The production of 2D material flakes in large quantities is a rapidly evolving field and a cornerstone for their industrial applicability. Although flake production has advanced in a fast pace, its statistical characterization is somewhat slower, with few examples in the literature which may lack either modelling uniformity and/or physical equivalence to actual flake dimensions. The present work brings a methodology for 2D material flake characterization with a threefold target: (i) propose a set of morphological shape parameters that correctly map to actual and relevant flake dimensions; (ii) find a single distribution function that efficiently describes all these parameter distributions; and (iii) suggest a representation system—topological vectors—that uniquely characterizes the statistical flake morphology within a given distribution. The applicability of such methodology is illustrated via the analysis of tens of thousands flakes of graphene/graphite and talc, which were submitted to different production protocols. The richness of information unveiled by this universal methodology may help the development of necessary standardization procedures for the imminent 2D-materials industry.

Industrial applications of nanomaterials require large-scale production methods, such as liquid phase exfoliation (LPE). Regarding this, it is imperative to characterize the obtained materials to tailor parameters such as exfoliation medium, duration, and mechanical energy source to the desired applications. This work presents results of statistical analyses of talc flakes obtained by LPE in four different media. Talc is a phyllosilicate that can be exfoliated into nanoflakes with great mechanical properties. Sodium cholate at two different concentrations (below and at the critical micelar concentration), butanone, and Triton-X100 were employed as exfoliation medium for talc. Using recent published statistical analysis methods based on atomic force microscopy images of thousands of flakes, the shape and size distribution of nanotalc obtained using the four different media are compared. This comparison highlights the strengths and weaknesses of the media tested and hopefully will facilitate the choice of the medium for applications that have specific requirements.

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ResumoOs fluidos de corte são empregados no processo de retificação com o intuito de lubrificar e refrigerar a peça/rebolo, além de amenizar problemas que afetam a integridade superficial da peça e também melhoram a eficiência do processo. Os fluidos de corte são muito utilizados na retificação, porém são tóxicos, dificilmente degradáveis e nocivos ao meio ambiente. Dessa maneira, é pertinente a formulação de fluidos menos agressivos. Neste trabalho, avaliou-se o desempenho de óleos vegetais como fluidos de corte em comparação com o fluido de corte integral no processo de retificação do aço ABNT 4340 temperado e revenido com dureza média de 52 HRc. O desempenho dos fluidos consistiu na análise de rugosidade, formação de espuma e odor. A caracterização dos óleos foi realizada pela viscosidade, densidade, ponto de fulgor, corrosão, índice de acidez total, índice de iodo e de refração. Os resultados mostraram que as peças retificadas com óleos vegetais apresentaram rugosidades próximas às peças usinadas com fluido integral. Na caracterização, os óleos vegetais apresentaram maior viscosidade que o integral e suas densidades foram próximas. No resfriamento, os óleos vegetais foram capazes de resfriar mais as peças que o integral, além de corroer menos. Nos outros aspectos analisados, o óleo de soja foi o que apresentou melhor desempenho. Esses resultados comprovam a eficiência dos óleos vegetais e viabilidade do uso no processo. Palavras-chave: Óleos vegetais; Fluidos de corte; Processo de retificação; Manufatura ecologicamente correta. STUDY ON THE UTILIZATION OF VEGETAL AND INTEGRAL OILS USED AS CUTTING FLUID IN GRINDING PROCESS AbstractCutting fluids are used in the grinding process in order to lubricate and cool the piece/grinding wheel, besides all aviate problems that affect the surface integrity of the piece and also improve the efficiency of the process. Cutting fluids are widely used in the grinding process, but are toxic, hardly degradable and environmental hazard. Thus, it is pertinent the formulation of less aggressive fluids. This study evaluated the performance of vegetable oils as cutting fluids compared with the integral fluid cutting in the grinding process of the hardened AISI 4340 steel with average hardness of 52 HRc. The performance of the fluids was based in the analysis of the surface roughness, temperature, foaming and odor. The characterization of the oils was performed by viscosity, density, flash point, corrosion, index total acidity, iodine value and refractive. The results showed that the pieces rectified with vegetable oils presented close values of surface rougness the machined pieces with the integral fluid. In characterization, vegetable oils showed higher viscosity than the integral and their densities were close. On cooling process, the vegetable oils were able to cool down more than the integral, in addition to corrode less. In other analyzed aspects, soybean oils howed the best performance. These results prove the efficiency of vegetable oils and the feasibility of using in the pro...