Abstract
A focused argon ion laser beam (514.5 nm) has been used to induce etching of manganese-zinc-ferrite ceramics in aqueous KOH solutions. In the absence of the laser beam the etching process did not take place even at the boiling point of the selected etchant. For KOH concentration above 2N, bubble-free etching took place in the presence of the laser beam. Within the range of 2~8N for KOH concentration, the depth of the etched grooves increased with increasing laser power, decreasing scan speed, and increasing KOH concentration. Evidence of decreasing average etch rate due to mass transport limitation was observed under low KOH concentration, high laser power, and low scan speed conditions. The width of the etched grooves increased with increasing laser power, but was relatively insensitive to the scan speed and the KOH concentration. The experimental findings of the laser-assisted etching of Mn-Zn-ferrite can be qualitatively interpreted by a thermally activated reaction mechanism: formation at and above a threshold temperature of an active chemical environment on the surface for the initiation of the etching process; more concentrated etchant allows more abundant supply of the reactive species and requires less heat input to reach the active state. Etching of ferrite occurs as a result of the reaction between the active etchant (possibly fused KOH) and either the solid or the molten ferrite, depending on the laser power. The etching process generates soluble product species and the profiles of the etched patterns are strongly influenced by the mass transport characteristics of the etching system. A mathematical model for the surface temperature distribution, which takes into account heat loss into the liquid, is also presented. © 1989, The Electrochemical Society, Inc. All rights reserved.