In-situ measurement method for metal resistivity at high temperature and high pressure

Abstract

The invention relates to an in-situ measurement method for metal resistivity under high temperature and high pressure. A van der Pauw four-wire method is taken as a measurement principle, and a cubic large-cavity press is taken as an equipment platform for generating high temperature and high pressure. Pyrophyllite is used as a pressure transmitting medium, a graphite tube and a graphite sheet are used as heaters, a hexagonal boron nitride tube is used as a sample bin, a hexagonal boron nitride cylinder is used as a filler, a metal wire is used as a test electrode, a thermocouple wire is used as a temperature measuring element, and the test electrode is introduced into the closed sample bin to be in close contact with a sample so as to meet the high-pressure experiment condition. According to the invention, the van der Pauw four-wire method is applied to the domestic cubic large-cavity press for the first time, the in-situ resistivity of the powder or blocky metal material at high temperature and high pressure can be rapidly and accurately measured, and the problem of high-pressure in-situ resistivity measurement is successfully solved; the metal iron is measured for multiple times under the conditions of 3-5 GPa and 300-1200 DEG C, and the result shows that the method can obtain accurate in-situ resistivity data.

Description

technical field [0001] The invention relates to the technical field of high-pressure experiments, in particular to a method suitable for rapid measurement of high-temperature and high-pressure in-situ resistivity of powder and bulk metals. Background technique [0002] High pressure science is a science that studies the properties of matter under conditions of extreme pressure. Under extreme pressure conditions, materials tend to exhibit properties that are not present at normal pressure. For example, the structural transformation caused by high pressure will make the substance have a crystal structure that does not exist under normal pressure, which expands our understanding of the material world and the development and utilization of new materials. High voltage can cause the material to transform from an insulator to a conductor, providing a development idea for room temperature superconductivity. In the field of material synthesis and preparation, high pressure can be u...

AI Technical Summary

Problems solved by technology

Generally speaking, there are two deficiencies in this technique: one is that the types of samples are limited, especially mixed material (non-pure metal) samples are inconvenient or impossible to be made into filaments due to their physical and chemical properties, This technology has limitations in the research object; the second is that the original regular filamentary sample will be deformed under high pressure extrusion, and this deformation is often impossible to be completely regular or symmetrical, making it difficult to accurately measure the slender sample. length and cross-sectional area, which eventually lead to unreliable calculation results

There is no agreement among all reported results of in situ measurements of metal resistivity at high voltage using the law of resistance

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