Development of an In-Process Technique for Measuring Temperatures and Micro-Geometry of High Temperature Surfaces by Using the Broad Range Spectroscopy

为了开发一种利用广谱光谱测量高温表面温度和微观几何形状的过程中技术，进行了一系列工作：对高速分光光度计系统进行了改进，使光谱范围扩大到0.35 ~ 14.5 μ m。采用波长连续可变滤光片。研究了几种不锈钢和高温合金在高温空气氧化过程中的瞬态反射特性。发现在粗糙的氧化表面上，用一些简单的干涉和辐射衍射规则来表征光谱。在空气中，在1000K左右的温度下，钯表面的近红外发射和反射光谱中发现了一个有趣的温度滞后现象。这是由于表面氧化和解缔合反应共同作用的结果。研制了一种椭球镜式反射计系统，用于测量实际表面的正入射半球面反射光谱。该系统已应用于金属粗糙表面的角特性和波长特性的测量。提出了一种描述粗糙金属表面反射特性的理论模型。表面被建模为一个分形的三维结构，它由离散的和统计控制的表面元素组成。计算了衍射/散射特性，验证了模型的正确性。提出了另一种处理实际工业环境中真实表面反射特性瞬态行为的方法。将上述曲面模型与三维非平行膜元模型相结合。实验发现的光谱跃迁行为很容易在计算机的基础上从理论上再现。

A series of works were performed for the development of an in-process technique for measuring temperatures and micro-geometry of high temperature surfaces by using the broad range spectroscopy :1. The high-speed spectrophotometer system was modified to extend the spectral region to 0.35-14.5mum. A wavelength continuous variable filter was used for it .2. Transient behavior in reflection characteristics was investigated on several kinds of stainless steels and super-alloys in an air-oxidation process at high temperatures. The spectra were found to be characterized by a few simple rules of interference and diffraction of radiation at the roughened oxidized surfaces.3. An interesting phenomenon of temperature hysteresis was found in the near -infrared spectra of emission and reflection at a paradium surface in air and at around 1000K. It was attributed to the combined oxidation and desociation reactions at the surface.4. An ellipsoidal mirror-type reflectometer system was developed to measure the normal-incident hemispherical reflectance spectra of real surfaces. The system was applied to the measurement of the angular and wavelength characteristics of rough metallic surfaces.5. A theoretical model was proposed to describe the reflection characteristics of rough metallic surfaces. The surface was modelled as a fractal-like three-dimensional structure which consists of discrete and statistically controlled surface elements. The diffraction/ scattering characteristics were calculated to demonstrated the reality of the model.6. Another idea was proposed to deal with the transient behavior in reflection characteristics of real surfaces in actual industrial environments. The above surface model was combined with a three-dimensional non-parallel film element model. The experimentally found behavior of the spectrum transition was readily reproduced theoretically on a basis of a computer.