Experimental Investigation Of The Effect On The Emissivity From Surface Oxide Film Of Steel And Brass

The emissivity of material surface is an important thermal physical property parameters. Which is an important technical index to weigh the quality of a variety of product. For example, in the field of infrared measuring technology, emissivity is occupid an important position. But in the measuring process of emissivity, there are lots of influencing factors, so that the accurate measurement of emissivity become a promble. Now researchers have proposed various material emissivity measurement methods and instruments, but there are no method and apparatus play a dominant position, which is due to the different requirements for different experiments and industries. So to understand the characteristics of the emissivity of material and to provide reliable experimental data make an important sense. In this article, we explore the important position of material emissivity in the future, and introduce emissivity measurement method. The laws of radiation about emissivity are simplely introduced, and the theory of blackbody is used to clarify the closed cavity hole radiation. We derived the influences on emissivity from the metal oxide film and its formula. the influences on emissivity from the metal oxide film are detailed, which is just my main work during my graduate.study.More and more kinds of metal materials(such as steel) can be found everywhere in our life, but we focus on their quality much more. The controlling and measurement of temperature in the production of metal products play an important role, it is necessary to improve the accuracy of emissivity. There are lots of influencing factors of emissivity, include the surface conditions of samples, measurement environment,the conditions of instrument equipment and so on. the optical experiment instruments of the emissivity measurement are introduced, which based on the theory of energy method and kirchhoff’s, and its composition, basic principles and advantages. In the early part of the article,some basic principles are introduced, such as the infrared radiation theory, the applications of the infrared radiation theories, the infrared technolgies and so on. In addition, various measuring methods of emissivity are simplely introduced.Here, an experimental device(the precision artificial intelligence temperature controller), including its structure and principle, is introduced. The relationships between the spectral emissivity(of brass, steel DC01 and steel 316L) and the temperature are in detail studied in the oxidizing environment with experiment. In this experiment, the surface temperature is measured by an infrared detector, and the radiant energy coming from the steel surface is received by a photodiode detector. The spectral emissivity varies with the heating time at the given temperature, and the spectral emissivity varies with the temperature at the given heating time. The behavior of spectral emissivity is discussed when the oxidation film on the specimen surface is grown, in particular at the early stage of heating duration. The conclusion is gained that the coefficients of analytic expressions between the spectral emissivity and the temperature are different from each other for the experimental results obtained at the different heating-duration time, though the polynomial functional form is suitable to fit all the measurements obtained in the present work.By studying and analyzing the experiment results in this paper, we summarized the relationships between the emissivity of metal materials and various influencing factors, and many important conclusions are obtained. The results of our research can be used to provide reliable reference for the detection and control of the materials in the process of industrial production.