerated and are forming secondary particles). (Powder - Theory and Applications Revised Group 2 Maru! Published by Co., Ltd. in 1978).Also, the sedimentation volume is the true volume I of the ceramic powder.
Expressed in volume per ce (CC). Table 1 shows the results. The 502 particle diameter of the powder was taken as the average particle diameter.

(The following is a blank space) Table 1 Wooden stamps are comparative examples Example 2 BaCO2 and TiO2 (average particle size of each is 066.1.2 μs) are used as ceramic powder, and both are weighed in equimolar amounts (approximately 150 g in total) The sedimentation volume and particle size were measured using the method described in Example 1. Table 2 shows the results.
It was shown to.

Table 2 Comparative Examples Example 3 After drying, the slurry No. 10 of Example 1 was placed in an alumina porcelain crucible and calcined at 850° C. for 2 hours to form a substantially single-phase slurry. This was coarsely ground using a stirring grinder (manufactured by Ishikawa Factory Co., Ltd.). 190g of this powder (average particle size 1.13μm)
The sedimentation volume and particle size were measured in the same manner as in Example 1 using ceramic powder. The results are shown in Table 3. In addition,
The grinding time is 15 hours.

Table 3 Part: Comparative Examples Table 3 (Continued) Part: Comparative Examples As is clear from the above examples, the method of the present invention is used, that is, the amount of water is less than four times that of the ceramic powder, a dispersant is used, and the diameter Ceramic powder ground using cobblestones with a diameter of 5 m or less has a significantly small sedimentation volume and a small average particle size. Even when using small-diameter cobblestones, the average particle size is smaller than that of large cobblestones, but by using small cobblestones, reducing the amount of water, and using a dispersant, it is possible to further increase the average particle size with the same grinding time. Can be made smaller. As seen in the examples, simply reducing the amount of water causes loss of fluidity and no pulverization at all. Additionally, simply adding a dispersant can have an effect on pulverization, but the effect is small.

The diameter of the boulder is 5-cm or less, and the smaller the diameter, the more suitable it is for fine pulverization. In the bot mill, cobblestones of 1 to 2+em were effective, but in the media agitation type grinder, even cobblestones with a diameter of about 0.5mm+ were effective for fine pulverization. Note that, in order to make the pulverization effective, it is preferable to make the ceramic powder in advance sufficiently smaller than the size of the cobblestone. The minimum amount of water required is such that the slurry has fluidity. Further, it is effective when the amount of the dispersant is 0.1 to 2 wt of the weight of the ceramic powder * (in terms of solid content).

Note that the scope of the present invention is not limited to the above-mentioned examples, and the type of cobblestone is not limited to the zirconia cobblestone of the example (alumina, silicon carbide, silicon nitride,
It may also be made of other materials such as glass. Further, ceramic powder other than those in the examples may be used. In addition, the liquid may be other liquids such as ethanol, trichloroethane, etc. that are outside the waterside. Various dispersants can be used depending on the type of liquid and ceramic powder. In the example, a bot mill was used for crushing, but other crushers that use liquid and cobblestones,
For example, any pulverizer such as a media agitation type pulverizer may be used.

Effects of the Invention As described above, by reducing the amount of water to 4 times or less the true volume of the ceramic powder, using a dispersant, and further pulverizing using cobblestones of 51 m1 or less, it can be easily pulverized into submicron particles. can. Furthermore, since the slurry has excellent dispersibility, it can be expected to be effective in mixing. In other words, when mixing two or more types of ceramic powder, in addition to the effect of fine pulverization,
The effect of homogeneous mixing can also be obtained. In addition, since the amount of liquid used in the pulverization method of the present invention is extremely small, there is also the effect that when two or more types of ceramic powders are pulverized and mixed, the ceramic powders are not separated from each other during slurry drying. ,
Since the amount of liquid used in the method of the present invention is significantly smaller, the volume of slurry is less than 172 to 174 mm compared to the conventional method for the same amount of powder. For this reason, a mill with the same capacity can provide several times the throughput compared to conventional milling methods.

Claims (6)

[Claims] (1) In a method of wet-pulverizing at least one type of ceramic powder using cobblestone as a medium, the volume of the liquid is set to four times or less the true volume of the ceramic powder, a dispersant is added, and the diameter A method for pulverizing ceramic powder, characterized by pulverizing it using cobblestones with a diameter of 5 mm or less. (2) In a method of wet-pulverizing at least one type of ceramic powder using cobblestone as a medium, the volume of the liquid is within the range of 0.75 to 2 times the true volume of the ceramic powder. 2. The method of pulverizing ceramic powder according to claim 1, further comprising adding a dispersant and pulverizing using cobblestones having a diameter of 5 mm or less. (3) The method for pulverizing ceramic powder according to claim 1, wherein at least one kind of the ceramic powder is a lead compound. (4) The method for pulverizing ceramic powder according to claim 1, wherein at least one kind of the ceramic powder is a barium compound. (5) The ceramic according to claim 1, wherein at least one type of ceramic powder is a lead compound, the liquid is water, and the dispersant is a polycarboxylic acid type dispersant. How to grind powder. (6) Claim 1, characterized in that at least one type of ceramic powder is a barium compound, the liquid is water, and at the same time, the dispersant is a polycarboxylic acid type dispersant. A method of grinding ceramic powder.