Nanomechanical properties of ceramic materials from the SiO 2-Al 2 O 3-(Na 2 O) - K 2 O - MgO system with an addition of SrO

The ceramic materials studied in this paper consist of finely dispersed crystalline phases embedded in a glassy matrix, which is similar to glass -ceramic materials, porcelain, and VC products. The strength depends then not only on the properties of the individual crystalline phases but also on their interactions and the matrix. Differences in mechanical properties for materials with similar chemical compositions are most likely related to diverging microstructures. Crystal orientation, grain -size distribution and shape, the ratio of the glass matrix to the crystalline phase, and homogeneity control the flexural strength of glass -ceramic materials. The subject of the study is whiteware ceramic materials from the SiO 2 -Al 2 O 3 -Na 2 O-K 2 O-MgO-SrO system, fired similarly to the regime used for VC products. The effect of the type of alkali oxide and the share of SrO were tested. This paper presents the results of hot -stage microscopy, X-ray diffraction (XRD), scanning electron microscopy with a microanalyzer (SEM-EDS) and biaxial flexural strength measurements. Additionally, nanoindentation technique was used to access local mechanical properties.