Nanocrystalline Zirconia Orthopedic Coating for Reduced Poyethylene Wear

描述（由申请人提供）：在本项目中，将开发一种用于骨科应用的新型氧化锆涂层。离子束辅助沉积将用于生长具有连续梯度金属/陶瓷粘附层的相稳定的纳米氧化锆耐磨层。在关节系统中，将聚乙烯磨损表面与坚硬、光滑的金属表面配对可以最大限度地减少聚乙烯磨损。氧化锆具有多种特性，使其成为耐磨应用的优秀组合。氧化锆非常硬，由于其独特的相变特性，它表现出“相变增韧”。“小裂缝在传播之前被夹断。相稳定性将通过在涂层中引入氧化钇来实现。由于纳米级的晶粒尺寸，Spire的氧化锆将表现出非凡的硬度和超塑性，这将进一步增加韧性。通过连续渐变过渡层，可实现耐磨层与基材的良好粘附。该层将为离子清洁的CoCr基材提供纯金属锆表面，并将逐渐氧化，直到外表面主要为锆。纳米晶氧化锆耐磨层将通过其天然离子键粘附到过渡层。 在这个项目中，我们将开发一种适用于骨科应用的新型氧化锆，由于其硬度和光滑度，将最大限度地减少聚乙烯磨损碎屑。尽量减少骨科磨损碎屑至关重要，因为磨损碎屑会导致植入物无菌性松动。这种松动是导致翻修手术的植入物失效的主要原因之一。

DESCRIPTION (provided by applicant): In this program a new zirconia coating will be developed for orthopedic applications. Ion beam assisted deposition will be used to grow a phase stabilized nanocrystalline zirconium oxide wear layer with a continuously-graded metallic/ceramic adhesion layer. In an articulating joint system pairing polyethylene wear surfaces with a hard, smooth metallic surface can minimize polyethylene wear. Zirconia has several properties that make it an excellent couple for wear resistance applications. Zirconia is extremely hard and, due to a unique phase change property, it exhibits "transformation toughening." Small cracks are pinched off before propagating. Phase stability will be achieved by incorporating yttria in the coating. Due to grain size in the nano-scale, Spire's zirconia will exhibit extraordinary hardness and a super-plasticity that will further increase toughness. Excellent adhesion of the wear layer to the substrate will be achieved with a continuously graded transition layer. This layer will present a pure metallic zirconium surface to the ion-cleaned CoCr substrate and will be gradually oxidized until the outer surface is mostly zirconium. The nano-crystalline zirconia wear layer will adhere to the transition layer through its native ionic bond. In this program we will develop a new form of zirconium oxide suitable for orthopedic applications that, due to its hardness and smoothness, will minimize polyethylene wear debris. Minimizing orthopedic wear debris is critical because wear debris leads to aseptic loosening of the implant. This loosening is one of the leading causes of implant failure leading to revision surgery.