Papers by Keyword: Brazing Alloy

Abstract: Process parameters play a crucial role in the final characteristics and properties of every product. The current work focuses mainly on improving the vacuum furnace brazing process for tungsten carbide reinforced Ni-based alloy (NiCrBSi) metallic composite coatings, by establishing the best set of parameters adapted to this specific chemical composition. In order to determine the optimum parameters, a fine adjustment of a typical vacuum brazing process was performed. The melting interval of the filler metal was identified by means of Differential Thermal Analysis. Morphology, microstructure and metallurgical bond of the cladding to the substrate material were investigated by Scanning Electron Microscopy and Light Microscopy combined with a Porosity Analysis Software. The process optimization resolved the initial problem of fractures and crack initiation, making possible to achieve high quality hardfacing coatings with a low degree of porosity (approximately 1 %).

Abstract: Aiming at the glass-to-metal seals serving in the Solar Thermal Power (STP), glass-to-metal vacuum brazed joints were studied. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were performed to examine the microstructure and element contents of interface seam on the glass-to-metal vacuum brazed joints. Also, the compositional concentration of the interface seam was measured by using energy dispersive spectroscopy (EDS).

Abstract: We investigated the method of joining silicon nitride having on its surface a thin layer of active silicon metal to carbon steel. The active silicon layer is formed through the thermal dissociation of silicon nitride (Si3N4) into silicon (Si) and nitrogen gas (N2). The active silicon layer is directly joined to carbon steel via an induced eutectic melting reaction between the silicon and iron (Fe) found in carbon steel, or via brazing of two materials using general brazing metal such as Ag-Cu alloys. This joining process does not require the use of expensive active brazing alloys such as Ag-Cu-Ti alloys or a sputtering method designed to coat the active metals on surface of silicon nitride.