Microstructure and mechanical properties of (TiZrHf)N/(AlSiB)N multilayer films by reactive magnetron sputtering

• Main Authors: Ming-Xuan Xiao, 蕭明軒
• Other Authors: Fuh-Sheng Shieu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5159037%22.&searchmode=basic

碩士 === 國立中興大學 === 材料科學與工程學系所 === 107 === In the research and application of hard film nowadays, the ultra-high hardness is not the only orientation. The different application requirements are considered, and the development of multi-functionality in which the multilayer film can have the characteristics of two materials at the same time, and the strength is higher than that of the original materials. Multilayer film can be applied to mechanical parts and cutting tools to extend lifetime. TiN, ZrN, and HfN are used as protective coatings because of their excellent mechanical properties and thermal stability. AlN, Si3N4 and BN have high oxidation resistance and chemical stability. They also have different characteristics. Among them, AlN has corrosion resistant, and Si3N4 performs well in fracture toughness.BN has excellent resistance due to its low coefficient of friction. In this experiment, TiZrHf three-element alloy(the molar ratio is equal to 1) and AlSiB three-element alloy(the molar ratio is equal to 1) were used as targets, The RF power input to the sputter target was 400 W and 200 W, respectively. Fixed nitrogen partial pressure=20%, substrate temperature 400 °C, film thickness 500 nm, and plated under different modulation periods (TiZrHf)N/(AlSiB)N multilayer film. The crystal structure, morphology and mechanical properties of the films were investigated in detail. Then, the (TiZrHf)N/(AlSiB)N multilayer film was annealed from 700 to 900 ℃ for 2 h in the vacuum (6×10-5 Torr) to evaluate the interface stability. This study is mainly divided into three parts: the first part is to change the interlayer material, such as AlSiB, (AlSiB)N, TiZrHf, and (TiZrHf)N, and deposits the (TiZrHf)N (4.5 nm)/(AlSiB)N (0.28 nm) multilayer film on them. When the interlayer is AlSiB layer, the columns width of the film is the finest. When the interlayer is (AlSiB)N layer, the columns width of the film is the largest. This is attributed to the difference in viscosity coefficient between interlayer and (TiZrHf)N. In terms of mechanical properties, the multilayer films of different interlayers have similar hardness and elastic modulus, which are 31 GPa and 247 GPa, respectively. In terms of adhesion, the film with the interlayer has a higher adhesion of 37-41 N than the film without the interlayer. The second part is to deposit the (TiZrHf)N (4.5 nm)/(AlSiB)N(0~1.40 nm) multilayer film with different (AlSiB)N thickness. As the thickness of (AlSiB)N increases to 0.28 nm, the crystallinity of the film increases due to the mutual promotion effect. The amorphous (AlSiB)N is transformed into the FCC phase due to the template effect, forming a superlattice structure, thus having the highest hardness value of 30 GPa and best wear resistance. After vacuum annealing at 700 ℃, there is some interdiffusion in the interfaces of multilayer film. When the annealing temperature reaches 800 ℃, the surface is oxidized slightly and its multilayer structure becomes unapparent. The third part is to deposit the (TiZrHf)N(0~100 nm)/(AlSiB)N (1 nm) multilayer film with different (TiZrHf)N thickness. As the thickness of (TiZrHf)N increases, the film structure changes from amorphous to FCC, and its hardness increases to 29.90 GPa. When the thickness of (TiZrHf)N is 50 nm, it has the best wear resistance and minimum friction coefficient 0.74. After vacuum annealing at 700 ℃, there is some interdiffusion in the interfaces of multilayer film. When the annealing temperature reaches 800 ℃, the surface is oxidized slightly and its multilayer structure becomes unapparent.