Study On Infrared Radiation Characteristics And Application Of Transition Metal Doped Copper-manganese Spinel

As the core competitiveness of porous energy-saving ceramic industry,infrared radiation materials will promote the energy saving and emission reduction of industrial kilns,boilers and gas stoves,which is of far-reaching significance to the efficient use of industrial energy and environmental protection production.In this paper,infrared radiation substrates were prepared by solid phase sintering and microwave sintering,and the effects of raw material formula,process parameters and different transition metal doping on the infrared radiation properties of the substrates were investigated.The infrared radiation coating with high thermal shock resistance was prepared on cordierite substrate by selecting high infrared emissivity substrate and adding proper amount of adhesive,defoaming agent and anti-settling agent.The phase,surface morphology,adhesion and infrared radiation properties of the coating were studied in detail.CuMn₂O₄ spinel infrared radiation base material was synthesized by solid state synthesis.Using chemically pure CuO 30wt%and MnO₂ 70wt%as raw materials,the infrared emissivity of CuMn₂O₄ spinel base material was as high as 0.92 when it was heated to 1050?in horse boiling furnace and kept for 2 hours.The infrared radiation base material is formed by the combination of solid phase and microwave firing.The situation of microwave synthesis of infrared radiation substrate is complicated.Using COMSOL Multiphysics simulation software to analyze and experiment,it is found that the performance of infrared substrate synthesized by 6 KW power using time-sharing switching microwave source is the best.Compared with the two sintering methods of microwave and solid phase,the results show that the spinel content in the base material synthesized by microwave is high and the particles are small and easy to grind,the infrared emissivity of the base material powder is higher than that of the solid phase sintering product,and the difference of the highest infrared emissivity is 0.02.The highest infrared emissivity of the base material sintered by microwave is 0.96.The effect of transition metals Ni,Co and Cr on the infrared radiation properties of the base material.The experimental results show that the Co^2+/3+of the doped Co can not only enter the spinel tetrahedral structure to replace Cu²⁺but also change the octahedral structure at high temperature,and the infrared radiation properties change continuously with the increase of doping amount.When the doping amount of Co₂O₃ is 10wt%,the infrared emissivity is 0.94;The incorporation of Cr leads to the existence of Mn₃O₄,in the product and the low infrared emissivity of Mn₃O₄ will lead to the decrease of the overall infrared emissivity of the substrate.When the amount of Cr₂O₃ doping is 10wt%,the infrared emissivity of the substrate is 0.95;Ni doping can greatly improve the infrared emissivity of the substrate.Ni²⁺replaces Cu²⁺in CuMn₂O₄ tetrahedron to form mixed spinel.When the amount of NiO doping is 15wt%,the infrared emissivity is 0.96.When silica sol,PVA and organosilicon defoamer are added to the high infrared radiation base material,the maximum thermal shock resistance times of the coating is 55 times when the solid-liquid ratio is 1:1.2,the defoamer is 1wt%,the silica sol/10wt%PVA ratio is 0.7 0.3,and the sintering temperature is 1000?.The coating is tested according to the national standard"GB/T 9286-1998".The adhesion of the coating is the second grade standard on the metal sheet and the first grade standard on the cordierite ceramic sheet.The coating phase is mainly composed of?CuNi?Mn₂O₄ spinel.With the repeated use of the coating,the content of spinel in the coating decreases slightly and there will be micropores and microcracks.The infrared emissivity of the coating is 0.96 at room temperature and 0.89 at 750?.