DECHEMA

About: DECHEMA is a nonprofit organization based out in Frankfurt am Main, Germany. It is known for research contribution in the topics: Corrosion & Oxide. The organization has 756 authors who have published 1307 publications receiving 25693 citations.

Microstructural evolution of germanium modified AlSi-slurry coatings on alloy 600 at 620 °C in metal dusting environment

Abstract: Germanium-modified AlSi-slurry coatings were produced via airbrush spraying of two different suspensions on the conventional Ni-base alloy 600, followed by a heat-treatment in Ar at 800 °C. The resulting coatings exhibit a thickness of approximately 130 μm and mainly consist of outer Al-rich β-Ni(Al,Ge) phase followed by inner Ni-rich β-Ni(Al,Ge). In the interdiffusion zone, a continuous layer of (Cr,Ni)3Ge phase formed. Long term exposure tests in carbonaceous atmosphere at 620 °C showed excellent metal dusting protection. Furthermore, the exposure tests revealed that the (Cr,Ni)3Ge layer acts as a diffusion barrier, preventing the diffusion of the major coating element aluminum into the substrate. Depletion of aluminum would be detrimental for the lifetime of the coating and consequentially for that of the structural component. Microstructural evolution of the coating during exposure showed inward diffusion of nickel into the coating, resulting in fine Ge3Ni5 precipitates, whose formation will be discussed based on the ternary phase diagram of Al-Ge-Ni.

1.08 – Stress Effects in High Temperature Oxidation

Abstract: This chapter describes the role of mechanical stresses in the high temperature oxidation of metallic materials. These stresses may result from oxide scale growth, surface curvature or edges, temperature variation, or from external forces. The different modes of scale failure are discussed and model equations are given quantifying the failure strains. Furthermore, measurement techniques are presented which allow the experimental determination of oxide scale failure strains. In addition, emphasis is placed on the healing behavior of oxide scales after mechanical failure while maintaining the protective effect of scales even after cracking or spalling. The protective effect is, however, limited by subsurface zone depletion in the metal, deteriorating the healing capacity of the alloy.

Electrification of Biotechnology: Quo Vadis?

Abstract: Electrobiotechnology has come a long way and has gained much interest among researchers all over the world. In the previous chapters of this book, an abundance of successful developments of lab-scale electrobiosynthesis and their underlying fundamentals are described. Thereby the individual needs and lines of research are highlighted. In this final chapter we will try to shed light on the overall performance of electrobiosynthetic processes with regard to their technological maturity, as well as the potential ecological and economic incentives for their industrial implementation.