Preparation of an electrochemical sensor for measuring the silicon content in molten iron

摘要

A silicon sensor for measuring the silicon content in molten iron that included a new membrane electrode was synthesized by coating a slurry of CaF_2, SiO_2 and 5% Polyvinyl alcohol (PVA) onto the surface of a ZrO_2 (MgO) solid electrolyte tube, followed by sintering in a high purity Ar atmosphere. The influences of the preparation conditions, such as the chemical composition, solid (CaF_2 + SiO_2 powder) to liquid (5% PVA solution) ratio and sintering temperature, on the coating layer adhesive properties, active ingredients and detection performance of the formed auxiliary electrode layer were systematically investigated. It is indicated that the synthesized coating layer showed strong adhesive properties and the main active ingredients were SiO_2 (ZrSiO_4) solid particles-CaOMgO·2SiO_2 solid solution under the optimum preparation conditions. The as-prepared silicon sensor, which was used to detect the silicon content in molten iron at 1450℃, exhibited superior performance. When the silicon content ranged from 0.5 to 1.5% in liquid iron, the testing result from the silicon sensor with a response time of 15 s and steady time greater than 30 s agreed well with the values from the chemical analysis method.