Porcelain versus Porcelain Stoneware: So Close, So Different. Sintering Kinetics, Phase Evolution, and Vitrification...

Understanding sintering behavior is crucial for optimizing ceramic production. Prior research has shown that porcelain and porcelain stoneware differ in microstructure and phase evolution. However, the specific mechanisms governing their sintering kinetics remain unclear. This gap motivated a detailed comparison of their sintering processes. The study aimed to clarify how phase evolution and melt properties influence densification. Researchers focused on how mullitization and melt viscosity affect sintering outcomes. They also examined the role of quartz and feldspar in stabilizing the material. The study addressed uncertainties about the buffering effect in porcelain stoneware. These findings aim to improve ceramic processing techniques.

The study aimed to compare sintering mechanisms in porcelain and porcelain stoneware. Researchers wanted to clarify how phase evolution influences densification rates. They examined the role of melt composition and microstructure in controlling sintering behavior. The goal was to understand how quartz and mullite affect high-temperature stability. The study also sought to identify the buffering effect in porcelain stoneware. Researchers focused on how feldspar melting impacts pyroplasticity. They aimed to determine the contribution of solid load and melt viscosity to deformation resistance. This work aims to inform ceramic processing strategies.

The study used five porcelain and porcelain stoneware batches with identical raw materials. All samples underwent optical dilatometry to track sintering kinetics. XRF was used to analyze chemical composition and phase evolution. XRPD-Rietveld provided quantitative phase analysis. FEG-SEM was used to examine microstructure and phase distribution. Technological properties were measured to assess sintering outcomes. The researchers compared sintering behavior under identical processing conditions. They focused on how phase changes influence melt viscosity and densification.

Porcelain and porcelain stoneware showed distinct sintering behaviors. Porcelain densified rapidly at lower temperatures due to mullitization. This process created a depolymerized melt and lower solid load. At higher temperatures, mullite aspect ratio increased melt viscosity. Porcelain stoneware relied on melt properties for sintering control. Quartz and mullite stability influenced melt viscosity and deformation resistance. A buffering effect preserved effective viscosity in porcelain stoneware. When soda-lime glass was used, no buffering occurred due to feldspar melting. In this batch, a feldspathic skeleton controlled pyroplasticity.

The study found that porcelain and porcelain stoneware differ in sintering mechanisms. Porcelain relies on microstructural features like mullitization for densification. Porcelain stoneware depends on melt properties and quartz/mullite stability. The buffering effect in porcelain stoneware prevents deformation. When feldspars melt, a feldspathic skeleton becomes crucial. The researchers propose that melt viscosity and solid load are key factors. They suggest that phase evolution and melt composition drive sintering outcomes. The findings highlight the need for tailored processing strategies. These conclusions align with the observed differences in sintering behavior.