Industrial Processes of Aluminizing and Tungsten Heater

Aluminum film is formed in the vacuum container. The high purity aluminum wire (generally up to 99.9%) is heated and vaporized at a relatively low temperature deposition surface of the fluorescent screen, thereby forming a thin and uniform dense aluminum. A fluorescent screen whose fluorescent material is a pure rare earth compound such as a compound of the formulas. Steamed aluminum screen is to evaporate aluminum film on the screen. Usually industrial processes of aluminizing and tungsten heater mainly include: aluminum wire insert → phosphor screen loading → first vacuum → second vacuum→ l vacuum measurement →preheating→evapotranspire →film thickness measurement  →cooling  → screen material blanking.

Tungsten heater is electrified in a vacuum vessel to form aluminum film after the gasification of aluminum wire. In other words, aluminum wire would obtain a certain power by a low voltage high current and then form an aluminum film by evaporation and gasification of aluminum wire after melting. Wolfram heater is main used in preheat evapotranspiration of the whole processes. The main purpose of preheat is to cleanup and purify gas adsorbed in the aluminum wire, making the process of evaporation can be carried out smoothly. In the beginning, the input current of heating element would increase with the voltage increases. After a long warm-up time, the temperature of heating element would rise, resulting in increase of resistivity.

In the process of evapotranspiration, solid aluminum molecules are escaped by electrical heating. In the process of evapotranspiration, voltage is applied to a certain value at first, such as 8.5V. Before the temperature reaches the melting temperature of aluminum, the change of current and power is the same as preheating process. When it reaches the evaporation temperature, aluminum would quickly evaporate and the current would reduce until the end of evaporation.

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