Study On Measurement Technology Of Hydrogen Content In Molten Aluminum With Concentration Difference Cell Method

Aluminum alloys are widely used in many fields because of their advantages of light weight,high strength and good electrical conductivity.In order to ensure the good performance of aluminum alloy castings,the gas content in aluminum liquid must be strictly controlled.Hydrogen is the only soluble gas in the aluminum melt,so it is important to monitor the hydrogen content in molten aluminum.Therefore,a variety of hydrogen determination methods have been developed both at home and abroad.The concentration cell method can monitor the hydrogen content in molten aluminum on line,so it has important research significance.Chinese scholars have begun to develop a hydrogen cell sensor based on cerium acid as matrix and zirconium acid as the base of concentration cell.but the application in industrial environment is rare at the moment.Domestic in hydrogen concentration cell sensor has already begun to develop proton conductors based on SrCeO₃ and BaCeO₃.But the concentration difference cell hydrogen probe has not yet achieved.abroad has been designed the hydrogen probe in the actual production.it is necessary for us to design the the concentration difference cell hydrogen probe.This project designs and makes the concentration cell hydrogen analyzer probe.In this study,a solid electrolyte tube was fabricated by CaZr_0.9In_0.1O_3-?with In.The subject uses Pt and Pt wire as the electrode.the Pt slurry is coated in the CaZr_0.9In_0.1O_3-?electrolytic tube,The Pt wire is wound at the electrolytic tube and is used as an electrode.The sintered electrolyte tube has excellent proton conductivity,and make the A type sensor after introducing the internal hydrogen partial pressure gas.In this paper,zirconium hydride was used as the reference electrode.Hydrogen absorption reaction is carried out under the hydrogen atmosphere by the zirconium in the electrolyte tube,The hydrogen gas released by zirconium hydride is used as the reference pole after the seal of the electrolyte tube is sealed.Hydrogen sensor sealing and hydrogen absorption reaction happened at the same time,we choice the NaCO₃,SiO₂,B₂O₃ as the raw material of the sealed glass.We would obtain a sealed glass with good sealing properties when cooled at 870?,it is the type B sensors.In order to improve the accuracy of sensor measurement,through the experiment on the two types of sensors,the sensor can more close to the actual value when measuring hydrogen,then we get the relationship between hydrogen partial partial pressure and temperature was obtained:lnP_???=-25078.2/T+32.9.The sensor is sealed at the end of the probe and is threaded with the probe main body,thereby saving the cost of updating the probe.The function of the probe is to collect temperature signals and electromotive force signals,and the two signals are respectively implemented by two circuits.After testing,the probe conforms to Nernst's law,and can measure the hydrogen content in the aluminum liquid accurately.Type A sensor probe measured hydrogen content in the gas accurately.B type sensor probe can be able to measure hydrogen content in liquid aluminum or gas accurately.