Cristian Arnaldo Faller

Iron-Rich Glass-Ceramics Obtained from Mill Scale

Mill scale contains high amounts of iron and it is classified as residue Class 2 – Not Inert (ABNT NBR 10.004:2004). Considering its availability, this study aimed to investigate glass-ceramics from this residue focused on its valorization. The influence of lithium oxide and zirconia was also evaluated. Six formulations were melted at 1350 °C and obtained frits were wet ground, dried and characterized: X-ray fluorescence, X-ray diffraction, thermal differential analysis and dilatometry. Pressed bodies were dried and heat treated at 950 °C. After, crystallized samples were characterized by different techniques: X-ray diffraction, apparent and theoretical density, coefficient of thermal expansion, hardness and bending strength. Results showed that lithium oxide and zirconia significantly influenced the thermal and structural behavior of obtained glass-ceramics.

The Influence of Dopants in the Grain Size of Alumina - A Review

Ceramic materials present interesting properties and generate products that meet engineering requirements referring to this class for several applications. Aluminum oxide is a very good example of this class of materials, being applied widely in high technology areas especially where the abrasive and erosive wear are strongly demanded. Many factors interfere on the wear of alumina: material composition, characteristics of the used oxides, and the manufacturing process that defines the final microstructure. It is know that the grain size of the alumina has a strong influence on the wear rate and is the focus of several studies. The grain growth during sintering as well as the diffusion process can be controlled by using dopants in the alumina composition. Thus the aim of this paper is to present a review about the dopants interference on the grain size of alumina, which in turn influences the wear behavior of the alumina. The results described allow broad understanding on the subject