Nanocrystalline Zirconia Orthopedic Coating for Reduced Poyethylene Wear

描述（由申请人提供）：在这个项目中，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纳米氧化锆磨损层。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。氧化锆具有几种特性，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”。小裂缝在扩展之前被掐掉。通过在涂层中加入钇来实现相稳定性。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，从而进一步提高韧性。使用连续渐变的过渡层将实现磨损层与基板的优异附着力。这一层将在离子清洗过的CoCr衬底上呈现纯金属锆表面，并逐渐氧化，直到外表面大部分是锆。纳米氧化锆磨损层将通过其固有的离子键附着在过渡层上。

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.