Browsing by Keyword "Coating"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Bringing non-isocyanate polyurethanes closer to industrial implementation using carbonated soybean oil-based amino hardeners(2023-12) Centeno-Pedrazo, Ander; Freixa, Zoraida; Feola, Roland; Lunzer, Florian; Garcia-Suarez, Eduardo J.; Ortiz, Pablo; Tecnalia Research & Innovation; BIOECONOMÍA Y CO2The polyaddition between cyclic carbonates and diamines to form non-isocyanate polyurethanes (NIPUs) is a safer alternative than traditional PU synthesis. However, the lower reactivity of cyclic carbonates requires of long reaction times and/or high temperatures for their curing, hampering their industrial implementation in the coating industry. Starting from carbonated soybean oil (CSBO) and amine excess, and through a stepwise addition process, cyclic carbonate full conversion has been achieved, yielding amino-terminal NIPUs with up to 62 % of biobased content. These amino-terminal NIPUs act as regular amino hardeners, and have been used to cure epoxy resins under the time and temperature required by the coating industry. The performance of these partially bio-based, NIPU-epoxy hybrid coatings was evaluated by pot-life, drying, hardness and solvent resistance, achieving comparable results to the industrial formulations. The simple synthesis process, the suitable curing conditions and the properties of the coatings, bring NIPU chemistry closer to industrial implementation.Item An experimental investigation of the effect of coatings and cutting parameters on the dry drilling performance of aluminium alloys(2006-02) Rivero, A.; Aramendi, G.; Herranz, S.; De Lacalle, L. N.López; SGAs a result of the need to automate assembly in the aircraft industry, along with economic and ecological reasons, industry and research institutions have been pushed to develop dry drilling for aluminium alloys to eliminate the need for cooling fluids. The main difficulties in dry drilling are accelerated tool wear due to workpiece material adhesion on the tool and the formation of bigger-sized burrs. This paper describes an experimental research study on machinability in the dry drilling of aluminium alloys and on the potential of the new design of tools and coatings. Dry drilling tests were performed using uncoated drills and two different coatings produced by means of an arc evaporation PVD process. Experiments consisted of machining with a 10-mm diameter three-edged drill to produce 25-mm deep holes. Tool wear evolution and burr size were analysed, as well as the impact of the process parameters on torque, power, feed force and tool temperature.Item Pathologies of a Glass Building Envelope that Affect Durability and Comfort(International Center for Numerical Methods in Engineering, 2020) Santamaria-Fernande, Susana; Eizaguirre-Iribar, Arritokieta; OlanoAzkune, Xabier; Serrat, Carles; Casas, Joan Ramon; Gibert i Armengol, Vicente; Ingenieria del FuegoThe durability of materials used in buildings has been widely studied and, in many cases, there are standards to assess it. However, studies on how pathologies affect the durability and comfort of the building users are not so common. The aim of this article is to explain different pathologies of the building envelope, considering glass as its main element and to analyze the causes of those pathologies, agents involved, and how they have affected durability. For that purpose, different cases of pathologies were analyzed on-site, both during the construction process and during the final use of the building. The effects of the different pathologies were also assessed. In each case, the technical data sheets available of the materials involved and the information on the design and the expected performance of the constructive solution were compiled. In some cases, the pathologies had caused an irreversible damage, so, the solution had to be drastic; while in other cases, they were detected early enough to propose remedial actions without affecting the final durability of the building. After having analyzed the different cases, the agents causing the pathology or those responsible for it and the phase in which the pathology occurred were identified. As a result, remedial actions were proposed to avoid the generation of pathologies during the design, construction and maintenance processes that affect the durability of the building and their user's comfort.Item Research on coatings and infiltration to strengthen ceramic lost cores used in high pressure die casting processes(Stowarzyszenie Techniczne Odlewnikow Polskich/Polish Foundrymen's Association, 2018) Merchán, Mikel; De Cortázar, Maider García; Galarraga, Haize; Bárcena, Jorge; Artola, Antxon; CIRMETAL; EXTREMATLost cores used to manufacture complex aluminium components through High Pressure Die Casting (HPDC) processes need to withstand very high pressures. Conventional sand cores used in other casting processes, such as sand casting or low pressure die casting, do not support these pressures, so advanced ceramic cores must be used. These cores must be strong enough to withstand the casting process and, at the same time, have enough porosity to be easily removed to obtain the finished part. Due to this porosity, aluminium penetrates the core surface during the casting process. In this work, two research lines have been followed to address this problem: application of coatings to seal the surface and infiltration with silica.Item Zirconia coating of carbon nanotubes by a hydrothermal method(2008-11) Garmendia, N.; Bilbao, L.; Muñoz, R.; Imbuluzqueta, G.; García, A.; Bustero, I.; Calvo-Barrio, L.; Arbiol, J.; Obieta, I.; PRINTEX; SISTEMAS FOTOVOLTAICOS; Tecnalia Research & InnovationCarbon nanotubes have unique mechanical properties that open attractive possibilities in many fields, such as the biomedical one. Currently, zirconia ceramics are widely used as femoral heads, but case studies show that delayed failure can occur in vivo due to crack propagation. Nanotubes could avoid the slow crack propagation and enhance the toughness of the ceramic material used for prostheses fabrication. In this work, single-wall carbon nanotubes and multi-wall carbon nanotubes have been partially coated with nanozirconia via hydrothermal synthesis and characterized by several techniques: X-ray diffraction, infrared spectroscopy, scanning electron microscope, transmission electron microscope, electron energy loss spectra, X-ray photoelectronic spectroscopy and atomic force microscopy. By means of these techniques, the existence of bonds between zirconium and the carbon nanotube has been proved. The as covered nanotubes should offer a better wettability in the ceramic matrix and improve the dispersion of the carbon nanotubes, to obtain the desired new ceramic biomaterial with a longer lifetime and better reliability.