Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học được đăng trên tạp chí toán học quốc tế đề tài: Composition and crystalline properties of TiNi thin films prepared by pulsed laser deposition under vacuum and in ambient Ar ga | Cha et al. Nanoscale Research Letters 2012 7 37 http content 7 1 37 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Composition and crystalline properties of TiNi thin films prepared by pulsed laser deposition under vacuum and in ambient Ar gas Jeong Ok Cha1 Tae Hyun Nam2 Mohammad Alghusun1 and Jeung Sun Ahn1 Abstract TiNi shape memory alloy thin films were deposited using the pulsed laser deposition under vacuum and in an ambient Ar gas. Our main purpose is to investigate the influences of ambient Ar gas on the composition and the crystallization temperature of TiNi thin films. The deposited films were characterized by energy-dispersive X-ray spectrometry a surface profiler and X-ray diffraction at room temperature. In the case of TiNi thin films deposited in an ambient Ar gas the compositions of the films were found to be very close to the composition of target when the substrate was placed at the shock front. The in-situ crystallization temperature ca. 400 C of the TiNi film prepared at the shock front in an ambient Ar gas was found to be lowered by ca. 100 C in comparison with that of a TiNi film prepared under vacuum. Background In recent years shape memory materials have attracted much attention as functional materials owing to a variety of industrial and medical applications. The shape memory effect and superelasticity especially in smart materials 1 and microelectromechanical systems MEMS have been extensively investigated in the past decades due to their potential use in several applications. TiNi shape memory alloys SMAs are most suitable for MEMS and Bio-MEMS microactuators . micropump 2 3 microwrapper 4 and blood vessels 5 because of their large working distance compared to bimetals and piezo materials. However slow thermal response due to a low cooling rate in bulk SMA is a barrier for MEMS application. On the other hand TiNi thin films has only a small amount of thermal mass to heat or cool .
