DEVELOPMENT OF POWDER JET PROCESSING METHOD AND A MECHANISM CHANGE IN PROCESSES OF MATERIAL REMOVAL AND POWDER DEPOSITION

微机械等微电子机械系统(MEMS)所需的亚毫米量级(约0.01-1 mm)的微传感器和微执行器的发展引起了人们的广泛关注。在这项研究中，我们开发了一种粉末喷射工艺，这是磨料射流加工的应用之一。在这个过程中，微粒子(φ0.1~几μm)在载气的加速下，在真空或大气条件下高速撞击并聚集在衬底上，形成厚膜。虽然沉积速率大到足以制造亚毫米尺寸的功能结构，但存在与结构的成形精度和密度相关的沉积速率和混合比不稳定的问题。这是因为载气和微颗粒的混合爆破机理不够完善。去年，我们开发了可以定量喷射微小颗粒的粉末喷射设备，并在…中在真空条件下更加稳定，并用该装置进行了实验。然而，由于真空条件下的各种限制，从实际应用来看，大气条件下的粉末沉积比真空条件下的粉末沉积更有用。因此，证实了大气条件下粉末沉积的可能性。接下来，我们研究了颗粒的过渡直径，在这个直径上，从材料去除到沉积的机制发生了变化。此外，还研究了爆破速度、爆破压力、粉料材料等爆破条件对形成的厚膜粘结强度的影响。实验结果表明，在常压下，氧化铝或碳化硅颗粒在玻璃或硅衬底上爆炸时，颗粒的过渡直径约为2μm，较小的颗粒表现出粘着现象。沉积高度在几秒钟后趋于稳定，厚度可达20-120μm。喷砂颗粒的动能和基材的硬度对粘接性能有很大的影响。此外，我们还提出了一种从显微硬度和动态硬度值的差值来评价薄膜力学性能的新方法。在这种方法中，在硅衬底上形成的膜的硬度比在玻璃上形成的膜的硬度要大。此外，还证实了电子工业材料，如PZT或铁氧体，可以在常压下沉积。较少

Much attention has been paid to a development of micro-sensors and micro-actuators on the order of sub-millimeter size (around 0.01-1mm), which are necessary for micro electrical/mechanical system (MEMS) such as a micro-machine. In this study, we developed a powder jet process, which is one of applications of abrasive jet machining. In this process, micro-particles ( φ 0.1-several μm), which are accelerated by a carrier gas, impinge with a high velocity and accumulate onto a substrate under vacuum or atmospheric condition, and forms thick film. Though the deposition rate is large enough to manufacture a functional structure of sub-millimeter size, there are problems that the deposition rate and mixture ratio, which are related to form accuracy and a density of the structure, are unstable. This is because a mixing and blasting mechanism of carrier gas and micro-particle is inadequate. Last year, we have developed the powder jet device that can blast micro-particles quantitatively and in … More termittently under vacuum condition, and experimented with the device. However, because there are various limitations under vacuum condition, taking practical use into consideration, powder deposition under atmospheric condition is more useful than under vacuum condition. Thus, a possibility of a powder deposition under atmospheric condition was confirmed. Next, we investigated a transition diameter of a particle, at which the mechanism changes from a material removal to a deposition. Furthermore, influences of blasting conditions such as blasting velocity and pressure, and matrials of powers and workpiece material on adhesive strength of formed thick film were investigated. The results of the experiments show that the transition diameter of particle is about 2.0μm and a smaller particle shows an adhesion phenomena when blasting alumina or silicon carbide particles to glass or silicon substrate under atmospheric pressure. And deposition height became stationary after several seconds and reached 20-120μm in thickness. And it becomes clear that kinetic energy of blasted particles and hardness of a substrate workpiece have a large influence on adhesive characteristics. In addition, we suggest a new evaluation method of mechanical properties of the film from a difference of micro-hardness and dynamic hardness values. In this method, the hardness of the formed film on a silicon substrate is bigger than on a glass. Furthermore, it is confirmed that electronic industry materials, such as PZT or ferrite, can be deposited under atmospheric pressure. Less