Study Of Modified Fiber Reinforced ZrO₂ Thermal Barrier Thick Composite Coating

Based on the"reinforced concrete structure"filament wound composite thermal barrier thick coating proposed by our laboratory.By analyzing the microstructure and mechanical properties of the composite coating,it is concluded that the composite coating fiber is not tightly integrated with the coating,the fiber"empty hanging"in the coating which lead to fiber not providing enough fastening force,sharing coating internal stress and improving the coating properties.In order to make full use of the structural effectiveness of the"reinforced concrete structure",it is suggested that the modified fibers should be added to the coating to improve the bonding effect between the fiber and the coating.The fiber modification process was studied experimentally.By comparing the surface morphology,mechanical properties and spraying suitability of the modified fibers prepared by different processes,the properties of the three fibers were closely related to the fiber toughening coating.The results show that fiber treated with vacuum degumming process at 450?and boiling 1h in the mixture of HF acid/concentrated nitric acid?4:6?,which has excellent performance and good combination with the coating.The bonding with the coating is identified good as a fiber modification process.In the experiment,the composite powder of 10%SiO₂/ZrO₂ was used for spraying.SiO₂ can enhance the ductility of droplet,reduce the impact of fibers on the droplet deposition process.This performance can protect the fiber from particle impact and it is conducive to the preparation of filament winding coating;Meanwhile,the good film forming property of SiO2 itself has the wetting effect on the binding of the coating material and fiber,which is helpful for the close bonding between the two and thus improving the performance of the coating.In this study,a comparative analysis is conducted to analyze the performance among the traditional YSZ thermal insulation coating,SiC fiber reinforced thermal insulation composite coating?SF-YSZ?and modified SiC fiber reinforced thermal insulation composite coating?modified SF-YSZ?.The results show that due to the addition of modified fibers,the fracture toughness of modified SF-YSZ coating reached2.28Mpa,compared to SF-YSZ heat insulation coating is increased by about 30%;modified SF-YSZ has superiority in thermal shock resistance,average thermal cycling life of coating of 4mm thickness is increased to 48.7 times;the coating thickness limit is raised to 4.8mm,insulation temperature?T increase from 524K to 578K.The modified fiber affects the overall performance of the coating by improving the binding effect of fiber and coating materials.The influences mainly improve the fracture toughness of coatings,reduce the porosity,improve the thermal shock performance and improve the coating thickness limit so as to compensate the effect of porosity reduction on heat insulation performance which improves the heat insulation performance of coating.Through research and analysis,it is found that the addition of the modified fiber to the coating achieves the expected goal of improving the bonding strength between the coating and the fiber,which improves the original loose reinforced concrete structure and makes the looser"reinforced concrete structure"play its structural effectiveness further.