Surface free energy of nickel and stainless steel at temperatures above the melting point

1976 ◽  
Vol 11 (2) ◽  
pp. 224-230 ◽  
Author(s):  
U. M. Ahmad ◽  
L. E. Murr
Keyword(s):  
Stainless Steel ◽  
Free Energy ◽  
Melting Point ◽  
Surface Free Energy

New Aspects on Melting and Annealing Behaviour of Polymers

1978 ◽  
Vol 33 (12) ◽  
pp. 1472-1483
Author(s):  
J. Haase ◽  
S. Köhler ◽  
R. Hosemann
Keyword(s):  
Free Energy ◽  
Melting Point ◽  
Partial Melting ◽  
Surface Free Energy ◽  
Average Crystallite Size ◽  
X Ray ◽  
State Diffusion ◽  
Crystallite Sizes ◽  
Dta Curves ◽  
Dta Curve

Abstract Poly( 1-butene) (PB) crystallizes from the melt in a metastable modification II (mod. II) which slowly transforms into the stable modification I (mod. I). X-ray wide angle (WAXS) measurements show that in mod. I the size of the microparacrystallites (mPC’s) in chain direction, D̅012, the polydispersity gD of the size distribution in this direction, the lateral size D̅110 and the paracrystalline g110-value do not change upon annealing at temperatures up to the melting point. In mod. II, however, the sizes D̅012 and D̅110 increase with rising annealing temperature Tann. At a certain Tann and beyond a sufficient annealing time tann the size D̅012 shows a logarithmic increase with tann whereas D̅110 stays constant. Measuring melting points Tm of mod. I-samples, we found a linear relationship between Tm and 1/D̅012 according to the Thomson equation resulting in a melting point for an infinite crystal of Tm∞ (mod. I) = 139 °C and a mean surface free energy of σ̅e′̅ (mod. I) = 47 ergs/cm2. T m versus 1/D̅012 for mod. II is linear only for high D̅012-values yielding Tm∞ (mod. II) = 130 °C and σ̅e′̅ (mod. II) = 29 ergs/cm2. However, a partially molten and afterwards quenched sample of mod. I with small mPC’s shows a mod. II-peak which fits the straight line extrapolated from the large D̅012-values. The DTA curves of mod. I-samples shift to higher temperatures and narrow after annealing although the crystallite sizes and size distributions remain as well as the paracrystalline distortions the same. X-ray and DTA measurements eliminate therefore surface premelting and selective melting of thinner and more distorted lamellae in mod. I. Upon annealing this modification, σ̅e′̅ decreases from 47 ergs/cm2 to 15 ergs/cm2 and the distribution of σe′ narrows. The latter determines predominantly the shape of the DTA curve. The Thomson equation therefore, applied to different samples links only the average crystallite size and the mean surface free energy with the melting point. In mod. I partial melting occurs independent of D̅012 and starts mainly at those mPC’s which have exposed surfaces with high σe′. At the beginning only single mPC’s or single lamellae melt, but no bundles of lamellae. The logarithmic increase of D̅012 in mod. II with tann can be explained according to Hosemann’s model of “lateral melting” also by a partial melting of mPC’s with unprotected lateral surfaces and by a consecutive solid state diffusion of their chainsegments into the two mPC’s adjacent in chain direction, increasing the averaged sizes of the long period and the lamellae thickness.

Smectic A-Smectic B interface : faceting and surface free energy measurement

1989 ◽  
Vol 50 (24) ◽  
pp. 3527-3534 ◽  
Author(s):  
P. Oswald ◽  
F. Melo ◽  
C. Germain
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Energy Measurement ◽  
Smectic A

Examination of the lubricant storing and releasing ability of thermally sprayed surfaces

2011 ◽  
Vol 2 (2) ◽  
pp. 101-105
Author(s):  
L. Fazekas ◽  
Z. S. Tiba ◽  
G. Kalácska
Keyword(s):  
Free Energy ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Essential Role ◽  
Index Number ◽  
Adhesion Ability ◽  
Thermally Sprayed ◽  
Proper Operation

Abstract The lubricant storing and releasing ability of the thermally sprayed surfaces plays an essential role in the proper operation of the components. In the case of porous sprayed surfaces the lubricant storing and releasing ability depends mainly on porosity and the surface energy (adhesion susceptibility). The adhesion ability can also be expressed indirectly with an index number that is by determining the surface free energy.

UGIMA 4404, UGIMA 316L

Alloy Digest ◽  
1998 ◽  
Vol 47 (12) ◽  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Melting Point ◽  
Physical Properties ◽  
Melting Process ◽  
Heat Treating ◽  
Aisi 316L

Abstract UGIMA 4404 (UGIMA 316L) is identical to UGINE 4404 (AISI 316L) in analysis, corrosion resistance, mechanical properties, and forging and welding ability, but not with respect to machinability. A specific melting process creates inclusions of malleable oxides with a low melting point. The inclusions improve machinability by 20-30% compared with AISI 316L (1.4404) stainless steel. This datasheet provides information on composition and physical properties. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SS-735. Producer or source: Ugine-Savoie.

Molecular orientation of liquid aliphatic hydrocarbons on the surface and at the interface with water

1989 ◽  
Vol 54 (12) ◽  
pp. 3171-3186 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Molecular Orientation ◽  
Phase Changes ◽  
Aliphatic Hydrocarbons ◽  
Water Molecules ◽  
Free Energies ◽  
Dispersion Component ◽  
System Water ◽  
Orientation Of Molecules

The validity of the Fowkes theory for the interaction of dispersion forces at interfaces was inspected for the system water-aliphatic hydrocarbons with 5 to 16 C atoms. The obtained results lead to the conclusion that the hydrocarbon molecules cannot lie in a parallel position or be randomly arranged on the surface but that orientation of molecules increases there the ration of CH3 to CH2 groups with respect to that in the bulk. This ratio is changed at the interface with water so that the surface free energy of the hydrocarbon, γH, rises to a higher value, γ’H, which is effective in the interaction with water molecules. Not only the orientation of molecules depends on the adjoining phase and on the temperature but also the density of hydrocarbons on the surface of the liquid phase changes. It is lower than in the bulk and at the interface with water. Moreover, the volume occupied by the CH3 group increases on the surface more than that of the CH2 group. The dispersion component of the surface free energy of water, γdW = 19.09 mJ/m2, the non-dispersion component, γnW = 53.66 mJ/m2, and the surface free energies of the CH2 and CH3 groups, γ(CH2) = 32.94 mJ/m2 and γ(CH3) = 15.87 mJ/m2, were determined at 20 °C. The dependence of these values on the temperature in the range 15-40 °C was also evaluated.

scholarly journals Effect of calcination temperature on neptunium dioxide microstructure and dissolution

2020 ◽  
Vol 7 (12) ◽  
pp. 3869-3876
Author(s):  
Kathryn M. Peruski ◽  
Brian A. Powell
Keyword(s):  
Grain Size ◽  
Free Energy ◽  
Surface Area ◽  
Calcination Temperature ◽  
Surface Free Energy ◽  
Neptunium Dioxide

Solubility of neptunium dioxide decreases as microstructure grain size increases, likely due to decreasing surface free energy and surface area.

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