NEW LUBRICANTS FOR ROTATING ANODE X-RAY TUBE BEARINGS

该项目将为轴承开发新的固体润滑剂涂层，这些轴承必须在高转速、高温和真空下运行，用于CT扫描仪和其他医疗和工业应用的旋转阳极x射线管。润滑剂将通过Spire公司开发的离子辅助工艺来应用，在该工艺中，高能离子束既溅射沉积涂层，又轰击沉积的材料。离子轰击首先改变衬底/涂层界面以增强附着力，并且在沉积过程中持续轰击致密化和均匀化微观结构以提高性能。涂层的成分可以远离相平衡，从而提供独特的润滑性能。在第一阶段，我们将确定和测试主要基于银和其他韧性金属混合物的有前途的涂层材料；一家x射线管商业制造商将在一个旋转阳极模拟器中，在真实的热-机械-真空条件下测试润滑过的轴承球。第二阶段将研究更广泛的润滑剂材料、加工参数和轴承部件，并在实际的x射线管中进行全面测试。建议的商业应用：轴承磨损是CT扫描仪和其他x射线设备中旋转阳极x射线管寿命的主要限制。新型轴承润滑油不仅可以延长管的使用寿命，还可以大大增加x射线强度，同时按比例减少暴露时间。用于旋转阳极x射线管和其他在真空环境中运行的精密机械的轴承的新型固体润滑剂立即存在商业市场。

The project will develop new solid lubricant coatings for bearings that must operate at high rotational speed, high temperature, and under vacuum in rotating anode X-ray tubes for CT scanners and other medical and industrial applications. The lubricants will be applied by an ion- assisted process developed by Spire Corporation, in which an energetic ion beam both sputter-deposits the coating and concurrently bombards the deposited material. Ion bombardment initially modifies the substrate/coating interface to enhance adhesion, and continued bombardment during deposition densifies and homogenizes the microstructure for improved performance. The coating's composition can be far from phase-equilibrium, thus providing unique lubrication properties. In Phase I, we will identify and test promising coating materials based primarily on mixtures of silver and other ductile metals; a commercial manufacturer of X-ray tubes will test lubricated bearing balls in a rotating anode simulator, under realistic thermal-mechanical-vacuum conditions. Phase II would investigate a wider range of lubricant materials, processing parameters, and bearing components and initiate full-scale testing in actual X-ray tubes. PROPOSED COMMERCIAL APPLICATIONS: Bearing wear is the principal limitation on rotating anode X-ray tube lifetime in CT scanners and other X-ray equipment. New bearing lubricants could not only extend tube lifetime but also allow a major increase in X-ray intensity, along with proportional reduction of exposure time. An immediate commercial market exists for new solid lubricants for bearings in rotating anode X-ray tubes and in other precision machinery that operates in a vacuum environment.