Laminated perovskite structure heat-barrier coating ceramic layer material

Abstract

The invention disclosed a kind of lamellar heat-proof smear layer and ceramic layer material which has the structure of calcium and titanium mine. The chemical formula of the material is BaLn2Ti3O10 in which Ln stands for one kind, two kinds or three kinds of La,Sm and Nd and 0<=x<=0.12,0<=y<=0.12. Because of the adulteration of rare earth ion and the lamellar structure of the calcium and titanium mine, the material has lower heat conductivity and higher coefficient of thermal expansion compared to the zirconium oxide which is stabilized by 7-8% yttrium oxide. After annealing the material at 1500DEG C for 168h the material can still maintain stable. The material can be designed to be heat-proof smear layer materials. The using temperature interval is ambient temperature to 1500DEG C, and the heat conductivity (1200DEG C) interval is 0.47-0.70 Wm-1K-1, the coefficient of thermal expansion (1200DEG C) interval is 11.5-14.0 10-6K-1.

Description

technical field [0001] The present invention relates to a ceramic layer material used as a thermal barrier coating, more particularly to a layered perovskite structure thermal barrier coating ceramic layer material. Background technique [0002] With the development of aero turbine engines in the direction of high flow ratio, high thrust-to-weight ratio and high inlet temperature, higher requirements are placed on the high temperature resistance of high temperature components. For example, the design inlet temperature of an aero-engine with a push ratio of 10 has reached above 1577°C, and the design inlet temperature of an aero-engine with a push ratio of 15 or more will exceed 1727°C. Although after years of development, the applicable temperature of superalloys used for turbine blades has been increased to about 1000°C, and the advanced film cooling technology can reduce the surface temperature of the workpiece by about 400°C, only for aviation with a push ratio of 10 The...

AI Technical Summary

Problems solved by technology

However, YSZ also has its shortcomings: ZrO 2 There are three phase transitions from room temperature to 2370 ° C: monoclinic phase (m) from room temperature to about 1170 ° C, from monoclinic phase to tetragonal phase (t) at about 1170 ° C, and from tetragonal phase at about 2370 ° C For the cubic phase (c)

4% volume shrinkage during the monoclinic to tetragonal phase transition leading to pure ZrO 2 Susceptible to fragmentation under thermal cycling conditions

After 7-8wt.%Y 2 o 3 After partial stabilization, ZrO 2 Cooling from high temperature to room temperature maintains a metastable tetragonal phase (t'), but if it is used above 1200°C for a long time, YSZ will also change from a metastable tetragonal phase (t') to a tetragonal phase and a cubic phase (t'+c) and then Transition to monoclinic phase, the coating undergoes volume change and cracks leading to failure

Obviously, YSZ, whose limit service temperature is 1200°C, can no longer meet the design requirements of current aero-engines. It has become an urgent task to explore and research new ceramic layer materials for thermal barrier coatings.

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