Effect of La_2O_3 on microstructure and high-temperature wear property of hot-press sintering FeAl intermetallic compound

FeAl intermetallic compound with different contents of rare earth oxide La2O3 addition was prepared by hot pressing the mechanically alloyed powders.Effect of La2O3 on microstructure and high-temperature wear property of the sintered FeAl samples was investigated in this paper.The results showed that 1 wt.% La2O3 addition could refine the microstructure and increase the density of the FeAl intermetallic compound,and correspondingly improved the high-temperature wear resistance.SEM and EDS analyses of the wo...

A novel molecular interaction chemical model for silicate melts

A novel molecular interaction chemical model （MICM） for silicate melts has been suggested based on statistical thermodynamics. It can simultaneously predict activities of all components in the CaO-FeO-SiO2 and CaO-Al2O3-SiO2 melts using only four binary parameters for each binary melt which can be determined by fitting activities of its two components. The results indicate that the predicted values of activity of FeO and SiO2 are in good agreement with the experimental data at 1823 K and 1873 K, and those of CaO, SiO2 and Al2O3 are in reasonable agreement with the graphical integration data of the Gibbs-Duhem equation. This shows that the model is effective in which the physical interaction plays a main role and the chemical one does the auxiliary function.

Simulation of 3D Heat and Mass Transfer in Glass and Oxide Melts Using the Inductive Skull Melting Technology

The inductive skull melting technology has many advantages for melting of innovative materials in the field of glasses and oxides.It offers high processing temperatures and the compliance of necessary purities at the same time. Applicable materials are in particular optical glasses,which are applied for lenses,fibers or filters,because the skull melting technology allows high process temperatures and high purities of the final product.In the production of glass materials strong requirements have to be fulfilled regarding the optical characteristics,which are mainly defined and influenced by the melting of the raw material and the following refining process.An unsolved problem in the melting process of glasses and oxides using the inductive skull melting technology was in the past the unknown heat and mass transfer in the melt because temperature and melt flow measurements in the melt are practically impossible due to the high temperatures.On the other hand the temperature and velocity distribution in the melt is very important regarding the safety of the melting process,the process control for producing the required properties of the material or the further development of skull melting installations.The paper describes a new numerical model which is able to simulate the instationary 3D melt flow of glasses and oxides.The numerical model takes into account electromagnetic,convection and Marangoni forces.By this a comprehensive view of the hidden processes in the practical experiments could be obtained. By means of the new numerical model different glass and oxide melting processes were simulated and the results were compared with experimental results.The comparisons show first of all a very good agreement between experimental and numerical results at the melt surfaces.Additionally the numerical results allow to look much deeper inside the melt and show interesting new effects of the heat and mass transfer below the melt surface which were unknown before.