Murray S F, Calabrese S J, Malanoski S B, Golding L R, Smith W A, Hamby M
Rensselaer Polytechnic Institute, Troy, New York, USA.
ASAIO J. 1997 Sep-Oct;43(5):M603-8.
A critical issue in the Cleveland Clinic Foundation (CCF) Innovative Ventricular Assist System (IVAS) blood pump is the selection of materials for the blood-lubricated journal bearing. Under normal operating conditions, the journal bearing geometry creates a thick blood film that separates the rotating and stationary surfaces. However, since start-up and certain transients could cause temporary contact, the material pair selected for these surfaces must be both tribologically and blood compatible. Combinations of two biocompatible alloys were tested: a titanium-zirconium-niobium alloy (Ti-13Zr-13Nb) and a zirconium-niobium alloy (Zr-2.5Nb). A standard pin-on-disk tester was used, with the contact surfaces lubricated by glycerol/saline mixtures simulating the viscosity range of blood. One test series evaluated start-up conditions; the other modeled a high-speed rub that might occur if the fluid film broke down. Results showed that the preoxidized Zr-2.5Nb pin/Ti-13Zr-13Nb disk combination was superior at all sliding velocities; a self-mated Zr-2.5Nb pair also showed promise. The oxide film on a self-mated Ti-13Zr-13Nb pair, and a Ti-13Zr-13Nb pin and Zr-2.5Nb disk combination did not show adequate wear life. More work remains to explain distinct performance differences of certain combinations, with more data needed on mechanical properties of thin, hard coatings on softer metal substrates.
克利夫兰诊所基金会（CCF）创新心室辅助系统（IVAS）血泵中的一个关键问题是血液润滑轴颈轴承的材料选择。在正常运行条件下，轴颈轴承的几何形状会形成一层厚厚的血膜，将旋转表面和静止表面分隔开。然而，由于启动和某些瞬态情况可能导致临时接触，为这些表面选择的材料对必须在摩擦学和血液兼容性方面都表现良好。测试了两种生物相容性合金的组合：一种钛锆铌合金（Ti-13Zr-13Nb）和一种锆铌合金（Zr-2.5Nb）。使用标准的销盘式试验机，接触表面用模拟血液粘度范围的甘油/盐溶液混合物进行润滑。一个测试系列评估启动条件；另一个模拟了如果液膜破裂可能发生的高速摩擦。结果表明，预氧化的Zr-2.5Nb销/Ti-13Zr-13Nb盘组合在所有滑动速度下都表现更优；自配对的Zr-2.5Nb对也显示出前景。自配对的Ti-13Zr-13Nb对以及Ti-13Zr-13Nb销和Zr-2.5Nb盘组合上的氧化膜没有表现出足够的耐磨寿命。仍有更多工作需要解释某些组合的明显性能差异，还需要更多关于较软金属基底上薄而硬涂层机械性能的数据。
