The Thin Film Thermocouples Tempreture Testing System Based On Magnetron Sputtering Technology

Development of Ni-Cr/Ni-Si thin-film thermocouples cutting tempereture testing system for chemical explosive maerial is surpported by China Academy of Engineering Physical (NO.2001Z0301). The present work dedicaes to the development of tempreture sensor-thinfilm thermocouples and the fabrication of it.Hard particales distributing randomly inside chemical explosive material. When machining such kinds of material, high instantaneous workpiece tempreture will occur. There will be much danger when the workpiece tempreture exceeds a special value. So it's significant to test the instantaneous tempreture quickly and accurately for war industry enterprise.The research team have ever fabricated the thin-film of ther mocouples by Multiple Arc Ion plating, and the contributions of the film are deviating from the target, so the Seebeck coeffcient is not in accordance with the normal thermocouples composed of Ni-Cr/Ni-Si wires, which lead to the larger error when Ni-Cr/Ni-Si wires was applied to the cuting test as compensation lead. In this paper, the fabrication method and process of Ni-Cr-Ni-Si thin-film thermocouples (TFT) are introduced reasonedly.Magnetron sputtering can improve electrous' use factor and ionization rate by imprisoning, changing and extending their moving path. There will be collisions of electrons with Ar atoms during electrons accelerating to substrate with electric field. The target will be bombrarded by ionized Ar+ with he accelerating electric field, at the same time, the sputtered target atoms will deposit on the substrate. Magnetron sputtering have become one of the best choises because of it's series of advantages, such as high deposition velocity, good quality, component consistency with target, controlled technological parameters, good repeatabilty and stability and so on.The stem contant are as follows: structure design of the tempreture sensor, the fabrication method for the thermocouples thin-film by the Magnetron Spurting, static calibration, dynamical calibration, error analysis of dynamical cutting tempreture and so on. Among these, the manufacturing of thin-film electrodes is the key project and has been emphasized in this paper.Compared with Multiple Arc Ion plating, the thin-film of thermocouple which are developed by the Magnetron Spurting are more compactive and smooth, the contributions are close to the target, and the depth of TFT' s hot junction is only 2.45 μ m. The static and dynamic calibration oftft are proposed, and it is concluded that the sensitivity are 40.1 u V/°C, linear error is no greater than 0.75% ,and the constant time is less 0.32ms. At last TFT are applied to the chemical explosive material simulation cutting test, and the conclusion is drew that the sensor can reflect the cutting tempreture accurately and rapidly. Tempreture pulse constant time is less than 0.35ms, which prove it can gain the point of constant tempreure monitoring.