Effect Of Hafnium Oxide On Mechanical Properties And Aging Properties Of Zirconium Based Ceramics

Zircon sand is the main raw material for the production of zirconia.However,China’s Zircon sand is mainly imported and highly dependent on foreign countries.China’s Zirconium resource reserves are 500000 tons,accounting for only 1%of the world.China is not a major producer of zirconium resources,but a major user of zirconium resources.In the face of the gradual control of non renewable resources by countries around the world,it can be expected that it will pose a new challenge to China’s Zirconium resource market in the future.In the process of producing high-purity zirconium and hafnium in the nuclear industry,a large number of hafnium free zirconia will be produced.These hafnium free zirconia will be treated as industrial waste,resulting in waste of non renewable resources and environmental pollution.Therefore,this paper studies the possibility of scientific and reasonable recycling of hafnium free zirconia from the aspects of mechanical properties and aging performance.In this paper,hafnium-free zirconia,zirconia(HfO2<3%),yttrium oxide,alumina and hafnium oxide are used as raw materials,and the ingredients are prepared according to a certain proportion.Hafnium 3YSZ ceramic samples and 3YSZ ceramics,no hafnium 3YSZ-xAl2O3(x=0.05,0.10,0.15,0.20,0.25,0.30wt%)ceramic materials and hafnium 3YSZ-xAl2O3(x=0.05,0.10,0.15,0.20,0.25,0.30wt%)ceramic materials,no hafnium 3YSZ-xHfO2(x=1,2,3,4,5,6wt%)three kinds of ceramic materials,by X-ray diffractometer(XRD),Raman spectroscopy(Raman)for phase characterization of ceramic samples.The phase composition and microstructure were analyzed by field emission scanning electron microscope(FE-SEM).The Vickers hardness,fracture toughness and three-point bending resistance of 3YSZ ceramic materials were characterized by testing instruments such as automatic Vickers microhardness tester and electronic universal testing machine.The mechanical properties and anti-aging properties of the prepared hafnium-free 3YSZ ceramics were compared with 3YSZ ceramics.The results show that the optimum sintering temperature is 1450℃ for 3h,and the average grain size of 3YSZ is 391nm.The average grain size of hafnium-free 3YSZ is 413 nm,and the microscopic size difference is not large.The hardness of the hafnium-free 3YSZ ceramics is 12.97GPa,the fracture toughness is 12.63 MPa m1/2,the flexural strength is 876.67 MPa,and the toughening mechanism is phase transformation toughening.The hafnium-free 3YSZ ceramics The aging resistance of the material is lower than that of the 3YSZ ceramic material.The effects of hafnium-free 3YSZ-xAL2O3(x=0.05,0.10,0.15,0.20,0.25,0.30wt%)ceramic materials on mechanical properties and aging properties were studied by adding different mass ratios of alumina to hafnium-free 3YSZ.Studies have shown that the addition of a trace amount of alumina can reduce the grain size,increase the density and improve the mechanical properties.Among them,the hafnium-free 3YSZ ceramic material doped with 0.25%alumina can obtain the highest mechanical properties,and also shows good anti-aging properties.The utilization value of hafnium free zirconia is improved.Finally,the mechanical properties of hafnium oxide on 3YSZ ceramics were studied.Taking 3YSZ ceramics as the matrix,the HfO2 content is 1～6%,and then the ceramic samples containing a certain proportion of hafnium oxide are prepared by high-energy ball milling.The results show that the 3YSZ ceramic material containing 3%HfO2 has the best mechanical properties when the sintering temperature is 1450℃ and the temperature is kept for 3h.In summary,hafnium free zirconia can be recycled,which not only improves the utilization efficiency of zirconia resources,but also saves energy and reduces emissions,which is in line with China’s goal of carbon neutralization.Hafnium free 3YSZ ceramic materials can fully reach the application level of industrial manufacturing and daily use.Based on the study of hafnium free 3YSZ ceramics,the mechanical properties and aging properties of hafnium free zirconia ceramics are improved by adding a small amount of alumina by high-energy ball milling.This research is of great significance for the recycling of zirconium resources and has a wide application prospect in the field of structural ceramics.