| The high radiation coating is coated on the surface lining or refractory,raised the non-steady-state radiation heat transfer rate,and it have achieved good energy saving effect on the hot stove of heat accumulation type and other equipment in the steel industry.In order to develop several infrared radiant coating with excellent performance,This experiment used high temperature sintering method,respectively obtained the infrared radiation coatings with Al2O3-Cr2O3-TiO2 system and its main components of MgAl2O4 spinel and MgAlCrO4 spinel infrared radiation coating.It is found that the several coating has excellent performance,which has a high practical value.This study firstly got a Al2O3-Cr2O3-TiO2 series infrared radiation coating. Through the review of related literature at home and abroad,we make with Al2O3,Cr2O3,TiO2 as the main raw material,and matches by SiC and ZrO2 as auxiliary materials,constant by the method of orthogonal experiment to select raw material proportioning,finally got the best formula of Al2O3-Cr2O3-TiO2 series infrared radiation coating.The emissivity of the coating can reach 0.85 or so,therefore,this coating has high practical value.In addition,we have got the other two infrared radiant coating with MgAl2O4 spinel and MgAlCrO4 spinel. The first kind of infrared radiant coaitng is MgO and Al2O3 as the main raw material,additives for NiO,got a major component of MgAl2O4 spinel infrared radiant coating,the emission rate can reach about 0.87;the second coating is the MgO,Al2O3 and Cr2O3 as the main raw materal,additives for NiO,got a main component of MgAlCrO4 spinel infrared radiant coating,itself also has the emission rate of more than 0.9,The study found that the size of the infrared radiant coating emissivity is directly related to the spinel content in the coating.In this experiment we found that the NiO in the coating has played a key role in the produce of spinel,it can be said with the joined of the NiO,it can produce so many component of spinel formed in the coatings.When there is no NiO to join,spinel yield little,and the emission rate is relatively low. So the NiO itself also became the main factors influencing the coating performance.Then,we further study whether it is university that the transition metal oxides promote the produce of spinel in the coating. NiO as a kind of transition metal oxides,in order to explore the transition metal oxides promote the produced of the spinel in the coating is universal,and find a best transition metal oxides,we respectively use MnO2,CoO,CuO and ZnO as additives to replace NiO.Through the continuous experiment,we find the selection of several transition metal oxides can effectively promote the formation of the spinel in the infrared radiation coating,CoO of the promoting effect of spinel is most obvious.Finally, we prepared the infrared radiant coating integrity with very high application value. After spray the infrared radiation coating on the surface of the refractory material,the surface emissivity rate can reaches about 0.87,which can improve the emission rate of substrate surface is about 28%,and added value of unit mass storage heat reached 32.75%.By scanning electron microscopy (SEM) images and found that the reaction happened between coating and matrix and formed a kind of composite material, can play a certain protective effect on refractory surface, prolong the service life of refractory brick. |
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