WC–10Co–4Cr复合涂层和04Cr13Ni5Mo合金堆焊层的泥沙冲蚀行为

采用超音速火焰喷涂和焊条电弧焊在Q345钢基体表面分别制备了WC–10Co–4Cr复合涂层和04Cr13Ni5Mo合金堆焊层,测量了2种涂层的显微硬度、孔隙率、断裂韧性和表面粗糙度,并对2种涂层的显微组织和耐泥沙冲蚀磨损性能进行了对比研究。结果表明,二者的体积冲蚀磨损率均随时间延长而增加。在低角度冲蚀磨损条件下,复合涂层的耐泥沙冲蚀磨损性能明显优于堆焊层,涂层的硬度和强度是耐泥沙冲蚀磨损的主要影响因素。在高角度冲蚀磨损条件下,2种涂层的耐泥沙冲蚀磨损性能相差不大,涂层的断裂韧性是主要影响因素。WC–10Co–4Cr复合涂层表现出偏脆性材料的冲蚀磨损特性,04Cr13Ni5Mo堆焊层则表现出典型塑性材料的冲蚀磨损特性。     

核电厂小尺寸阀门内壁新型冲蚀减缓技术的研发应用

以WCB钢为基材,采用国产化小型超音速火焰喷涂(HVOF)设备喷涂Ni60镍基合金涂层.通过扫描电子显微镜(SEM)及能谱仪(EDS)分析、显微硬度计测试、拉伸试验、磨粒磨损试验和冲蚀磨损试验,考察了Ni60涂层的组织形貌、微观结构、孔隙率、显微硬度、结合强度、耐磨粒磨损性能和耐冲蚀磨损性能,并对实际小尺寸疏水阀门内壁进行喷涂,分析该工艺的实际可行性.结果表明,所制备的Ni60涂层的孔隙率为(0.27±0.04)％,显微硬度为843 HV(载荷300 g),界面结合强度高达200 MPa以上.该涂层主要由弥散分布着碳化物等硬质相的Ni基固溶体组成,具有比WCB基材更优良的耐磨粒磨损和耐冲蚀性能,其冲蚀失效形式主要为犁沟加塑形变形.小尺寸阀门内壁经喷涂后,表面涂层质量及配合性均符合要求.     

纳米环氧树脂复合涂层耐冲蚀磨损性能研究

研究了固化剂低分子聚酰胺、有机蒙脱土和纳米Al2O3的用量对环氧树脂胶粘涂层拉伸剪切强度和耐冲蚀磨损性能的影响。试验表明,有机蒙脱土和纳米Al2O3能有效提高涂层拉伸剪切强度和耐冲蚀磨损性能,在最佳配方下,涂层的耐冲蚀磨损性能是Q235钢的10.83倍。     

端环氧基聚氨酯的合成及其改性环氧涂层的冲蚀磨损性能

采用两种不同摩尔质量的聚丙二醇与二苯基甲烷二异氰酸酯及缩水甘油反应,合成了两种不同聚醚链段长度的端环氧基聚氨酯(ETPU1000和ETPU2000),并对合成产物进行了红外表征。拉伸和剪切粘接强度测试表明,适量聚氨酯的加入可以提高环氧树脂(EP)/ETPU共混物的粘接强度且EP/ETPU2000的粘接强度更大。随着ETPU含量的增加,EP/ETPU共混物的缺口冲击强度先增大而后有所降低,ETPU2000表现出更好的增韧效果。ETPU2000改性EP涂层的冲蚀磨损测试表明,ETPU2000能够显著改善EP涂层的抗冲蚀磨损性能,当ETPU2000质量分数在15%左右时,冲蚀磨损量达到最小,随着ETPU2000含量的进一步增加,冲蚀磨损量又有所增大;冲蚀磨损表面的扫描电子显微镜照片分析发现,适当添加ETPU2000能够抑制纯EP涂层因脆性大而易产生的疲劳脱落。     

高温球阀喷涂Al2O3-TiO2和WC-Co涂层的耐磨粒磨损性能

采用激光等离子喷涂技术在已失效的高温球阀基体材料上制备Al2O3-TiO2与WC-Co金属陶瓷涂层,在摩擦磨损试验机上对涂层的耐磨粒磨损性能进行研究,利用扫描电镜、光学显微镜对涂层的显微组织结构、磨损表面及其相组进行分析,并采用维氏显微硬度计、WE-50型液压拉伸验机和箱式电热炉对涂层的显微硬度、结合强度及抗热震性进行测试.结果表明,Al2O3-TiO2金属陶瓷涂层的综合性能最好,可以用于失效高温球阀的再制造.     

氩弧熔覆铁基合金 TiB2-Al2 O3涂层冲蚀磨损性能研究

为提高Q255的冲蚀磨损性能,利用氩弧熔覆方法制备了铁基合金TiB2-Al2 O3涂层。熔覆层显微硬度最高为913．5 Hv0．2是基体硬度的5．9倍;熔覆层的冲蚀磨损性能较基体提高了1．77～4．22倍。熔池组织均匀细小,XRD分析显示,熔覆层由Fe、Al、TiO2、TiB2、Fe2 B、Al2 O3相组成。     

NiCrN涂层相成分调控及腐蚀磨损机理

采用电弧离子镀技术在42CrMo钢基体上沉积NiCrN涂层,通过改变N2流量来调控涂层的相成分,并研究其对腐蚀磨损性能的影响规律。研究表明:随着N2流量的增加,CrN相含量增加,金属Ni、Cr相含量相对降低,并导致涂层的硬度由530 HV逐渐升高至710 HV。涂层的腐蚀电位随着CrN相含量增加而逐渐正移,腐蚀电流密度基本维持在同一数量级。在腐蚀磨损的中后期,涂层的失效形式以点蚀为主。随着涂层中CrN相含量增加,涂层的耐点蚀性能变差。最后,详细讨论了涂层的腐蚀磨损机理。     

碳纳米管增强胶黏陶瓷涂层的制备及性能表征

利用溶胶凝胶法制备了胶黏陶瓷涂层,为了提高涂层的综合性能,在涂层中添加了少量的羟基化碳纳米管.对涂层的形貌、显微硬度、摩擦磨损特性进行了分析,结果表明:添加碳纳米管的涂层光滑平整且碳纳米管在涂层中分散均匀;添加0.3wt％碳纳米管的涂层,显微硬度达到最大值750 HV,碳纳米管再次增加时,显微硬度开始下降;植入0.5wt％碳纳米管的涂层,摩擦系数和磨损量分别为0.35和0.573×10-3 mm3/Nm,涂层的摩擦磨损特性最佳.     

超音速等离子喷涂MoWCu合金涂层的性能

采用超音速等离子喷涂技术在45CrNiMoVA钢表面制备了MoWCu合金涂层。利用场发射扫描电镜、能谱仪、X射线衍射仪、维氏显微硬度计和球-盘式摩擦磨损试验机考察了涂层的形貌、成分、显微硬度和耐磨性,采用四探针法测量其导电性。MoWCu涂层的显微硬度平均值为486.2 HV0.1,比基体硬度提高1倍,与纯Mo涂层的显微硬度相当,但比MoW涂层的显微硬度略低。MoWCu涂层与基体的结合强度为45.3 MPa,表现为机械结合。MoWCu涂层的导电率为8.83%IACS,比纯Mo涂层高2/5左右。与纯Mo涂层和MoW涂层相比,在相同摩擦条件下,MoWCu涂层的磨损体积最小,摩擦因数最低,主要以粘着磨损为主,同时伴有轻微的氧化磨损。     

WC陶瓷/环氧树脂复合涂层的抗泥沙冲蚀磨损性能

在环氧树脂中分别添加占体系总质量0%、10%、20%和30%的碳化钨(WC)陶瓷颗粒,制备出WC陶瓷/环氧树脂复合涂层,考察了它们的洛氏硬度、抗拉结合强度和抗泥沙冲蚀磨损性能。通过扫描电镜观察了涂层冲蚀试验后的表面形貌,探讨了涂层在泥浆中的冲蚀磨损机理。WC陶瓷/环氧树脂涂层的洛氏硬度均高于纯环氧涂层的洛氏硬度(49 HR),为103~107 HR,且随着WC陶瓷颗粒的用量增多而提高。当WC加入量为10%时,复合涂层的抗拉结合强度最大,达16 MPa;且磨损率最小,为0.017%。WC陶瓷颗粒与环氧树脂基体发生协同作用,既降低了环氧树脂被磨损的概率,又很好地固定住WC陶瓷颗粒,使其难以被挖出脱落,从而使WC陶瓷/环氧树脂复合涂层获得较好的抗冲蚀性能。     

Erosion resistance and toughening mechanism of AlBO and BNw whiskers modified thermal barrier coatings

In order to improve the erosion resistance and toughness of thermal barrier coatings, YSZ coatings, 20 vol%-AlBOw whisker modified YSZ coatings and 20 vol%-BNw whisker modified YSZ coatings were prepared by plasma spraying. The cross-section structure, morphology, composition and phase composition of coatings and powders were analyzed by SEM, EDS and XRD. The erosion resistance of three coatings was tested by self-made erosion tester. The crack growth resistance of coatings was tested and calculated by Vickers hardness tester. The results show that the density of the coating is improved by adding AlBOw and BNw. The whisker inhibits the crack propagation through the mechanisms of crack deflection, whisker pull-out and whisker bridging. The addition of whisker improves the erosion resistance of YSZ coating by 8.17% and 13.94%, which can effectively improve the service life of thermal barrier coating.     

Improvement of anti-erosion performance of TiN coatings through using a filtration cathode vacuum arc deposition method

Sand erosion is a major factor that shortens the service life of aircraft in desert regions. The anti-erosion performance of titanium alloys may be improved using TiN coatings. However, few studies have employed Ti sputtering on Ti transition layers to improve the erosion resistance of the coatings. Herein, TiN coatings with a sputtering layer between the Ti transition layer and the TiN layer were deposited on a Ti–6Al–4V alloy by filtered cathodic vacuum arc deposition. For comparison, another group of TiN coatings without a Ti sputtering layer but processed using the same deposition parameters were prepared. The effects of the nanoscale sputtering layer on the microstructure, mechanical properties, and anti-erosion performance of the coatings were investigated using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and nanoindentation. The results show that the introduction of a Ti sputtering layer promoted the growth of TiN grains, leading to the formation of finer and denser TiN columnar grains. The preferred orientation of the coatings with the sputtering layer is (111) plane, whereas that of the coatings without the sputtering layer is (200) plane. The TiN coatings containing a sputtering layer exhibit higher hardness, elastic modulus, and H³/E² ratio, which enhances the anti-erosion performance of the coatings. The coatings with a sputtering layer exhibited better erosion resistance (erosion rate reduced by 75%) than the coatings without a sputtering layer. The underlying mechanism to understand the effect of the sputtering layer on the erosion resistance was discussed based on variations in the microstructure and mechanical properties of the coatings with and without the Ti sputtering layer. Ti sputtering layer was finally proved to be an effective method to improve the erosion resistance of TiN coatings.     

硼酸铝晶须增强涂料的冲刷磨损性能研究

为了提高涂料的耐冲刷性能,采用在环氧酚醛涂料里添加分散好的硼酸铝晶须的方法,制备出一种晶须增强涂料。采用冲刷磨损试验机测试涂料的耐冲刷性能,结果表明,晶须增强涂料的冲刷磨损失重量明显小于环氧酚醛涂料,最合理配比为10%硼酸铝晶须+涂料,其冲刷磨损量为环氧酚醛涂料的1/3。晶须的钉扎连接作用消除了涂料固化的孔洞,提高了涂料的耐磨性能。     

脉冲电沉积纳米镍-碳化硅复合镀层的性能

分别采用直流(DC)和换向脉冲电流(PRC)电沉积法制得纳米Ni-SiC复合镀层。采用X射线衍射仪、扫描电镜、能谱仪对比研究了纯Ni镀层和Ni-SiC复合镀层的微观结构、宏观残余应力、表面形貌及成分。用浸泡法研究了不同镀层在3.5%(质量分数)NaCl和10%(体积分数)H2SO4溶液中的腐蚀行为。结果表明,脉冲电沉积能改变镀层的微观结构,有效提高镀层硬度,降低宏观残余应力。脉冲电沉积所得到的纯Ni镀层和纳米Ni-SiC复合镀层在3.5%NaCl及10%H2SO4溶液中的耐蚀性均优于直流镀层。脉冲镀层在3.5%NaCl溶液中受腐蚀很轻,主要腐蚀形态为点蚀,而在10%H2SO4溶液中,SiC粒子作为增强相使镀层的耐腐蚀性进一步提高。     

Erosion of atmospheric plasma sprayed rare earth oxide coatings under air suspended corundum particles

Atmospheric plasma sprayed (APS) zirconium oxide based coatings are used widely in aero engine components for providing thermal insulation, improving the corrosion and oxidation resistance. Despite its wide spread industrial use, little is known about the basic erosion behaviour and the mechanisms by which such coatings erode. In this paper, the erosive wear behaviours of Yttria Stabilized Zirconia (YSZ) coatings; Lanthanum Zirconate (LZ) coatings and Inconel 738 base material (BM) were studied and compared under air jet erosion conditions with corundum particles as erodent material. The erosion behaviour was studied with respect to the different porosity volume percentages of the coatings and the changes in velocity of erodent, impact angle of erodent and erodent particle flux. It was found that in solid particle erosion, the wear resistances of YSZ and LZ coatings were the best at their lowest porosity volume and it decreased with the increase in the percentage volume of porosity. There was a linear increase in the wear resistance with the increase in hardness. Further, relationships among the erosion parameters with respect to erosive wear loss were derived by using the response surface methodology and the erosion mechanisms were discussed adequately.     

Effect of precoated carbon layer on microstructure and anti‐erosion properties of SiC coating for 2D‐C/C composites

To improve the erosion resistant of carbon‐carbon composites, an SiC coating was synthesized on carbon‐carbon composites by the in situ reaction method. They are firstly coated with carbon layer by slurry, and then SiC coatings are obtained by chemical vapor reaction. The effects of precoated carbon layer on the microstructure and anti‐erosion properties of SiC‐coated C‐C composites were studied and characterized. The thickness of the SiC coating increased with the increase in the precoated carbon layer thickness. The different thickness of carbon layer affects hardness of the SiC coatings, resulting in diverse erosion resistance of the coatings. The SiC coating prepared with moderate thickness of precoated carbon layer exhibits the best erosion resistance, and show better resistance at an impact angle of 30° than 90°. The eroded surface revealed that coating cracking and brittle fracture, fiber‐matrix debonding, fiber breakage, and material removal, and the additional microcutting and microploughing at oblique impact angle are the major erosion mechanism of SiC coating for C/C composites.     

石墨烯光固化涂料的制备及防腐性能研究

为了提高光固化涂料的耐腐蚀性,将不同质量分数的石墨烯添加到光固化涂料中,制备了石墨烯复合光固化防腐涂层。对不同含量石墨烯复合光固化防腐涂层的硬度、耐冲击性、附着力等物理性能进行测试,并通过极化曲线、电化学阻抗谱等对其电化学性能进行了研究。最后,采用盐雾试验对不同石墨烯添加量的光固化涂层的防腐性能进行了评价。结果表明：当石墨烯的添加量为 0.1%时,涂层的硬度、耐冲击性以及附着力等物理性能得到显著增强,此时涂层的腐蚀电位最高,腐蚀电流密度最低,具有优异的耐腐蚀性能。     

气相二氧化硅对瓷器文物修复仿釉涂料性能的影响

瓷器文物修复作色上釉时使用的无色透明有机涂料称为仿釉涂料,目前常用于瓷器文物修复的仿釉涂料普遍存在着耐老化性差和硬度不足这两个问题。为了使仿釉涂料更好地满足修复需求,研究使用气相二氧化硅粉体材料,对陶瓷修复常用的三种仿釉涂料(硝基涂料、丙烯酸光油和水性聚氨酯涂料)进行改性实验,并对改性前后涂膜的硬度、光泽度、接触角、附着力和抗老化性进行了一系列测试。测试结果表明,在加入气相二氧化硅粉末体积比为5%时硝基涂料涂膜铅笔硬度提升到3H,丙烯酸涂料和聚氨酯涂料涂膜铅笔硬度均能提升到H,且三种涂料的涂膜附着力、抗光老化性、环境耐候性和抗污能力有明显提升,但涂膜会损失一定光泽度。     

Effect of WC-10Co on cavitation erosion behaviors of AlCoCrFeNi coatings prepared by HVOF spraying

The (AlCoCrFeNi)_1-X(WC-10Co)_X composite coatings were fabricated by HVOF spraying and their microstructures, mechanical properties and cavitation erosion behaviors were tested. The effects of WC-10Co on the cavitation erosion mechanisms were discussed by compared the differences of volume losses and eroded surface morphologies between the coatings. The cavitation erosion resistance of the coatings was about 3 times as that of the 06Cr13Ni5Mo steel. With the addition of WC-10Co, the cavitation erosion resistance of the coating was slightly increased. In the initial stage of cavitation erosion test, the cavitation erosion damage was concentrated on the interface, which was caused by the uncoordinated deformation and poor mechanical properties of the interface between HEA and WC-10Co. When the WC-10Co distributed below the HEA region, the WC-10Co played a strong supporting role and improved the impact resistance of the HEA region. The cavitation erosion mechanism of the HEA1 coating was lamellar spalling. The cavitation erosion mechanisms of the HEA2 and HEA3 coatings were particles spalling and lamellar spalling.     

聚氨酯/微米Si_3N_4复合材料的性能研究

对聚氨酯/微米Si3N4复合材料的性能进行了研究,实验表明：聚氨酯/Si3N4复合材料具有优异的性能,聚氨酯/微米Si3N4复合材料,其硬度、力学性能和抗冲蚀磨损性能比纯聚氨酯优异;在微米Si3N4含量为3%时,其硬度、力学性能最佳;在微米SiN含量为5%时,其抗冲蚀磨损性能最佳。