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

亚毫米量级（约0.01-1mm）的微传感器和微致动器是微机械等微机电系统（MEMS）所必需的，其发展受到了广泛的关注。在本研究中，我们开发了一种粉末射流工艺，这是磨料射流加工的应用之一。在此过程中，微粒（φ 0.1 ~几μm）在载气的加速下，在真空或常压条件下高速撞击并积聚在基片上，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，但存在与结构的形状精度和密度相关的沉积速率和混合比不稳定的问题。这是因为载气和微粒的混合爆破机制不充分。去年，我们研制了一种能在真空条件下定量、连续地喷射微颗粒的粉末喷射装置，并进行了实验。但由于真空条件下存在各种局限性，考虑到实际应用，常压条件下的粉末沉积比真空条件下更有用。从而证实了常压条件下粉末沉积的可能性。接下来，我们研究了一个粒子的过渡直径，在这个过渡直径下，材料的去除机制转变为沉积机制。此外，还研究了爆破速度、爆破压力等条件、动力材料和工件材料对成形厚膜粘接强度的影响。实验结果表明，在常压下，氧化铝或碳化硅颗粒与玻璃或硅衬底爆破时，颗粒的过渡直径约为2.0μm，较小的颗粒表现出粘附现象。沉积高度在几秒后趋于稳定，厚度达到20 ~ 120μm。结果表明，喷砂颗粒的动能和基材工件的硬度对胶粘剂特性有较大的影响。此外，我们还提出了一种从显微硬度值和动态硬度值的差异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。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