| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 91 === The main purpose of this study is to receive TiN ceramic films with silver and tungsten dopants and research the tribological properties and turning performance of Ti-Ag-N and Ti-W-N coatings by sputtering titanium, silver and tungsten targets separately with (i) a medium frequency Twin magnetron sputtering and unbalanced magnetron sputtering hybrid system and (ii) closed unbalanced magnetron sputtering system.
It contains two parts of research in this study：PartⅠ& PartⅡ.About PartⅠ,Ti-Ag-N coatings ,it has two stages. Find out the best nitrogen flow and add silver dopant of TiN in first stage. Confer to the effects of nitrogen flow and silver dopant of films on tribological properties. Changing the bias of substrate in second stage. Finally, a dry turning of coated inserts will be undergone to understand the turning performance of coatings. At PartⅡ,Ti-W-N coatings, add tungsten dopant in TiN film directly. To discover the perfect range of tungsten content in films and carry out a dry turning, too. Then we can obtain the best tool of coated inserts.
Via PartⅠexperiment results in first stage, we acknowledge that the coating prepared under the 20 sccm of nitrogen flow has optimum TiN film. The hardness of coatings will be raised with the nitrogen flow increase. In Ti-Ag-N films, after SRV and Pin-on-disk tribological test, when the silver content is 0.17at%, due to the influence of Fine-grained Strengthening, we get the maximum hardness and the best wear resistance. Besides the turning performance of coatings in the second stage, it will have the minimum flank wear and the three times tool life more than uncoated one under the 14.57at% of silver content of coated inserts.
On the other hand ,PartⅡTi-W-N coatings, by way of TF-XRD analysis, we acquire that the intensity of δ-WN phase and hardness of coatings will be step up with the tungsten content increase. The hardness will 2.5 times more than TiN film under 37.9 at% of tungsten content. After SRV and Pin-on-disk tribological test, when the tungsten content in 13.72at% we get the best wear resistance, and in 6.45 at% one the wear coefficient is minimum. To mention the turning performance of coatings, it will have the minimum flank wear and the three times tool life more than uncoated and TiN ones under the 13.72at% of tungsten content of coated inserts.
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