DE1084100B - Evaporation device for vacuum evaporation, especially with aluminum - Google Patents

Description

The invention relates to an evaporation device for evaporation in a vacuum, especially with aluminum, whereby the vaporized material is continuously fed to the evaporator as a wire or strip and wherein a radiant heated block of refractory material in a bore of an electrical Heizwiderstanides is arranged so that the bore wall does not touch the evaporator block. The invention relates to the problem of giving the evaporator a longer service life than 10 ^ this was previously possible.

The evaporation process usually takes place in a vacuum chamber, which contains a small crucible, in which the metal to be vaporized is placed and through a resistance heating element or through electromagnetic heater heated to the evaporation temperature by wind.

Because certain metals, especially aluminum, with known refractories, previously used for the crucible used, react, unsuccessful attempts have been made, other substances to use it. Those substances that have been shown to be useful are invariably very expensive, such as tungsten or tungsten carbide. The known crucibles mostly have cylindrical ones Shape or cuboid shape and are housed in a recess of a carbon resistance heater. The top surface of the crucible ■ is designed as a work surface. The work surface is Subject to wear during operation of the device, which is why the crucible is replaced by a new crucible Must be replaced when the work surface has deteriorated too far. As the wear and tear takes place very quickly and -egg crucible --- · material is extremely expensive, the necessity of frequent replacement of the very expensive crucible must can be described as extremely disadvantageous. The invention is based on this disadvantage to overcome.

According to the invention, the object is achieved in that a cube block for the evaporator block whose six surfaces are work surfaces that are used one at a time can.

According to the invention, through the successive use of several work surfaces of a single Evaporator block achieved a significant extension of the service life for each evaporator block or a very significant reduction in the cost of the evaporator coils. If all six Surfaces of the cube are used as working surfaces one after the other, arises over the familiar a six-fold increase in service life or a reduction in costs of around 83%.

Evaporation device

for vacuum deposition,

especially with aluminum

Applicant:

Edwards High Vacuum Limited,
Crawley, Sussex (UK)

Representative: Dipl.-Ing, H. Marsch, patent attorney,
Schwelm, Drosselstr. 31

Dennis Walter Barker, Crawley, Sussex

(Great Britain),
has been named as the inventor

Under these circumstances it is possible without disadvantage to use the advantageous but very expensive substances, such as for Example tungsten, tungsten carbide or tantalum carbide to be used for the evaporator block.

The device according to the invention further comprises a heater made of carbon for the evaporator, which is attached by clamps and at the same time serves as a conductor for the heating current, wherein the clamps expand and flex the heater up and down allow. -

An embodiment for a device according to the invention is shown in the drawing as an example.

Fig. 1 shows a partially sectioned, schematic view of the device, and

FIG. 2 shows a plan view of FIG. 1.

The rod-shaped heater 1 made of carbon already has one for this purpose proposed shape and is held by clamps 2 and 3. Screws 4 and 5 are used for adjustment the clamping pressure. The clamping devices rest on a base plate 6 and serve as electrodes for supplying the heating current for the carbon rod 1.

When the temperature of the coal rises, it wants to expand and bend in a direction namely up or down. In the arrangement shown, the carbon rod stretch and bend without breaking, maintaining good contact with the clamps

009 547/216

will. In order to avoid overheating of the electrodes, water-cooled tubes 7 and 8 are provided, which in certain cases can also be used to press the electrodes 2 or 3 against one another.

The recess 9 accommodates an evaporator in the form of a cube 10 made of refractory material, e.g. B. made of refractory carbide such as tantalum carbide or tungsten. From the drawings it can be seen that the recess 9 is so large that it has a free all around between the cube 4 and its wall Leaves space which serves to prevent molten metal from flowing out of the ingot and to come into direct contact with the heating device. Form the walls of the recess a heat-radiating surface from which any metal vapors entering the recess are reflected, so that damage to the heater is reduced or eliminated. The usage one cube creates six working faces, and when one face is worn out you need the cube just turn to bring up a new face. Usually the life span of a surface a cube made of tantalum carbide takes about two hours, so that with one cube a whole Lifespan of twelve hours is achieved, while with a cylinder that only has two working surfaces has a lifespan of only four hours. In the particular embodiment described the cube has an edge length of 14 mm, and the service life mentioned was increased when 2.01 g of aluminum reached per minute.

The metal to be evaporated, namely aluminum, is on the surface of the evaporator 10 by a Supply roll 12 is supplied from in the form of a wire 11, the evaporator mainly through Radiation from the carbon rod 1 is heated. The wire goes through a guide tube 13 to be roughened Discs or wheels 14, both of which are positively driven. For this purpose are the discs 14 attached to the sides of gear wheels not shown, which mesh with each other and are coupled to a drive motor. From the traction sheaves 14, the wire goes through another one Guide tube 15, which is held by a frame 16 and the wire forcibly against the Surface of the cube 10 directs. An important advantage of the feed arrangement described is that that they allow a precise adjustment of the desired area of the refractory block against which the Aluminum lays, relieved. It has been shown that the direct point-like application of the wire against the block creates a recess in the block surface in the direction of where the wire hits is, as shown in Fig. 1 at 17. By rotating the block around its vertical axis, new surfaces can be created of the block can be chosen so that before it is necessary to work on a new face of the To begin with the block, a number of indentations can be made on the first work surface that intersect in the middle of the workspace. The exact wire feed makes it possible that the surfaces of the cube-shaped block can be processed evenly.

Claims (3)

Patent claims: 1. Evaporation device for steaming in a vacuum, especially with aluminum, with the vaporized material passing through the evaporator continuously is supplied as a wire or strip and a block heated by thermal radiation Refractory material is arranged in a bore of an electrical heating resistor so that the Bore wall does not touch the evaporator block, characterized by the use of a Cube block, the six faces of which are work surfaces that are used one after the other can. 2. Evaporation device according to claim 1, characterized in that the evaporator (10) consists of a block of tantalum carbide, tungsten carbide or tungsten. 3. Evaporation device according to claim 1 or 2, characterized in that the heating device (1) for the evaporator (10) consists of carbon and is held by clamping means (2, 3, 4, 5) is, which also serve as electrodes for the heating current supply, the clamping means (2j 3, 4, 5) are provided so that they are a Allow the coal heater (1) to expand and bend up and down. Considered publications:
U.S. Patent No. 2,772,318. 1 sheet of drawings 547/216 6.60