| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 101 === According to a lot of literatures, the boron is an effective element to produce a nanocomposite structure. Recently, a substantial amount of studies has been toward the direction of nanocomposite structure.In this study, a co-sputtering method of dual-targets was adopted to fabricate a serious of Ti-Zr-B-N coatings containing various B concentrationts. Control the Ti and ZrB2 targets to sputter Ti-Zr-B-N films of rich-Ti, and control the Zr and TiB2 targets to sputter Zr-Ti-B-N films of rich-Zr, respectively. The first stage was that these substrates were placed due to the difference of position between the Ti and ZrB2 targets to deposit Ti-Zr–B–N thin films,and were denoted as B and E series. The second stage was that these substrates were placed due to the difference of position between the Zr and TiB2 targets to deposit Zr–Ti-B–N thin films,and were denoted as G series. Above two stages were in order to sputter with compositional gradients of Ti-Zr-B-N thin films. The third stage was that adjust targets power to deposit Zr–Ti-B–N thin films with uniform compositions,and were denoted as HT and HZ series. For films of each stage, analyze the phases, microstructure, surface color and the surface roughness, and examine the hardness, toughness, adhesion, tribological properties and corrosion resistance. The effects of Zr and B contents were investigated in relation to the microstructure, adhesion, tribological and mechanical properties of thin films. The results showed that the boron content reduced to 0.8-5.4 at.%, the two phases nanocomposite structure consisting of fine columnar grains surrounded by very thin amorphous BN phase is clearly seen. Furthermore, the addition of the transition metal atoms were transformed into substitutional solid solution, generate solid solution strengthening effect. The hardness rise 26-35 GPa, along with golden color and smooth surface, good toughness and adhesion, low coefficient of friction, excellent wear and corrosion resistance capabilities. When the boron content was greater than 20 at.%, it formed the larger volume fraction of soft amorphous BN phase cover nano grains.The amorphous BN phase restrained grains growth,make the grain size constraint about 3-5 nm.But it strongly soften the films. All in all,the boron could refine grain and promote the formation of nanocrystalline/ amorphous nanocomposite structure in the Ti-Zr-B-N thin films, then effectively enhance the mechanical properties and improve corrosion ability.
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