| The energy issue has increasingly become a major issue that has attracted much attention in the process of social development.The development and utilization of nuclear energy conforms to the concept of green development and sustainable development in today's society,so it has attracted much attention.Zirconium alloys are often used as cladding materials for fuels because of their relatively low thermal neutron absorption cross-section and better toughness under radiation conditions.After the Fukushima nuclear power plant accident in 2011,fault-tolerant materials that can improve the safety of nuclear power plants have received widespread attention and are in urgent need of research and development.Preparing coatings on the surface of zirconium alloys is an effective method.The current research on zirconium alloy protective coatings is mainly to develop materials with better oxidation and corrosion resistance.This article comprehensively compares the electrochemical corrosion resistance and high temperature corrosion resistance of several commonly used zirconium alloy cladding coatings,which has important scientific significance and significant engineering practical application significance for the safe use of zirconium alloys.In this paper,the method of arc ion plating is used to prepare TiN coating,Ti Al N coating,Ti Al coating and CrAl coating on the surface of Zr-4 alloy.The electrochemical corrosion resistance and high temperature corrosion resistance of the four coatings are studied respectively.According to the experimental results,the following conclusions are drawn:(1)On the surface of Zr-4 alloy,TiN coating with(111)crystal plane orientation and typical face-centered cubic structure is prepared,Ti Al N coating with(200)crystal plane orientation as main structure,and Ti Al with multiple phase structures coexisting And CrAl metal coating.(2)Through the immersion corrosion experiment,it can be found that the corrosion resistance of the four coatings in the neutral Na Cl solution is relatively good,and the phase structure of the four coatings has not changed significantly.The corrosion resistance of the four coatings in the KOH solution is better than that of the Zr alloy substrate.The surface of both Ti Al and CrAl metal coatings has been significantly oxidized.The surface of the Ti Al N coating is broken,and the surface structure of the TiN coating is maintained.Complete,with the best corrosion resistance.In the electrochemical experiments,the protective effects of the four coatings on the Zr alloy substrate are relatively obvious.The TiN coating in the neutral Na Cl solution and the KOH solution shows the best corrosion resistance.The electrochemical resistance of the ceramic coating Corrosion is better than metal coating as a whole.(3)Through high-temperature air oxidation experiments,it is found that the oxidation resistance of Ti Al and CrAl metal coatings is significantly better than that of TiN and Ti Al N ceramic coatings.The working temperature of TiN coating is below600?,and the working temperature of Ti Al N coating should be set at Around 800?,the working temperature of Ti Al coating can reach 800?-1000?,and CrAl coating still has good oxidation resistance at 1000?.(4)Through the high temperature steam oxidation experiment,it is found that the CrAl coating will produce a dense Al2O3 and Cr2O3 oxide film during oxidation,which hinders the mutual diffusion of oxygen and coating elements,so the high temperature water vapor oxidation resistance of the CrAl coating should be obvious Better than Ti Al N coating.(5)A comprehensive comparison of the oxidation resistance of the two ceramic coatings and the two metal coatings shows that the ceramic coating represented by TiN has better corrosion resistance when an aqueous solution at room temperature is used as the corrosive medium;in the high temperature oxidation process,CrAl coating The oxidation resistance of the metal coating represented by the layer is significantly better than that of the ceramic coating.Based on this result,it is feasible to design a composite cladding coating of metal and ceramic to cope with more complex working environments. |
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