Neutron and X-ray experiments at high temperature
2014 Advanced technologies, like for instance aerospace or nuclear engineering require the most exhaustive information on the behaviour of materials used at very high temperature such as ceramics, refractory alloys or molten metals. Among high temperature techniques, X-rays and more recently neutron scattering have appeared as powerful tools to get information, mainly structural, on these materials in their working conditions. High temperature devices (above 2 000 K) developed for that purpose, based on various heating techniques (induction, imaging furnaces, lasers, gas-flame heaters and principally Joule heated devices) are reviewed. Some crucial points are particularly emphasized such as : 2014 the determination of the real temperature (thermocouples and optical pyrometry) in the scattering zone hardly accessible partly due to the unavoidable thermal gradients, 2014 the chemical reactivity of the sample with its surrounding, i.e. atmosphere and sample holder. Neutrons, mainly because of their low absorption by matter, allow the work on real bulky materials and give a greater freedom in the conception of high temperature scattering devices compared to X-rays. At the present time thermal neutron high flux reactors offering a wide range of neutron wavelengths are available, and a new generation of more and more efficient multidetectors has emerged in the last decade; the data acquisition and consequently the high temperature exposure time have been notably reduced, opening a way for precise and reliable experiments in the 3 000 K range. This very high temperature domain already studied by a few other techniques can also be investigated by neutron scattering. Revue Phys. Appl. 19 (1984) 649-662 SEPTEMBRE 1984, PAGE (*) The author’s personal work has been done at the ILL (HFR Grenoble). Now with the Equipe de Physico-Chimie Moleculaire, CENG-DRF, 85X, 38041 Grenoble Cedex, France. REVUE DE PHYSIQUE APPLIQUEE. T. I9, N° 9, SEPTEMBRE 1984 45 Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/rphysap:01984001909064900
A high temperature (3000°C) graphite furnace for laboratory use
The construction is described of a high temperature (3000°C) graphite resistance furnace incorporating two new features. These are the use of a graphite guard-tube to facilitate easy replacement or renewal of the element and the use of carbon felt and carbon wool as a thermal insulator in place of carbon black. The assembly is simple to operate and can be constructed easily and relatively inexpensively.
Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.