CoO Addition Research Articles

Effect of 1 wt% CoO addition on dielectric and microstructural behaviour of (SrO·TiO2)-(2SiO2·B2O3) glass and glass ceramic

Glass of the nominal composition 64 wt%(SrO·TiO2)·35 wt%(2SiO2·B2O3)-1 wt%(CoO) was prepared. The glass samples were subjected to heat treatment at 900 and 950 C. The phase progression in these glass ceramics from X-ray diffraction studies shows the formation of Sr2B2O5 as primary crystalline phase followed by rutile (TiO2), Sr3Ti2O7, SrB2Si2O8 and Sr3B2SiO8 as secondary phases. The first DTA exothermic peak of glass corresponds to the crystallization of Sr2B2O5, rutile and Sr3Ti2O7 phase while second crystallization peak may be assigned to the formation of SrB2Si2O8 and Sr3B2SiO8 phases. From microstructure studies we find that strontium borate grows with larger grain size whereas the other phases like Sr3Ti2O7, TiO2 appear smaller in size. Cobalt oxide content in the strontium titanate borosilicate glass ceramic gives the thermal stability to dielectric behaviour and decreases the dielectric loss.

Effect of cobalt oxide addition on Co-Pt media

The effect of CoO addition on the magnetic, microstructure and recording properties of CoNiPt media is discussed. Both Hc and squareness increased with increasing CoO. This was attributed to the uniform grains of CoNiPt-CoO which were isolated by a channel of about 10-20 /spl Aring/. This results in an increase in SNR of about 6 dB for 2% of CoO. The OW of CoNiPt-CoO media was found to be higher than the CoNiPt media sputtered in presence of oxygen.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Raman spectroscopic study of MoO3/γ‐Al2O3 and CoO(or NiO)‐MoO3/γ‐Al2O3 oxide catalysts prepared by different methods

AbstractRaman spectroscopy has been used to characterize various MoO3/γ‐Al2O3 and CoO (or NiO)‐MoO3/γ‐Al2O3 catalysts containing 12 wt% MoO3 and 3 wt% CoO (or NiO) prepared by different methods. No significant differences between samples prepared by the wet impregnation and the pore volume method could be observed in molybdena‐supported catalysts; in these samples the majority of Mo is present as isolated distorted MoO42− tetrahedra due probably to a low coverage of the alumina surface (SBET=240 m2 g−1). Addition of NiO to the molybdena‐supported catalysts seems to cause only a slight increase in the distortion and interaction between MoO42− species. In contrast, CoO addition to the molybdena‐supported catalysts changes considerably the spectra features, suggesting that the Mo species are highly distorted, presumably in different surroundings on the alumina surface, due to the strong interaction of Co with Mo species. However, simultaneous impregnation of both MoO3 and CoO or NiO results in a more regular arrangement of Mo species and an increase in formation of polymeric Mo species, particularly with Co‐containing catalyst, where a relative higher degree of polymeric aggregation may occur.