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5961 |
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Wednesday, May 22, 2019, Saal Brüssel 1:40 PM Diffusion brazing and bonding |
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Control of deformation and material issues during diffusion bonding of micro process devices |
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Thomas Gietzelt* / KIT/IMVT, Germany Volker Toth / KIT/IMVT, Germany Torsten Wunsch/ KIT/IMVT, Germany R. Dittmeyer/ KIT/IMVT, Germany |
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The Deformation during diffusion bonding depends not only on bonding temperature, bonding time and bearing pressure but also on aspect ratio and the cross section area itself. Since surface roughness of mating surfaces must be levelled for enabling diffusion of atoms, multilayered parts exhibit a larger deformation. Mechanical microstructures in the dimension of the materials microstructure may facilitate grain boundary sliding. Hence, for micro process apparatuses it is complicated to control deformation and to ensure vacuum tightness. This is especially a problem for manufacturing of prototypes and small scale series. Since often very corrosion resistant materials are used, surface layers may prevent atomic diffusion. An overview emphasizing material aspects like stability of passivation layers, grain growth and influence of polymorphic transformation on formation of a monolithic compound during diffusion welding is given. |