Preparation methods and application fields of molybdenum copper alloys

Application field

           The excellent properties of molybdenum copper alloys make them widely used in various fields. The adjustable coefficient of thermal expansion and high thermal conductivity make molybdenum copper alloy can be used to install and seal integrated circuits and high-power semiconductor devices, such as Super high frequency metal ceramic tubes, high-power transistors, substrates, inserts, connectors and cooling elements in high-power microwave devices. Non magnetism, constant expansion coefficient and high elastic modulus enable Mo Cu alloy to meet the requirements of some special instruments, such as vibrating wire pressure sensor, magnetron and low-noise Traveling-wave tube. Good mechanical properties, ablation resistance and thermal shock resistance make Mo Cu alloy suitable for ultra-high voltage electrical contact materials, nozzle throat lining, electron beam target and other high-tech devices, and can be used as plasma oriented Divertor materials in Nuclear fusion devices. Due to its lower density and easier deformation processing compared to tungsten copper materials, molybdenum copper alloys have certain applications in aerospace and military industries, such as being used as guide materials for magnetic cannons and ammunition casings for armor piercing shells.

Preparation Method

          Molybdenum and copper are not miscible with each other and have poor wettability, so the liquid phase sintering densification rate of molybdenum copper alloys is slow and the degree of densification is low. Therefore, people have attempted to prepare molybdenum copper alloys using different methods. Mo-30% Cu nanocomposite powders with grain size less than 30 nm were prepared by spray drying calcination hydrogen thermal reduction method. This method can accurately control the composition of composite powder using conventional equipment, and the preparation process is simple. Molybdenum copper composite materials containing more than 30% copper are suitable for preparation by powder sintering method. Molybdenum copper alloy can be prepared by rapid sintering under ultra-high pressure, which can produce molybdenum copper alloy with a relative density of over 98% in one go, and the copper content can be adjusted within a wide range. In recent years, chemical methods such as coprecipitation method, sol gel method, gel casting method and metal oxide co reduction method have been applied in the preparation of molybdenum copper ultrafine composite powder. Using Ammonium heptamolybdate and Copper(II) oxide as raw materials, the ultrafine molybdenum copper composite powder with 20% copper and dispersed components was prepared by gel co reduction process. After sintering, the relative density of the alloy reached over 99.65%, close to full density. A high copper volume fraction molybdenum copper alloy with uniform distribution of molybdenum particles and a density of over 99% was prepared by squeeze casting method, and the molybdenum copper interface was clean and smooth, without any interfacial reactants or amorphous layers.

Development prospects

         The density of molybdenum copper alloys is the main factor affecting their thermal conductivity, conductivity, and strength. Currently, ordinary molybdenum copper alloys produced in industry have relatively low relative density (about 85% to 95%), uneven pore distribution, and high gas content. When the density of molybdenum copper alloy is high, it usually significantly improves the performance of the alloy. Therefore, in order to improve the density and properties of molybdenum copper alloys, scholars at home and abroad have conducted extensive research,Some achievements have been made, such as activation sintering, mechanical alloying and nano powder sintering. Further improving the preparation process, increasing the density of molybdenum copper alloys, and achieving high strength and high airtightness are still urgent issues that need to be addressed.