Fabrication of Nitride Thin Films by Co-Sputtering of High Entropy Alloys and Tungsten

• Main Authors: Chen, Yan Tong, 陳彥彤
• Other Authors: Hsu, Chun-Yao
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/fj4ax7

碩士 === 龍華科技大學 === 機械工程系碩士班 === 107 === This work studies the co-deposition by DC-reactive magnetron sputtering of tungsten (W) coatings over soda glass and SUS 304 stainless steel substrates. A high entropy equimolar alloy (AlCrNbSiTiV) target (diameter 2 in) and a W target (diameter 3 in) were bombarded with Ar and N2 reactant gasses to form plasma. The N2/(Ar+N2) flow ratio (0, 5, 10, 15, 20%) was adjusted under a fixed sputtering power (200 W), a fixed reaction time (15 min), a fixed substrate temperature (150°C) and observed the influence of these parameters over the properties such as surface morphologies, hardness, wear resistance, surface roughness, corrosion resistance and microstructure such as grain sizes, crystalline structures and elemental contents of the sputtered films. From results it was seen that as N2/(Ar+N2) flow ratio increased, the structure of the films changed considerably, from a single W structure with low concentrations of the other elements to a W2N structure. When RN=20%, the best (AlCrNbSiTiV-W)N film was achieved. From XRD measurements of the high entropy alloy nitride compound, it was evident that at 2θ angle of 40° there was a major W (110) diffraction peak, displaying preference for columnar crystalline structures. SEM images showed homogeneous growth of the nitride layer, with dense structures, no cracking and grain-like structure. From EDS analyses, the nitrogen concentration was highest (39.3%) when N2/(Ar+N2) flow ratio was 20%. Moreover, W concentration had a tendency to decrease as N2/(Ar+N2) flow ratio increased. The smallest average grain size was D: 7.1 nm, the highest hardness was 37.52 GPa (682.3HV), and the highest Young’s modulus was E: 210.4 GPa. The lowest friction coefficient was 0.516, while the lowest surface roughness was Ra: 3 nm, and the best corrosion resistance observed was Ecorr: -221.6 mV/ Icorr: 0.793µAmp/cm2.