Low Melting Point Gallium Based Liquid Metalas The Base Carrier Fluid Of Temperature Sensitive Magnrtic Fluid

Temperature-sensitive magnetic fluid is a functional material that is extremely sensitive to temperature changes and has both magnetic and fluid properties.It is ideally suited as a medium for energy transport and energy conversion.It is widely used in temperature measurement,temperature differential power generation,temperature difference drive,magnetic thermal medicine,heat dissipation components and other fields.At present,most of the temperature-sensitive magnetic fluids use oil or water as the carrier fluid,which have the problems of large viscosity,large wettability(small contact angle),low thermal conductivity,and low temperature-sensitive with the change of magnetic field intensity,etc.The liquid metal gallium and its liquid alloy,which are non-toxic,high conductivity and good thermal conductivity,are the ideal choice of temperature-sensitive magnetic fluid carrier fluid.However,gallium and its liquid alloys have high erosivity and adhesion,so it is difficult to keep good contact with glass or metal for a long time,and according to the current research,the melting point of Gallium alloys is mostly in the tenth degree Celsius,so there is still a certain gap with the ideal base carrier fluid,and there is more room for progress.In this article,liquid Gallium is modified by adding Indium,Tin,Zinc,Aluminum,Germanium.The main research results of this paper are as follows:(1)The effect of the addition of Indium,Tin,Zinc,Aluminium and Germanium elements on the melting point of Gallium-based alloys was investigated.The doping effectively lowered the melting point of gallium alloys,and many Gallium-based alloys were obtained that were liquid at room temperature.When single element additions were made,the addition of Indium was found to have the strongest effect on reducing the melting point of Gallium-based alloys,based on which multi-element Gallium-based alloys were investigated,the melting point of gallium-indium-tin ternary alloys was even lower,while the addition of trace amounts of Al,Zn,Ge was later found to further reduce the melting point to 8℃.(2)The wetting performance of different Gallium-based liquid alloys on four different substrates(Copper,Aluminum,Silica and Teflon)was investigated.It was found that the contact angles of all the Gallium-based alloys on the four substrates were larger than 90°,and their wetting properties were poor,among which the contact angle on the interface on Teflon was the largest,reaching about 140°,which was the most suitable for carrying Gallium-based liquid alloys.(3)The fluidity of Gallium-based liquid alloys was investigated.It was found that the Gallium-based liquid alloy showed pseudoplasticity,its viscosity decreased with the increase of shear rate,and it was a viscoelastic fluid.The viscosity of most Gallium-based liquid alloys was around 3 m Pa?s at 20℃,about three times that of water with good flowability.(4)Gallium-based liquid alloy was modified by micro-nano-bubble technology.The results show that the hydrogen argon mixture containing8% hydrogen can enter the Gallium-based liquid alloy and affect its melting point,wettability and viscosity.(5)Gallium-based liquid alloy magnetic fluids were successfully prepared and their magnetic properties were investigated.The results show that this magnetic fluid has good soft magnetic properties and excellent temperature sensitivity,with a saturation magnetization strength of 8.4 emu/g at room temperature.