Font Size: a A A

Preparation And Luminescent Properties Of ZrO2 Transparent Ceramics

Posted on:2016-12-18Degree:MasterType:Thesis
Country:ChinaCandidate:M GuoFull Text:PDF
GTID:2271330503952152Subject:Materials engineering
Abstract/Summary:PDF Full Text Request
Zirconia transparent ceramics are excellent optical materials due to their high toughness, flexural strength, refractive index, such as the 8mol% Y2O3 doped ZrO2(8YSZ) with a high refractive index, good optical clarity and chemical stability exhibits cubic structure. It has a wide range of applications in aviation, aerospace,defense industry and other fields. And the the Er and Yb are doped in zirconia transparent ceramics, which could expand its application in laser transparent ceramics.The nanoscale powdes of 8YSZ(or Er3+/Yb3+:8YSZ) were prepared by the co-precipitation method using ZrOCl2?8H2O, Y2O3 and ammonia as the raw materials.The zirconia transparent ceramics were fabricated by atmosphere sintering under hydrogen atmosphere. The microstructure, mechanical properties and optical property of the ceramics were investigated. The influence of sintering aids on microstructure and properties of ZrO2 transparent ceramics and luminescent properties of Er3+ and Er3+/ Yb3+doped 8YSZ were also evaluated.The results showed that the 8YSZ powders prepared by co-precipitation were nearly spherical, uniform(particle size of 20nm) and well dispersed and no serious reunion was found when the dilute ammonia was as the precipitating agent and the concentration of the salt solution was 0.2mol%. All of the powders calcined at different temperatures consisted of the single cubic zirconia phase. The Lattice constant of the 8YSZ reached the maximum value of 5.1322? at 800℃ with perfect crystallization.The relative density of the samples increased with increasing the sintering temperatures. The hardness and fracture toughness increased first, reaching a maximum value of 18.26 GPa and 5.96MPa·m1/2 at 1570℃, respectively, and then decreased. At the same time, the grain boundary was clear and the grain size distribution was uniform with the grain size of 10~20μm. All of the density, hardness,fracture toughness and transmittance of the samples prepared by adding ZnO were higher than those of without addition. The additives could effectively reduce the sintering temperature and improve transmittance and the properties of the zirconia transparent ceramics.With the increase of Er3+ concentration from 0.5mol% to 2.5mol% and the calcined temperature from 500℃ to 900℃, the luminescence intensity enhanced first,reaching a maximum value at 1.5 mol% and 800℃, and then weakened. The green and red upconversion emission intensity reached a maximum value when the calcined temperature reaches 800℃ and the green upconversion emission intensity reached the maximum value when concentration of doped Er3+ was 1 mol%. The blue shift of Er3+/Yb3+:8YSZ fluoresces existed with increasing the Er3+/Yb3+doped concentration.The upconversion luminescence intensity of Er3+/Yb3+:8YSZ reached a peak when the concentration of doped Er3+ reached to 4 mol%. Moreover, the red light emission intensity was much larger than that of the green.
Keywords/Search Tags:8YSZ, Transparent ceramics, Coprecipitation method, Sintering aids, Luminescent properties
PDF Full Text Request
Related items