Valle Chiro, Jorge Antonio
Total activity: 23
Department
Department of Materials Science and Metallurgy
School
Barcelona School of Industrial Engineering (ETSEIB)
E-mail
jorge.antonio.valleestudiant.upc.edu
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1 to 23 of 23 results
  • Mechanical properties and resistance to low temperature degradation of surface nitrided 3Y-TZP

     Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Garcia Marro, Fernando; Anglada Gomila, Marcos Juan
    Journal of the european ceramic society
    Date of publication: 2013-12
    Journal article

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    3Y-TZP has been one of the most applied ceramics in the biomedical field, specifically for hip, knee and dental implants, given its high strength, moderate fracture toughness and excellent biocompatibility. However, hydrothermal degradation has meant an important disadvantage, as surface t-m transformation, followed by microcracking, can lead to the premature failure of the implant. In this work, surface nitriding at 1600, 1500 and 1400°C for 1, 2 and 4h with N2 gas and ZrN powder was applied and optimised to avoid hydrothermal degradation. Nitriding at 1600 and 1500°C produces a harder low-toughness surface, not adequate for structural implants. It is shown that the most favourable condition is nitriding at 1400°C for 1h, since the mechanical properties of the original 3Y-TZP are not affected with the advantage of retarding hydrothermal degradation by a factor close to 10.

    3Y-TZP has been one of the most applied ceramics in the biomedical field, specifically for hip, knee and dental implants, given its high strength, moderate fracture toughness and excellent biocompatibility. However, hydrothermal degradation has meant an important disadvantage, as surface t–m transformation, followed by microcracking, can lead to the premature failure of the implant. In this work, surface nitriding at 1600, 1500 and 1400 °C for 1, 2 and 4 h with N2 gas and ZrN powder was applied and optimised to avoid hydrothermal degradation. Nitriding at 1600 and 1500 °C produces a harder low-toughness surface, not adequate for structural implants. It is shown that the most favourable condition is nitriding at 1400 °C for 1 h, since the mechanical properties of the original 3Y-TZP are not affected with the advantage of retarding hydrothermal degradation by a factor close to 10.

  • Thermal stability in air of surface nitrided 3Y-TZP

     Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    Journal of the european ceramic society
    Date of publication: 2011-06
    Journal article

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    Surface nitriding can be optimised to protect 3Y-TZP against hydrothermal degradation and at the same time to keep the mechanical properties of the surface and the bulk unchanged. However, thermal stability is a concern that can limit its use above room temperature. In this work, surface nitrided 3Y-TZP was heat treated in air at 200, 400, 600 and 800◦C for 8 h. Treatments up to 600◦C did not change microstructure and Vickers hardness, but heating at 800◦C produced surface defects, inner cracks and grain decohesion, conducing to a dramatic decrease in mechanical strength. Heat treatments above 400◦C led to an increase of indentation fracture toughness and to a complete loss of the hydrothermal degradation resistance achieved by nitriding.

  • Sliding wear behaviour of surface nitrided zirconia

     Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Garcia Marro, Fernando; Anglada Gomila, Marcos Juan
    Congreso Ibérico de Tribología
    Presentation's date: 2011-06-16
    Presentation of work at congresses

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    Tetragonal polycrystalline zirconia stabilised with 3% molar yttria (3Y-TZP) has found wide applications in orthopaedics and dentistry because of its excellent mechanical properties (flexural strength above 1000 MPa, fracture toughness about 5 MPa·m1/2, hardness above 12 GPa) and biocompatibility. However, 3Y-TZP has a strong drawback: poor resistance to hydrothermal ageing also referred to as low temperature degradation (LTD). Nitriding of 3Y-TZP can make the surface resistance to LTD, but surface mechanical properties are also affected. In this work, the sliding wear resistances of as sintered and nitrided 3Y-TZP have been studied and compared. Nitriding has been carried out by embedding 3Y-TZP in a powder of ZrN and posterior heat treatment at 1400, 1500 and 1600 °C in a nitrogen atmosphere. The sliding wear behaviour of as sintered and nitrided surfaces was studied by means of ball on disc tests. The results show that by nitriding at 1400 °C the nitrided surface is resistance to LTD without any significant drop in the surface mechanical properties, so that it has similar sliding wear behaviour and surface mechanical properties as those of the starting 3Y-TZP. The results are discussed in terms of the change in the microstructure induced by nitriding.

  • Surface modification of 3Y-TZP with cerium oxide

     Garcia Marro, Fernando; Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    Journal of the european ceramic society
    Date of publication: 2010-11
    Journal article

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  • Relación entre integridad estructural y microestructura en la degradación hidrotérmica de 3Y-TZP

     de Armas Sancho, Zamir; Fargas Ribas, Gemma; Muñoz Tabares, Jose Alejandro; Garcia Marro, Fernando; Valle Chiro, Jorge Antonio; Kiran Chitapalli, Ravi; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    Sociedad Española de Cerámica y Vidrio
    Presentation's date: 2010-10
    Presentation of work at congresses

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  • Low temperature degradation of zirconia

     Valle Chiro, Jorge Antonio; Anglada Gomila, Marcos Juan; Gaillard, Yves; Jimenez Pique, Emilio; Mestra Rodríguez, Alvaro Miguel; Kiran Chitapalli, Ravi; de Armas Sancho, Zamir
    International Conference on Advanced Materials Research EEIGM / AMASE / FORGEMAT
    Presentation of work at congresses

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  • Nitruración de 3Y-TZP para evitar la degradación hidrotérmica

     Valle Chiro, Jorge Antonio; Jimenez Pique, Emilio; Gaillard, Yves; Anglada Gomila, Marcos Juan
    Congreso Nacional de Materiales
    Presentation's date: 2010-06-18
    Presentation of work at congresses

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  • Mecanismos de desgaste en policristales de circona dopada con 3% molar de itria

     Mestra Rodríguez, Alvaro Miguel; Hvizdos, Pavol; Valle Chiro, Jorge Antonio; Anglada Gomila, Marcos Juan
    Anales de mecánica de la fractura
    Date of publication: 2009
    Journal article

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    En el presente trabajo se estudia el comportamiento tribológico de policristales de circona dopada con 3% molar de itria con diferente tamaño de grano utilizando la técnica de desgaste por deslizamiento de bola sobre disco a diferentes velocidades. Se identifican los regímenes de desgaste en función de la velocidad y se ha encontrado que el daño ocurrido aumenta significativamente al aumentar la velocidad de deslizamiento. La transición del desgaste suave a severo ocurre a 10-5 mm3/mN, la cual coincide con los datos de la literatura. Los mecanismos de desgaste se discuten en detalle en función del régimen de desgaste. Se ha constatado que en el régimen de desgaste suave ambos materiales se comportan de forma similar mientras que, en el régimen de desgaste severo el material con tamaño de grano más pequeño presenta mejor resistencia al desgaste.-------- This paper studies the tribological behaviour of zirconia polycrystals stabilised by 3% of yttria with different grain size using a ball on disc technique in dry conditions at different sliding speeds. The wear regimes as a function of speed have been identified. The wear damage increased significantly with increasing sliding speed. The mild to severe wear transition occurred at the wear rate of 10-5 mm3/mN which is in accordance with literature data. The wear damage micromechanisms corresponding to various degrees of wear have been studied and discussed in detail. It has been found that at the low wear regime both materials behave identically while under more severe conditions the material with finer grains exhibited better wear resistance.

  • Nanoindentation of Yttria Doped Zirconia Under Hydrothermal Degradation

     Gaillard, Yves; Jimenez Pique, Emilio; Muñoz Tabares, Jose Alejandro; Valle Chiro, Jorge Antonio; Anglada Gomila, Marcos Juan
    Advances in Bioceramics and Porous Ceramics: Ceramic Engineering and Science Proceedings
    Date of publication: 2009-04-01
    Journal article

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  • Degradation resistance of 3Y-TZP ceramics sintered using spark plasma sintering

     Kiran Chitapalli, Ravi; Garcia Marro, Fernando; Valle Chiro, Jorge Antonio; Yan, Haixue; Reece, Michel; Anglada Gomila, Marcos Juan
    IOP Conference Series: Materials Science and Engineering (Online)
    Date of publication: 2009
    Journal article

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    Commercially available tetragonal zirconia powder doped with 3 mol% of yttria has been sintered using spark plasma sintering (SPS) and has been investigated for its resistance to hydrothermal degradation. Samples were sintered at 1100, 1150, 1175 and 1600ºC at constant pressure of 100 MPa and soaking for 5 minutes, and the grain sizes obtained were 65, 90, 120 and 800 nm, respectively. Samples sintered conventionally with a grain size of 300 nm were also compared with samples sintered using SPS. Finely polished samples were subjected to artificial degradation at 131 0C for 60 hours in vapour in auto clave under a pressure of 2 bars. The XRD studies show no phase transformation in samples with low density and small grain size (<200 nm), but significant phase transformation is seen in dense samples with larger grain size (>300 nm). Results are discussed in terms of present theories of hydrothermal degradation.

  • Improvement of 3Y-TZP hydrothermal degradation resistance by surface modification with ceria without impairing mechanical properties

     Garcia Marro, Fernando; Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    IOP Conference Series: Materials Science and Engineering (Online)
    Date of publication: 2009
    Journal article

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    Surface modification with cerium oxide of tetragonal zirconia polycrystals stabilised with 3 % molar yttria (3Y-TZP) has been investigated in order to avoid low temperature degradation. The surface modification was performed by annealing 3YTZP with surface coated CeO2 powder at temperatures of 1400 ºC and 1500 ºC for periods of time up to 10 hours. These heat-treatments diffused cerium up to about 10 mm depth. The bulk fracture toughness, Vickers hardness and Young modulus of the surface modified specimens showed no significant deviation as compared to the nontreated original material. Even the surface mechanical properties measured by penetration curves corresponding to nanoindentations of up to 2 mm depth, did not show significant differences after surface modification. All heat-treatments produced an increase in the surface grain size and a large increase in resistance to degradation.

  • Influence of hydrothermal degradation on wear behaviour of zirconia tetragonal polycristals doped with 3% molar of yttria

     Kiran Chitapalli, Ravi; Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    Anales de mecánica de la fractura
    Date of publication: 2009
    Journal article

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    The goal of this work is to analyse the influence of hydrothermal degradation on wear behaviour on samples of tetragonal polycrystals doped with 3% molar of yttria in air under dry sliding conditions on samples artificially aged at 0, 10 and 60 hours in autoclave at 131°C. The samples were prepared by conventional compaction and sintering at 1450°C. The study was carried out by performing scratch tests and ball on disc experiments against 3Y-TZP balls. At low loads the damage was not distinctive, but under high loads the damage mechanisms were different suggesting a clear effect of degradation after long ageing times. On the contrary, in samples degraded during 60 hours the wear rates in both experiments were initially higher than on non-aged specimens and decreased with increasing load and/or sliding distance.

  • Effect of ageing on scratch resistance of 3Y-TZP

     Hvizdos, Pavol; Chintapalli, Ravi Kiran; Valle Chiro, Jorge Antonio; Anglada Gomila, Marcos Juan
    Kovove materialy-Metallic materials
    Date of publication: 2009
    Journal article

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  • CENTRE D'INTEGRITAT ESTRUCTURAL I FIABILITAT DELS MATERIALS (CIEFMA)

     Salán Ballesteros, Mª Núria; Góez Úsuga, Alexey; Llanes Pitarch, Luis Miguel; Fargas Ribas, Gemma; Valle Chiro, Jorge Antonio; de Armas Sancho, Zamir; Zapata Dederlé, Ana Cristina; Heredero Alari, Francisco; Mestra Rodríguez, Alvaro Miguel; Mateo Garcia, Antonio Manuel; Coureaux Mustelier, David; Rueda Arango, Astrid Oasis; Camposilvan, Erik; Botero Vega, Carlos Alberto; Mir Carbonell, Jordi; Garcia Marro, Fernando; Jimenez Pique, Emilio; Kiran Chitapalli, Ravi; Muñoz Tabares, Jose Alejandro; Anglada Gomila, Marcos Juan
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  • ANÁLISIS MEDIANTE TOMOGRAFÍA ELECTRÓNICA DEL DAÑO POR ARENADO, ENVEJECIMIENTO Y FATIGA DE CONTACTO EN ESTRUCTURAS LAMINARES CERÁMICA

     Muñoz Tabares, Jose Alejandro; Kiran Chitapalli, Ravi; Salán Ballesteros, Mª Núria; Fargas Ribas, Gemma; de Armas Sancho, Zamir; Heredero Alari, Francisco; Rueda Arango, Astrid Oasis; Camposilvan, Erik; Jimenez Pique, Emilio; Mestra Rodríguez, Alvaro Miguel; Garcia Marro, Fernando; Valle Chiro, Jorge Antonio; Anglada Gomila, Marcos Juan
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  • RED DE NANOMECÁNICA

     Kiran Chitapalli, Ravi; Valle Chiro, Jorge Antonio; Garcia Marro, Fernando; Jimenez Pique, Emilio; Anglada Gomila, Marcos Juan
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  • Thermal stability in air of surface nitrided 3Y-TZP

     Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    International Conference on Advanced Materials Research EEIGM/AMASE/FORGEMAT
    Presentation's date: 2009-11
    Presentation of work at congresses

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  • Influence of hydrothermal degradation on wear behaviour of zirconia tetragonal polycrystals doped with 3% molar of yttria

     Kiran Chitapalli, Ravi; Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    Encuentro del Grupo Español de Fractura
    Presentation's date: 2009
    Presentation of work at congresses

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    The goal of this work is to analyse the influence of hydrothermal degradation on wear behaviour on samples of tetragonal polycrystals doped with 3% molar of yttria in air under dry sliding conditions on samples artificially aged at 0, 10 and 60 hours in autoclave at 131°C. The samples were prepared by conventional compaction and sintering at 1450°C. The study was carried out by performing scratch tests and ball on disc experiments against 3Y-TZP balls. At low loads the damage was not distinctive, but under high loads the damage mechanisms were different suggesting a clear effect of degradation after long ageing times. On the contrary, in samples degraded during 60 hours the wear rates in both experiments were initially higher than on non-aged specimens and decreased with increasing load and/or sliding distance.

  • Enhancing hydrothermal resistance of 3Y-TZP using ceria diffusion

     Garcia Marro, Fernando; Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Horwat, David; Anglada Gomila, Marcos Juan
    International Conference on Advanced Materials Research EEIGM/AMASE/FORGEMAT
    Presentation's date: 2009-11
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  • Improvement of 3Y-TZP hydrothermal degradation resistance by surface modification with ceria without impairing mechanical properties

     Garcia Marro, Fernando; Valle Chiro, Jorge Antonio; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    International Conference on Advanced Materials Research EEIGM / AMASE / FORGEMAT
    Presentation's date: 2009
    Presentation of work at congresses

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    Surface modification with cerium oxide of tetragonal zirconia polycrystals stabilised with 3 % molar yttria (3Y-TZP) has been investigated in order to avoid low temperature degradation. The surface modification was performed by annealing 3YTZP with surface coated CeO2 powder at temperatures of 1400 ºC and 1500 ºC for periods of time up to 10 hours. These heat-treatments diffused cerium up to about 10 mm depth. The bulk fracture toughness, Vickers hardness and Young modulus of the surface modified specimens showed no significant deviation as compared to the nontreated original material. Even the surface mechanical properties measured by penetration curves corresponding to nanoindentations of up to 2 mm depth, did not show significant differences after surface modification. All heat-treatments produced an increase in the surface grain size and a large increase in resistance to degradation.

  • Tribological behaviour of surface nitrided zirconia

     Valle Chiro, Jorge Antonio; Jimémez-Piqué, E.; Mestra Rodríguez, Alvaro Miguel; Anglada Gomila, Marcos Juan
    European Inter-Regional Conference on Ceramics
    Presentation's date: 2008-09-03
    Presentation of work at congresses

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  • Nitriding of 3Y-TZP surfaces to avoid hydrothermal degradation

     Valle Chiro, Jorge Antonio; Jimenez Pique, Emilio; Gaillard, Yves; Anglada Gomila, Marcos Juan
    Meeting of the European School of Materials Science and Engineering
    Presentation's date: 2007-06
    Presentation of work at congresses

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  • Fatiga y degradación a bajas temperaturas de Y-TZP: diseño de un material con mejores propiedades mecánicas y con una superficie modificada con mayor resistencia a la degradación

     Anglada Gomila, Marcos Juan; Salán Ballesteros, Mª Núria; Jimenez Pique, Emilio; Valle Chiro, Jorge Antonio
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