Pulsed water jet treatments of the surfaces of metal alloys for biomedical applications

每年有超过10万加拿大人需要膝关节或髋关节置换术。目前的技术使用钛合金 将植入物附着到骨上，但在界面处出现了问题，这些问题可以通过脉冲水射流来解决 (PWJ)VLN Advanced Technologies Inc.开发的技术。合金的表面通常是 通过用氧化铝颗粒喷砂来粗糙化，以促进器件上的细胞生长。但 颗粒嵌入钛表面。一旦进入病人体内， 并导致周围组织中的细胞死亡和植入物松动，这是翻修的主要原因 手术相比之下，脉冲水射流使用超声波将连续的水流打破成一系列的高压水射流。 通过目标的循环加载产生机械侵蚀而不嵌入任何外来物质的速度脉冲 材料 与VLN一起，我们将开发一种使用PWJ的经济有效的方法，以消除对喷砂的需求 并创造出更好的生物相容性表面。为了使钛植入物在骨中具有良好的粘附性， 植入物需要具有尺寸跨越微米尺度下至纳米尺度的表面特征 模仿周围的生物纹理。自然相分离为两种的冶金合金 组件在其纹理结构中创建具有多长度比例特征的图案，这些特征可以模仿 生物系统。外科用钛合金分离成较强和较弱的组件。我们将设计 用脉冲水射流机械蚀刻掉较弱的组分并留下 具有微米和纳米尺度特征的粗糙表面。物理结构，化学和 处理过的表面的机械性能将在达尔豪西大学用一套工具来表征 以确定最佳PWJ参数。最后，我们将探讨工程表面的可能性 通过改变达尔豪西目前正在开发的钛合金中的晶粒结构，

Each year, over 100,000 Canadians require knee or hip replacement. Current technology uses a titanium alloy to attach the implant to the bone, but problems arise at the interface that could be solved with pulsed water jet (PWJ) technology developed at VLN Advanced Technologies Inc. The surface of the alloy is typically roughened by grit blasting with aluminum oxide particles to promote cell growth on the device. However, the particles get imbedded into the titanium surface. Once inside the patient, the particles can become dislodged and lead to cell death in the surrounding tissue and the loosening of the implant, the leading cause for revision surgery. In contrast, pulsed water jets use ultrasound to break a continuous water stream into a series of high speed pulses that create mechanical erosion by cyclic loading of the target without embedding any foreign material. Together with VLN, we will develop a cost effective way of using PWJs to eliminate the need for grit blasting and create a better biocompatible surface. For good adhesion of a titanium implant in bone, the medical implant needs to have surface features with sizes that span the micron scale down to the nano-scale in order to mimic the surrounding biological textures. Metallurgical alloys that naturally phase separate into two components create patterns in their grain structure with multi-length scale features that can imitate those of biological systems. Surgical titanium alloy separates in to a stronger and weaker component. We will design the techniques to mechanically etch away the weaker component with pulsed water jets and leave behind a rough surface with features on the micron- and nano-length scales. The physical structure, chemistry and mechanical properties of the treated surfaces will be characterized with a suite of tools at Dalhousie University to identify the optimal PWJ parameters. Finally we will explore the possibility of engineering the surface morphology by modifying the grain structure in titanium alloys currently being developed at Dalhousie.