The ability of using the cavitation phenomenon as a tool to modify the surface characteristics in micro- and in nano-level

Abstract

The aim of this paper is to investigate the possible application of the cavitation phenomenon as efficient method to modify the surface properties (e.g. the surface roughness) in the nano and micro levels. Aluminum alloy (AlSiMg) specimens were subjected to high speed submerged cavitating jets under various working conditions, for short time periods between 15 and 30 seconds. The force generated by the cavitating jet is employed to modify the surface roughness of the specimen. The target surface was analyzed with optical microscopy, white light interferometry, atomic force microscopy (AFM) and also with electrostatic force microscopy (EFM). The results show the possibility to use the cavitation bubbles as a nanofabrication method e.g. for shotless surface peening. With AFM, the deformation mechanism and the formation of planar or wavy slip were also investigated. EFM shows that the changes in the surface roughness also have a strong influence on the electrostatic field above a biased sample.

BME VIK Annual Research Report on Electrical Engineering and Computer Science 2016

“…We demonstrated that cavitation could be utilized as a tool to purposefully modify the surface characteristics of these materials (in other worlds increase their surface roughness in a controllable fashion) in the micro-and nano-levels [52,53]. The relation between the behavior of the cavitation erosion process and the geometrical parameters of the generator (e.g.…”

Study and analysis of the cavitating and non-cavitating jets - Part two: Parameters controlling the jet action and a new formula for cavitation number calculation

“…On the other hand, the destructive power of cavitation can be deliberately used to modify and enhance the surface or mechanical properties of target materials, e. g. for cleaning, cutting or peening with relatively low energy consumption. Cavitating water jets have received much attention also in the environmental industry for the possibility to use them for the decomposition of toxic substances and the water treatment [1][2][3][4][5][6][7][8].…”

“…Until now many experimental --------------studies on cavitating water jets have been made concerning jet driven pressure, shape and size of a nozzle, cavitation number, etc. [1,2,[5][6][7]. However, the structure of the cavitating jet and the behavior of the unsteady cavitation bubbles are still in question, mostly due to the difficulty to observe the interior of cavitating flows [9][10][11][12][13].…”

Study and analysis of the cavitating and non-cavitating jets - Part one: Parameters controlling force, power and the jet behavior

“…The optimization of the working conditions such as geometrical and hydrodynamical conditions is an important process to intensively utilize the jet destructive power (cavitation destructive power). The cavitating water jets have been widely utilized for cleaning of complicated mechanical products, cutting of solid materials, and surface improvement of materials in various industry fields [1][2][3][4]. It has received much attention also in the environmental industry for the possibility of applications to the decomposition of toxic substances and purification of sewage [5][6][7][8][9].…”