探索热丝化学气相沉积(hot filament chemical vapor deposition,HFCVD)合成高效优质的金刚石已成为研究热点。采用可提高金刚石颗粒单次沉积产量的新型多片式栅状衬底,应用FLUENT流体仿真软件,在原有单个出气口数量及进气总流量保持不...探索热丝化学气相沉积(hot filament chemical vapor deposition,HFCVD)合成高效优质的金刚石已成为研究热点。采用可提高金刚石颗粒单次沉积产量的新型多片式栅状衬底,应用FLUENT流体仿真软件,在原有单个出气口数量及进气总流量保持不变的情况下,优化传统模型,将单个进气口拆分成5个大小相等的进气口,对影响金刚石单晶颗粒均匀性的进气口数量和排布方式工艺参数进行仿真,对比分析HFCVD系统内气体的物理场。结果显示:4组优化模型均提高了衬底温度及流速的均匀性,有利于金刚石单晶颗粒的均匀生长,但对其沉积速率影响不显著;进一步分析优化模型的温度场,发现5个进气口及单个出气口分别位于反应腔体顶部和底部的中间位置时系统的温度差最低,最满足金刚石单晶颗粒在多片式硅衬底上均匀生长的条件。HFCVD金刚石单晶颗粒沉积试验验证了仿真结果的正确性。展开更多
用热丝化学气相沉积法(hot filament chemical vapor deposition,HFCVD)制备金刚石涂层刀具时,衬底温度对金刚石涂层分布的均匀性有重要影响。利用仿真软件ANSYS中的FLUENT模块,对GAMBIT中建立的三维HFCVD批量刀具反应模型进行分析,并...用热丝化学气相沉积法(hot filament chemical vapor deposition,HFCVD)制备金刚石涂层刀具时,衬底温度对金刚石涂层分布的均匀性有重要影响。利用仿真软件ANSYS中的FLUENT模块,对GAMBIT中建立的三维HFCVD批量刀具反应模型进行分析,并运用耦合热传导、热对流、热辐射等3大传热方式对该模型衬底温度分布情况进行仿真预测,对影响涂层分布均匀性的刀具底部支撑台材料散热方式进行分析、优化。仿真结果显示:相较于传统的铜质支撑台和石墨支撑台,热导率小的陶瓷材料支撑台的刀体平均温差最小,为37.82℃,比采用铜材料为支撑台时的刀体平均温差降低了45℃,更有利于制备膜厚、质量均匀的CVD金刚石涂层刀具。展开更多
Amorphous Si O2（a-Si O2） films were synthesized on WC-Co substrates with H2 and tetraethoxysilane（TEOS） via pyrolysis of molecular precursor.X-ray diffraction（XRD） pattern shows that silicon-cobalt compounds for...Amorphous Si O2（a-Si O2） films were synthesized on WC-Co substrates with H2 and tetraethoxysilane（TEOS） via pyrolysis of molecular precursor.X-ray diffraction（XRD） pattern shows that silicon-cobalt compounds form at the interface between a-Si O2 films and WC-Co substrates.Moreover,it is observed by transmission electron microscope（TEM） that the a-Si O2 films are composed of hollow mirco-spheroid a-Si O2 particles.Subsequently,the a-Si O2 films are used as intermediate films and chemical vapor deposition（CVD） diamond films are deposited on them.Indentation tests were performed to evaluate the adhesion of bi-layer（a-Si O2 ＋ diamond） films on cemented carbide substrates.And the cutting performance of bi-layer（a-Si O2 ＋ diamond） coated inserts was evaluated by machining the glass fiber reinforced plastic（GFRP）.The results show that a-Si O2 interlayers can greatly improve the adhesive strength of diamond films on cemented carbide inserts;furthermore,thickness of the a-Si O2 interlayers plays a significant role in their effectiveness on adhesion enhancement of diamond films.展开更多
文摘讨论了在热丝化学汽相沉积(HFCVD)法沿Si(111)晶面异质生长SiC薄膜的过程中,预处理工艺对SiC成膜的影响.采用硅烷、甲烷作为反应气源,利用X射线衍射(XRD)、扫描电子显微分析(SEM)等分析手段,进行预处理工艺的研究.获得了在低温下700~800℃制备高质量SiC薄膜的预处理工艺参数:热丝碳化温度2 000℃;HF酸蚀30 s;H2刻蚀10 min.
文摘探索热丝化学气相沉积(hot filament chemical vapor deposition,HFCVD)合成高效优质的金刚石已成为研究热点。采用可提高金刚石颗粒单次沉积产量的新型多片式栅状衬底,应用FLUENT流体仿真软件,在原有单个出气口数量及进气总流量保持不变的情况下,优化传统模型,将单个进气口拆分成5个大小相等的进气口,对影响金刚石单晶颗粒均匀性的进气口数量和排布方式工艺参数进行仿真,对比分析HFCVD系统内气体的物理场。结果显示:4组优化模型均提高了衬底温度及流速的均匀性,有利于金刚石单晶颗粒的均匀生长,但对其沉积速率影响不显著;进一步分析优化模型的温度场,发现5个进气口及单个出气口分别位于反应腔体顶部和底部的中间位置时系统的温度差最低,最满足金刚石单晶颗粒在多片式硅衬底上均匀生长的条件。HFCVD金刚石单晶颗粒沉积试验验证了仿真结果的正确性。
文摘用热丝化学气相沉积法(hot filament chemical vapor deposition,HFCVD)制备金刚石涂层刀具时,衬底温度对金刚石涂层分布的均匀性有重要影响。利用仿真软件ANSYS中的FLUENT模块,对GAMBIT中建立的三维HFCVD批量刀具反应模型进行分析,并运用耦合热传导、热对流、热辐射等3大传热方式对该模型衬底温度分布情况进行仿真预测,对影响涂层分布均匀性的刀具底部支撑台材料散热方式进行分析、优化。仿真结果显示:相较于传统的铜质支撑台和石墨支撑台,热导率小的陶瓷材料支撑台的刀体平均温差最小,为37.82℃,比采用铜材料为支撑台时的刀体平均温差降低了45℃,更有利于制备膜厚、质量均匀的CVD金刚石涂层刀具。
基金Project(20130073110036)supported by the Research Fund for the Doctoral Program of Higher Education of China
文摘Amorphous Si O2（a-Si O2） films were synthesized on WC-Co substrates with H2 and tetraethoxysilane（TEOS） via pyrolysis of molecular precursor.X-ray diffraction（XRD） pattern shows that silicon-cobalt compounds form at the interface between a-Si O2 films and WC-Co substrates.Moreover,it is observed by transmission electron microscope（TEM） that the a-Si O2 films are composed of hollow mirco-spheroid a-Si O2 particles.Subsequently,the a-Si O2 films are used as intermediate films and chemical vapor deposition（CVD） diamond films are deposited on them.Indentation tests were performed to evaluate the adhesion of bi-layer（a-Si O2 ＋ diamond） films on cemented carbide substrates.And the cutting performance of bi-layer（a-Si O2 ＋ diamond） coated inserts was evaluated by machining the glass fiber reinforced plastic（GFRP）.The results show that a-Si O2 interlayers can greatly improve the adhesive strength of diamond films on cemented carbide inserts;furthermore,thickness of the a-Si O2 interlayers plays a significant role in their effectiveness on adhesion enhancement of diamond films.
