With the development of the social economy, many monocrystalline silicon manufacturers are relatively skilled in the use of graphite thermal fields for two reasons:

At the front, the graphite felt has a good insulation effect, and the thickness reaches 100 mm, which effectively guarantees the condition that the radial gradient temperature may be small.

Second, the reason for the long heat is that the thickness of the graphite crucible can reach 250 mm, so the diameter of the upper, middle and lower insulation barrels will be large enough to have sufficient longitudinal heat dissipation. It is well known that the problems in the use of graphite crucibles will reduce the use time of graphite crucibles, and then increase the cost of the manufacturers themselves. If you have a history of manufacturing graphite crucibles and hot-field processed parts, let's talk about graphite heat in detail. How should we deal with common problems in field production?

The components of the thermal field, such as heater, three-petal crucible, graphite holder, heat shield, etc., are all made of graphite. During the production process, the heating equipment is often damaged. What is the reason for the damage of the graphite equipment, and what method should be used to extend the life of the graphite equipment? The damage of graphite equipment is mainly caused by man-made and deterioration. As long as the human aspect strengthens management and strengthens employees' awareness of prevention, the loss can be reduced to a lower point. Deterioration is first discussed here. First of all, let's understand the relevant properties of graphite,

1. High temperature resistance, the melting point of graphite is higher. It is 3850 degrees in vacuum, and progresses under low pressure, and the progress temperature is 2200 degrees. Unlike ordinary materials, when the temperature rises, graphite not only does not soften, but its strength increases, at 2500 degrees. When the temperature is high, the tensile strength of graphite doubles instead.

2. Special thermal shock resistance, the thermal expansion of graphite is anisotropic, so the microscopic expansion coefficient is not large, in the case of sudden temperature changes, the volume of graphite does not change much, plus its excellent Heat conduction function, so the thermal shock resistance of graphite is excellent. As mentioned in the above two points, graphite parts should be able to work stably at high temperatures for a long time.

Under normal circumstances, compared with other graphite equipment such as heat preservation covers and heaters, the petal pot is the same material, the same manufacturer, and the same operating environment. Why is the service life far lower than that of the heat preservation cover and heater? The primary reason for the cracking of the three-petal crucible comes from the quartz crucible. 1. Because the density of molten silicon is greater than that of solid silicon, the bottom material of the pot will break the quartz crucible during the cooling process, and the quartz crucible is attached to the three-petal crucible. When the stress caused by the splitting of the quartz crucible is greater than the stress received by the three-petal crucible, the three-petal crucible will crack. 2. The heating time is too long, the quality of the quartz crucible is not satisfactory, and the pH of the raw material does not meet the requirements, which will cause silicon leakage and silicon infiltration. The molten silicon enters the gap between the three-petal crucible and cools down. It is to make the three-petal pots adhere to each other, and when the furnace is cleaned, they may form cracks respectively. 3. During the heating process, only the heat source of the three-petal crucible comes from two aspects, one is the radiation of the heater, and the other is from the conduction of the quartz crucible, which causes the three-petal crucible to be heated unevenly and expand in certain directions during heating. Large, shrink in other directions, and then cause the three-petal crucible to crack.