High Temperature Oxidation Behavior Of Nickel Base Alloy And High Temperature Protective Coating

In order to meet the needs of high temperature resistant parts of aircraft engine blades,a kind of Ni based superalloy was designed and prepared,using scanning electron microscopy?SEM/EDAX?and X ray diffraction?XRD?,the surface and cross section morphology of oxide film were observed,and the phase structure of the oxidation products was analyzed.The oxidation mechanism of the alloy and the coating were analyzed.Alloy in 900?and 1000?the kinetic curve at the initial stage of oxidation,rapid growth,but the oxidation rate decreases,respectively in the oxidation of 22h and 14h,the alloy specimen surface to form a continuous protective oxide film,then oxidation weight gain rate decreased,increased weight loss,alternately,the kinetic curve of wavy slow weight gain.The alloy sample was oxidized at 900?after 100h,and the surface of Ni O,Ti O₂,,Cr₂O₃,and Al₂O₃ were formed.The surface oxides were composed of Ti O₂,Cr₂O₃ and Cr Ti₂O₅,Ni Cr₂O₄,Co Si O₄ and 300h groups.Alloy samples at 1000?after100h oxidation,the surface of Al₂O₃,Ti O₂,Ni Cr₂O₄,Cr Ti O₃,Co Cr₂O₄,after the oxidation of 300h,the surface oxide by Al₂O₃,Ni Cr₂O₄,Cr Ti O₃,Co Cr₂O₄,Cr₂O₃ and Co₂Si O₄ and Co Co₂O₄ and.The outer oxide layer is dominated by Cr₂O₃ and Ti O₂,and the cracking and peeling off of the oxide film under the action of thermal expansion stress and growth stress.The element O enters into the oxide film and diffusion along the grain boundary,and the selective oxidation of Al occurs.CoNiCrAlTaY coating can improve the oxidation resistance of the alloy.In 1000?the kinetic curve at the initial stage of oxidation,rapid growth,with 22h as the turning point,the formation rate of weight gain decreased continuously after the protective oxide film,and weightlessness appear alternately,kinetic curve wavy,but still maintain a slow weight gain.In the 1100?of oxidation,the oxidation kinetics curve is 8h as the turning point,and the dynamic curve of the continuous protective oxide film is in the form of wave weight loss.Coating specimens at 1000?after 100h oxidation,coating surface oxide mainly composed of?-Al₂O₃,300h oxidation,oxide coating surface by?-Al₂O₃,composite oxide AlTaO₄.Coating specimens at 1100?after oxidation for100h coating surface oxides?-Al₂O₃ and?-Al₂O₃ composed;300h oxidation,surface oxide by?-Al₂O₃,Ta2O5,AlTaO₄.