New Type of Rare Earth Tellurium Copper Alloy and the Study on the Oxidation Resistance

Abstract: Copper and copper alloy, because of excellent electric and thermal conductivity, are widely applied in electronic seal material, silicon chip substrate, electrical pick-off contact support and contact materials, contact switch, electrode material used in welding and so on. Along with the improving of the industry request standard, it is an urgent demand to research and develop special-purpose copper alloy with high strength and high electroconductibility. At present, the research of copper alloy with high strength and high electroconductibility is concentrate on Cu-Cr, Cu-Zr, Cu-Mg, the Cu-Fe series, but all those alloy has its own shortcomings, such as high cost, feeding difficulty and low conductivity. Therefore, the research of new copper alloy with high strength and high electroconductibility is necessary. What’s more, copper is easy to be oxidized in high temperature that will increase the resistance, lessen working efficiency, and even causes the component failure. So improve the oxidation resistance ability of copper in high temperature is very important to expand the use of copper.At present,the ore hot stove electrode in China is is mostly made of tin bronze, zirconiumbronze, chromiumbronze and zirconium-chromiumbronze. Though with high conductivity, this kind of electrode material has low strength, low hardness and low softening temperature.So its life is very short, also, the electrode material is very easy to expended, but the multi-dimensional rare earth tellurium copper alloy material has high strength,high electric conductivity, high hardness and high softening point and so on, therefore it can be used in complex operating mode for its better combinationproperty index and longer service life. With the development of modern industry, higher standards of strengh, softening point, and conductivity of electrode materials are demanded. Particularly the stove electrode, the brasses, the collecting ring, the wiring board, the conticaster crystallizer, the blast-furnace tuyere and the main body have higher demands of properties,such as the strength in high temperatures, the property of gas corrosion in high temperature, oxidation resistance in high temperatures, electric conductivity and heat conduction performance in high temperature. So the research and development on related material is significant.With the combination of the application of new type tombarthite tellurium copper that is researched in our group in actual working condition, in which there is the problem of oxidation. This article discusses the tensile strength and electrical conductivity of the multielement alloy material which is made of copper mixed with Te and Ce. The performance of oxidation and corrosion of the alloy in medium to high temperature and the mechanism and antioxidant effect caused by the adding of Te and tombarthite with rich Ce into copper. The aim of this research is to put this material into use on stove electron-conductive tile, collecting ring, blast-furnace tuyere, the support of contact and contact materials and etc.. It is expected that there will be a certain conducting impact on the research and application of copper alloy engineer.Metallography microscope, X-ray diffraction, scanning electron microscope, and power spectrum are used in the research of new type tombarthite-tellurium-copper alloy materials mixed with different content of Ce. The results demonstrates:(1) The grain could be refined and the grain boundary could be cleansed by adding tombarthite with rich Ce into tellurium copper alloy. Furthermore, the material would become more compact, thus the tensile strength and conductivity could be improved a lot, as well as the antioxidation property in high temperature and gas corrosion ability in high temperature.(2) The tensile-strength of tombarthite-tellurium-copper alloy increase under 20℃、300℃、400℃, it manifest rare-earth refine the alloy structure, tiny grain means minuteness asymmetry deformation, small stress focus, difficulty to craze, so tensile-strength improved.(3) Microelement cerium-rich mix tombarthite can improve alloy’s conductance in high temperature (400℃). It mostly because when melting tombarthite get reaction with impurity, simultaneity clean out slag, purify the alloy, improve alloy’s pureness and decrease impurity’s jeopardize.(4) The content of tombarthite added into tellurium copper alloy should be controlled between the range of 0.02%-0.3%. Only in this range, would the effection of refining grain and cleansing boundary be notable, no matter what aspects of properties, such as tensile strength,conductivity and anticorrosion, the datum are very good. That means excellent Combinationproperty. But with the increasing of content, the strength of material will increase, and inversely, the plasticity will decrease.(5) In lower temperature, compared with pure copper, the antioxidation ability of tombarthite-tellurium-copper alloy will drop.But in high, reverse.(6) The relationship of the proportion of alloy oxide and the oxidation time conforms to the regular pattern of parabola.(7) The crack on oxidation film with the adding of Ce in the material is shorter than that on the oxidation film without the adding of Ce in the material.
Key words: Tombarthite-tellurium-copper alloy; Oxidation resistance; Electric conductivity;

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