Study of adhesion-active surface structures in P6M5 high-speed steel

2018 ◽  
Vol 84 (12) ◽  
pp. 40-44 ◽  
Author(s):  
V. A. Kim ◽  
Ch. F. Yakubov ◽  
E. V. Shchelkunov ◽  
E. V. Samar
Keyword(s):  
Free Energy ◽  
Surface Energy ◽  
Metal Cutting ◽  
Chemical Potential ◽  
High Surface ◽  
Active Surface ◽  
Surface Structures ◽  
Active Centers ◽  
Structural Formation ◽  
High Surface Energy

Adhesive processes are the main reason for wear of the metal-cutting tool. Adhesion-active surface structures (micro and meso-scale zones with increased density of defects having a crystal structure and high surface energy) can be identified by treating the surface with reactants by analogy with etching of a metalgraphic shlif. The level of free energy of the structural formation was estimated by the degree of darkening (dark gray color intensity) of the microstructure revealed by etching. The degree of darkening can be described and rankes quantitatively using color segmentation. Most specialized programs for metallographic image processing contain similar algorithm. The images were studied using the following indices of the structural arrangement of adhesion-active centers: the density of microstructural objects with a high value of the free energy, their relative surface area and dark gray color coefficient. A high value of the coefficient corresponds to the larger chemical potential. A comparative analysis of the character of distribution of adhesion-active zones in the surface structures of the crude and tempered P6M5 highspeed steel revealed that tempered structure contains more structural elements with high free energy (or chemical potential). Their distribution on the surface forms local zones of increased hardness, possessing high surface energy, as well as adhesion-active centers acting as potential foci for the formation of strong islet growths or zones of formation of stable adsorption films.

scholarly journals Morphology Effect on the Kinetic Parameters and Surface Thermodynamic Properties of Ag3PO4Micro-/Nanocrystals

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Zai-Yin Huang ◽  
Xing-Xing Li ◽  
Zuo-Jiao Liu ◽  
Liang-Ming He ◽  
Xue-Cai Tan
Keyword(s):  
Activation Energy ◽  
Free Energy ◽  
Surface Energy ◽  
Thermodynamic Properties ◽  
High Surface ◽  
Surface Energies ◽  
Lower Activation ◽  
High Surface Energy ◽  
Energy Activation ◽  
Lower Activation Energy

Considerable effort has been exerted using theoretical calculations to determine solid surface energies. Nanomaterials with high surface energy depending on morphology and size exhibit enhanced reactivity. Thus, investigating the effects of morphology, size, and nanostructure on the surface energies and kinetics of nanomaterials is important. This study determined the surface energies of silver phosphate (Ag3PO4) micro-/nanocrystals and their kinetic parameters when reacting with HNO3by using microcalorimetry. This study also discussed rationally combined thermochemical cycle, transition state theory, basic theory of chemical thermodynamics with thermokinetic principle, morphology dependence of reaction kinetics, and surface thermodynamic properties. Results show that the molar surface enthalpy, molar surface entropy, molar surface Gibbs free energy, and molar surface energy of cubic Ag3PO4micro-/nanocrystals are larger than those of rhombic dodecahedral Ag3PO4micro-/nanocrystals. Compared with rhombic dodecahedral Ag3PO4, cubic Ag3PO4with high surface energy exhibits higher reaction rate and lower activation energy, activation Gibbs free energy, activation enthalpy, and activation entropy. These results indicate that cubic Ag3PO4micro-/nanocrystals can overcome small energy barrier faster than rhombic dodecahedral Ag3PO4micro-/nanocrystals and thus require lower activation energy.

Bio-mimicking hybrid polymer architectures as adhesion promoters for low and high surface energy substrates

2021 ◽  
Author(s):  
Monisha Baby ◽  
Vijayalakshmi K. Periya ◽  
Bhuvaneshwari Soundiraraju ◽  
Nisha Balachandran ◽  
Suchithra Cheriyan ◽  
...  
Keyword(s):  
Surface Energy ◽  
High Surface ◽  
Hybrid Polymer ◽  
Energy Substrates ◽  
Adhesion Promoters ◽  
Polymer Architectures ◽  
High Surface Energy

Passivation of High-Surface-Energy Sites of Milled Ibuprofen Crystals via Dry Coating for Reduced Cohesion and Improved Flowability

2013 ◽  
Vol 102 (7) ◽  
pp. 2282-2296 ◽  
Author(s):  
Xi Han ◽  
Laila Jallo ◽  
Daniel To ◽  
Chinmay Ghoroi ◽  
Rajesh Davé
Keyword(s):  
Surface Energy ◽  
High Surface ◽  
Dry Coating ◽  
High Surface Energy

scholarly journals A Highly Active Oxygen Evolution Catalyst for Lithium-Oxygen Batteries Enabled by High-Surface-Energy Facets

Joule ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 1511-1521 ◽  
Author(s):  
Nien-Chu Lai ◽  
Guangtao Cong ◽  
Zhuojian Liang ◽  
Yi-Chun Lu
Keyword(s):  
Surface Energy ◽  
Oxygen Evolution ◽  
High Surface ◽  
Active Oxygen ◽  
Highly Active ◽  
High Surface Energy ◽  
Lithium Oxygen Batteries

Electrochemical supermolecular templating of mesoporous Rh films

Nanoscale ◽  
2019 ◽  
Vol 11 (22) ◽  
pp. 10581-10588 ◽  
Author(s):  
Kenya Kani ◽  
Jeonghun Kim ◽  
Bo Jiang ◽  
Md. Shahriar A. Hossain ◽  
Yoshio Bando ◽  
...  
Keyword(s):  
Surface Energy ◽  
High Surface ◽  
Soft Templating ◽  
High Surface Energy

Making mesoporous rhodium (Rh) with traditional soft-templating methods is challenging because Rh has a high surface energy compared to other metals.

scholarly journals Magnetic Properties, Adhesion, and Nanomechanical Property of Co40Fe40W20 Films on Si (100) Substrate

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wen-Jen Liu ◽  
Yung-Huang Chang ◽  
Sin-Liang Ou ◽  
Yuan-Tsung Chen ◽  
You-Cheng Liang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Surface Energy ◽  
Resonance Frequency ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
High Surface ◽  
Contact Angles ◽  
Thickness Effect ◽  
High Coercivity ◽  
High Surface Energy

In this study, a Co40Fe40W20 alloy was sputtered onto Si (100) with thicknesses (tf) ranging from 18 to 90 nm, and the corresponding structure, magnetic properties, adhesive characteristics, and nanomechanical properties were investigated. X-ray diffraction (XRD) patterns of the Co40Fe40W20 films demonstrated a significant crystalline body-centered cubic (BCC) CoFe (110) structure when the thickness was 42 nm, and an amorphous status was shown when the thickness was 18 nm, 30 nm, 60 nm, and 90 nm. The saturation magnetization (Ms) showed a saturated trend as tf was increased. Moreover, the coercivity (Hc) showed a minimum 1.65 Oe with 30 nm. Hc was smaller than 4.5 Oe owing to the small grain size distribution and amorphous structure, indicating that the Co40Fe40W20 film had soft magnetism. The low-frequency alternating current magnetic susceptibility (χac) decreased as the frequency was increased. The χac revealed a thickness effect when greater thicknesses had a large χac. The maximum χac and optimal resonance frequency (fres) of Co40Fe40W20 were investigated. The maximum χac indicated the spin sensitivity and was maximized at the optimal resonance frequency. The 90 mm thickness had the highest χac 0.18 value at an fres of 50 Hz. The contact angles of the Co40Fe40W20 films are less than 90°, which indicated that the film had a good wetting effect and hydrophilicity. The surface energy was correlated with the adhesion and displayed a concave-down trend. CoFeW films can be used as a seed or buffer layer; therefore, the surface energy and adhesion are very important. The highest surface energy was 30.12 mJ/mm2 at 42 nm and demonstrated high adhesion. High surface energy has corresponding strong adhesive performance. The increased surface roughness can induce domain wall pinning effect and high surface energy, causing a high coercivity and strong adhesion. The increase of hardness and Young’s modulus could be reasonably inferred from the thinner CoFeW films. The hardness and Young’s modulus of CoFeW films are also displayed to saturated tendency when increasing thickness.

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