發(fā)布時間：2018-09-17 10:05

【摘要】：近些年來,熱噴涂技術(shù)得到了廣泛的發(fā)展和應(yīng)用。隨著大氣等離子噴涂技術(shù)的逐漸成熟,新型的低壓等離子噴涂技術(shù)也受到了越來越廣泛的關(guān)注。超低壓等離子噴涂技術(shù)是在較低的壓強(qiáng)(50-100Pa)下,利用大功率的等離子噴槍,可以使等離子射流的噴射速度達(dá)到超音速,繼而沉積得到不同于傳統(tǒng)的層狀結(jié)構(gòu)的涂層。本文主要運用三種不同的等離子噴涂方法,即大氣等離子噴涂、低壓等離子噴涂和超低壓等離子噴涂,分別噴涂兩種不同的YSZ納米團(tuán)聚粉末(燒結(jié)粉末和未燒結(jié)粉末),制備各種不同的涂層。實驗中,還將分別使用兩種不同的等離子工作氣體(Ar-H2和Ar-He)來獲得不同的等離子射流。然后,再將在不同條件下得到的涂層進(jìn)行鑲嵌、打磨、拋光、熱腐蝕,繼而在掃描電鏡下觀察涂層的橫斷面,來分析其組織結(jié)構(gòu)的特點。實驗結(jié)果表明：使用納米團(tuán)聚YSZ粉末,采用大氣等離子噴涂可以制備出多孔的等軸晶熱障涂層。在低壓和超低壓條件下,氣體成分對涂層的微觀組織有很大的影響,采用Ar-H2等離子氣體制備的涂層中存在大塊晶粒及較大的氣孔。采用Ar-He等離子氣體制備的涂層中晶粒更加均勻和細(xì)小,并可以制備出完全納米等軸晶的涂層。在低壓/超低壓條件下,等離子體的射流特性與大氣壓下有很大區(qū)別,低壓和超低壓下可以制備出完全納米等軸晶的涂層。超低壓下制備的涂層晶粒更加細(xì)小。
[Abstract]:In recent years, thermal spraying technology has been widely developed and applied. With the maturation of atmospheric plasma spraying technology, new low pressure plasma spraying technology has been paid more and more attention. The ultra-low pressure plasma spraying technology can make the injection velocity of plasma jet reach supersonic speed under lower pressure (50-100Pa) and use the high power plasma spray gun, and then deposit the coating which is different from the traditional layered structure. This paper mainly uses three different plasma spraying methods, namely, atmospheric plasma spraying, low pressure plasma spraying and ultra low pressure plasma spraying. Two kinds of YSZ nano-agglomerated powder (sintered powder and unsintered powder) were sprayed to prepare different coatings. Two different plasma working gases (Ar-H2 and Ar-He) will be used to obtain different plasma jets. Then, the coatings obtained under different conditions were inlaid, polished, polished and hot corroded, and then the transverse sections of the coatings were observed under scanning electron microscope to analyze the structural characteristics of the coatings. The experimental results show that porous equiaxed thermal barrier coatings can be prepared by using nano-agglomerated YSZ powder and atmospheric plasma spraying. Under the condition of low pressure and ultra low pressure, the composition of gas has a great influence on the microstructure of the coating. There are large grains and large pores in the coating prepared by Ar-H2 plasma gas. The coating prepared by Ar-He plasma gas is more uniform and finer, and can be used to fabricate the complete nano-equiaxed coating. The characteristics of plasma jet at low / ultra-low pressure are different from those at atmospheric pressure, and a complete nano-equiaxed coating can be prepared under low pressure and ultra-low pressure. The grain size of the coating prepared at ultra low pressure is smaller.
【學(xué)位授予單位】：大連海事大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB306

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本文編號：2245528