A new class of infrared transmitting glass-ceramics based on controlled nucleation and growth of alkali halide in a sulphide based glass matrix

Lithium zinc silicate (LZS) glass-ceramics with compositions: (a) Li2O-ZnO-SiO2-Na2OB2O3- P2O5 and (b) Li2O-ZnO-SiO2-K2O-Al2O3-B2O3-P2O5 have been prepared by controlled nucleation and crystallization. The effect of ZnO/(ZnO+SiO2) ratio on various thermo-physical properties was investigated by changing the ratio from 0.1 to 0.31 in the case of (a). Different crystalline phases have been identified by X-ray diffraction studies in glass-ceramics including cristobalite, Li3Zn0.5SiO4 and Li2SiO3. Density ( r) was found to increase from 2.62 to 2.82 gm cm-3 while microhardness (VHN) decreased from 6.56 to 5.79 GPa with increase in ZnO/(ZnO+SiO2) ratio in the glass-ceramics. Average thermal expansion coefficient (TEC) in the temperature range 30 to 450oC increased from 125x10-7 to 185x10-7 /oC. The increase in TEC and decrease in microhardness are thought to be due to the formation of different phases, which in turn influence the rigidity/bonding in the glass-ceramics. A remarkable difference in the microstructure close to interface of the glass-ceramics to Cu seal was seen in both the cases [high ZnO content (a) of ZnO/(ZnO+SiO2) ratio 0.31 and low ZnO content (b) of ZnO/(ZnO+SiO2) ratio 0.024]. Both the microstructures showed globally two contrast phases of bright and dark dispersed in the glass matrix. An interesting dandritic phase observed towards core in the microstructure for the high zinc content is not seen in the microstructure for low zinc content glass-ceramic. The seal withstands a vacuum of ~ 10-6 torr at helium leak rate of 3x10-10 torr litre/sec.

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Controlled Nucleation and Growth of Carbon Nitride Films on CNT Fiber Fabric for Photoelectrochemical Applications

Advanced Sustainable Systems ◽

10.1002/adsu.202000265 ◽

2021 ◽

pp. 2000265

Author(s):

Neeta Karjule ◽

Moumita Rana ◽

Menny Shalom ◽

Jesús Barrio ◽

Juan José Vilatela

Keyword(s):

Carbon Nitride ◽

Nucleation And Growth ◽

Controlled Nucleation ◽

Cnt Fiber ◽

Fiber Fabric

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Molecular Beam-Controlled Nucleation and Growth of Vertically Aligned Single-Wall Carbon Nanotube Arrays

The Journal of Physical Chemistry B ◽

10.1021/jp051531i ◽

2005 ◽

Vol 109 (35) ◽

pp. 16684-16694 ◽

Cited By ~ 119

Author(s):

Gyula Eres ◽

Anika A. Kinkhabwala ◽

Hongtao Cui ◽

David B. Geohegan ◽

Alexandar A. Puretzky ◽

...

Keyword(s):

Carbon Nanotube ◽

Molecular Beam ◽

Nucleation And Growth ◽

Nanotube Arrays ◽

Single Wall Carbon Nanotube ◽

Single Wall Carbon ◽

Carbon Nanotube Arrays ◽

Vertically Aligned ◽

Controlled Nucleation

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Immobilisation of Simulated Plutonium-Contaminated Material in Phosphate Glass: An Initial Scoping Study

MRS Proceedings ◽

10.1557/proc-932-89.1 ◽

2006 ◽

Vol 932 ◽

Cited By ~ 8

Author(s):

Paul A. Bingham ◽

Russell J. Hand ◽

Charlie R. Scales

Keyword(s):

Phosphate Glass ◽

Glass Matrix ◽

Glass Ceramics ◽

Additional Benefit ◽

Phosphate Glasses ◽

X Ray Diffraction ◽

X Ray ◽

Pu Isotopes ◽

Waste Loading ◽

Low Levels

ABSTRACTVitrification is a potential route for the immobilisation of Plutonium Contaminated Material (PCM). This is an Intermediate Level Waste (ILW) arising from operations in which there is contact with Pu isotopes. PCM consists of low levels of Pu combined with metals, masonry, glass, ceramics, polymers and other carbonaceous materials. Simulated PCM containing CeO2 as a PuO2 surrogate was mixed with a phosphate precursor and vitrified. Pre-oxidation of PCM simulant prior to vitrification minimised the violence of batch reactions. No pre-oxidation produced inhomogeneous slag-like materials with high residual metals and particulates. Pre-oxidation at 600°C in air and at 1200°C in an O2-rich atmosphere produced more favourable results, with increasingly vitreous products resulting from more oxidised PCM simulant. The most oxidised PCM simulant produced phosphate glasses with low levels of particulate inclusions, as confirmed by x-ray diffraction and scanning electron microscopy. Particulates included iron-rich metallics and aluminous oxides. Increased melting times and temperatures may have reduced the number of inclusions slightly, but O2 bubbling during melting resulted in little additional benefit. Waste loading equivalent to ∼60 weight % of untreated waste may be possible. There was little evidence of Ce partitioning, indicating that it was immobilised within the glass matrix and had little preference for metallic or crystalline phases. These results demonstrate the potential feasibility for vitrification of PCM in phosphate glass, justifying further investigation into this potentially novel solution.

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