Open Access
Influence of friction coefficient on the performance of cold forming tools
(MDPI, 2023) Barba Areso, Eneko; Salcedo Pérez, Daniel; Claver Alba, Adrián; Luri Irigoyen, Rodrigo; García Lorente, José Antonio; Ingeniería; Ingeniaritza
The automotive industry has undergone significant advancements and changes over time, resulting in the use of more complex parts in modern vehicles. As a consequence, the parts used in the manufacturing process are subject to higher stress levels, which reduce their service life. To mitigate this issue, surface treatments can be applied to improve the mechanical properties of the tools. In this study, we examined the impact of surface treatments on reducing tool stress during a cold forming process. The process involved reducing the thickness of a sheet from 6 mm to 2.5 mm, which generated high stresses in the tooling. We used finite element stress calculations to analyze the process and found that by reducing the friction coefficient to 0.1, tool stresses can be reduced by 20%, leading to an increase in tool life. Moreover, the press force and tool wear were also reduced by 18%. To validate the theoretical calculations, we performed field tests in a real manufacturing process.
Open Access
Estudio comparativo de las propiedades tribomecánicas de recubrimientos DLC depositados mediante HIPMINS con pulsos positivos sobre aceros herramientas
(2020) Claver Alba, Adrián; García Lorente, José Antonio; Escuela Técnica Superior de Ingeniería Industrial, Informática y de Telecomunicación; Industria, Informatika eta Telekomunikazio Ingeniaritzako Goi Mailako Eskola Teknikoa
Los recubrimientos DLC(Diamond Like Carbon)tienen gran importancia en la actualidad gracias a que combinan excelentes propiedades; como una dureza relativamente alta y coeficiente de fricción muy bajo, con la posibilidad de personalizar las propiedades utilizando elementos dopantes como Cr, W, Si o H entre otros en su composición. Uno de los problemas de este tipo de recubrimientos es que su adherencia no es tan buena como la de otros recubrimientos PVD. En este estudio se analizarán las propiedades tribomecánicas (adhesión, nanodureza, resistenciaal desgaste...) de recubrimientos DLC mediante el empleo del innovadorsistema de HIPIMScon pulsos positivos depositados sobre diferentes aceros herramienta. Este sistema mejora la adherencia de los recubrimientos con el substrato; aumentando así su interés industrial. Por tanto, el trabajo se centrará en la realización, análisis y comparación de los resultados de ensayos de nanoindentación, scratch test, fricción y desgaste.Los ensayos se llevaron a cabo sobre 3 aceros herramienta; vanadis-4, vancron yK-360, recubiertos con los DLC ta-Cy WC:C. Los aceros seleccionados son de gran interés por su aplicabilidad industrial y los recubrimientos mejoran considerablemente las propiedades tribológicas y la dureza superficial.Los resultadosobtenidos de los ensayos han mostrado un extraordinario comportamiento tribológico y mecánico de los recubrimientos; con valores de carga crítica LC3 en el scratch test superiores a los 70 N en alguno de los casos, durezas de entre 15 y 27 GPa dependiendo del recubrimientoy valores muy bajos de resistencia al desgaste en todos ellos.
Open Access
Improvement of the tribocorrosion properties of cemented carbide (WC-Tic-Co) samples with PVD coating
(MDPI, 2022) García Lorente, José Antonio; Claver Alba, Adrián; Marques, Mikel; Almandoz Sánchez, Eluxka; Fernández de Ara, Jonathan; Azkona, Ibon; Institute for Advanced Materials and Mathematics - INAMAT2
This study aims to investigate the improvement of the tribocorrosion properties of WC-TiC-Co substrates by coating them with hard coatings such as AlCrSiN using cathodic arc deposition. WC-TiC-Co is commonly used in the fabrication of machining and cutting tools; however, there are some materials such as titanium or stainless steel that are difficult to work with; furthermore, in aggressive environments or under high temperatures the performance of the machining tools can be affected, and a failure may occur. This coating is intended to ensure the correct performance of the tools in any conditions. The coatings were characterized by glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Tribocorrosion, tribology and corrosion tests were performed to evaluate the tribocorrosion properties of the samples. Furthermore, mechanical and adhesive properties of the coating were studied using scratch and nanoindentation tests. The results showed improved tribocorrosion properties in the samples combined with good adhesive and mechanical properties. These results show the possibility of using these coated materials in the most demanding cutting and machining applications.
Open Access
Study of effect of nickel content on tribocorrosion behaviour of nickel-aluminium-bronzes (NABs)
(MDPI, 2023) Berlanga Labari, Carlos; Claver Alba, Adrián; Biezma Moraleda, María Victoria; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
The simultaneous existence of mechanical erosion and electrochemical corrosion is a common scenario for engineering alloys used in marine environments, such as pump impellers and valves. Nickel–aluminium–bronzes (NABs) are widely used alloys in these environments due to their combination of high corrosion resistance and effective mechanical properties. However, NAB alloys are increasingly cast with reduced nickel content due to its high price and low availability. In this study, we examined the tribocorrosion behaviour of two nickel–aluminium bronzes (C95500 and C95400) with different nickel contents (4.8% and 1.0%, respectively) by means of a pin-on-disk device combined with in situ electrochemistry under 1 M NaCl solution. We conducted tests for pure wear in distilled water, pure corrosion using in situ electrochemistry under 1 M NaCl solution, and a combination of wear and corrosion, called tribocorrosion, to understand the overall synergism that exists between the two. We analysed our results using gravimetric as well as volumetric analysis; in addition, we defined the friction coefficient to compare the effect of open-circuit potential (OCP). We also applied the Tafel method and compared corrosion rates for the different scenarios. We employed confocal microscopy to delimitate the impact of the surface topography of pure wear and its synergistic effect with corrosion, and used an optical microscope to study the materials’ microstructures as cast conditions. We also utilised XRD in the Bragg–Brentano configuration to determine the chemical composition of corrosion products. From the experiments conducted, we concluded that an important synergistic effect existed between the wear and corrosion of both NABs, which was associated with corrosion-induced wear. We found NAB C95400 to be more susceptible to erosion under both conditions compared with NAB C95500 due to the chemical composition and lubricant effect of corrosion products formed during the tribocorrosion tests, which were supported by the enriched Ni corrosion products, particularly the presence of nickel-rich copper chloride, 3Cu3(CuNi)(OH)6CuCl2, in the C95500 alloy. We concluded that, because it increased the nickel content, the NAB alloy offered better wear and corrosion behaviour in sea water conditions due to its protective film nature.
Open Access
Study and optimization of the punching process of steel using the Johnson-Cook damage model
(MDPI, 2024) Claver Alba, Adrián; Hernández Acosta, Andrea; Barba Areso, Eneko; Fuertes Bonel, Juan Pablo; Torres Salcedo, Alexia; García Lorente, José Antonio; Luri Irigoyen, Rodrigo; Salcedo Pérez, Daniel; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
Sheet metal forming processes are widely used in applications such as those in the automotive or aerospace industries. Among them, punching is of great interest due to its high productivity and low operating cost. However, it is necessary to optimize these processes and adjust their parameters, such as clearance, shear force or tool geometry, to obtain the best finishes and minimize crack generation. Thus, the main objective of this research work is to optimize the punching process to achieve parts that do not require subsequent processes, such as deburring, by controlling the properties of the starting materials and with the help of tools such as design of experiments and simulations. In the present study, tensile tests were performed on three steels with different compositions and three sample geometries. The information obtained from these tests has allowed us to determine the parameters of the Johnson-Cook damage criteria. Moreover, punching was performed on real parts and compared with simulations to analyze the percentage of burnish surface. The results obtained show that the methodology used was correct and that it can be extrapolated to other types of die-cutting processes by reducing the percentage of surface fractures and predicting the appearance of cracks. Furthermore, it was observed that clearance has a greater influence than processing speed, while the minimum percentage of the burnish area was observed for the minimum values of clearance.
Open Access
Biodegradable magnesium alloys for personalised temporary implants
(MDPI, 2023) Hendea, Radu Emil; Raducanu, Doina; Claver Alba, Adrián; García Lorente, José Antonio; Cojocaru, Vasile Danut; Nocivin, Anna; Stanciu, Doina; Serban, Nicolae; Ivanescu, Steliana; Trisca-Rusu, Corneliu; Campian, Radu Septimiu; Institute for Advanced Materials and Mathematics - INAMAT2
The objective of this experimental work was to examine and characterise the route for obtaining demonstrative temporary biodegradable personalised implants from the Mg alloy Mg10Zn-0.5Zr-0.8Ca (wt.%). This studied Mg alloy was obtained in its powder state using the mechanical alloying method, with shape and size characteristics suitable for ensuing 3D additive manufacturing using the SLM (selective laser melting) procedure. The SLM procedure was applied to various processing parameters. All obtained samples were characterised microstructurally (using XRD—Xray diffraction, and SEM—scanning electron microscopy); mechanically, by applying a compression test; and, finally, from a corrosion resistance viewpoint. Using the optimal test processing parameters, a few demonstrative temporary implants of small dimensions were made via the SLM method. Our conclusion is that mechanical alloying combined with SLM processing has good potential to manage 3D additive manufacturing for personalised temporary biodegradable implants of magnesium alloys. The compression tests show results closer to those of human bones compared to other potential metallic alloys. The applied corrosion test shows result comparable with that of the commercial magnesium alloy ZK60.
Open Access
Study of the industrial application of diamond-like carbon coatings deposited on advanced tool steels
(MDPI, 2024) Barba Areso, Eneko; Claver Alba, Adrián; Montalá, Francesc; Luis Pérez, Carmelo Javier; Sala, Neus; Colominas, Carles; García Lorente, José Antonio; Ingeniería; Ingeniaritza
The utilization of diamond-like carbon (DLC) coatings has emerged as a promising strategy to enhance the performance, durability, and functionality of industrial tools and components. Recognized for their exceptional attributes such as hardness, wear resistance, low friction, and biocompatibility, DLC coatings have achieved widespread acclaim for their potential to improve the capabilities of tool steels for different applications. This present study shows a comprehensive investigation into the application of DLC coatings on a diverse range of tool steel substrates, encompassing 1.2379, 1.2358, Caldie, K340, HWS, and Vanadis 4. The main aim is to show the effects of DLC coatings on these substrates and to provide an in-depth analysis of their properties during forming processes. Furthermore, this study explores the practical utilization of DLC-coated tool steel components, with a particular focus on their role in cold forming dies. Additionally, the study reviews the application of duplex treatments involving plasma nitriding to enhance DLC coating performance. To sum up, this study pursues a threefold objective: to investigate DLC coatings’ performance on diverse tool steel substrates; to assess the potential for improvement through nitriding; and to evaluate the behavior of DLC coatings in the cold stamping of S235 steel, which is of great technological and industrial interest to the cold forging sector.
Open Access
Improved adhesion of the DCL coating using HiPIMS with positive pulses and plasma immersion pretreatment
(MDPI, 2021) Gómez Alonso, Íñigo; Santiago, José A.; Fernández, Iván; Diaz, Cristina; Mändl, Stephan; García Lorente, José Antonio; Claver Alba, Adrián; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería; Gobierno de Navarra / Nafarroako Gobernua, 0011-1408-2018-000000
Diamond-like carbon (DLC) coatings are used due to their extraordinary tribomechanical properties, great hardness, high elastic modulus, high wear resistance, low friction coefficient and chemical inertness, which provide them with biocompatibility. Compared to other physical vapor deposition (PVD) coatings of transition nitrides and carbonitrides, DLC has limited adhesion, so it is necessary to develop new techniques to overcome this limitation. This work reports the results of scratch testing for the measurement of adhesion and of tests for wear resistance and nanoindentation in AISI 316L stainless steel coated with a WC:C coating, produced using novel high-power impulse magnetron sputtering (HiPIMS) technology with positive pulses. In addition, the use of a preceding surface modification technique, specifically plasma immersion ion implantation (PIII), was studied with the aim of optimizing the adhesion of the coating. The results show how the coating improved the tribomechanical properties through the use of positive pulse HiPIMS compared to conventional HiPIMS, with an adhesion result that reached critical load values of 48.5 N and a wear coefficient of 3.96 × 10−7 mm3/nm.
Open Access
Recycling bovine ear tags for phase change material encapsulation via electrospinning
(Elsevier, 2025-10-01) Alfonso de Miguel, Iker; Calvo-Correas, Tamara; Eceiza, Arantxa; Claver Alba, Adrián; Torresi, Stefano; García Lorente, José Antonio; Zalakain Iriazabal, Iñaki; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this study, thermoplastic polyurethane (TPU) from waste bovine ear tags has been processed and recycled as shell material to encapsulate phase change materials (PCMs), enabling the fabrication of thermoregulating core-shell nanofibers via coaxial electrospinning. Notably, this process was achieved in few steps and without the need for heating equipment to melt the injected materials, enhancing its simplicity. Two PCMs were selected based on their melting points; octadecane (OCTA) near room temperature and eicosane (EICO) near body temperature. Composite fibers were prepared at different core solution concentrations (10, 20, 40 and 80 % w/v), with the highest encapsulation efficiency and thermal properties obtained for samples with 80 % (w/v). TPU/PCM electrospun nanofibers were observed by scanning electron microscopy (SEM) with average diameters between 400 and 700 nm. The Fourier transform infrared spectroscopy (FTIR) suggested no further chemical reactions during the fabrication process. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated good thermal stability, with latent heats of 62.9 2 J/g and 81.4 J/g for TPU/OCTA80 and TPU/EICO80 membranes, respectively. Thermal cycling tests were conducted for 150 cycles, showing a 5 % enthalpy reduction in TPU/OCTA80 due to crystalline phase degradation, while TPU/EICO80 exhibited a 2 % increase, likely due to PCM restructuring; however, long-term trends suggest a potential decline. This simple, cost-effective and environmentally friendly fabrication process highlights the potential of upcycling TPU waste and offers a scalable approach for developing TPU/PCM membranes with promising applications in textile thermal management systems.
Open Access
Duplex treatments prepared by HiPIMS and sol-gel on biodegradable ZK60 magnesium alloy for biomedical applications
(Elsevier, 2025-09-01) Claver Alba, Adrián; Quintana, Iban; Fernández, Iván; Santiago, José A.; Díaz-Rodríguez, Pablo; Panizo-Laiz, Miguel; Zalakain Iriazabal, Iñaki; Urroz Unzueta, José Carlos; García Lorente, José Antonio; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua
The utilization of magnesium-based biomaterials in biomedical applications has grown considerably in recent years due to their favourable biocompatibility, biodegradability, and mechanical properties that closely resemble those of bones. However, the use of Mg-based alloys in aggressive environments, such as human bodily fluids, is hindered by their susceptibility to rapid corrosion, which compromises their mechanical properties. This can lead to infections in the body due to uncontrolled corrosion. In this study, a novel approach was employed to enhance the corrosion resistance of biodegradable ZK60 magnesium alloy and achieve optimal surface properties that can potentially enhance its antibacterial performance, hardness, and toughness. This approach involved the application of duplex treatments consisting of TiN doped with Cu coatings deposited via high power impulse magnetron sputtering (HiPIMS) followed by a Sol-gel top layer. The study systematically investigated the surface properties (wettability, roughness, and morphology), hardness, toughness and adhesion of the coatings to the substrate. To assess the corrosion resistance, mass change and hydrogen evolution of the samples, they were immersed in Hanks Balanced Salts Solution. Electrochemical tests were conducted to estimate the corrosion behavior of the samples. The in-vitro corrosion tests results demonstrated that the duplex treatments enhanced the corrosion resistance of the uncoated magnesium alloy samples. The duplex treatments exhibited suitable properties, including high corrosion resistance, hardness, toughness and adequate values of wettability and porosity-roughness. Therefore, they can be considered a promising option for use in biodegradable magnesium implants.