Interfacial fatigue of functionally gradient coatings processed by plasma spray method

• Main Authors: Dar-chuen Lin, 林大春
• Other Authors: Hsien-Kuang Liu Ph.D.
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/47002767395915608795

碩士 === 逢甲大學 === 材料與製造工程所 === 95 === In order to show that fatigue property of anisotropic microstructure of flat coatings, we deposited functionally graded materials coatings and traditional double layers materials coatings by using atmosphere plasma spray technigue to analysis cohesive property. In oreder to study effect of cohesive property, we define that the direction parallel with the direction of spray gun as out-of-plane coatings and the direction perpendicular to the direction of spray gun as in-plane coatings. We used traditional double layers materials coatings that including NiCrAlY materials and CoCrAlY materials and used functionally graded materials coatings to do tensile strength test and shear strength test and high cycle fatigue test. We also used nonlinear regression method to find the parameter of curves and to understand the cohesive property of microstructure of the out-of-plane coatings and in-plane coatings. Results of high cycle fatigue test show that specimens can tolerate durable property under circulate stress condition. We used nonlinear regression method to analysize data of fatigue test. The results show that the fatigue strength of out-of-plane coatings and in-plane coatings of NiCrAlY and CoCrAlY of traditional double layers materials coatings are all better than functionally graded materials coatings. This study shows that process parameters of APS interact each other and bonding strength between coatings and substrates and cohesive strength of coatings are affected by sprayed process and sprayed particle size and microcrack etc. The curves that we got by nonlinear regression method can use to be the base to predict the relation of melt coatings and life time of fatigue.