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Stainless steels containing both C and N have unique characteristics while requiring unconventional manufacturing methods. This latter feature also translates into a lack of systematic investigations into their properties. In this work, a series of 13 wt%Cr steels with various interstitial solid solutions of C and N was synthesized by high temperature solution nitriding, HTSN, of commercial 13 wt%Cr martensitic steels. Light optical microscopy was applied to reveal the microstructural features, which consisted of a combination of martensite and austenite in various ratios depending on the C and N content. The mechanical response was characterized by nanoindentation. Data analysis assumed a fixed hardening exponent and provided an estimate of the yield strength and Young’s modulus of the synthesized steels and their microstructural components. The comparison with literature data indicated that this estimate is sound for martensite, while the data for austenite suggests an underestimation of the hardening exponent for this phase. The investigation demonstrates the potential of HTSN for the synthesis of novel 13 wt%Cr steels alloyed with both C and N. Moreover, it suggests that the use of nanoindentation for extracting the mechanical properties is limited by the non-uniqueness of the method with regard to the hardening exponent.

While maraging steels are excellent candidates for additive manufacturing of high-strength materials, most of them provide little to no corrosion resistance. In this study, the surface of additively manufactured maraging steel is augmented with diffusion-based chromizing. The diffusion of chromium into the surface results in the formation of α-Cr, σ-phase and austenite depending on the chromium content at the respective distance from the surface. The bulk consists of a ductile bcc martensite hardened by precipitation of intermetallics during a low temperature ageing treatment. The σ-case provides a very high hardness, while the austenite phase is rather soft and unaffected by the ageing treatment. The chromizing treatment significantly reduced the corrosion rate of the maraging steel up to a factor of 14. Decomposition of the σ-case into a uniform case of austenite (austenitic stainless steel) further improved the corrosion resistance almost 24 times. This showed the strong potential of the chromizing treatment on a highstrength material to obtain a combination of their beneficial properties.

A fully enzymatic method for the determination of inulin in serum or plasma without deproteinization is described. The assay is carried out by means of a fructose determination after hydrolysis of inulin via inulinase and simultaneous oxidation of the native glucose using glucose oxidase and H2O2. This time-saving procedure of high specificity, sensitivity and accuracy requires only small sample volumes. The usefulness of the method is shown by analysis of blood levels in humans and rabbits after an intravenous administration of Inutest.

Es wird eine enzymatische Bestimmung von Maltose im Blut mitgeteilt. Die Methode arbeitet nach neutraler Enteiweisung mit der Hexokinase-Technik [6–7] und α-Glukosidase [8]. Sie ist praktikabel, von hoher Prazision und kommt mit kleinen Probenvolumina aus. Die Anwendbarkeit des Verfahrens wird anhand von Blutspiegeluntersuchungen unter der Infusion von Maltose beschrieben.

An enzymatic method for the determination of maltose in blood is described. In this method after neutral deproteinization the assay is carried out by the hexokinase technique [6--7] after splitting of the maltose with alpha-glucosidase [8]. This time-saving procedure of high specificity and sensitivity requires only small volumes of blood. The practicability of the method is shown by analysis of blood level during an infusion of maltose.