Activation of the ceramic surface to improve its wetting and brazing

DOI: 10.62564/M4-VK9531

Vladislav Zhuravlyov, Vitalyi Krasovskyy

Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Brazing is a physicochemical process that combines adsorption, diffusion, dissolution, wetting, capillary flow, adhesion, melting and crystallization. The joining of materials of different nature, despite significant progress in this direction, still requires detailed fundamental research - physical, chemical, technological and improvement of already existing technological processes and solders, development of new multi-component solders, metallization coatings and methods of their application [1–4] . The purpose of this work is to find means of reducing the destruction of the surface of a ceramics during its metallization by rubbing with new designs of tools for rubbing, to determine their effect on wetting and brazing modes of oxide ceramics with metal solders. Three new types of Ti tools for grinding non-metals using a spongy porous structure and a foil with a thickness of 0.07-0.10 mm have been produced. Samples of A995 and VK94-1 high-alumina ceramics metallized by the proposed method were obtained. It was established that the surface roughness of non-metals affects the composition and microstructure of the applied coating in air. As the roughness decreases, both the density and oxidation of the coating increase. Wetting of ceramics with this coating with PSr72 solder (copper-silver eutectic) was studied, soldered joints were obtained, and the microstructure of the metal-oxide contact zone was studied. Studies of the microstructure of the soldered joint showed that the PSr72 melt permeates the titanium coating, saturates with Ti and wets the ceramics. That is, such metallization does not require coating density and accelerates the saturation of the melt with Ti. The main role of metallization by rubbing is to supply Ti to the base of the solder melt. The advantages of rubbing ceramics with titanium in the form of a porous spongy structure and foil in comparison with a compact metal tool are given. The best results are obtained using a tool made of porous Ti.

Keywords
metallisation by friction, titanium foil, spongy porous structure, brazing oxides, filler metal alloys

Acknowledgments
Not provided

References
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