Hydrogen Assisted Fracture of 30MnB5 High Strength Steel: A Case Study

When steel components fail in service due to the intervention of hydrogen assisted cracking, discussion of the root cause arises. The failure is frequently blamed on component design, working conditions, the manufacturing process, or the raw material. This work studies the influence of quench and tempering and hot-dip galvanizing on the hydrogen embrittlement behavior of a high strength steel. Slow strain rate tensile testing has been employed to assess this influence. Two sets of specimens have been tested, both in air and immersed in synthetic seawater, at three process steps: in the delivery condition of the raw material, after heat treatment and after heat treatment plus hot-dip galvanizing. One of the specimen sets has been tested without further manipulation and the other set has been tested after applying a hydrogen effusion treatment. The outcome, for this case study, is that fracture risk issues only arise due to hydrogen re-embrittlement in wet service

Antifragile Philosophy in R&D Projects: Applying Q Methodology and the Possibility of Open Innovation

Antifragile philosophy can be the key to improving the management of organizations that base their activity on research and development (R&D) projects. These are types of projects with the greatest uncertainty in all aspects, and the application of antifragile philosophy can result in streamlining their management and development. In this article, the Q methodology is used to investigate whether organizations in R&D environments have antifragile characteristics. To this end, 15 innovation experts from research institutes located in Northern Spain were interviewed about their position regarding project management behaviors that are related to antifragile philosophy. As a result, it was verified that the characteristics of an ideal system of a research institute with antifragile philosophy are multidisciplinary and autonomous teams with a capacity for rapid response and adaptation to the environment

Wear And Friction Evaluation Of Different Tool Steels For Hot Stamping

The aim of this work is to investigate the durability of tool steels for hot stamping by comparing the wear resistance of three hot work tool steels. Friction and wear behaviours of different tool steels sliding against a 22MnB5 uncoated steel at elevated temperatures were investigated using a high-temperature version of the Optimol SRV reciprocating friction and wear tester at temperatures of 40 and 200°C. Our results show that friction decreased with increasing temperature, whereas wear of the tool steel increased with temperature for the second and the third tested tool steels. The slightly better wear behaviour of steel specimen 1 comes from the hardness of the carbides in the martensitic microstructure, which are rich in vanadium.The authors gratefully acknowledge the funding provided by the Department of Research and Universities of the Basque Government under Grant no. IT947-16 and the University of the Basque Country UPV/EHU under Program no. UFI 11/29

Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels

Most high-hardness tool steels comprising forming dies require expensive finish machining operations to compensate for the dimensional distortion and surface oxidation caused by the die heat treatment. Precipitation-hardening (PH) tool steels allow for soft finish machining followed by an aging treatment without major deformation or oxidation in the die, but exhibit poor wear performance owing to the lack of carbides in their structure. This drawback can be overcome by combining laser cladding technology, austenite retention, and cryogenic treatments. Hence, an alternative die manufacturing route based on laser cladding was explored. The forming surface of a modified chemistry tool steel die was subjected to cladding. The martensite finish (M-f) temperature of the steel was tuned to enhance austenite retention at room temperature. The cladded surface was then machined in a reduced-hardness condition resulting from retained austenite formation. Subsequent deep cryogenic treatment of the die favoured the retained-austenite-to-martensite transformation, thereby increasing the die hardness without major distortion or oxidation. This process combined the advantages of high-carbide-bearing tool steels and PH steels, allowing for a die with hardness exceeding 58 HRC to be finish machined at <52 HRC. Controlling the occurrence of retained austenite represents an effective strategy for achieving new manufacturing scenarios.The authors gratefully acknowledge the funding provided by the Department of Research and Universities of the Basque Government under Grant No. IT947-16 and the University of the Basque Country UPV/EHU under Program No. UFI 11/29

Comparing conventional and microwave-assisted heating in PET degradation mediated by imidazolium-based halometallate complexes

The catalytic activity of two halometallate complexes based on imidazolium cations, (dimim)[FeCl4] (1) and (dimim)2[Fe2Cl6(μ-O)] (2), was evaluated in the glycolysis of polyethylene terephthalate (PET), either under conventional heating or microwave-assisted conditions. The two procedures led to the formation of bis(2-hydroxyethyl)terephthalate (BHET) as the major product with high yields, also allowing the isolation and structural characterization of a new polymorph. The influence of the halometallate structure on the catalytic activity was investigated, and additional experimental studies proved the involvement of both the imidazolium cation and metal anion in the reaction mechanism. The comparison of both approaches showed the advantages of the microwave methodology in terms of efficiency and time saving. Indeed, the use of ground PET and microwave heating provided quantitative yields of BHET. Under conventional heating conditions, the dinuclear iron complex gave a slightly lower yield than (dimim)[FeCl4] (74% vs. 77% for post-consumer PET) after 24 h of reaction. However, the microwave-assisted process led to comparable results in remarkably shorter reaction times (2 h). Interestingly, complex 2, containing the dipolar [Fe2Cl6(μ-O)]2− moiety, provided higher yields than 1 with the non-dipolar [FeCl4]− anion (77% vs. 69%). This behaviour has been rationalized on the basis of dielectric heating mechanisms (polarization and conduction), and it suggests a new approach towards obtaining more efficient catalysts by tailoring the catalytic species to be active in both heating mechanisms.Financial support from the Spanish Ministerio de Ciencia e Innovación (Projects MAT2014-55049-C2-R and MAT2016-75883-C2-1-P), Universidad del País Vasco/EuskalHerrikoUnibertsitatea (GIU17/50 and PPG17/37). Universidad de Cantabria (Proyecto Puente convocatoria 2018 financed by SODERCAN-FEDER)

Aerogels of 1D Coordination Polymers: From a Non-Porous Metal-Organic Crystal Structure to a Highly Porous Material

The processing of an originally non- porous 1D coordination polymer as monolithic gel, xerogel and aerogel is reported as an alternative method to obtain novel metal- organic porous materials, conceptually different to conventional crystalline porous coordination polymer ( PCPs) or metal- organic frameworks ( MOFs). Although the work herein reported is focused upon a particular kind of coordination polymer ([ M( mu - ox)( 4- apy) 2] n, M: Co( II), Ni( II)), the results are of interest in the field of porous materials and of MOFs, as the employed synthetic approach implies that any coordination polymer could be processable as a mesoporous material. The polymerization conditions were fixed to obtain stiff gels at the synthesis stage. Gels were dried at ambient pressure and at supercritical conditions to render well shaped monolithic xerogels and aerogels, respectively. The monolithic shape of the synthesis product is another remarkable result, as it does not require a post- processing or the use of additives or binders. The aerogels of the 1D coordination polymers are featured by exhibiting high pore volumes and diameters ranging in the mesoporous/ macroporous regions which endow to these materials the ability to deal with large- sized molecules. The aerogel monoliths present markedly low densities ( 0.082- 0.311 g center dot cm - 3), an aspect of interest for applications that persecute light materials.This work has been funded by Ministerio de Economia y Competitividad (MAT2013-46502-C2-1-P), Eusko Jaurlaritza/Gobierno Vasco (Grant IT477-10) and Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (EHUA14/09, UFI 11/53, postdoctoral fellowship for Sonia Perez-Yanez). Technical and human support provided by SGIKer (UPV/EHU, MINECO, GV/EJ, ERDF, and ESF) is gratefully acknowledged

Bis(1,10-phenanthroline-κ2 N,N′)bis­(thio­cyanato-κN)cadmium

The title compound, [Cd(NCS)2(C12H8N2)2], has been obtained from the decomposition reaction of dithio­oxamide in a dimethyl­formamide solution containing 1,10-phenanthroline (phen) and Cd(NO3)2·4H2O. Its crystal structure is formed by monuclear CdII entities in which the metal atom is sited on a twofold rotation axis. The CdII atom is six-coordinated in the form of a distorted octa­hedron by two chelating phenanthroline mol­ecules and two thio­cyanate anions coordinated through their N atoms. In the crystal, C—H⋯N hydrogen bonds are established between the phenanthroline and thio­cyanate ligands of neighbouring complexes

Optimized manufacturing of gas diffusion electrodes for CO2 electroreduction with automatic spray pyrolysis

Despite being one of the most promising CO2 utilization strategies some aspects still hinder the scaling up of CO2 electroreduction processes. One of them is the fabrication of the electrodes, which is currently rudimentary and depends fundamentally on the human factor. Here, we report an automated spray pyrolysis technique coupled with a plasma surface treatment to fabricate Bi-based gas diffusion electrodes for a enhanced CO2 electroreduction to formate. Three fabrication parameters, namely i) spraying nozzle height, ii) step distance, and iii) ink flow rate, are evaluated to determine the optimal fabrication conditions. The results confirm the reproducibility of the fabrication method, improving the overall performance of the electrodes fabricated with a manual airbrushing method, and leading to formate rates of up to 10.1 mmol m-2 s-1 at 200 mA cm-2. Besides, plasma treatment can improve formate concentration by up to 12 % in comparison with the untreated electrode. As a result, this work provides novel insights into the development of more efficient methods to manufacture electrodes for CO2 electroreduction, which will eventually bring this technology closer to an industrial scale.The authors fully acknowledge the financial support received from the Spanish State Research Agency (AEI) through the projects PID2020-112845RB-I00, TED2021–129810B-C21, PID2019-104050RA-I00, and PLEC2022-009398 (MCIN/AEI/10.13039/501100011033). Jose Antonio Abarca gratefully acknowledges the predoctoral research grant (FPI) PRE2021-097200

Manganese(II) pyrimidine-4,6-dicarboxylates: Synthetic, structural, magnetic and adsorption insights into the system

A series of manganese(II) coordination polymers containing the bridging ligand pyrimidine-4,6-dicarboxylate (pmdc) have been prepared. The stoichiometries and structural features of these materials, which range from the one-dimensional (1D) chains in {[Mn(\ub5-pmdc)(H2O)3]\ub72H2O}n (1) and {[Mn2(\ub5-pmdc)2(H2O)5]\ub72H2O}n (2) to the two-dimensional layers in {[Mn(\ub53-pmdc)(H2O)]\ub7H2O}n (3) or the three-dimensional porous network in {[Mn(pmdc)] \ub7 2H2O}n (4), are extremely dependent on the synthetic conditions (i.e., temperature and solvent). In spite of the structural diversity of these systems, crystallographic studies revealed that the pmdc ligand typically displays a tetradentate \ub5-(\u3baO,\u3baN:\u3baO\u2032\u2032,\u3baN\u2032) coordination mode with the carboxylate groups almost coplanar with the pyrimidine ring [as in compounds 1 and 2 and compound 5 described below)]. In compound 3, the pmdc moiety adopts a pentadentate \ub53-(\u3baO,\u3baN:\u3baO\u2032\u2032,\u3baN\u2032:\u3baO) coordination mode. The thermal, magnetic, and adsorption properties of these systems were also studied. The results showed that these compounds behave as antiferromagnets as a consequence of ef\ufb01cient magnetic exchange through the pmdc bridges. Compound 4 possesses permanent porosity, as proved by gas sorption data (N2 at 77 K and CO2 at 293 K). Finally, the heteronuclear iron(II)/manganese(II) compound {[FeMn(\ub5-pmdc)2(H2O)5]\ub72H2O}n (5), which is isomorphous to 2, was also prepared and fully characterized

Slot-Die Process of a Sol–Gel Photocatalytic Porous Coating for Large-Area Fabrication of Functional Architectural Glass

The slot-die process is an appealing technology for the fabrication of coatings on large-area substrates. However, its application on the production of photocatalytic coatings based on sol–gel formulations remains virtually unexplored. Thus, assessing the suitable formulation of the sol and operational parameters that allow one to yield high-efficacy photocatalyst coatings is a current challenge. This work aims to analyze the transferability of titania sol formulation optimized for dip-coating processes to slot-die technology. In this sense, firstly, the sol formulation is optimized by analyzing the influence of several types of surfactants on the microstructural features and photoactivity of TiO2 coatings’ growth on glass substrates. All formulations rendered a meaningful porosity and nanoscopic anatase crystallites (11–15 nm) with optical band gap values close to the expectation (3.25–3.31 eV). Accordingly, the performance of the photocatalytic dye degradation was closely related to the porosity and crystallite size led by each titania sol, and no meaningful differences were found between the results provided by the coatings developed by dip-coating and the slot-die method, which demonstrates the capability of the latter for its application on a large-scale fabrication of photocatalytic coatings.This research was funded by the Basque Government (IT1291-19), the Spanish Ministry of Science and Innovation (MICINN project: PID2019-108028GB-C21), and the European Union’s Horizon 2020 research and innovation program (grant agreement N° 792103 SOLWARIS)