Nanoparticulate sol-gel pretreatments as barrier coatings and adhesion promoters for metallic corrosion protection

The Spanish University Carlos III de Madrid has developed sol-gel coatings for the corrosion protection of alloys. Sol-gel coatings represent a physical barrier between the metallic substrate and the aggressive environment of exposition and act as adhesion promoters through interfacial bonding. Optimization of the coating’s properties may be easily achivied by changing the processing parameters and formulation of the layer. Interest in licensing the applied patent or technical cooperation with companies that would like to incorporate this technology

Protección frente a la corrosión metálica mediante pretratamientos sol-gel nanoparticulados promotores de adhesión metal/pintura orgánica

La Universidad española Carlos III de Madrid ha desarrollado recubrimientos de tipo sol-gel aplicados para la protección frente a la corrosión de aleaciones metálicas. Dichos recubrimientos constituyen una barrera física entre el metal y los agentes agresivos externos y aumentan la adherencia metal/pintura orgánica de aplicación posterior mediante uniones en interfase. La modificación de las variables del proceso de síntesis y la formulación del recubrimiento permiten optimizar sus propiedades. Se busca la licencia de la patente solicitada o un acuerdo de cooperación técnica con empresas que deseen incorporar esta tecnología

Feedstocks development for Metal Injection Moulding

Today, more tan 90% of used feedstock for MIM in Europe, came from BASF (exclusive patent), with low possibility for change compositions or costs (in Japan or USA, the percentage is quite smaller). In our research group (Powder Technology Group) we can develop new feedstocks formulation that can be used directly by the MIM parts manufacturers and fulfilling their composition requirements. Interest in licensing the applied patent or commercial agreement with technical assistance with companies that would like to incorporate this technology

Desarrollo de feedstocks para el moldeo por inyección de metales (MIM).

En la actualidad, más del 90% del feedstock utilizado en Europa, es un feedstock que se vende bajo patente de la multinacional BASF, con escasas posibilidades de modificación en cuanto a composiciones y con poco margen de costes (en Japón o EEUU el porcentaje es muy inferior). Nuestro grupo de investigación, Grupo de Tecnología de Polvos (GTP), está capacitado para el desarrollo de feedstocks a medida y con posibilidad de ser desarrollado ‘in situ’ por y para cualquier fabricante de piezas vía MIM. Se busca la licencia de la patente solicitada o acuerdo comercial con asistencia técnica con empresas que deseen incorporar esta tecnología

Oxidation and corrosion protection by halide treatment of powder metallurgy Ti and Ti6Al4V alloy

The aim of this work is to study the effect of halide treatment in powder metallurgy Ti-6Al-4V alloy, in order to improve high temperature oxidation and electrochemical corrosion resistance. Halide treatment was performed by immersing samples in a powder mixture containing 3 wt% NH4Cl, at 200 degrees C and 950 degrees C. Oxidation resistance was assessed by exposure to 600 degrees C for 300 h. The microstructure and phase constitution of the formed oxide layers was characterized. Corrosion resistance in aircraft simulated environment was evaluated with electrochemical impedance spectroscopy. Notable improvement in oxidation and corrosion resistance was observed for samples treated at 200 degrees C.The authors wish to thank the Ministry of Education and Science for funding through R&D Project MAT2012-38650-C02-01, and the Community of Madrid for its funding through ESTRUMAT program (S-2009/MAT-1585)

Estudio de la síntesis de polvos de la fase MAX Ti3SiC2 por sinterización sin presión

MAX phases exhibit excellent combination of ceramic and metallic-like properties. In this work, MAX phase Ti3SiC2 powder was synthesized starting-off with different combinations of elemental powders and carbides. The powders used were Ti, Si, C, SiC and TiC in different combinations, molar ratios and powder size. Powders were heat treated on a vacuum furnace for different times and temperatures for in situ production of the Ti3SiC2 MAX phase. High purity synthesized samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to identify and quantify the different phase constituents present. The main phase constituents in the powders produced were Ti3SiC2 and TiSi2. Up to 94% of Ti3SiC2 MAX phase was obtained using Ti:SiC:C as starting powders in a molar ratio of 3:1.5:0.5. Different phase constitution was observed on the surface and the centre of the samples. An optimal starting powder composition, molar ratio, heat treatment temperature and time is proposed for the formation of high purity Ti3SiC2 MAX phase. Selected mixture was studied thermodynamically and a reaction mechanism of formation of the MAX phase is proposed.Las fases MAX presentan una excelente combinación de propiedades cerámicas y metálicas. En este trabajo se sintetizaron polvos de fase MAX Ti3SiC2 a partir de diferentes combinaciones de polvos elementales y carburos. Los polvos utilizados fueron Ti, Si, C, SiC y TiC en diferentes combinaciones, proporciones molares y tamaño de partícula. Los polvos se sinterizaron en un horno de vacío a diferentes tiempos y temperaturas para la producción in situ de la fase MAX Ti3SiC2. Las muestras sintetizadas de alta pureza se analizaron mediante difracción de rayos X (XRD) y microscopía electrónica de barrido (SEM) para identificar y cuantificar las diferentes fases constituyentes presentes. Las principales fases constituyentes en los polvos producidos fueron de Ti3SiC2 y TiSi2. Se obtuvo hasta un 94% de fase MAX Ti3SiC2 utilizando como polvos de partida Ti:SiC:C en una proporción molar de 3:1,5:0,5. Se observó diferente formación de fase en la superficie y en el centro de las muestras. Finalmente, se propone una composición óptima de polvo de partida, relación molar, temperatura de sinterización y tiempo para la formación de la fase MAX de Ti3SiC2 de alta pureza. La mezcla seleccionada se estudió termodinámicamente y se propone un mecanismo de reacción para la formación de la fase MAX.The authors would like to thank the funding provided for this research by the Regional Government of Madrid (Dir. Gral. Universidades e Investigación) through the project P2018/NMT4411 (ADITIMAT-CM), the Spanish Government through the Ramón y Cajal contract RYC-2014-15014 and the project MAT2012-38650-C02-01

The effect of the organosilane content on the barrier features of sol-gel anticorrosive coatings applied on carbon steel

The main objective of this work was to determinate the influence of the molar ratio of two compounds on the structure of the molecular net synthesized by sol-gel technology for the protection corrosion coating on carbon steel. Three different molar ratio were use to prepared the organic–inorganic hybrid materials by hydrolysis and condensation of (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and tetraethylorthosilane (TEOS) in an ethanol/water solution. The behavior of the three different syntheses was evaluated by chemical, physical, and electrochemical methods. The evolution of the synthesis was determinate by FT-IR and viscosity until the optimal moment prior to apply the sol to the metallic substrate. Chemical cross-linking of xerogel was determined by solid state of 29Si-NMR and the behavior on thermal stability is given by TGA analysis. Samples of carbon steel were coated by the synthesis and the coatings were characterized using scanning electrochemical microscopy (SEM) finding considerably differences between the three coatings. Potentiodynamic polarization and impedance measurements were carried out to study the effect of the corrosion resistance of the synthesis in 10 mM NaCl solution.The authors acknowledge the financial support from the Regional Government of Madrid through the program MULTIMAT-CHALLENGE (S2013/MIT-2862). The authors acknowledge the financial support from the European Union and Government of Spain through the program RETOS COLABORACIÓN. RECORD (RTC-2015-3513-S) [i.e. RTC-2015-3513-5

Powder injection moulding: processing of small parts of complex shape

This paper is a revised and expanded version of a paper entitled ‘Torque rheology of zircon feedstocks for powder injection moulding’, presented at Feedstock Development for Powder Injection Molding of Zirconium Silicate PM2011 Euro Congress – Powder Injection Moulding – Processing, Barcelona, Spain, 9–12 October, 2011.Powder Injection Moulding (PIM), Metal Injection Moulding (MIM) when is limited to metals, is a fabrication route of parts with the final shape desired. This process combines the high capability of polymer injection moulding to produce complex shapes with the advantages of a powder route to process metallic, ceramic or composites materials. The process has some limitations that comes from different technological steps involved in the production of the part (feedstock production, injection, debinding and sintering). All of these different steps can be industrially controlled, being the PIM process a real alternative to produce complex parts in a high rate production method that can compete with many other processing methods to produce materials. In this work, we will go through the different steps of this manufacturing process, making special emphasis on the solutions provided by the powder technology group of the University Carlos III of Madrid (UC3M)

Thermal stability and degradation kinetics of feedstocks for powder injection moulding - A new way to determine optimal solid loading?

Degradation kinetics and the thermal stability of zircon powder injection moulding feedstocks (PIM) based on cellulose acetate butyrate (CAB) and polyethylene glycol (PEG) binders were investigated using simultaneous thermogravimetric analysis (STA). The initial decomposition temperature (IDT) and the integral procedure decomposition temperature (IPDT) were used to analyse the thermal stability of the binder system as a function of the solid loading content. The degradation kinetics was studied, and the degradation activation energy was assessed for varying zircon powder contents using isoconversional methods. All the methodologies revealed changes in the thermal degradation behaviours of the feedstocks for solid loadings that were previously determined to correspond to optimal solid loadings using other experimental procedures. These results may promote the proposal of thermodynamic degradation studies of feedstocks as an alternative or complementary technique to determine optimal solid loading contents in powder injection moulding (PIM). The studies in this paper also examined PIM process operation temperatures for zircon feedstocks.The authors also wish to thank GUZMÁN GLOBAL S.L. and MIMTECH ALFA for their collaboration on the ECOPIM project (ref. IPT-2011-0931-20000) that was funded by the Spanish Ministry of the Economy and Competitiveness. Furthermore, the authors would like to acknowledge the strong support from the ESTRUMAT projects (ref. S2009/MAT-1585), which were funded by the CAM-Consejería Educación Dir. Gral. Universidades e Investigación, and from the COMETAS project (ref. MAT2009/14448-C02-02), which was funded by the Spanish Ministry of the Economy and Competitiveness.Publicad

Torque rheology of zircon feedstocks for powder injection moulding

In this work, a cellulose acetate butyrate (CAB) and polyethylene glycol (PEG) blend is used as the binder system in a zirconium silicate mineral powder feedstock for powder injection moulding. These irregular zircon powders make the mixing process and the selection of an optimal solid loading level a difficult task. Torque rheology methodologies combined with other techniques are used for evaluation of the parameters affecting the mixing process and determination of the critical powder volume concentration (CPVC). Temperature variations during the mixing process are monitored and used as an indicator of the friction energy of the system and thus for the optimal solid loading selection. There have thus far been limited amounts of work conducted on torque rheology of highly loaded feedstocks that incorporate a study of the system's temperature evolution. A detailed study could be a key factor for understanding the mixing behaviour of highly loaded feedstocks.The authors would like to acknowledge the companies GUZMÁNGLOBAL S.L and ALFAMIMTech for their support and partnership in the project IPT-2011-0931-020000 granted from the Spanish Ministry of the Economy and Competitiveness and the European Funds for Regional Development (FEDER). They would also kindly thank the Applied Mechanics Department of FEMTO-ST Institute and the ENSMM (Besançon, France) where some of the experimental works were performed. The suggestions and technical support of T. Barriere and G. Michele were much appreciated