A Research On The Spectral Emissivity Of Cobalt And Nickel

Spectral emissivity is an important thermal physical parameter,playing an important role in many industries.As the development of the science,the accurate measurement of the emissivity is urgent.So,the study of the emissivity has a significant meaning in pushing the improving of some industries.In chapter one the article give a brief introduction of the definition and the classification of the emissivity and several methods measuring the emissivity.Meanwhile the article summarizes the current situation of the study of the emissivity.In chapter two,the article analyze the influence of temperature?wavelength?surface situation and circumstance on the emissivity and introduce some important laws of infrared field.In chapter three,the article give a description of the measuring apparatus composed of sample furnace?FTIR?blackbody furnace and optical system in the laboratory.The temperature range of the apparatus is from 300 to 1273 K and the wavelength range is from 8 to 15,in addition,the measuring range of the apparatus can be changed by replacing some parts.The apparatus focus on the emissivity of the metals in the far infrared wave band.In chapter four,the spectral emissivity characteristics of pure nickel were studied systematically.The results show that between 8-10 the emissivity of the nickel increases with the wavelength and between 10-15 the emissivity decreases with the wavelength;the spectral emissivity of nickel increases as the the temperature rises,and the emissivity becomes larger with the roughness getting bigger.The influence of the roughness on the emissivity of nickel is not linear.Oxidation has a remarkable influence on the emissivity,indicating that the emissivity of the oxidation of nickel is higher than that of nickel,meanwhile the phenomenon is related to the interference effect on the oxidation film.In chapter five,using the emissivity measuring apparatus,the article study the emissivity properties of the metal cobalt.Cobalt and nickel are in the same family,they have many same properties,for example,they are all magnetic materials.The studies find that the emissivity of the cobalt increases as the temperature rises.In addition,like nickel,the influence of the roughness on the emissivity of cobalt is remarkable.The effect of the oxidation on the emissivity is complex: 0-90 min,the emissivity curves vibrate obviously;after 90 min,the emissivity curve tends to be stable,which related to various types of the oxidation of cobalt.