本文選題：涂層　切入點(diǎn)：力學(xué)性能　出處：《昆明理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：Al2O3-40wt%TiO2涂層(AT40涂層)廣泛的應(yīng)用于機(jī)械、紡織、冶金等工業(yè)領(lǐng)域。等離子噴涂沉積Al2O3-40wt%TiO2涂層具有高硬度、高耐磨性、摩擦系數(shù)低、化學(xué)性能穩(wěn)定等特點(diǎn)。隨著工業(yè)服役條件越來越苛刻,對(duì)涂層的性能提出了更高的要求。納米材料有強(qiáng)的比表面活性和小尺度效應(yīng),納米結(jié)構(gòu)Al2O3-40wt%TiO2涂層具有更加優(yōu)異的性能,但是制備納米結(jié)構(gòu)涂層工藝更復(fù)雜,工藝參數(shù)更加難控制。另外,梯度Al2O3-40wt%TiO2涂層和多層Al2O3-40wt%TiO2涂層能夠減小涂層中的應(yīng)力梯度,延長涂層的壽命。由于梯度涂層和多層涂層是經(jīng)過多次噴涂制備而成,因此梯度和多層涂層中有更多的層間界面。在制備過程和服役過程中,缺陷很容易在層間界面上形成并擴(kuò)展,最后導(dǎo)致涂層失效。通過摻雜也能改善涂層的性能,本文研究了 Y2O3摻雜對(duì)Al2O3-40wt%TiO2涂層性能的影響。通過雙路送粉單次噴涂制備含有金屬陶瓷過渡區(qū)的Al2O3-40wt%TiO2涂層(MAT40涂層),金屬陶瓷過渡區(qū)代替AT40涂層中粘結(jié)層與陶瓷層的界面。本論文討論了金屬陶瓷過渡區(qū)對(duì)涂層性能以及失效機(jī)制的影響。獲得的主要研究結(jié)論有如下幾點(diǎn):(1)采用等離子噴涂雙路送粉單次噴涂方法制備了含金屬陶瓷過渡區(qū)的Al2O3-40wt%TiO2涂層(MAT40)。比較AT40涂層和MAT40涂層的力學(xué)性能及失效機(jī)制發(fā)現(xiàn),在熱震試驗(yàn)和彎曲試驗(yàn)時(shí)MAT40涂層系統(tǒng)中應(yīng)力梯度變小。形成的金屬陶瓷過渡區(qū)替代了原本AT40涂層中陶瓷層與粘結(jié)層的界面,使得在MAT40涂層體系中除去粘結(jié)層與基體之間的界面外沒有其它連續(xù)的界面。金屬陶瓷過渡區(qū)的出現(xiàn)提高了涂層的抗熱震性能和力學(xué)性能。通過分析試驗(yàn)過程中涂層的失效機(jī)制發(fā)現(xiàn),金屬陶瓷過渡區(qū)通過降低涂層內(nèi)的應(yīng)力梯度、偏轉(zhuǎn)涂層中的裂紋擴(kuò)展方向、塑性變形提高涂層的斷裂韌性。(2)Al2O3-40wt%TiO2涂層中的層狀相分布主要受預(yù)先沉積的表面形貌以及噴涂參數(shù)的影響。R/h≤al是形成非致密層狀相分布的必要條件;預(yù)先沉積形貌的傾斜角(θ)決定非層狀相分布的位置。(3)在維氏硬度測(cè)試過程中,應(yīng)力釋放機(jī)制主要受界面缺陷影響。當(dāng)涂層中有很多的界面缺陷(微觀裂紋、孔隙等)時(shí),在維氏硬度計(jì)壓頭的作用下,裂紋很容易進(jìn)一步沿著相與相之間的界面擴(kuò)展。另外,在菱形壓痕的尖角處也是應(yīng)力集中的地方,容易產(chǎn)生裂紋。隨著越來越多的裂紋與涂層中的孔隙連接導(dǎo)致涂層崩塌。涂層的崩塌使得硬度測(cè)量值變小。對(duì)于界面缺陷少的涂層,通過裂紋在菱形壓痕的尖端形成并擴(kuò)展來釋放涂層中的應(yīng)力。當(dāng)裂紋的始端與末端相連接時(shí),則會(huì)導(dǎo)致涂層的小塊崩落并釋放涂層中的應(yīng)力。(4)熱震試驗(yàn)和彎曲試驗(yàn)時(shí),涂層內(nèi)的裂紋在陶瓷區(qū)內(nèi)是沿著柱狀晶的晶間界面擴(kuò)展。由于裂紋沿著多邊形柱狀晶的晶間界面擴(kuò)展,在熱震試驗(yàn)失效的表面能夠發(fā)現(xiàn)規(guī)則的折線狀形貌。在三點(diǎn)彎曲試驗(yàn)時(shí),裂紋在陶瓷區(qū)域內(nèi)同樣是沿著柱狀晶晶間界面生長,在斷裂截面上能夠明顯看到柱狀晶的晶界。NiAl合金區(qū)在彎曲試驗(yàn)中主要承受拉應(yīng)力,在承受拉應(yīng)力時(shí)發(fā)生拉伸塑性變形來釋放應(yīng)力直到斷裂。(5)Y2O3的摻雜會(huì)降低AT40涂層的結(jié)構(gòu)均勻性。8wt%Y2O3摻雜的Al2O3-40wt%TiO2涂層具有最高的耐磨性。耐磨性的提高主要是由于Y2O3的摻雜改善了 Al2TiO5的力學(xué)性能。(6)通過正交試驗(yàn)法分析得到沉積Al2O3-40wt%TiO2涂層的參數(shù)為:噴涂電流為500A、N2速率為2600mL/h、噴涂距離為110mm、送粉電壓為8V。N2速率是對(duì)涂層硬度影響最大的參數(shù),噴涂距離是對(duì)涂層磨損率影響最大的參數(shù)。獲得的 Al2O3-40wt%TiO2涂層的最高硬度達(dá)到 1126HV0.2,Al2O3-40wt%TiO2涂層的最低磨損率為0.0387 mg/N.m。
[Abstract]:Al2O3-40wt%TiO2 coating (AT40 coating) is widely used in machinery, textile, metallurgy and other industrial fields. With high hardness of Al2O3-40wt%TiO2 coatings deposited by plasma spraying, high wear resistance, low friction coefficient, chemical stability and other characteristics. With the industrial service conditions have become increasingly demanding, put forward higher requirements on the performance of the coating nano materials have. Strong surface activity and small scale effect, nanostructured Al2O3-40wt%TiO2 coating has a more excellent performance, but the preparation of nanostructured coating process is more complex, more difficult to control the process parameters. In addition, the gradient Al2O3-40wt%TiO2 coating and multilayer Al2O3-40wt%TiO2 coatings can reduce the stress in the coating gradient, prolong the life of the coating. The coating and gradient the multilayer coating was prepared after spraying, so the gradient and multilayer coatings have more interface. Served in the preparation process and the In the process, defects easily in interface formation and expansion, resulting in failure of the coatings. The performance can also improve by doping coating, this paper studies the impact of Y2O3 doping on the properties of Al2O3-40wt%TiO2 coatings. Through dual single powder spraying Al2O3-40wt%TiO2 coating preparation containing ceramic metal transition zone (MAT40 coating). The metal ceramic transition zone instead of interfacial layer and ceramic layer in AT40 coatings. This paper discussed the influence of metal ceramic transition zone on the coating performance and failure mechanism. The main conclusions are as follows: (1) using a single powder spraying method Al2O3-40wt%TiO2 metal ceramic coating containing transition zone was obtained dual plasma spraying (MAT40). AT40 and MAT40 coatings, the mechanical properties and failure mechanisms are found in thermal shock test and bending test of MAT40 coating system in stress gradient formation. The metal ceramic interface transition zone replaced the ceramic layer and the bonding layer AT40 coating, the MAT40 coating system to remove the bond between the coating and the substrate interface interface. No other continuous metal ceramic transition region of the coating increased the thermal shock resistance and mechanical properties. Through the analysis of the failure mechanism of coating test in the process of discovery, metal ceramic transition zone by reducing the stress gradient coating, crack deflection in the coating growth direction, improve the plastic deformation of the fracture toughness of coatings. The influence of Al (2).R/h Al2O3-40wt%TiO2 lamellar phase in the coating distribution is mainly affected by the surface morphology of pre deposited and spraying parameters is a necessary condition for the formation of the non dense lamellar phase distribution; pre tilt angle (theta) morphology determines the non layered distribution position. (3) in the Vivtorinox hardness testing process, stress release mechanism is mainly affected by the world Effect of surface defect. When the coating has many interface defects (microcracks, pores), indenter hardness in Vivtorinox under the action of crack easily further along the interface between phases is extended. In addition, the diamond indentation at the angle of stress is concentrated, easy to crack with crack. With more and more pores in the coating coating. The coating of connection leads to collapse collapse makes the hardness measurement value becomes smaller. The coating interface less defects, extended to release the stress in the coating is formed by a crack in the diamond tip and indentation crack. When connected to the beginning and end to end, it will lead to small caving coating and relax the stress in the coating. (4) the thermal shock test and bending test, the crack in the ceramic coating area along the columnar crystal interface. The crack extended along the interface expanding polygon columnar crystal crystal In the exhibition, thermal shock test failure surface can be found in line shape rules. In the three point bending test, the crack in the ceramic region is the same along the columnar crystal growth interface, can the columnar grain boundary of.NiAl alloy in bending test mainly tensile stress was seen in the fracture section. In the tensile plastic deformation to release the stress until the fracture tensile stress. (5) the structure of the Y2O3 doped AT40 can reduce the coating uniform Al2O3-40wt%TiO2 coating doped with.8wt%Y2O3 has the highest wear resistance. The wear resistance is improved due to the doping of Y2O3 can improve the mechanical properties of Al2TiO5 (6) by. Orthogonal test analysis of parameters of Al2O3-40wt%TiO2 coating deposited by: spraying current of 500A, the N2 rate is 2600mL/h, the spraying distance is 110mm, the powder feeding rate is the maximum voltage of 8V.N2 parameters on the hardness of the coating, spraying Distance is the most influential parameter on the wear rate of the coating. The highest hardness of the obtained Al2O3-40wt%TiO2 coating reaches 1126HV0.2, and the lowest wear rate of the Al2O3-40wt%TiO2 coating is 0.0387 mg/N.m..

【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG174.4

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