Crystallization in Metal-Metalloid Multilayers

1995 ◽  
Vol 382 ◽  
Author(s):  
R. Sinclair ◽  
T. J. Konno ◽  
T. Itoh ◽  
N. C. Zhu
Keyword(s):  
Phase Diagrams ◽  
Crystallization Temperature ◽  
Metal Layer ◽  
Eutectic Phase ◽  
Crystal Nucleation ◽  
General Phenomenon ◽  
Crystalline Phases ◽  
Reaction Systems ◽  
Binary Eutectic ◽  
Rapid Diffusion

ABSTRACTWe have studied the reactions which occur in metal-metalloid multilayers made from elements which have binary eutectic phase diagrams. The metal mediates crystallization of the amorphous as-deposited metalloid by crystal nucleation inside the metal layer followed by rapid diffusion through the metal from amorphous to crystalline phases. The metalloid crystallization temperature is significantly reduced by this reaction. Systems showing this behavior are Al-Si, Ag-Si, Ag-Ge, Co-C, Ni-C and Fe-C. We believe, therefore, that it is a general phenomenon which we have now extended to the case of Ag-SiC.

Effects of gravity on processing heavy metal fluoride fibers

1997 ◽  
Vol 12 (9) ◽  
pp. 2223-2225 ◽  
Author(s):  
Dennis S. Tucker ◽  
Gary L. Workman ◽  
Guy A. Smith
Keyword(s):  
Heavy Metal ◽  
Crystallization Temperature ◽  
Normal Gravity ◽  
Crystal Nucleation ◽  
Sounding Rocket ◽  
Metal Fluoride ◽  
Reduced Gravity ◽  
Rocket Flight ◽  
Heavy Metal Fluoride

The effects of gravity on the crystal nucleation of heavy metal fluoride fibers have been studied in preliminary experiments utilizing NASA's KC-135 reduced gravity aircraft and a microgravity sounding rocket flight. Commercially produced fibers were heated to the crystallization temperature in normal and reduced gravity. The fibers processed in normal gravity showed complete crystallization while the fibers processed in reduced gravity did not show signs of crystallization.

Development of Mica-Based Glass-Ceramic with 4 Mol% of Fluorapatite

2014 ◽  
Vol 1077 ◽  
pp. 8-13
Author(s):  
Bai Jia ◽  
Chaysuwan Duangrudee
Keyword(s):  
Vickers Hardness ◽  
Glass Ceramic ◽  
Crystallization Temperature ◽  
Bending Strength ◽  
Crystalline Phases ◽  
Three Point Bending ◽  
Heat Treated ◽  
Dental Applications ◽  
Glass Heat ◽  
Natural Tooth

SiO2, Al2O3, MgO, MgF2, SrCO3, CaCO3, CaF2 and P2O5 were used to prepare machinable glass-ceramic with 4 mol% of fluorapatite for restorative dental applications. XRD showed that the glass heat treated at 792°C (the first crystallization temperature+20°C) for 6 hours consisted of calcium-mica, fluorapatite, strontium apatite, anorthite, forsterite, fluorite and stishovite crystalline phases. The microstructures of the resultant glass-ceramic, observed by SEM, were found to exhibit plate-like mica crystals and many tabular particles embedded in the mica phases. The particles, determined by EDS, were rich in calcium. The three-point bending strength (158 MPa) closely matched that of nature tooth. Average Vickers hardness of the received glass-ceramic (2.6 GPa) was lower than that of natural tooth.

Mutual transformation between crystalline phases and dielectric properties of coordination polymers with the formula [Cd(N-methylimidazole)2(H2O)x(glutarate)]·nH2O (x = 0 or 1; n = 0 or 4)

CrystEngComm ◽  
2014 ◽  
Vol 16 (42) ◽  
pp. 9857-9865 ◽  
Author(s):  
Chen Xue ◽  
Heng Xu ◽  
Rong-Yi Huang ◽  
Xiao-Ming Ren
Keyword(s):  
Dielectric Properties ◽  
Coordination Polymers ◽  
Crystallization Temperature ◽  
Mutual Transformation ◽  
Crystalline Phases

Two pseudo-polymorphs obtained through controlling the crystallization temperature are mutual transformable via absorbing or losing water.

On the Formation of AlPO4-Based Molecular-Sieves in the Presence of Cyclohexylamine

1993 ◽  
Vol 46 (2) ◽  
pp. 171 ◽  
Author(s):  
J Batista ◽  
V Kaucic ◽  
S Hocevar
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Crystallization Temperature ◽  
Molecular Sieves ◽  
Chemical Compositions ◽  
Crystalline Phases ◽  
Complete Breakdown ◽  
Solid Phases ◽  
Synthesized Materials

The hydrothermal synthesis of the AlPO4-17, SAPO-44, MnAPSO-44 and intermediate solid phases [samples (APO)N, (APSO)N and Mn (APSO)N] in the presence of cyclohexylamine (cha) is described. (APO)N, (APSO)N and Mn (APSO)N represent unknown, layer-type, crystalline phases with different chemical compositions. These phases are predominantly formed at a high cha concentration and low crystallization temperature. All synthesized materials contain protonated cha in their structure, but only in AlPO4-17, (APO)N,(APSO)N and Mn (APSO)N is the -OH group also found. The calcination of the unknown phases leads to the loss of crystallinity and causes a complete breakdown of the crystal structure above 270°C.

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