Research On Preparation Of Thermal Barrier Coating Using Compound Powder Of Nanometer Zirconium Oxide

In order to resolve such two problems both bonding strength is low in the interface between metallic matrix and Zirconium oxide coating,and the coating can be flaked easily, the new technology that pre-permeating nanometer particle into the gap of matrix has been invented to prepare Thermal Barrier Coating(TBC) of nano zirconium.The step as follows: first,matrix formation is formed by the method of dry press;second,ceramic slurry is sprayed into a place under the surface of matrix by airbrush.Nano particle sprays into much deep part in matrix randomly and without markedly interface between ceramic layer and matrix,by this method gradient material will form before sintering.After sintering Thermal Barrier coatings connect with matrix firmed,which overcome the huge difference in coefficient of thermal expansion.In the experiment,8Y-ZrO₂ nano powder is the main material of coating,Iron and Nickel is the basic materials of matrix,the process of making TBC can be divided into mixing,shaping,discharging plastic and sintering,etc.Formation is by dry press,and sintering process is in an environment of Ar gas at all times.After the sintering experiment,through analogy microstructure of ceramics showing SEM photo,it is shown that the best preparation craft is W5,sintering temperature of W5 is 1100℃,holding time is 60min,Argon is shield gas.It is contrast by each group of ingredient,the ingredient T3(including zirconium oxide 30%) is the best,the phenomenon is founded that metal covertures ceramic particle,this phenomenon is may enhance the bonding strength of the interface between matrix and ceramic coating.Results of XRD show that a new phase(Zr₅Al₃)₂O is discovered,the phase Zr₅Al₃ is high melting-point phase.The new phase may enhance the resistance to elevated temperatures of material surface;testing results of Thermal Shock Resistance show that the coating of sample has not presented flaking phenomenon under such testing condition as heating 15 minutes in 1000℃,and then taking out cooling fleetly in the air or water.The reason is that TBC was prepared by means of the technology of pre-permeate nanometer particle into the gap of matrix,nano particle random spray into deeper matrix without markedly interface between ceramic layer and matrix,the interface can effective enhance the Thermal Shock Resistance of material. Results of heat insulation test show that heat insulation effect related with the thickness of thermal barrier coating,in this experiment thermal barrier coating with thickness of 1.51 mm has been prepared,and the heat insulation effect achieves 160℃under the testing condition of heating to 1010℃.