TY - JOUR

T1 - Protection of yttria-stabilized zirconia for dental applications by oxidic PVD coating

AU - Hübsch, C.

AU - Dellinger, P.

AU - Maier, H. J.

AU - Stemme, F.

AU - Bruns, M.

AU - Stiesch, M.

AU - Borchers, L.

N1 - Funding information: This study was supported by the German Research Foundation within the framework of “Sonderforschungsbereich 599”. The authors would like to thank Vita Zahnfabrik, Bad Säckingen, Germany, for kindly donating the material used in this study, Jürgen Strempel, Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Hannover, Germany, for providing the AFM image, and David Donnet, FEI Company, the Netherlands, for his assistance with the FIB-SEM analysis.

PY - 2015/9/30

Y1 - 2015/9/30

N2 - In this study, the application of transparent physical vapor deposition (PVD) coatings on zirconia ceramics was examined as an approach to retard the low-temperature degradation of zirconia for dental applications. Transparent monolayers of titanium oxide (TixOy) and multilayers consisting of titanium oxide-alumina-titanium oxide (TixOy-AlxOy-TixOy) were deposited onto standardized discs of 3Y-TZP using magnetron sputtering. Using X-ray photospectroscopy and time-of-flight secondary-ion mass spectrometry, the compositions of the coatings were verified, and an approximate thickness of 50 nm for each type of coating was ascertained. After aging the coated and uncoated samples in water vapor at 134°C and 3 bar for 4, 8, 16, 32, 64 and 128 h, the monoclinic phase content was determined using X-ray diffraction, and its impact on mechanical properties was assessed in biaxial flexural strength tests. In addition, the depth of the transformation zone was measured from scanning electron microscopy images of the fracture surfaces of hydrothermally aged samples. The results revealed that the tetragonal-to-monoclinic phase transformation of the zirconia ceramic was retarded by the application of PVD coatings. During the first stages of aging, the coated samples exhibited a significantly lower monoclinic phase content than the uncoated samples and, after 128 h of aging, showed a transformation zone which was only ∼12-15 μm thick compared to ∼30 μm in the control group. Biaxial flexural strength decreased by ∼10% during aging and was not influenced by the application of a PVD coating.

AB - In this study, the application of transparent physical vapor deposition (PVD) coatings on zirconia ceramics was examined as an approach to retard the low-temperature degradation of zirconia for dental applications. Transparent monolayers of titanium oxide (TixOy) and multilayers consisting of titanium oxide-alumina-titanium oxide (TixOy-AlxOy-TixOy) were deposited onto standardized discs of 3Y-TZP using magnetron sputtering. Using X-ray photospectroscopy and time-of-flight secondary-ion mass spectrometry, the compositions of the coatings were verified, and an approximate thickness of 50 nm for each type of coating was ascertained. After aging the coated and uncoated samples in water vapor at 134°C and 3 bar for 4, 8, 16, 32, 64 and 128 h, the monoclinic phase content was determined using X-ray diffraction, and its impact on mechanical properties was assessed in biaxial flexural strength tests. In addition, the depth of the transformation zone was measured from scanning electron microscopy images of the fracture surfaces of hydrothermally aged samples. The results revealed that the tetragonal-to-monoclinic phase transformation of the zirconia ceramic was retarded by the application of PVD coatings. During the first stages of aging, the coated samples exhibited a significantly lower monoclinic phase content than the uncoated samples and, after 128 h of aging, showed a transformation zone which was only ∼12-15 μm thick compared to ∼30 μm in the control group. Biaxial flexural strength decreased by ∼10% during aging and was not influenced by the application of a PVD coating.

KW - Hydrothermal aging

KW - Monoclinic phase

KW - PVD

KW - Zirconia

UR - http://www.scopus.com/inward/record.url?scp=84925147089&partnerID=8YFLogxK

U2 - 10.1016/j.actbio.2014.09.042

DO - 10.1016/j.actbio.2014.09.042

M3 - Article

C2 - 25278443

AN - SCOPUS:84925147089

VL - 11

SP - 488

EP - 493

JO - Acta biomaterialia

JF - Acta biomaterialia

SN - 1742-7061

ER -