Low-melting non-toxic alloys as matrices of composite compounds for permanent connection of heterogeneous materials
V.М. Skachkov, L.А. Pasechnik, S.P. Yatsenko
The Institute of Solid State Chemistry of the Ural Branch of RAS, Yekaterinburg, Russia
Abstract: A number of diffusion-hardening composite solders for flux-free connection of heterogeneous materials are considered. The possibilities of changing the thermal expansion coefficient of connecting soldering joints are checked. The manufacturability of using solder pastes of different composition is shown and recommendations for connecting of heterogeneous materials are given. Joining of heterogeneous materials with the use of composite alloys by applying pastes at room temperature and subsequent low-temperature treatment (< 180 °C) with the production of vacuum-tight and durable joints finds wide application in new equipment (gyroscopes, optical quantum generators, solar panels, electronic systems, etc.). The introduction of heterodesmic compounds into the composition of composite materials allows one to obtain a connecting seam with a thermal expansion coefficient value, which is intermediate between the connected parts. Mechanochemical activation, ensuring the generation of non-equilibrium defect structures, makes it possible to dramatically improve the reactivity and synthesize new phases with a high chemical activity. A non-toxic tooth filling material has been created, which has a convenient manufacturability period and mechanical properties exceeding those of toxic amalgams, «metallogent»/silver amalgam: compression strength after 1 h 160 / 110 MPa; microhardness after 24 h 2000 / 1200 MPa. The compositions based on a matrix of gallium alloys with copper or copper with tin, zinc, silver, indium, bismuth etc. powders are hardened forming mainly medium-temperature (450 – 550 °C)) compounds.
Keywords: gallium, diffusion-hardening solder, flux-free soldering, powder, alloy.
Skachkov, V.М. Low-melting non-toxic alloys as matrices of composite compounds for permanent connection of heterogeneous materials / V.М. Skachkov, L.А. Pasechnik, S.P. Yatsenko // Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials: Interuniversity collection of proceedings / Ed. by V.M. Samsonov, N.Yu. Sdobnyakov. – Tver: TSU, 2019. – I. 11. – P. 654-664.
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