JPS5939775A - Ceramic injection molded body degreasing method - 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] This light is L! Relates to the IJ method for degreasing a lamic extrusion molded body.

The applications of reramic hori are rapidly expanding, such as small automatic parts, heat-resistant parts, electronic parts, etc., and the shape of the products is also becoming more complex.

Therefore, ceramic materials can be made into molded products with complex shapes.
As a precise and efficient method of molding, a so-called injection molding method is employed, in which a mixture of an appropriate organic substance and a ceramic material 31 is molded.

However, when molded by injection molding method, after molding,
Removal of the organic matter, ie, degreasing, must be carried out i).

Conventionally, degreasing of such ceramic injection molded bodies has been carried out in air,
Alternatively, the molded body was heated in an inert gas atmosphere.

However, when heating in air, the heating rate should be adjusted to prevent deformation and cracking of the molded product caused by gas generated by oxidation reactions and severe thermal decomposition of organic matter. I had to comb it, and it was inefficient. Moreover, no matter how slow the temperature increase rate was, it was impossible to avoid the occurrence of some defective products.

- Heating in a permanent active gas atmosphere has the advantage of not causing oxidation reactions, but it also thermally decomposes organic matter.
This method was also inefficient and unsuitable for racial production, as the fat drying temperature had to be reduced to 1112 fat temperature in air in order to remove it.

Furthermore, in either case, in air or in an inert gas atmosphere, the decomposition products of the 41 aircraft are removed by volatilization.
Despite the need for constant gas flow ('heating'), it was difficult to control the gas flow rate.

The present invention has been devised in view of the above circumstances, and it prevents defects such as deformation and cracking of ceramic injection molded products during degreasing, and shortens the distance between the degreasing parts itself, making the work easier. It provides an efficient 1111 method.

That is, the m>fat Ij method of the present invention is to degrease a ceramic injection molded article by heating it with a vacuum strip f'l+. Here, the vacuum condition is 10-1 mm1
-1! ] ~10-4mmHu culm's 1f force is good. In addition, heat leakage is usually 200 to 35%, except for special exceptions.
The temperature is about 0°C.

As the ceramic material for the ceramic injection molded body that can be degreased by the method of the present invention, conventional heramic materials can be used as they are. Examples include silicon nitride (Si3N4), silicon carbide (SiC), alumina (A1203), zirconia (Zr02), aluminum nitride (AIN), and boron nitride (BN). As sintering aids for nitrides, magnesia (MgO), alumina (A1103), in-1-rea (Y2O2), beryllium oxide (BcO),
A mixture of selenium oxide (CeO) or the like may also be used.

In addition, the organic substances to be mixed include boria 1" pyrene,
Polymers such as polyethylene, polystyrene, ethylene-vinyl acetate copolymer, atta, tateic polypropylene, synthetic rubber, paraffin, wax, suderic acid, diethyl phthalate, and the like can be used.

When degreasing is performed by the method of the present invention, the organic matter that oozes out onto the surface of the ceramic injection molded body upon heating is quickly volatilized and removed under reduced pressure, so that it can be efficiently degreased. Furthermore, since oxidation reactions are also suppressed, the generation of defective products is prevented.

Hereinafter, the present invention will be specifically explained based on Examples.

First Example First, the inner diameter is 2Qmm, the outer diameter is 50mm, (<50m
A large number of cylindrical ceramic injection molded bodies having a diameter of m were prepared.

This is made by adding 4% each of spinel (MgAt 204 ) and yttria (Y2O2) as sintering aids to silicon nitride (Si 3N4) powder, as well as 9% of atactic polypropylene and 1-tyrene vinyl acetate. Copolymer (
5III
A cylindrical beret 1~ of lφX101III was formed using a common injection molding machine with a resin f'1 of 4180 DEG C. and an injection pressure of 900 kg/cm2.

This ceramic injection molded body is 10-3 mm and 11 g.
In a vacuum at room temperature to 350°C - 10"C/b.

At the old speed! After fiI thirsty, 350:ni/I I
+, 'l, then cooled to room temperature.

The surfaces and cut surfaces of the degreased products, which had been degreased with sea urchin, were observed using a stereomicroscope, and the interior of the uncut products was observed using X-ray photography. Of the 50 products, cracks, No abnormalities such as blistering or peeling were observed.

On the other hand, when degreased products that were degreased at a vacuum level of 10''lmm 1-1g and all other conditions were the same, those with abnormalities such as cracks on the surface were found to have a 50%
1 out of 50 had an internal abnormality.

Next, each of the 111 degreased products was heated and fired at 1750° C. for 4 hours in a nitrogen (N2) atmosphere, and the obtained fired crystals were examined by X-ray imaging. As a result, no abnormality was observed in all 50 pieces that were fired after degreasing with 10-311111118g, but 25 out of 50 pieces were fired after degreasing with 10-' mm 1-1g. , an abnormality had occurred.

In addition, for comparison, when we inspected popular products that had been degreased and fired, we found that all 50 had abnormalities.

In this example, degreasing was performed using the apparatus shown in the figure in row 0 41.

Therefore, it can be heated under reduced pressure (1) Shelf (1) inside the heating furnace (10)
01, place the lamic injection molded product 2 on J2, and use the vacuum pump 12 to pump the inside of the furnace to 10-3 mm1l (J or l
Reduce the pressure to 1g per day for Q -1+nn, and use a heating heater 100
r350 ℃ J:, and there is C゛ heated as shown in the previous). A trapper 11 is installed between the vacuum pump 12 and the heating furnace main body 10 to absorb the decomposition products of the 41 units. The inside of the zipper 11 is filled with Suanresu Refmic fiber 110, and a cooling vibrator 111 is wrapped around the zipper 11.

Second Practical Example In the second example, the month of the molded product of Refumitsukuro 1 is 1
As an example, alumina (Δ1203) powder was used, and to this were added 9% polyethylene, 5% 1-tyrene vinyl acetate Jl-small polymer, and 1% rose twine as organic substances.

Other conditions are the same as in the first embodiment.

That is, the shape of the molded product has an inner diameter of 2Qmm and an outer diameter of 1)0m.
I111 is a cylinder with a length of 5 mm, which is 10-3
It was heated to 350° C. at 10° C./hour under reduced pressure of mmH(] or (10 −′ mm1−1 g), kept at 350° C. for 4115 hours, and then cooled.

As a result, no abnormalities were observed in either the surface or internal X-ray photographs of the molded product degreased with 10-3 mn+I-to.

On the other hand, 10”-1mm1-1o-(1152 fat L
GEL, 50 pieces had abnormalities such as cracks on the surface, and X-ray inspection showed that 12 out of 50 had abnormalities inside. Met.

Next, the molded product thus obtained was treated in the same way as in the first example.
The crystals were fired by heating to 1750° C. for 4 hours in a nitrogen atmosphere, and the resulting fired crystals were examined by X-ray photography.

As a result, no abnormality was observed in all 50 pieces of 10-3 mm1-19 sintered after degreasing, but the 10-1 mm1-19 sintered after degreased Abnormalities were observed in 23 out of 50 samples.

As is clear from the detailed description of the examples above, when the method of the present invention is carried out, deformation,
Preventing defects such as cracks in the right column is C.
Giru. Furthermore, compared to degreasing under an inert gas atmosphere, degreasing can be completed at a lower temperature, making it more efficient and economical.

[Brief explanation of the drawing]

The figure is a schematic diagram of equipment for carrying out steps 11 and 2 of the present invention. 10... Heating furnace main body 100... Heating heater 1
01...Shelf 2...Ceramic IJJ molded product 1
1...1~Ratsupa 12...Vacuum Pump Special 51 Applicant 1~]Yu Jidosha Co., Ltd. Agent Patent Attorney 1
Hiroshi Okawa

Claims (2)

[Claims] (1) A method for degreasing a ceramic injection molded body, in which a ceramic Kenzan molded body obtained by D=J injection molding of a mixture of Hiramic and 41 pieces is heated (), and the organic matter is removed from the Hiramic injection molded body, The heating was carried out under reduced pressure.
1. 'C, 11; 2 ++b fat yj method for lamic cut molded bodies characterized by high fat content. (2) The degreasing method according to claim 1, wherein the reduced pressure is a vacuum higher than about 10 3 mm 1 g.