In this paper, a pH microprobe technique was developed to measure in situ the pH value on the cathode/solution interface, and iridium oxide was used as a pH sensitive material which is of a good response behavior in the measured solutions. During electrodeposition process of bioceramic coatings of calcium phosphates, the interfacial pH change, for example, was first measured. The experimental results indicated that the pH value on the cathode/solution interface first jumped to a maximum, then slowly decreased with the increase of the electrodeposition time. The interfacial pH value was increased with the applied current density or cathode overpotential.
