Abstract No.:

A plasma torch which designed for low pressure plasma spraying and formation of yttria stabilized zirconia coatings

Yang Gao* / thermal spray center of Dalian maritime university, China
De-Ming Yang/ Dalian maritime university, Chins
Cheng-qi Sun/ Dalian maritime university, China

To enhance deposit efficiency and improve quality of the Yttria stabilized zirconia (YSZ) coatings in the relative low-power energy plasma jet and low-pressure environment two kind plasma touches with different nozzle size and an internal powder feedstock were designed. The optical emission spectroscopy method was used for evaluating powder melted and vaporized degrees. The results indicated that the feedstock powder of YSZ could be partially vaporized in a 700 A plasma arc by using the both of plasma torches, but different melting degrees. Denser equiaxed microstructure YSZ coatings were first successfully deposited at an arc current of 700 A by changing the plasma gas and spraying distance. With compared conventional plasma torch a new designed plasma torches has high efficiency for high melting point powder such as Yttria stabilized zirconia. A denser coating was obtained in this experiment which was attributed to a small quantity of vaporized powder, but the microstructure of the coating lost its columnar form due to the limited quantity of the vapor phase.

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