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Titanium alloys are widely used as biocompatibles materials, due to their chemical stability inside of the body, a good relationship between density/resistance, fatigue resistance, corrosion resistance and other. The capacity of these materials to develop a naturally passive oxide layer on the surface, makinge them favorable for different applications. However, the stability of the film is affected by aggressive environment. Therefore, the surface modification process has been an alternative to improve the corrosion resistance, and some mechanical properties. This research evaluated the effect of the heating rate on the thermal oxidation of titanium alloys (Ti6Al4V). The method consisted in producing oxide films by thermal oxidation at 600, 700 and 800°C at different heating rates 3, 4 and 5 °Cmin-1 and isothermal cooling in furnace. Morphological characterization was carried out through Scanning Electronic Microscopy, and the corrosion resistance test was carried out by potentiodynamic polarization study using Ringer's solution as an electrolyte. The results showed the influence of the temperature and heating rate on the thickness of the oxide layer in factorial design 3². Thermally oxidized samples at 600 and 800°C showed the best results regarding corrosion resistance compared to untreated samples, and the hardness increased 2.5 fold in samples oxidized at 800°C compared to the base alloy. [ABSTRACT FROM AUTHOR]

En esta investigación se modela a partir de los parámetros del proceso el espesor de la capa de óxido y la microdureza de los aluminios Al3003 y Al6063 anodizados. Para ello se realizaron estudios de la microdureza y espesor de capa de la superficie anodizada, utilizando técnicas de análisis multifactorial y diseño robusto. Se establecieron los siguientes niveles de los parámetros del proceso: temperatura [15 °C, 25 °C], tiempo [30 min; 60 min], concentración de electrolito [1,2 M; 2 M], densidad de corriente [1 Amp/dm²; 3 Amp/dm²], aluminio [Al3003,Al6063] y como variable de ruido, la deformación plástica [0%, 10%, 20%, 30%]. Se propuso un diseño fraccionado 2(7-2) mixto, con el cual se efectuó un total de 48 pruebas usando soluciones electrolíticas de ácido sulfúrico. La medición de microdureza se realizó con un indentador Vickers con carga de 400 g; el espesor de la capa de óxido se captó mediante microscopia electrónica. A los resultados se les realizó un análisis de varianza (ANOVA), para determinar los factores significativos y la robustez de los efectos. Se encontraron resultados de microdureza [HV] [85,74-308,87]; y espesor de óxido [µm] [12,82- 94,69]. Finalmente, se muestran los modelos de predicción de cada una de las respuestas en función de los factores significativos estas ecuaciones permitirán seleccionar la microdureza y espesor de la capa de óxido para cumplir los requerimientos de un producto particular mediante una selección apropiada de los parámetros del proceso.In this research, the thickness of the oxide layer and the microhardness of anodized aluminum Al3003 and Al6063 are modeled based on process parameters. To this end, studies of the microhardness and the thickness layer of the anodized surface were made, via techniques of multifactorial analysis and robust design. The following levels of the process parameters were established: temperature [15°C, 25°C], time [30min; 60min], electrolyte concentration [1,2M; 2M], current density [1Amp/dm²; 3Amp/dm²], aluminum [Al3003, Al6063], and as a noise parameter, the plastic deformation [0%, 10%, 20%, 30%]. A combined fractional design 2(7-2) was proposed, based on which a total of 48 tests were performed using sulfuric acid electrolytic solutions. The measurement of microhardness was performed using a Vickers indenter loaded at 400g, and the thickness of the oxide layer was captured using electron microscopy. Variance analysis (ANOVA) was applied to the results in order to determine the significant factors and the robustness of the effects. Results of microhardness [HV] [85,74-308,87]; and the oxide layer thickness [µm] [12,82 – 94,69] were determined. Finally, the equations for the prediction models are shown for each response as a function of the significant factors, these equations will allow the selection of the microhardness and thickness of oxide layer to fulfill the requirements of a particular product using an appropriate selection of process parameters.

In this research, the thickness of the oxide layer and the microhardness of anodized aluminum Al3003 and Al6063 are modeled based on process parameters. To this end, studies of the microhardness and the thickness layer of the anodized surface were made, via techniques of multifactorial analysis and robust design. The following levels of the process parameters were established: temperature [15 °C, 25 °C], time [30min; 60min], electrolyte concentration [1,2M; 2M], current density [1Amp/dm2; 3Amp/dm2], aluminum [Al3003, Al6063], and as a noise parameter, the plastic deformation [0%, 10%, 20%, 30%]. A combined fractional design 27-2 was proposed, based on which a total of 48 tests were performed using sulfuric acid electrolytic solutions. The measurement of microhardness was performed using a Vickers indenter loaded at 400g, and the thickness of the oxide layer was captured using electron microscopy. Variance analysis (ANOVA) was applied to the results in order to determine the significant factors and the robustness of the effects. Results of microhardness [HV] [85,74-308,87]; and the oxide layer thickness [µm] [12,82-94,69] were determined. Finally, the equations for the prediction models are shown for each response as a function of the significant factors, these equations will allow the selection of the microhardness and thickness of oxide layer to fulfill the requirements of a particular product using an appropriate selection of process parameters. [ABSTRACT FROM AUTHOR]

In this research, the thickness of the oxide layer and the microhardness of anodized aluminum Al3003 and Al6063 are modeled based on process parameters. To this end, studies of the microhardness and the thickness layer of the anodized surface were made, via techniques of multifactorial analysis and robust design. The following levels of the process parameters were established: temperature [15°C, 25°C], time [30min; 60min], electrolyte concentration [1,2M; 2M], current density [1Amp/dm2; 3Amp/dm²], aluminum [Al3003, Al6063], and as a noise parameter, the plastic deformation [0%, 10%, 20%, 30%]. A combined fractional design 27-2 was proposed, based on which a total of 48 tests were performed using sulfuric acid electrolytic solutions. The measurement of microhardness was performed using a Vickers indenter loaded at 400g, and the thickness of the oxide layer was captured using electron microscopy. Variance analysis (ANOVA) was applied to the results in order to determine the significant factors and the robustness of the effects. Results of microhardness [HV] [85,74-308,87]; and the oxide layer thickness [µm] [12,82 – 94,69] were determined. Finally, the equations for the prediction models are shown for each response as a function of the significant factors, these equations will allow the selection of the microhardness and thickness of oxide layer to fulfill the requirements of a particular product using an appropriate selection of process parameters. [ABSTRACT FROM AUTHOR]