Two key points of electrical contacts: copper-chromium alloy contacts

    The second of the "two key points" is the new electrical contact material for DC appliances. Under the vigorous promotion of government departments, the development trend of new energy electric vehicles in my country is very fast, and a trillion-yuan sales market will be generated in the next 10 years. The total number of DC power switches, DC circuit breakers, and DC automotive relays for the construction of supporting facilities for new energy electric vehicles and charging piles is extremely large. Copper-chromium alloy contact manufacturers will fully consider the requirements of solar power generation, energy storage technology and DC power transmission and transformation projects, and various DC electrical appliances will enter a period of great growth. Under the DC standard, the precision copper-chromium alloy contacts have encountered many difficulties technically different from those in communication applications. For example: because the current does not cross the zero point, the electrical contact has to bear the long-term corrosion of the electrical isolation; and the electrical contact material works under the DC field, the migration of the material will also appear to be very serious; in addition, the DC electrical appliance Medium electric contacts are generally sealed in indoor spaces filled with N2, Ar2, H2 and other different atmospheres or in vacuum solenoid valves. The closed natural environment leads to high operating temperature of electric contacts, which is very easy for arc welding in work. . To cope with this technical challenge, the current scientific research focus of electrical contact materials for DC appliances is mainly focused on Cu-based materials.

    On the one hand, scientific researchers are diligently improving the current CuCr, CuW, and CuMo materials, and on the other hand, they are vigorously developing and designing various new Cu-based materials. Cu-based electrical contact material has excellent electrical conductivity and heat transfer properties, and the price is relatively cheap. It is an effective electrical contact material in vacuum pumps or oil power switches. Just because the high-quality copper-chromium alloy contact material is very easy to reflect with 02 and produces a non-conductive air oxide layer, if it is necessary to divide the bangs in the gas to cut off the flow, it will only be removed when the contact stress is large or in a short period of time. used in replacement household appliances. Improving the oxidation resistance of Cu-based electrical contact materials is a specific new technology development prospect. At present, the key to current products is to add diamond to Cu to produce some specifications of AC contactors and Cu selected for power switches of molded case circuit breakers. Based on electrical contact materials, the performance of commercial products cannot be generalized to Ag-based electrical contact materials. However, new C materials such as graphene and carbon nanotubes may have a breakthrough change in the macroscopic structure of Cu substrates and the methods of electrical conductivity and heat transfer, which have become the main technical development prospects in the future. Jinan University basic research on the harm of carbon nanotubes, graphene and nanotechnology carbon powder to the structure and properties of copper, and try to improve the oxidation resistance of Cu by adding rare elements (Pr, Nd, Sm); Harbin Institute of Technology, Nanchang Aeronautical universities are trying to design and fabricate new Cu-based electrical contact materials d based on the addition of graphene oxide. Once the new Cu-based electrical contact material is improved, it will not only promote the development trend of DC appliances, but also provide a great change for the electrical contact materials used in current communication places.