Among the forage species cultivated in South America, the genus Urochloa is the most used, and the cultivar Marandu of U. brizantha is the most widely planted in Brazil. The objective of this study was to evaluate forage performance in association with Azospirillum brasilense, combined with nitrogen (N) fertilisation. The study was conducted under field conditions in Araguaína, Tocantins, in the central region of Brazil, between March 2016 and March 2017. Four N fertiliser rates (0, 12.5, 25 and 50kg/ha of N per cutting cycle) were combined with two inoculation treatments (inoculated and non-inoculated), with evaluations carried out in three periods of the year (transition, dry and wet seasons). Marandu grass plants inoculated with A. brasilense had greater plant height, number of tillers and forage production than non-inoculated plants, regardless of the N rate. Inoculation with A. brasilense allowed a 20% reduction in N fertilisation. Our results indicate that inoculation with A. brasilense in Marandu grass, as well as increasing forage production, can help to mitigate the stresses caused by the dry season.

The consumption of dissolved oxygen (DO) during the corrosion of commercially pure magnesium specimens was investigated by localized corrosion techniques. The concentration of oxygen and the local current density on the near‐surface of magnesium were measured simultaneously by a micro‐optode DO sensor and the scanning vibrating electrode technique (SVET), respectively. Diamond microelectrodes were also used for DO mapping. Significant DO depletion was found since the initial immersion time of Mg in NaCl 0.5 m, and a correlation could be established between DO consumption and areas of anodic and cathodic activity. These findings assume particular relevance for the corrosion of Mg alloys or magnesium components with impurity levels higher than the tolerance limit. Moreover, this study points out the significance of the partial oxygen pressure as an influential parameter during magnesium corrosion.

Cobalt-cemented carbide micro-end mills were coated with diamond grown by chemical vapor deposition (CVD), with the purpose of micro-machining cemented carbides. The diamond coatings were designed with a multilayer architecture, alternating between sub-microcrystalline and nanocrystalline diamond layers. The structure of the coatings was studied by transmission electron microscopy. High adhesion to the chemically pre-treated WC-7Co tool substrates was observed by Rockwell C indentation, with the diamond coatings withstanding a critical load of 1250 N. The coated tools were tested for micro-end-milling of WC-15Co under air-cooling conditions, being able to cut more than 6500 m over a period of 120 min, after which a flank wear of 47.8 μm was attained. The machining performance and wear behavior of the micro-cutters was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Crystallographic analysis through cross-sectional selected area electron diffraction patterns, along with characterization in dark-field and HRTEM modes, provided a possible correlation between interfacial stress relaxation and wear properties of the coatings. Overall, this work demonstrates that high adhesion of diamond coatings can be achieved by proper combination of chemical attack and coating architecture. By preventing catastrophic delamination, multilayer CVD diamond coatings are central towards the enhancement of the wear properties and mechanical robustness of carbide tools used for micro-machining of ultra-hard materials.

Carbon‐on‐carbon materials carry the potential to be a major disruptive technology in fields like energy storage and electronics. In the present work, hot filament chemical vapor deposition (HFCVD) is used to synthesize carbon nanowall (CNW) tetrapods coupled to nanocrystalline diamond in a 3D hybrid network form. The CNW/diamond phase proportion as well as the structural morphology can be easily adjusted by the CVD parameters, allowing a single‐step synthesis of CNW micro‐ and nanopillars or CNW/diamond 3D hybrid materials, in the powder form or as interconnected free‐standing specimens. Additionally, the direct incorporation of SnO2 catalyst particles during the one‐step CVD process is demonstrated. µ‐Raman and electron microscopy are used to understand the evolution of the morphological characteristics associated to the growth mechanism. The electrowettability behavior of the novel CNW/diamond hybrid material is demonstrated by electrochemical polarization studies. Such multifunctional carbon‐based hybrid 3D nanomaterials can find promising applications in advanced technologies such as energy storage.

The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron-hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al-Cu-CFRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell.