Abstract: On the selfmanufactured plasma spraying profile modeling machine,the 7.5 meters screws are dealt with plasma spraying of nanophase doped with Al2O3+13%TiO2.AT13 ceramics coating doped 30% nanometer prepared by ash plasma spraying method.The microstructure and the phase of AT13 plasma spraying powder and ceramics coating with doping nanometer and prefabricating are investigated by modern material analysis means such as SEM and EDS and XRD etc.The results show that the powder structure using plasma spraying doping nanometer is micrometer and the cladding nanometer in its surface is hemp regiment structure,the fluidity of the powder is good in 50~70μm and indicated to the ash plasma spraying.The doping nanometer will improve the homogeneity of element distribution in plasma spraying ceramics coating and reduce porosity and make the inner of the ceramics coating appear（Al₂O₃）_5.333 and Al₂TiO₅ phase by orthorhombic crystalline state.The analysis of the ceramics coating fracture proves that volumes of vermiculate whiskers with 10nm diameter are found in ceramics coating doping nanometer,the fracture method become the trans-granular fracture with toughness.The analysis of the fracture illustrates that a great amount of 10nm nano-crystals,which changes the fracture mechanism and provides the structure evidence for the long-life of the screw-pump.

Key words: crew-pump, nano-doping plasma spraying, AT13(Al₂O₃+13%TiO₂ composition and structure of coating