金属密封球阀热喷涂技术研究

介绍了应用于恶劣工况金属密封球阀涂层所采用的火焰重融和超音速喷涂技术,同时对其喷涂原理、工艺特点、选材要点及喷涂过程中易产生的问题进行了分析,并通过大量的试验对涂层的性能做出了总结。     

硬密封球阀耐冲蚀陶瓷涂层研究

利用多功能超音速火焰喷涂技术，在金属硬密封球阀的阀芯上制备了WC-12Co金属陶瓷涂层，用于提高球阀的耐冲蚀磨损性能。试验表明，涂层机械力学性能好，与基体结合强度超过70MPa，孔隙率小于2％，硬度超过HV1000，耐冲蚀磨损性能比基体提高5倍以上，有效地提高了球阀的使用寿命和密封可靠性。     

超音速等离子喷涂12Co-WC涂层的组织及在含细沙油润滑条件下的摩擦学性能

为了解决含沙油润滑条件下材料的磨损问题,采用超音速等离子喷涂技术制备了12Co-WC涂层,使用SEM、XRD及T11球盘式摩擦磨损试验机测试了涂层的组织结构及在含细沙油润滑条件下的摩擦学性能。结果 发现由于具有很高的粒子飞行速度,超音速等离子喷涂12Co-WC涂层组织致密,孔隙率小于1％,WC的氧化和分解少,结合强度高,涂层在含细沙油润滑条件下具有良好的摩擦磨损性能,相同条件下的摩擦因数比灰铸铁小,耐磨性比灰铸铁提高4—8倍。     

超音速火焰喷涂涂层特性研究

研究分析了ＷＣ－Ｃｏ和ＮｉＣｒＢＳｉ两种超音速火焰喷涂涂层的内聚结合强度、残余应力、显微组织结构、孔隙率、显微硬度和耐磨性能。对热喷涂涂层残余应力的测试与分析采用了改进的Ａｌｍｅｎ试验方法,并测得了客观的涂层残余应力及其与涂层厚度和喷涂工艺的关系。应用单摆冲击划痕试验法测得了热喷涂涂层内聚结合强度。     

提高300M钢零件HVOF涂层结合力的方法

在飞机起落架制造上,超音速火焰喷涂代替镀硬铬工艺在中航飞机起落架有限责任公司燎原分公司的应用尚属国内首次。生产中某型飞机起落架300M钢活塞杆零件超音速火焰喷涂WC10Co4Cr后,涂层时有出现裂纹、起皮、剥落和剥离等结合力差的现象,成为制约交付的瓶颈因素。通过对影响HVOF涂层结合力的主要因素——表面状态、喷涂参数、喷涂过程控制(预热、喷枪清理及残余应力)及涂层的磨削参数进行分析,总结出了几种提高300M钢零件超音速火焰喷涂WC10Co4Cr涂层结合力的实用方法,经过实践的长期检验,其效果显著。同时对涂层结合力及结合强度的检测方法做了简要的介绍。     

HVOF超音速火焰喷涂WC10Co4Cr涂层的研究

通过对HVOF超音速火焰喷涂WC10Co4Cr涂层的工艺研究,确定合理的喷涂工艺参数,并探讨喷涂工艺各因素对涂层的影响。涂层的金相组织、显微硬度、结合强度等性能测试结果表明:HVOF超音速火焰喷涂WC10Co4Cr涂层符合图纸的涂层性能要求。     

Q235钢表面超音速电弧喷涂制备FeCrBSiNi耐磨涂层的性能

以FeCrBSiNi丝材为原料,利用自有专利技术的超音速电弧喷枪及喷涂装置在工业锅炉用Q235钢表面制备FeCrBSiNi涂层,研究了涂层的孔隙率、微观形貌、显微硬度、耐磨性能和结合强度。结果表明:超音速电弧喷涂制备的FeCrBSiNi涂层的孔隙率为0.71%,涂层与基体的结合界面相对平整,涂层没有明显的分层现象,涂层结构致密,孔洞较少;FeCrBSiNi涂层的平均显微硬度为720HV0.3,远高于基体Q235钢的;涂层与基体以机械结合为主,结合强度可达到60MPa;摩擦磨损试验后,基体的质量损失是涂层的28倍,涂层的耐磨性能远优于基体的。     

超音速电弧喷涂不锈钢涂层结构及性能的研究

运用超音速电弧喷涂系统,通过光学显微镜,电子扫描显微镜和拉伸试验法对３Ｃｒ１３涂层的组织结构和性能进行了研究,结果表明,超音速电弧喷涂的颗粒细小,涂层表面光滑,组织致密,结合强度和硬度高,可广泛地应用于零件和设备的表面耐磨,耐蚀强化处理与机械零件加工尺寸超差的恢复等。     

安装螺栓激光强化及火焰喷涂CuNiIn工艺研究

研究激光强化及超音速火焰喷涂CuNiIn涂层对阻尼器安装螺栓疲劳性能的影响。结果表明,采用激光强化工艺可提升阻尼器安装螺栓的疲劳性能,超音速火焰喷涂制备的CuNiIn涂层致密均匀,与螺栓基体结合良好,且对基体的疲劳极限影响不大;涂层防护后,为粘着磨损和磨粒磨损,CuNiIn涂层可以有效改善抗微动磨损性能。在试验条件下,涂层使用后磨损体积减少了41%～55%,采用激光强化及超音速火焰喷涂CuNiIn涂层在设计给出的五级疲劳载荷的试验条件下没有发生断裂。     

高效能超音速等离子喷涂技术的研究与开发应用

根据“高效能、超音速”等离子喷涂枪的设计指导思想，对超音速等离子喷涂枪的枪体、水路、气路、阴阳极结构及送粉结构进行了全新设计，利用等离子体物理学、流体力学和工程热力学的理论设计了独特的单阳极Laval喷嘴。通过对该喷涂枪和制备的涂层性能测试研究表明，该喷涂枪实现了低功率（＜80kW）、小气体流量（＜6m^3/h)条件下的高效能超音速等离子喷涂，在有效喷涂距离内的粒子飞行速度达450m/s。喷枪的主要性能指标：焰流速度、粉末沉积效率、涂层与能耗比、电极的性价比均达到或超过了美国TAFA公司的PlazJet高能高速等离子喷涂枪。制造陶瓷涂层的结合强度、孔隙率、显微硬度等性能明显优于METCO.9M普通等离子喷，但运行成本仅为国外超音速PlazJet等离子喷涂的一半。高效能超音速等离子喷涂技术在工业、国防、航空的功能领域具有广阔的应用前景。     

新型陶瓷涂层硬质合金刀具的涂层机理和切削性能

以异丙醇铝为前驱物,将溶胶-凝胶工艺应用于硬质合金刀片涂层,研制成功一种新型的陶瓷涂层刀片,从而为涂层刀具制造展示了一种全新的涂层方法。使用浸渍提拉法对刀具基体进行涂层,然后经凝胶、干燥和1200℃热处理后可以得到厚度适宜的α－Al2O3涂层,涂层完整,无宏观缺陷,并且在初步的切削试验中显示出一定效果。涂层在1140℃左右转化成α－Al2O3,在1200℃烧结致密,而在1250℃以上涂层发生明显收缩,晶粒明显长大,最终的涂层为多晶体结构,涂层界面未生成弱化相,硬质合金中的部分钴元素扩散到涂层中,有助于提高涂层和基体间的粘结强度。切削试验的结果表明,所得涂层能有效地阻止前刀面上的粘结磨损,从而提高了刀具的使用寿命。     

超音速火焰喷涂碳化钨钴合金涂层对橡胶密封件的磨损研究

通过磨合试验,比较了超音速火焰(HVOF)喷涂碳化钨钴合金涂层与传统的含氰镀铬镀层与橡胶密封件对磨时的磨损情况.结果表明:HVOF喷涂碳化钨钴合金涂层具有良好的耐磨性和致密性,始终保持较良好的表面状况,对非金属密封件具有良好的适应性.     

涂层硬质合金铣刀组织性能研究

针对3种涂层硬质合金铣刀铣削性能差异,通过表面轮廓仪、接触角测量仪,表征涂层的表面状态和基体的硬度,洛氏硬度压痕法和Zeiss超景深三维显微镜表征涂层与基体的结合强度,扫描电镜(SEM)、能量分散光谱法(EDS)分析涂层表面-界面形貌、化学元素分布,铣削420模具钢实验表征切削性能,研究涂层刀具组织差异对切削性能的影响,为涂层选用提供实际和理论依据。结果表明:涂层铣刀铣削性能不仅与涂层种类和结合力相关,还与铣刀基体材料有关。涂层铣刀涂层种类较好,涂层结合力优异,基体脆性小,切削性能优异;涂层刀具涂层种类优异,涂层结合力一般,基体脆性小,切削性能良好;涂层刀具涂层种类优异,涂层结合力良好,基体脆性大,切削性能一般。     

Wear mechanisms of PVD-coated cutting tools during continuous turning of Ti-6Al-4V alloy

The aim of this study was to investigate the damage of cutting tools coated by physical vapor deposition (PVD) during the continuous turning of a titanium alloy. The investigation utilized scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), and transmission electron microscopy (TEM). It was found that a TiN coating on the tool wore faster than an uncoated cemented carbide tool. The damage mode of the coating on the rake face was fracture without plastic deformation. Additionally, there was a pattern to the crystal orientation relationship at some of the interfaces between the adhered workpiece material and the TiN coating. The crystal orientation relationship presumably produced a strong bond between the adhered material and the coating. The coating damage was thus caused by the force exerted by the adhered materials on the grain boundary on the damaged coating surface. A comparison of the tool damages during the machining of Ti-6Al-4V alloy and alloy 718 suggested that the damage of the coating depended on the interfacial strength between the adhered material and the coating, as well as the strength of the adhered material at a high temperature. Hence, to prevent the damage of the tool during the machining of a titanium alloy, it is preferable to use a ductile material (e.g., cemented carbide) rather than a brittle material (e.g., ceramic).     

CVD涂层技术对硬质合金材料形成脱碳层(η相层)影响分析

采用CVD技术对硬质合金材料涂层时,温度超过1000℃很容易在基体材料表面形成脱碳层。先进行900℃以下的中温TiCN、TiN涂层作为保护层,再进行高温涂层,能有效降低脱碳层的厚度。本文分析了脱碳层对基体材料抗弯强度的影响,并对不同涂层刀片的切削性能进行了对比分析。     

Ni基、Ni-W基涂层刀片加工高强度钢的切削性能研究

用新研制的Ni基、Ni W基涂层刀片与未涂层刀片进行了高强度合金钢的对比车削试验和切削性能研究 ,结果表明 ,新型涂层刀片切削性能良好 ,磨损较小 ,耐用度提高。通过适当研磨Ni基涂层刀片的前刀面 ,可有效提高刀片涂层的抗剥落能力     

TiC-TiN-TiC-Al_2O_3涂层CP3型硬质合金抗弯强度及其分散性的研究

通过X衍射法对CP3型硬质合金涂覆TiC TiN TiC Al2 O3 四层硬质层的组织结构进行了研究 ,用扫描电镜观察了涂层的断口形貌 ,用划痕法测定了涂层与基体的结合力 ,用三点弯曲法测定了涂覆前、后该硬质合金的抗弯强度 ,并应用Weibull统计方法对该材料的抗弯强度及其分散性进行了分析。研究结果表明 :涂层组织由TiC、TiN和Al2 O3 组成 ,涂层中无发达的柱状晶 ,涂层与基体结合良好 ,涂覆后硬质合金的平均抗弯强度从涂覆前的2 119MPa下降到 15 80MPa ,但其抗弯强度的分散性变化不大     

淬硬钢的铣削加工

介绍适合于淬硬钢铣削加工的刀具材料与刀具涂层技术。针对淬硬钢的铣削加工,通过切削实验,比较硬质合金铣刀不同涂层材料的切削性能,探索适合高度金属材料的高速加工方法。     

High temperature friction and wear characteristics of various coating materials for steam valve spindle application

Various coatings such as chromium carbide (deposited by plasma spraying and detonation gun techniques), chromium oxide, chromium oxide+titania+silica, NiCrAlY, and Al₂O₃+NiAl, all deposited by plasma spraying; stelliting, and surface nitriding have been applied on X20CrMo V121 steel. This steel is used for high temperature applications such as steam turbine valve spindle. Friction and wear behavior of the surface coated and treated materials have been studied at an elevated temperature of 550°C while rubbing against graphite-filled stellited steel. These studies have been carried out on SRV Optimol reciprocating tribometer. Test parameters for tribological studies have been selected with a view to simulate operating conditions encountered in operation. Additionally, the structure, porosity, hardness, bond strength, and thermal cycling behaviour of these surface coated/treated materials have been characterised. Based on these laboratory investigations, chromium carbide coating deposited by plasma spraying technique has been identified as the most suitable coating for steam turbine valve spindle application. Process parameters have been established for deposition of chromium carbide coating by plasma spraying technique on actual valve spindles. The field results obtained are found to be commensurate with the laboratory findings.     

Rhenium-iridium coating effect of tungsten carbide mold for aspheric glass lens

Recently, with increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lenses are unable to satisfy the required performance. An aspheric glass lens is fabricated by high temperature and pressure molding using a tungsten carbide molding core; so precision grinding and coating technology for the molding core surface is required. In this paper, Aspheric glass lens for 5 megapixel 4 time zoom camera phone modules was developed. The grinding condition of the tungsten carbide molding core was found after applying design of experiments (DOE). Also, the ultra-precision grinding process was investigated under this condition by experiment. Rhenium-iridium (Re-Ir) coating was applied on the ground surface of the tungsten carbide molding core. The influence of Re-Ir coating was compared and evaluated. The surface roughness of the molding core were improved by application of Re-Ir coating on the surface of the tungsten carbide molding core. Aspheric lenses were also molded with the non-coated molding core and the Re-Ir coated molding core. The surface roughness of the aspheric glass lens improved by about 0.4 nm (aspheric surface) and 0.5 nm (plane surface).