JPH0597549A - Graphite crucible for metal evaporation - Google Patents

Abstract

PURPOSE:To obtain a graphite crucible for metal evaporation suitable for induction heating by impregnating glassy carbon in the pores on the surface of a graphitized crucible material. CONSTITUTION:The objective graphite crucible for metal evaporation is produced by impregnating glassy carbon in the pores on the surface of a graphitized crucible material. The impregnation of the glassy carbon can be carried out by impregnating a thermosetting resin such as phenolic resin or furan resin and curing and baking the impregnated resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite crucible for vapor deposition of metal, which is used for vapor deposition of a molten metal such as aluminum or silver on a sheet.

[0002]

2. Description of the Related Art Conventionally, graphite crucibles for metal vapor deposition use carbon powder such as coke and graphite powder as an aggregate, and add a binder such as pitch to this, knead and crush it, and then mold it into the crucible shape. It was manufactured by firing and graphitizing. However, since such a graphite crucible is used at a high temperature, molten metal easily enters the surface pores of the crucible, and the metal reacts with the graphite to generate a metal carbide, which causes cracks or damage in a short time. Was a problem.

Therefore, in order to eliminate such a problem,
The present inventor has focused on glassy carbon that is homogeneous, isotropic, has excellent gas impermeability, and is more stable and corrosion resistant to metals than general carbon materials. Such a glassy carbonaceous graphite crucible is obtained by adding and kneading a thermosetting resin to carbon powder, crushing this, then shaping it into a crucible shape, firing and graphitizing.

[0004]

However, although such a graphite crucible is dense and excellent in impermeability, its physical properties become high in electrical resistivity, and the metal is heated and melted by induction heating. A new problem arises in that it is not suitable for a graphite crucible and that the thermal shock resistance is poor and cracking occurs during temperature rise or temperature decrease.

Therefore, the present inventor has conducted earnest research to develop a glassy carbonaceous graphite crucible whose electrical resistivity is the same as that of a conventional graphite crucible, and as a result, produces glassy carbon from the raw material stage. It was found that a graphite crucible having a high electric resistivity is produced when a thermosetting resin is added.

The present invention has been made on the basis of such knowledge, and an object of the present invention is to provide a glassy carbonaceous graphite crucible suitable for induction heating.

[0007]

That is, the present invention is
The content is "graphite crucible for metal vapor deposition, characterized in that glassy carbon is impregnated into pores on the surface of a graphitized crucible base material".

The graphitized crucible base material is a petroleum-based or coal-based pitch, coke, graphite powder or the like as an aggregate, and a binder such as tar or pitch is added thereto and kneaded by heating, and the kneaded product is crushed, It is obtained by shaping into a crucible shape, firing and graphitizing.

The glassy carbon is impregnated into the surface pores of the obtained crucible substrate by impregnating, curing and firing a thermosetting resin such as phenol resin or furan resin. Vacuum impregnation is recommended for the impregnation to sufficiently penetrate the pores. In this case, the pressure is 1 kg / cm.
Higher pressure is preferable in the range of ^{2 to 20} kg / cm ² . The firing temperature is in the range of 600 ° C to 3500 ° C, preferably 2000 ° C to 3000 ° C.

In order to make it more precise,
It is desirable to repeat the impregnation, curing and firing several times.

As the thermosetting resin, phenol resin,
In addition to the furan resin, an epoxy resin, a polyimide resin, a thermosetting resin (copna resin) described in JP-A-62-156124, or the like can be used. Among these, from the viewpoint of carbonization yield, coplanar resin can be used. It is recommended to use resin or furan resin.

[0012]

The graphite crucible according to the present invention is a glassy carbonaceous material obtained by adding and kneading a thermosetting resin to carbon powder, crushing this, and then molding it into a crucible shape, followed by firing and graphitization. Unlike the graphite crucible, the surface pores of the crucible substrate are impregnated with glassy carbon, so that its electrical resistivity does not have the characteristics of glassy carbon, similar to conventional graphite crucibles. It has electrical resistivity.

For this reason, the metal can be heated and melted by induction heating, and further, it has corrosion resistance against metals which is a characteristic of glassy carbon.

[0014]

EXAMPLES Next, examples will be described.

Example 1 50 parts by weight of pitch coke having an average particle size of 10 μm, 15 parts by weight of artificial graphite powder, and 35 parts by weight of coal tar pitch were mixed and kneaded while heating at 240 ° C. in air. The crushed material was molded into a crucible shape by a rubber press, and the crucible was subjected to primary firing at 1100 ° C. and secondary firing at 2800 ° C. to obtain a crucible base material. Furan resin was applied to the surface of the obtained crucible substrate at a vacuum degree of 76 Torr, 10 kg / c.
It was pressure-impregnated with m ² and fired at 2800 ° C. in a non-oxidizing atmosphere to obtain a graphite crucible. Table 1 shows the electrical resistivity and gas permeability of this graphite crucible. Further, using this graphite crucible, aluminum was vapor-deposited for 2 hours, and once this was used, the durability was examined. The results are shown in Table 1.

Example 2 65 parts by weight of artificial graphite powder having an average particle size of 13 μm and 35 parts by weight of coal tar pitch are mixed and kneaded while heating in air at 240 ° C. The crushed product was molded into a crucible shape by a rubber press, and this was primarily fired at 1100 ° C and secondarily fired at 2800 ° C to obtain a crucible base material. Furan resin was applied to the surface of the obtained crucible substrate at a vacuum degree of 7
It was pressure-impregnated at 6 Torr and 10 kg / cm ² , and fired at 2800 ° C. in a non-oxidizing atmosphere to obtain a graphite crucible.
Table 1 shows the electrical resistivity and gas permeability of this graphite crucible. Using this graphite crucible, durability was examined in the same manner as in Example 1. The results are shown in Table 1.

Example 3 The surface of the crucible substrate obtained in Example 1 was impregnated under pressure with Kopuna resin at a vacuum degree of 76 Torr and 10 kg / cm ² and fired at 3000 ° C. in a non-oxidizing atmosphere to form a graphite crucible. Got Table 1 shows the electrical resistivity and gas permeability of this graphite crucible. In addition, using this graphite crucible, Example 1
Similarly, the durability was examined. The results are shown in Table 1.

Example 4 The surface of the crucible substrate obtained in Example 2 was impregnated under pressure with Kopuna resin at a vacuum degree of 76 Torr and 10 kg / cm ² and fired at 3000 ° C. in a non-oxidizing atmosphere to make a graphite crucible. Got Table 1 shows the electrical resistivity and gas permeability of this graphite crucible. In addition, using this graphite crucible, Example 1
Similarly, the durability was examined. The results are shown in Table 1. Comparative Example 1 50 parts by weight of pitch coke having an average particle size of 10 μm, 15 parts by weight of artificial graphite powder and 35 parts by weight of coal tar pitch are mixed and kneaded while heating in air at 240 ° C. A crushed product was molded into a crucible shape by a rubber press, and the crucible was subjected to primary firing at 1100 ° C. and secondary firing at 2800 ° C. to obtain a graphite crucible. Table 1 shows the electrical resistivity and gas permeability of the obtained graphite crucible. Further, using this graphite crucible, aluminum was vapor-deposited for 2 hours, and once this was used, the durability was examined. The results are shown in Table 1.

[0019]

[0020]

As described above, since the graphite crucible for metal vapor deposition according to the present invention is obtained by impregnating glassy carbon into the surface pores of the crucible substrate, its electrical resistivity is It is the same as a graphite crucible, and therefore it can be heated and melted by induction heating, and has resistance to corrosion of metals, which is a characteristic of glassy carbon. It also has the excellent effect of being rich.

Claims (1)

[Claims] 1. A graphite crucible for vapor deposition of a metal, characterized in that glassy carbon is impregnated into pores on the surface of a graphitized crucible substrate.