In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

Thermal Analysis of Grinding

As the size of electronic and mechanical devices shrinks to the nanometre regime, performance begins to be dominated by surface forces. For example, friction, wear and adhesion are known to be central challenges in the design of reliable micro- and nano-electromechanical systems (MEMS/NEMS). Because of the complexity of the physical and chemical mechanisms underlying atomic-level tribology, it is still not possible to accurately and reliably predict the response when two surfaces come into contact at the nanoscale. Fundamental scientific studies are the means by which these insights may be gained. We review recent advances in the experimental, theoretical and computational studies of nanotribology. In particular, we focus on the latest developments in atomic force microscopy and molecular dynamics simulations and their application to the study of single-asperity contact.

/pdf/recent-advances-in-single-asperity-nanotribology-1bex87lgbi.pdf

Recent advances in single-asperity nanotribology

Ultra-precision grinding is primarily used to generate high quality and functional parts usually made from hard and difficult to machine materials. The objective of ultra-precision grinding is to generate parts with high surface finish, high form accuracy and surface integrity for the electronic and optical industries as well as for astronomical applications. This keynote paper introduces general aspects of ultra-precision grinding techniques and point out the essential features of ultra-precision grinding. In particular, the keynote paper reviews the state-of-the-art regarding applied grinding tools, ultra-precision machine tools and grinding processes. Finally, selected examples of advanced ultra-precision grinding processes are presented.

Ultra-precision grinding

Design and application of magnetostrictive materials

Defect-free fabrication for single crystal silicon substrate by chemo-mechanical grinding

Several molecular dynamics simulations are performed, in order to clarify the atomic-scale stick-slip phenomenon which is commonly observed in the surface measurement using an atomic fine microscope (AFM). In the molecular dynamics simulations, a specimen and a slider are assumed to consist of monocrystalline copper and rigid diamond, respectively, and a Morse potential is postulated between a pair of atoms. Atomic behavior in a plane corresponding to the (111) crystal plane is simulated, dealing with a planar strain problem where the effect of the three-dimensional interatomic force and the spring constant of the AFM cantilever are also taken into consideration. Influence of the cantilever stiffness and dynamics of the specimen surface atoms on the atomic-scale stick-slip phenomenon are investigated. The simulation confirms that the atomic-scale stick-slip phenomenon can be expressed by a molecular dynamics simulation and that the stick-slip phenomenon of the surface atoms of the specimen affects the stick-slip phenomenon of the spring force. These results indicate that molecular dynamics simulation has an advantage in deciding the spring constant of cantilevers.

https://iopscience.iop.org/article/10.1088/0957-4484/9/2/014/pdf

Molecular dynamics simulation of friction on the atomic scale

Simulation and experimental analysis of super high-speed grinding of ductile material

Discussed in this report are the material removal mechanisms below and beyond its static plastic wave propagation rate. The ductile materials are expected to behave elastically throughout most of its strength range, and apparently become “brittle” as cutting speed exceeds its static propagation rate. This behavior leads to a significant reduction in plastic flow/deformation and work hardening during the machining process, so as possibly to improve the total surface integrity. In order to achieve such high speed machining, a super high speed grinding machine has been newly developed by using the latest technologies, which is able to attain 600 m/s peripheral speed and 10 nm/step positioning accuracy. This study particularly investigates the cutting speed effect on the typical ductile metals of pure aluminum (A1199) and aluminum alloy (A5056), and reveals that static propagation rate is a breaking point from where the removal mechanism is different.

Material removal mechanism beyond plastic wave propagation rate

Sponsored by New Energy and Industrial Technology Development Organization (NEDO) and the Ministry of Education, Science and Culture (MESC) of Japan, this project has developed an advanced machining system for ∅ 300 mm silicon wafer, using fixed abrasive instead of conventional free slurry, to provide a totally integrated solution for achieving the surface roughness R a R y

Hiroshi Eda

Papers

Defect-free fabrication for single crystal silicon substrate by chemo-mechanical grinding

Molecular dynamics simulation of friction on the atomic scale

Simulation and experimental analysis of super high-speed grinding of ductile material

Material removal mechanism beyond plastic wave propagation rate

Three-dimensional kinematical analyses for surface grinding of large scale substrate