Open AccessInfluence research of an α–form alumina type on the properties of samples from vibrocasting mullite corundum granular masses
Author(s) -
V. V. Martynenko,
P. A. Kushchenko,
I. G. Shulyk,
K. I. Kushchenko,
Yu. O. Krakhmal,
Л. П. Ткаченко
Publication year - 2020
Publication title -
naukovì doslìdžennâ z vognetrivìv ta tehnìčnoï keramìki. zbìrnik naukovih pracʹ
Language(s) - English
Resource type - Journals
ISSN - 2663-3566
DOI - 10.35857/2663-3566.120.04
Subject(s) - corundum , mullite , materials science , grinding , dispersion (optics) , metallurgy , dispersant , casting , composite material , ceramic , physics , optics
The technology of refractories vibrocasting was developed by JSC "URIR named after A. S. Berezhnoy" in particular highly refractory mullite corundum crucibles for melting of heat-resistant alloys in induction furnaces. At manufacturing of highly refractory vibrocasting mullite corundum refractories a-form alumina, as a dispersion binder, which milling to a particles size of less than 10 μm (the content of particles less than 4 μm in such alumina is more than 50 %) is used. For improvement the casting characteristics of vibrocasting masses dispersants are used. At research milling kinetics alumina of all brands was milling in a vibration mill for a specified time. For this research a certain amount of the investigated alumina of each brand was loaded into a vibration mill, and after a specified grinding time (30, 45, 60, 75 and 90 min), a sample of alumina after milling was taken in a specified amount. In this work, the kinetics of changes the dispersion of alumina (S, N and NR brands) during their milling was studied. The dispersion of alumina which were needed (the content of particles less than < 10 μm in such alumina is not less than 90 %, the content of particles less than < 4 μm — not less than 50 %) was achieved in almost the same milling time was found (~ 45 min). With a further increase of milling time to 60, 75 and 90 minutes, the dispersion of alumina N and NR brands increases in comparison with alumina S brand and after 90 minutes of milling, the content of particles < 4 μm in alumina, respectively, is ~ 60, ~ 75 and ~ 80 %. After fired at a temperature of 1580 °C the properties of vibrocasting mullite corundum samples, which contain alumina S, N and NR brands, are characterized by a high level of apparent density (above 3 g/cm3), open porosity (less than 16 %) and cold crushing strength (above 140 N/mm2). The high properties make it possible to use a-form alumina N and NR brands along a-form alumina S brand in the technology of vibrocasting mullite corundum refractories, including the highly refractory mullite corundum crucibles.