Hypersonic plasma particle deposition of Si–Ti–N nanostructured coatings
Hypersonic plasma particle deposition of Si–Ti–N nanostructured coatings
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DOI：
10.1016/j.surfcoat.2004.08.226
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发表时间：
2004-11
影响因子：
5.4
通讯作者：
J. Hafiz;Xiaoliang Wang;R. Mukherjee;W. Mook;C. Perrey;J. Deneen;J. Heberlein;P. Mcmurry;W. Gerberich;C. B. Carter;S. Girshick
中科院分区：
文献类型：
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作者：
J. Hafiz;Xiaoliang Wang;R. Mukherjee;W. Mook;C. Perrey;J. Deneen;J. Heberlein;P. Mcmurry;W. Gerberich;C. B. Carter;S. Girshick
采用超音速等离子体粒子沉积（HPPD）技术在钼基体上制备了不同成分的Si-Ti-N涂层。在该方法中，气相前体（TiCl 4、SiCl 4和NH3）在DC等离子体电弧中解离，并且热气体在快速喷嘴膨胀中淬火以使纳米颗粒成核。然后这些纳米颗粒在高超音速流中加速，使它们通过弹道冲击在喷嘴下游的基底上沉积存款。在200至850 °C的衬底温度范围内，根据反应物流速，以2-10 μm/min的速率沉积厚度为10-25 μm的薄膜。当反应气体预混合时，涂层由nc-TiN、nc-TiSi_2、nc-Ti_5Si_3和非晶Si_3 N_4组成。对于未预混反应物的情况下，涂层由游离Si，nc-TiN和非晶Si 3 N4。沉积膜的硬度通过抛光膜横截面的纳米压痕来评价。测量的硬度值，平均超过10-15个位置的每一个膜，范围从16-24 GPa。在具有相同条件的单独实验中，通过将取样探针放置在与膜基底相同的位置处来测量粒度分布。采样的气溶胶被快速稀释并递送到扫描迁移率粒度仪（SMPS）。原位粒度分布测量证实，涂层是由5-15 nm范围内的纳米颗粒的冲击形成的，反应物流速越高，颗粒越大。聚焦离子束（FIB）铣削用于观察膜的横截面和孔隙率。对于含有孔隙的沉积膜，原位等离子体烧结用于致密化膜而没有晶粒生长。
Si–Ti–N coatings with various compositions were deposited on molybdenum substrates using hypersonic plasma particle deposition (HPPD). In this method, vapor phase precursors (TiCl4, SiCl4and NH3) are dissociated in a DC plasma arc and the hot gas is quenched in a rapid nozzle expansion to nucleate nanoparticles. These nanoparticles are then accelerated in hypersonic flow, causing them to deposit by ballistic impaction on a substrate placed downstream of the nozzle. Films of 10–25 μm thickness were deposited at rates of 2–10 μm/min, depending on reactant flow rates, at substrate temperatures ranging from 200 to 850 °C. When the reactant gases were premixed the coatings consisted of nc-TiN, nc-TiSi2, nc-Ti5Si3and amorphous Si3N4. For the unpremixed reactants case, the coatings consisted of free Si, nc-TiN and amorphous Si3N4. Hardness of as-deposited films was evaluated by nanoindentation of polished film cross-sections. Measured hardness values, averaged over 10–15 locations for each film, ranged from 16–24 GPa. In separate experiments with the same conditions, particle size distributions were measured by placing a sampling probe at the same location as the film substrate. The sampled aerosol was rapidly diluted and delivered to a scanning mobility particle sizer (SMPS). In-situ particle size distribution measurements confirmed that the coatings were formed by impaction of nanoparticles in the 5–15 nm range, with higher reactant flow rates producing larger particles. Focused ion beam (FIB) milling was used to observe film cross-section and porosity. For as-deposited films containing pores, in-situ plasma sintering was used to densify the film without grain growth.