Study On The Effect Of Gd ₂ 3 -NiO Co - Doped On The Thermal Insulation Performance Of Yttrium Stabilized Zirconia

With the increase of thrust and work efficiency in the aircraft engine, the temperature of TBCs (thermal barrier coatings) is rising as well. Therefore, it is urgently desired to develop new TBCs with the properties such as thermal stability, thermal barrier, low radiation. These TBCs are the premise to obtain breakthrough development for the high power, high efficiency of aeroengine.In this dissertation, we synthesized NiO-Gd2O3-YaO3-ZrO2 ceramics through solid state reaction method using Gd2O3,Y2O3,NiO and ZrO2 as the raw materials. The phase composition, microstructure and high temperature stability were studied using X-ray diffraction technology (XRD) and Scanning electron microscope (SEM) methods; Using Laser thermal conductivity meter, high-temperature thermal expansion instrument, and Fourier transform infrared instrument, we studied the thermal diffusivity of, thermal expansion coefficient, infrared transmittance of ceramic solid solutions. The main contents are as follows:The XRD results indicated that Gd2O3 and NiO are completely dissolved in the crystal lattice of YSZ ceramics after sintered at 1500℃.GN-YSZ was heated treated in 1300℃ had better phase stability.The SEM results indicated that the microstructure of the N-YSZ and GN-YSZ ceramics after sintered at 1500℃.these ceramics doped NiO which show good compactness, sintering performance and had no grain boundary and rules in the shape of particles.However the ceramics without doped NiO exists in the form of rules of particles.Show that doping NiO have the effect that reduce the sintering temperature of the ceramic material.Thermo-physical properties test results show that at the temperature range from room temperature to 1300℃, the thermal conductivity of GN-YSZ is ranged from 1.50W/m·K to 2.22W/m-K after co-doped Gd2O3 and NiO, which is lower than traditional YSZ materials. The average thermal expansion coefficients of GN-YSZ ceramic material at room temperature is higher than the thermal expansion coefficients at 800℃ to 1200℃. Besides, the introduction of NiO can hinder the radiation effect at high temperatures, which release the thermal conductivity of YSZ ceramic material at 700℃ to 1300℃ to back up to some extend.the ceramic material after doping transition metal NiO in YSZ, GN-YSZ cceramic material in the wavelength of 2.5 u m～Sum infrared transmittance is 0.8200～0.92024. which dope NiO can effectively reduced infrared transmittance and increasd infrared emissity at short wavelength 2.5 um～5um, At the wavelength of 1.3～14.1um, the infrared emissivity is improved.so reduced thermal barrier coating permeability of infrared radiation heat transfer and reduce the radiation heat transfer.