高强度涂层结合性能的试验研究及有限元分析

采用线切割沿涂层/基体界面切成对称切口,两边粘结后直接拉伸的试验方法对高强涂层抗拉结合强度进行评价.并借助有限单元法对涂层/基体交界面上的应力分布及切口附近的应力集中进行了分析,为正确评价涂层/基体的结合强度提供了理论依据.按此方法对不同工艺参数的热喷涂烧结涂层结合强度进行了评价.结果表明,此方法可对高强涂层与基体的结合强度进行评价.     

热喷涂涂层的钎焊工艺

使用钎焊方法对热喷涂H08低碳钢涂层、4Cr13马氏体不锈钢涂层与20钢进行连接,研究了这些热喷涂涂层的钎焊工艺性、接头的力学性能以及接头的金相组织形貌.试验结果表明,锡焊可以很好地连接2种低碳钢潦层或将低碳钢涂层与低碳钢基材连接起来;银焊不但可以连接低碳钢涂层.还可连接低碳钢基体与马氏体不锈钢涂层;2种钎焊接头的抗拉结合强度都高于涂层层间结合强度.     

再制造热喷涂涂层切削加工研究现状

综述了涂层磨削加工中砂轮的选用、不同磨削工艺的特点、磨削加工存在的问题。对涂层车削加工中刀具的选用进行了论述,对涂层车削加工中切削参数的选择进行了总结,并给出了可供实际加工的参考数据。最后对涂层车削加工中残余应力分布和涂层结合强度进行了讨论。利用Abaqus对涂层车削加工进行仿真,得到了残余应力分布云图。借鉴垂直拉伸法,对回转体涂层结合强度进行了较为准确的测量。     

火焰喷涂尼龙1010涂层强度测量方法研究

利用理论分析与实验相结合的方法,模拟平面火焰喷涂,设计了一套简单、方便的平面结合强度拉拔实验模具及配套夹具,用于测量火焰喷涂聚合物涂层与基体的结合强度.试验结果表明:所得实验值与理论分析相符,当拉拔试件活塞直径为2mm左右时,比较适合用于火焰喷涂聚合物涂层与基体的结合强度的测量.证明这套模具在评价火焰喷涂聚合物涂层与基体结合强度方面有一定的实用价值.     

微粒轰击Fe基非晶电弧喷涂层性能强化

为了减小热喷涂层残余应力对涂层质量的不利影响,采用喷丸(砂)微粒轰击与高速电弧喷涂相互循环交替的工艺制备了Fe基非晶涂层,使涂层残余拉应力变为残余压应力,喷丸(砂)强化涂层表面残余应力由未处理涂层表面残余拉应力277 MPa分别变为残余压应力-177 MPa(-91 MPa)。利用电子扫描显微镜、纳米压痕仪、摩擦磨损试验机等分别对涂层的微观形貌、力学性能和摩擦磨损性能进行了测试。结果表明:经过微粒轰击后的涂层表面致密平整,组织结构密实,喷丸(砂)强化涂层的孔隙率仅为1.0%(1.5%),结合强度可达44.6 MPa(56.4 MPa),经过微粒轰击后涂层硬度、弹性模量及摩擦磨损性能都有所提升。喷丸强化涂层局部过度的轰击会使涂层结合强度及摩擦磨损性能略有下降。     

有色金属热喷涂陶瓷涂层研究进展

介绍了国内外有色金属材料热喷涂陶瓷涂层技术研究所取得的成就和存在的问题,对陶瓷涂层材料的设计和热喷涂工艺的选择、涂层与基体的结合机理以及结合强度进行了综述,并对有色金属材料热喷涂技术的应用进行了展望.     

超音速热喷涂316L合金涂层在实际炼油环境中的冲蚀行为

利用超音速热喷涂技术在碳钢基体上制备出了316L合金涂层，研究了该涂层在实际炼油环境中的冲蚀行为。结果表明：超音速热喷涂316L合金涂层在实际炼油环境中具有非常好的抗冲蚀性能，长期现场挂片后涂层仍保持完整，仅表面有轻微的冲蚀痕迹，涂层表面形成的保护性氧化膜、涂层金属自身良好的耐蚀性以及涂层较高的硬度是其具有优异抗冲蚀性能的主要原因。     

铝合金热喷涂技术的研究进展和应用展望

分析了国内外铝基材料热喷涂技术研究所取得的成就和存在的问题，提出了涂层材料的设计和热喷涂工艺选择的原则，探讨了涂层与基体的结合机理以及提高其结合强度的措施，并对铝基材料采用热喷涂技术的应用进行了展望。     

喷涂工艺参数对纳米NiCr/WC涂层与基体间结合强度的影响

以纳米NiCr/WC粉末为原料,采用活性燃烧超音速火焰喷涂技术制备了NiCr/WC金属陶瓷涂层。通过XRD衍射以及能谱分析等方法研究了工艺参数对纳米NiCr/WC涂层与基体之间结合强度的影响。结果发现,在喷涂材料确定的条件下,热喷涂涂层与基体之间的结合强度主要取决于热喷涂工艺。尤其是喷涂距离,对涂层与基体之间的结合强度的影响非常明显。     

热喷涂铝过渡层对FEP涂层与钢基体结合强度的影响

研究了喷砂工艺和热喷涂铝过渡层对聚全氟乙丙烯(fluoroethylenepropylene,FEP)涂层与钢基体结合强度的影响.结果表明,喷砂处理后,涂层和基体结合强度随基体表面粗糙度增加先增后降.采用热喷涂工艺在钢基体上制备了铝过渡层,用扫描电镜和表面粗糙度测量仪研究了喷砂以及铝过渡层的表面形貌和表面粗糙度,用拉开法测定了FEP涂层和钢基体的结合强度.铝过渡层具有粗糙多孔的表面结构,在一定程度上增进了 FEP涂层与基体的结合强度.     

SiCf/SiC复合材料表面Si/Yb2Si2O7双层涂层结合强度分析

目的 通过选择合适的复合材料拉伸方向和涂层制备工艺,在SiCf/SiC复材上获得高结合强度的Si/Yb2Si2O7双层涂层.方法 采用真空等离子喷涂技术在2.5D编织的SiCf/SiC复合材料表面制备Si涂层、Si/Yb2Si2O7双层涂层.采用金相、XRD、SEM和EDS对试样进行表征,采用拉伸试验测试涂层的结合强度...     

高温树脂基复合材料防护用轻质陶瓷涂层的制备

研究了采用Ni-3％Al粉末和纯铝、纯锌作为打底材料在碳纤维增强聚酰亚胺复合材料(PMC)基体上制备Al2O3轻质陶瓷防护涂层的可行性,测试了涂层的剪切结合强度和耐热循环性能。结果表明,等离子喷涂Ni-3％Al粉末会对PMC基体造成破坏,不适合于作为PMC基体上的打底材料。电弧喷铝也会对基体造成一定程度的破坏,结合强度和耐热循环性能较低。采用低电压、小电流电弧喷锌,可以获得和基体结合良好打底涂层,涂层剪切结合强度达10．45MPa。在其上制备的Al2O3陶瓷防护涂层耐热循环性能良好。     

钛合金表面原位生成钛酸钾生物陶瓷涂层的制备及其生物相容性

采用原位干混合煅烧合成法在钛合金基体上成功制备了K2Ti6O13涂层，并对涂层的微观形貌、相组成、涂层-基体的结合强度进行了研究，通过模拟体液实验对其生物活性进行了评估。结果表明，涂层与基体间结合牢固，能够经受空冷条件下的冷热冲击，热膨胀系数的良好匹配是结合强度提高的主要原因。涂层粗糙的表面和气孔可为骨的向内生长提供有利位置。经模拟体液浸泡，涂层表面形成了钙磷比接近人体骨骼的钙磷层，表明涂层具有良好的生物活性。     

提高摩托车塑料制品涂着效率的方法

目的提高摩托车ABS部品涂着效率,达到节约成本、降低环境负荷的效果。方法从涂装设备、涂装方法、涂装作业者等因素出发,采用低压空气喷涂、分业涂装方式、手工静电喷涂、自动涂装设备导入、增加单位涂装面积等方法,逐一验证提高涂着效率的效果。结果经过近几年的改善,与传统手工空气喷涂相比,低压空气喷涂配合分业涂装可以提高ABS部品涂着效率5%~10%,静电喷枪配合空气喷枪可以提高10%~15%,自动涂装机可以提高20%~25%。根据部品形状的差异,ABS部品的综合平均涂着效率可以提高约10%。结论涂着效率受综合因素的影响,在作业者、喷涂设备、喷涂方法、挂装方式等方面进行改进,都可以提高涂着效率。但是由于摩托车ABS部品的尺寸普遍存在差异,若单纯采用某一种改善方式,涂着效率的提高幅度不大。从QDC综合因素考虑,针对面积大的部品,应采用手工静电喷枪配合低压空气喷涂的方式;针对面积小的部品,应采用增加挂装数量、提高喷涂面积配合低压空气喷枪等方式。     

高速电弧喷涂不锈钢涂层的旋转回归试验研究

对比研究了３Ｃｒ１３不锈钢高速电弧喷涂涂层和普通电弧喷涂层的孔隙率、氧化物含量、涂层结合强度和滑动磨损性能,并采用多因素正交旋转回归设计和单因素对比试验的方法了高速电弧涂工艺参数对３Ｃｒ１３不钢涂层显微硬度的影响,用微机回归得到了喷涂工艺参数与涂层硬度之间的定量关系式。结果表明,和普通电弧喷涂涂层相比,高速电弧喷涂涂层组织致密、孔隙度低、涂层氧化物含量增多,涂层－基体界面结合强度大于４０ＭＰａ,比     

Improvement of the adhesion of a ceramic coating on a ceramic substrate

The structure and adhesion of an alumina coating on a ceramic substrate with NiCrAlY alloy bond coating was investigated by heating at 1573 and 1673 K in the air. Phases of NiO, NiCrO₃, NiAl₂O₄, αAl₂O₃, and Ni were revealed in a 100 μm thick bond coating on heating at 1573 and 1673 K. A veined structure was also detected in the coating heated at 1573 K. The adhesion strength of the coating was improved and reached approximately 20 MPa on heating at 1573 and 1673 K for 14.4 ks in air although the strength of the as-sprayed coating was only 2 MPa. The improvement of adhesion strength may arise from the formation of NiAl₂O₄ with a spinel structure at the interfaces of the top coating/bond coating/substrate coating system. The adhesion strength of the coating improved on decreasing the bond coating thickness and reached approximately 45 MPa for a 20 μm thick bond coating which was heated at 1673 K. Only NiAl₂O₄ oxide was formed in the bond coating.     

面向工业设计的塑料表面铝涂层的结合强度

目的采用电弧喷涂方法在环氧树脂和ABS塑料表面喷涂铝涂层,研究涂层结合强度的影响因素。方法第一组试验是塑料表面喷砂后,喷涂铝涂层;第二组是塑料表面喷砂后,涂覆一层高强度环氧树脂结构胶,再喷涂铝涂层。选择喷涂气体压力、喷涂电流和喷涂距离三因素进行正交试验,采用粘结拉伸法测试结合强度,并用照相法测量铝液和环氧树脂塑料、Q235钢的接触角。结果本试验条件下,二种塑料电弧喷涂铝涂层结合强度的影响因素主次顺序为:空气压力喷涂电流喷涂距离。最优方案是:喷涂气体压力为0.7 MPa,喷涂电流为220 A,喷涂距离为160 mm。未涂覆高强度环氧树脂结构胶的涂层,结合强度最大不超过3 MPa;涂覆高强度环氧树脂结构胶的涂层,结合强度达到近20 MPa。铝液和Q235钢的接触角是45°,和环氧树脂塑料的接触角是135°。结论环氧树脂和ABS塑料表面电弧喷涂铝涂层的结合强度低的主要原因是铝液和它们之间的润湿性差。涂覆高强度环氧树脂结构胶后,喷涂工艺参数对涂层的结合强度影响不明显,结合强度受控于环氧树脂结构胶的粘接作用,使涂层的结合强度显著提高。     

Effects of coating thickness and residual stresses on the bond strength of ASTM C633-79 thermal spray coating test specimens

Wire-arc-sprayed nickel-aluminum is widely used in the aircraft industry for dimensional restoration of worn parts and as a bond coat for thermal barrier coatings and other top coats. Some repair applications require thick coatings, which often result in lower bond strength. A mechanism being investigated to ex-plain this decrease in bond strength is the free edge effect, which includes both coating residual stresses and coating thickness. The layer-removal method was used to determine experimentally the residual stresses in wire-arc-sprayed nickel-aluminum coatings of different thicknesses. Bond strength evalu-ations were performed using an improved ASTM C 633-79 test specimen. Finite-element analysis and fracture mechanics were used to investigate the effects of coating thickness and residual stress state on coating bond strength.     

Ceramic coating on ceramic with metallic bond coating

The change in structure and adhesion strength of the interface by heating in air has been investigated for a plasma- sprayed alumina coating on a ceramic substrate with a 50Ni- 50Cr alloy bond coating. A veined structure composed of NiO, NiCr ₂O₄, and NiAl₂O₄ oxides grew from the bond coating into cracks or pores in the top coating and the alumina substrate after heating at 1273 K for 20 h in air. The NiAl₂O₄ spinel may have formed by the oxidization of nickel, which subsequently reacted with the alumina coating or the substrate. The mechanism of the penetration of the spinel oxides into the cracks or pores is not clear. The adhesion strength of the coating is increased to about 15 MPa after heating at 1273 K for 20 h in air, compared to an as- sprayed coating strength of only 1.5 MPa.     

Influence of bond coat on shear adhesion strength of erosion and thermal resistant coating for carbon fiber reinforced thermosetting polyimide

Arc-sprayed Al, Zn, and plasma-sprayed Al, Zn, Ni3Al and Cu were deposited on carbon fiber reinforced polyimide substrate as bond coats for erosion and thermal resistant coating. Shear adhesion strength of different materials was tested, and microstructures of bond coats were analyzed with scanning electron microscope. The results showed that the substrate was thermally damaged when Ni3Al or Cu was deposited as bond coat, and the bond coat was delaminated from the substrate. Arc-sprayed and plasma-sprayed Al and Zn could be used as bond coat materials. For Zn as bond coat material, depositing method had little influence on shear adhesion strength. While for Al as bond coat material, plasma spray was superior to arc spray. Preheating could improve shear adhesion strength with plasma sprayed Al as bond coat. The maximum shear adhesion strength obtained in this paper was 14.15 MPa, with plasma-sprayed Al as bond coat, and the preheating temperature was 250 °C.