Boriding of Laser-Clad Inconel 718 Coatings for Enhanced Wear Resistance

Nickel-based superalloys are particularly suitable for applications under corrosive conditions. Economic advantages can be achieved by limiting the use of materials to the surface region. Furthermore, the tribological property profile can be significantly improved by surface hardening. In the present study, the possibility of a process combination comprising a coating and a surface hardening technology was investigated. For this purpose, Inconel 718 coatings were applied to austenitic stainless steel by laser cladding. Subsequently, a thermochemical surface hardening by boriding was carried out. Scanning electron microscopic (SEM) examinations were performed to evaluate the microstructure. The phase composition was determined by means of X-ray diffraction (XRD) for the different states of the coating system. The influence of thermochemical hardening was investigated for different wear conditions. The increase in microhardness and wear resistance clearly demonstrates the utilization potential of the presented process combination.

Structure and Tribo-Mechanical Properties of MoSx:N:Mo Thin Films Synthesized by Reactive dcMS/HiPIMS

Modifying MoS2 thin films by additional elements shows great potential in order to adjust the property profile and to meet the increasing requirements regarding high wear resistance and low friction properties of industrial components. Within that context, MoSx:N:Mo thin films were deposited by a reactive hybrid dcMS/HiPIMS process. By systematically increasing the Mo target cathode power, an investigation of the structural and the mechanical properties was conducted to understand the evolution of the tribological behavior. A low Mo target cathode power of 1 kW is related to the formation of the preferential (002) MoS2 basal-plane and thus a low friction with µ = 0.2. With an increasing amount of Mo, the film loses its solid lubricant MoS2 properties and a nitride constitution of the thin film is developing due to the formation of crystalline Mo and MoN phases. Related to this transformation, the hardness and elastic modulus are increased, but the adhesion and the tribological properties are impaired. The film loses its plasticity and the generated film material is directly removed from the contact area during the sliding contact.

Preparation of Tubular Biocellulose Implants and Its Use in Surgery—A Review

This review highlights the current state regarding the preparation and characterization of tubular biocellulose materials as well as their application and application potential with a special focus on abdominal oncologic surgery. Biocellulose is a natural polymer synthesized by acetic acid bacteria from low molecular sugars and alcohols as a mechanically stable nanofiber network at the interface between the aqueous culture medium and air. This hydrogel is characterized by very high purity and biocompatibility, dimensional stability, and good surgical handling. With this property profile, biocellulose proves to be a promising candidate for the development of novel medical soft tissue implants. This requires close R&D cooperation between chemists, material scientists, biotechnologists, and surgeons. In this sense, this review spans from the natural polymer to the design of biocellulose implants and surgical suitability. It is also a concern of this article to show concretely the great need for such implants and the fields of application in oncological abdominal surgery where tubular biocellulose is or could be the focus of research. Furthermore, a critical assessment for the use of biocellulose materials concerning incidence malignancy and surgical interventions, complication rates, and current studies is emphasized. The regeneration of damaged bile ducts by the use of biocellulose implants is a first example.

Molecular generation by Fast Assembly of (Deep)SMILES fragments

Background In recent years, in silico molecular design is regaining interest. To generate on a computer molecules with optimized properties, scoring functions can be coupled with a molecular generator to design novel molecules with a desired property profile. Results In this article, a simple method is described to generate only valid molecules at high frequency ($$>300,000$$ > 300 , 000 molecule/s using a single CPU core), given a molecular training set. The proposed method generates diverse SMILES (or DeepSMILES) encoded molecules while also showing some propensity at training set distribution matching. When working with DeepSMILES, the method reaches peak performance ($$>340,000$$ > 340 , 000 molecule/s) because it relies almost exclusively on string operations. The “Fast Assembly of SMILES Fragments” software is released as open-source at https://github.com/UnixJunkie/FASMIFRA. Experiments regarding speed, training set distribution matching, molecular diversity and benchmark against several other methods are also shown.

PVD-Hartstoffschichten für Schleifwerkzeuge zum Bearbeiten von Superlegierungen/Wear resistant PVD coatings for cBN grinding tools

Das Aufbringen von Beschichtungen bei Werkzeugen mit geometrisch bestimmter Schneide gehört seit vielen Jahren zum Stand der Technik. Die Hartstoffschichten werden häufig mittels PVD-Technik auf dem Substrat abgeschieden. Die Schichten zeichnen sich durch eine hohe Härte und Verschleißbeständigkeit, sowie gute tribologische und chemische Eigenschaften aus. Dieses Eigenschaftsprofil bietet somit auch großes Potenzial zur Standzeitverbesserung von thermisch und mechanisch hochbeanspruchten Schleifwerkzeugen bei der Bearbeitung von Superlegierungen. In diesem Beitrag werden unterschiedliche Schichtsysteme auf ihre Anwendbarkeit auf galvanisch gebundene cBN-Schleifwerkzeuge untersucht und diskutiert.   The application of coatings to cutting tools with geometrically defined cutting edge has been state of the art for many years. The coatings are often deposited on the substrate using PVD technology. The coatings are characterized by high hardness and wear resistance as well as good tribological and chemical properties. Therefore, this property profile also offers great potential for improving the tool life of grinding wheels that are subject to high thermal and mechanical stress, especially during grinding difficult to machine materials. In the following article, different coatings are examined and discussed for their applicability to electroplated cBN grinding tools.

Sulfoxide hemithioindigo tweezers – visible light addressable capture and release

Hemithioindigo based molecular tweezers with a comprehensively improved property profile are obtained by simple oxidation of the sulfur atom.

Characterization of Biomethanol–Biodiesel–Diesel Blends as Alternative Fuel for Marine Applications

The ambitious new International Maritime Organization (IMO) strategy to reduce greenhouse gas emissions from ships will shape the future path towards the decarbonization of the fleet and will bring further ecological challenges. In order to replace the larger oil-based part of marine fuel with components from renewable sources, it is necessary to develop multi-component blends. In this work, biomethanol and biodiesel with two additives—dodecanol and 2-ethylhexyl nitrate—in 20 blends with marine diesel oil (MDO) were selected as alternative components to replace the pure marine diesel oil-based part of marine fuel. For this purpose, two base blends of diesel and biodiesel with and without additives were produced with biomethanol from 0 to 30% (volume basis). Of all the blends, the blends with 5% (volume basis) methanol had the best property profile in terms of density, kinematic viscosity, calorific value, cloud point, and cetane index according to the ISO 8217:2017 standard (DMB grade) in compliance with the IMO requirements for marine fuels. However, the flash point must be increased. The boiling behavior of the blends was also investigated. A cluster analysis was used to evaluate the similarity between the blends based on their different physical properties.