本文關(guān)鍵詞：活塞裙表面等離子噴涂鉬涂層的研究　出處：《江蘇科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 等離子噴涂 Mo涂層 正交試驗(yàn) 涂層性能 超聲沖擊處理

【摘要】：本文采用等離子噴涂技術(shù)在鑄鐵表面制備了Mo涂層。以涂層結(jié)合強(qiáng)度、孔隙率、顯微硬度為綜合指標(biāo),對(duì)等離子噴涂工藝參數(shù)進(jìn)行正交試驗(yàn),得出噴涂Mo涂層的優(yōu)化工藝參數(shù)。然后按優(yōu)化工藝參數(shù)制備Mo涂層,采用SEM、EDS、XRD等分析方法對(duì)其顯微組織和物相結(jié)構(gòu)進(jìn)行了研究,并對(duì)涂層的結(jié)合強(qiáng)度、顯微硬度及孔隙率進(jìn)行了測(cè)定;通過(guò)熱震試驗(yàn)和摩擦磨損試驗(yàn)研究了涂層的熱疲勞壽命及其摩擦性能;對(duì)Mo涂層進(jìn)行超聲沖擊處理,研究了改善涂層綜合性能方法的可行性。研究結(jié)果表明,在本試驗(yàn)選定的參數(shù)范圍內(nèi):等離子噴涂工藝參數(shù)對(duì)涂層綜合性能影響的主次順序?yàn)?噴涂功率主氣流量噴涂距離送粉速率。采用優(yōu)化工藝參數(shù)制備的Mo涂層,結(jié)合強(qiáng)度為67.16MPa、涂層孔隙率為5.78%、顯微硬度為310HV。等離子噴涂過(guò)程中無(wú)氧化行為發(fā)生,涂層組織均勻致密,結(jié)合良好,結(jié)合方式為機(jī)械錨合。Mo涂層的表面硬度和橫截面硬度都存在較大的分散性,且表面硬度比橫截面硬度高,顯著地服從Weibull分布。Mo涂層熱疲勞壽命較好,達(dá)到了較高的宏觀啟裂次數(shù)和失效次數(shù);Mo涂層在熱震過(guò)程中部分形成物相Mo O和Mo O3;熱震后涂層的顯微硬度增大,但仍存在較大的分散性。干摩擦條件下,鑄鐵基體的耐磨性能優(yōu)于涂層。常溫下,Mo涂層主要磨損機(jī)制是疲勞磨損和氧化磨損;基體的磨損機(jī)制主要是粘著磨損和磨粒磨損,兼有氧化磨損。潤(rùn)滑條件下,涂層的摩擦性能有了明顯的改善,涂層的摩擦系數(shù)隨著載荷的增大而增大,隨著轉(zhuǎn)速的增大而減小。同等條件下涂層的耐磨性能優(yōu)于基體。常溫下,基體的磨損機(jī)制與干摩擦條件下相同,而涂層的磨損機(jī)制發(fā)生改變,以粘著磨損為主,兼有氧化磨損。采用超聲沖擊處理技術(shù)能夠顯著的改善Mo涂層的綜合性能。涂層表面粗糙度由Ra=35.279um降為2.845um;涂層表面硬度平均提高了35%;近表面層孔隙率降低了41.4%;涂層熱疲勞壽命在一定程度上得到了提高。
[Abstract]:This paper adopts the cast iron surface Mo coating was prepared by plasma spraying technology. The bonding strength, porosity, microhardness as comprehensive indexes, orthogonal experiments were carried out on the technological parameters of plasma spraying, the optimum technological parameters of spray coating of Mo. Then according to the optimum process parameters of preparation of Mo coating by SEM, EDS, XRD and other analysis methods the research on the microstructure and phase structure, and the bonding strength of the coating, micro hardness and porosity were determined; the thermal shock test and the friction and wear properties of the coating on the thermal fatigue life and friction performance of Mo coatings; ultrasonic impact treatment, study the feasibility of improving the comprehensive performance of coating method. The results show that in the range of parameters selected in our experiment in order: the influence of plasma spraying parameters on the comprehensive performance of coating for spraying main gas flow from the spraying power From the powder feeding rate. The optimal technological parameters for preparing Mo coating, bonding strength of 67.16MPa coating, the porosity is 5.78%, the microhardness of 310HV. plasma spraying oxidation behavior in the process of combining with the microstructure of the coating is uniform and compact, good surface hardness and hardness of cross section by means of mechanical anchoring of.Mo coatings are dispersed larger than the cross section and the surface hardness, high hardness, obviously obeys the Weibull distribution of.Mo coating on thermal fatigue life better, to achieve a higher number of macro crack initiation and failure number; Mo coating on the thermal shock in the process of forming part of the phase Mo O and Mo O3; the microhardness of coating is increased after thermal shock, but still there is a large dispersion. The dry friction condition, wear resistance of cast iron matrix is better than that of Mo coating coating. Under normal temperature, the main wear mechanism is fatigue wear and oxidation wear; wear mechanism of matrix if adhesive wear And abrasive wear, oxidation wear. Both the lubrication condition, the friction properties of the coatings was improved obviously, the friction coefficient of the coating increases with the increase of the load, and decreases with the increase of speed. The wear performance is better than that of coating under the same condition. Under normal temperature, the wear mechanism of the matrix and dry friction conditions of the same change, and wear mechanism of the coating, adhesive wear, oxidation wear. The comprehensive performance of both the ultrasonic peening treatment technology can improve Mo coating significantly. The surface roughness is reduced from Ra=35.279um to 2.845um; the coating hardness was increased by 35%; near surface layer porosity decreased by 41.4%; the thermal fatigue life of the coating has been improved to a certain extent.

【學(xué)位授予單位】：江蘇科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG174.4

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