Study On Large Size Cylinder By Plasma Solid Outside Deposition

In this paper, we researched the deposition technology of the large size cylinder, which is prepared with high frequency plasma as heat source, natural high purity quartz powder as raw material. And we use the outside deposition method. On the basis of the research, we improved the experiment device. The preparation process is as below. Under the high frequency electromagnetic field, use Ar gas to cause electric arc, then ignite the compressed air to form the plasma flame. The quartz powder with suited microelements and size distribution transfer to the plasma burner automatically through the feeding system. After the plasma flame high temperature heating molten, the molten powder will adhere on the rotating central tube. Its diameter will increase layer by layer. At last we get a certain specification and precision large size cylinder. The high frequency plasma equipment we des’igned and developed anode is in the range of 10 ～ 12 kv, and melted temperature is 1800 ～ 2100℃, and the deposition rate is 21～23 g/min.The experiment results showed that, using natural high purity quartz powder as raw material, high frequency plasma as heat source, and solid phase deposition way can prepare a large size cylinder. The large size cylinder prepared with high frequency plasma solid-phase sedimentary way melted natural high purity quartz powder has many advantages. Such as large size(diameter≥150mm), low content of hydroxyl(OH-≤10ppm),little trace elements(12 kinds of trace elements≤15ppm), high vitrification degree and suitable refractive index, etc. By the subsequent drawing experiment, the large size cylinder can meet the requirements of the optical fiber preparation.