The Anode Layer in the Electrolytic Polishing of Copper

Abstract

The viscosities and electrical conductivities of solutions of CuHPO4 in aqueous phosphoric acid and phosphoric acid‐glycerol‐ethylene glycol mixtures were measured with a view to investigating the anode layer formed when copper is electrolytically polished in these solutions. Dissolved copper was found to raise the viscosity considerably, the increase being greater in the mixtures with glycol and glycerol than in phosphoric acid alone. The copper concentration near the anode during electrolysis was measured, and current‐voltage relationships were studied using a rotating copper anode. The effective thickness of the anode layer was estimated to be about 10−3 cm.

The Influence of a Surface Active Agent on the Electropolishing of Copper

“…The anode film is a thin layer of solid material or adsorbed atoms or molecules (4,5). The polishing action is considered (8)(9)(10)(11) to be due to a diffusion-controlled anodic solution process being set up through the anode layer and film.…”

“…It is known (4,5,8,9) that the anodic surface finish obtained in an electropolishing bath depends on the characteristics of the anode layer and the 1 Manuscript received July 16, 1954. 479 anode surface film.…”

Buffered electropolishing parameters on niobium sheet

“…Oppositely, we thought it represented that the flow rate of electrolyte was just fast enough to carry the complex compound of the niobium oxide layer around the niobium sample surface away. That fast flow rate was necessary especially to the high viscosity BEP acid solution because the high viscosity would make the anodic compound oxide layer [13][14][15] have a larger voltage drop as compared with that of a common acid solution. So, the faster electrolyte flowed, the more external complex composition of the compound oxide layer could be carried away, leading to an enhanced electric field strength in the compact layer near the anode surface.…”

The Electrolytic Polishing of Amphoteric Metals

“…If the electrode is made the anode, metal ions are liberated into this surface layer compartment of the solution. Chemical reactions or ionic associations may follow, producing an increased concentration of metal ion compounds in the layer, even to the extent, in some cases, of exceeding the solubility of some soluble salt (17). The composition of the layer and the exact nature of the compounds thus formed critically determine such electrical and mechanical properties of the layer as: mechanical strength, or extent and nature of crossbonding; the viscosity of the layer; the conductivity and diffusion coefficient of charged and uncharged particles in the layer.…”