Effects of Zirconia on the Properties of Leucite-based Porcelain Powder

In this paper two distinctive methods were adopted to introduce zirconia into the dental leucite precursor as contrast.One-step synthesis method was employed to synthesize zirconia-leucite composite porcelain powder by the solid-state method using potash feldspar,zirconia and potassium carbonate as raw materials.Another synthesis method was the introduction of zirconia after synthesizing the porcelain powder.X-ray diffraction(XRD) and Scanning Electron Microscopy(SEM) were used to characterize the phase structure of the porcelain powder,the universal testing machine for the bending strength and the thermal expansion instrument for the thermal expansion coefficient.The results indicate that the addition method of zirconia has great influence on the properties of the porcelain powder.The addition of zirconia into the leucite-based porcelain powder is unfavorable for the improvement in the properties of the prepared porcelain powder.On the contrary,the one-step synthesis method is very favorable for the improvement in the properties of the as-prepared porcelain powder not only in the increase of the bending strength,but also in the regulation of the thermal-expansion coefficient.As the result,the bending strength of porcelain powder reaches up to 112 MPa with the 8% ZrO2,the sintering temperature of 1200 ℃ and the corresponding fusing temperature of 900 ℃.The obtained product has many advantages such as cheap materials,simple preparation process and good performance and is quite promising in the clinical applications of dental restoration.