Jan Pfeiffer

PVA Vacuum Processing Services

High temperature applications demand high quality and reliable joints, which offer an outstanding corrosive and thermal resistance. These requirements have pushed conventional brazing technologies to their limits. One new possibility to solve this problem is reactive partial transient liquid phase diffusion bonding, which combines an active interla...

This paper focuses on the process of ultrasonically assisted induction brazing with regard to titanium brazing. The titanium alloy TiAl6V4 was brazed using an aluminum-based filler alloy (AlMg2.5Cr0.3). It was apparent that the layer thickness of the brazing foil as well as the brazing temperature and the intensity of the ultrasound are significant...

Despite the broad field of applications for active filler alloys for brazing ceramics, as well as intense research work on the wetting and spreading behavior of these alloys on ceramic surfaces within the last decades, the manufactured joints still exhibit significant variations in their properties due to the high sensitivity of the alloys to chang...

Studies of the spreading kinetics of molten metals on ceramic substrates provide valuable information about the processes determining the interaction between these two materials. Based on experimental and theoretical works, two determining wetting types have been proposed for a variety of high-temperature systems – the reaction limited wetting and...

Reactive air brazing (RAB) has been developed as a method to join ceramics and steel, using CuO as a reactive agent that interacts with the surface of the ceramic, enabling a wetting by the molten filler metal. A major benefit of this method is the fact that the joining process can be carried out in an ambient atmosphere, in contrast to active braz...

Despite the fact that active brazing is a suitable and well-established method to join ceramics to each other and to metals, issues concerning possible influences on the wetting properties of the used filler alloys are not yet entirely clarified. It is well known that process parameters such as the temperature, the surface roughness of the ceramic,...

Das Diffusionslöten stellt ein Verfahren dar, bei welchem im Vergleich zum Diffusionsschweißen erheblich niedrigere Temperaturen und Drücke zu ähnlich hochwertigen Verbunden führen können. Eine Bildung der als Lot verwendeten Flüssigphase beruht auf chemischen Prozessen bei konstanter Temperatur unterhalb der Schmelztemperatur der eigentlichen Füge...

Um die begrenzend wirkenden konstruktiven Restriktionen bezüglich Bauteilgröße und -komplexität von keramischen Bauteilen zu umgehen, sowie die Reproduzierbarkeit der Verbundeigenschaften zu steigern, ist eine fundierte Kenntnis der physikalisch-chemischen Grenzflächenvorgänge zwischen Lot und Keramik nötig. Die in diesem Beitrag zusammengefassten...

The presented work compares a new WC-FeCrAl-matrix feedstock powder with a standard WC-Co powder. The investigation covers the powder analysis, spray jet properties, splat flattening and coating properties as well as XRD analyses of the feedstock powders and as sprayed coatings. As the formation of single splats sets up the foundation for any therm...

Our effort is to develop an innovative process to join Al sheets at moderate temperatures (200-300 degrees C) by accumulative roll bonding (ARB) combined with transient liquid phase bonding utilising Ga. Solid state joining of Al is limited by the surface Al2O3 that hampers the Al atom diffusion despite the intimate contact between the metal sheets...

Due to the specific properties of ceramics such as wear and corrosion resistance as well as high hardness, these materials are frequently used for numerous of applications especially in combination with metal joining partners. When it comes to manufacture high strength joints, comonly machining is used for surface preparation in order to decrease t...