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研究适合快速砂型铸造用模具的表面涂层材料,该涂层材料由环氧树脂CYD-128、稀释剂660A和固化剂组成,并添加一定量的微米级Al2O3颗粒。在WTM-1E微型磨损实验机上研究该涂层的耐磨性能,并用扫描电镜和原子力显微镜分析磨损后的表面形貌。结果表明:随Al2O3颗粒含量的增加,复合涂层的摩擦因数逐渐增大,磨损率逐渐降低,当Al2O3颗粒质量分数为5%时,磨损率最低;随Al2O3颗粒含量的增加,复合涂层的磨损机制由黏着占主导逐渐转变为犁削沟占主导;采用该涂层材料处理后的快速砂型铸造用模具具有一定的耐磨性。 相似文献
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采用综合热分析仪对冷喷涂铬锆铜合金涂层进行了示差扫描热(DSC)分析,并利用激光共焦扫描高温成像显微镜对其组织在加热过程中的演变进行了原位观察,测试了退火前后涂层的硬度。结果表明:涂层在加热过程的DSC曲线上有三个峰,分别对应涂层的变形组织回复阶段、再结晶形核与晶粒长大阶段、内部颗粒界面消失阶段;经过前两阶段后涂层的显微硬度从159.69 HV逐渐降至77.57 HV;第三阶段显微硬度变化不大,与烧结工艺中颗粒界面融合过程相似;加热至350℃时涂层显微组织未发生变化,至550℃时涂层组织具有原始粉体的等轴晶形貌,至900℃时涂层组织颗粒界面逐渐均一化,与原始粉体相近。 相似文献
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CeO_2对镍基TiC陶瓷涂层微观组织和摩擦学性能的影响 总被引:1,自引:0,他引:1
采用W150SA YAG激光焊接机45#钢基材表面熔覆含CeO2的镍基TiC陶瓷涂层,研究添加不同含量CeO2对涂层的微观组织和摩擦学性能的影响.研究结果表明:添加适量CeO2对涂层的微观组织、显微硬度、涂层与基材结合区,以及涂层的摩擦学性具有改善作用;CeO2能减弱熔池中TiC陶瓷相的生长方向性,避免相邻的TiC颗粒桥接生长,细化和球化TiC颗粒,并使之且分布均匀;CeO2能促使TiC硬质相弥散分布,涂层组织趋向均匀化,并减少杂质和气体的不良影响,提高涂层的组织性能;CeO2能促进涂层与基材之间形成合理的成分梯度,得到良好的结合区;CeO2能促进摩擦过程中涂层表面氧化膜的形成并提高氧化膜的热稳定性,减少涂层的大片层状剥落,降低涂层的黏着磨损和磨粒磨损. 相似文献
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基体Ti-6Al-4V合金表面为羟基磷灰石(HA)涂层的植入体,已经广泛应用于外科整形临床手术中.为了提高涂层和基体的结合强度,本试验分别制备了90HA-10ZrO2和70HA-30ZrO2(按质量分数计)2种成分的复合涂层和纯HA涂层.复合粉末采用机械搅拌法制备粒径约为75~106μm,采用装备有NX100型Aotoman机械手的Metco 9M喷涂设备制备涂层.测量了涂层的结合强度(ISO 137794:2002),采用SEM对涂层表面形貌和涂层微结构进行了分析,XRD分析了涂层相组成和结晶度.结果表明采用等离子喷涂(APS)制备的HA涂层熔化效果很好,但涂层中有未熔化的ZrO2颗粒,而且30%ZrO2的未熔颗粒明显多于前者.2种复合涂层的结合强度都要高于纯HA涂层. 相似文献
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A layer of AlTiN coating was deposited on YT14 cutting tool by cathodic arc ion plating (CAIP) and the coefficients of friction (COFs) of the AlTiN coating under different loads at a temperature of 800°C were investigated with a high-temperature wear tester. The wear morphologies, chemical elements, and phases of the coating after wear were analyzed with scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD), respectively, and the contours of wear tracks were investigated with a comprehensive measurement tester for material surface performance. The effects of loads on COFs and wear resistance of the AlTiN coating were analyzed, and the wear mechanism of the AlTiN coating at high temperature is discussed. The results show that the mixed oxides of Al2O3 and TiO2 are produced under high temperature to improve the lubrication performance and wear resistance of the AlTiN coating. The average COFs of the coating under loads of 5, 7, and 9 N are 0.6495, 0.5897, and 0.3898, respectively. The COFs of the coating decrease with increasing load; as a result, the AlTiN coating is suitable for heavy loads at high temperature. The friction and wear mechanisms of the AlTiN coating are primarily composed of oxidation wear and abrasive wear, accompanied by fatigue wear and adhesive wear. 相似文献
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依据紫外光学系统中紫外反光镜的使用要求,并结合汞灯发光光谱,提出了R93%@300~450 nm(R为反射率);T_(avg)85%@500~1 000 nm(T_(avg)表示平均透过率)的近紫外区宽带高反射率的设计指标。选用Ta_2O_5和SiO_2分别作为高低折射率材料,并采用正交试验法确定了Ta_2O_5和SiO_2膜料的折射率、消光系数和制备工艺参数。在规整周期性膜系的基础上,利用膜系设计软件进行优化设计,同时分析了膜层的敏感度,保证了镀制的可重复性。通过曲线测试和环境试验结果表明,该膜系满足设计使用要求。 相似文献
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用解析法计算高速切削单涂层刀具瞬态温度分布 总被引:4,自引:0,他引:4
为研究涂层在切削中对刀具温度的影响,为设计刀具涂层提供理论依据,分析高速切削过程中切削热的产生和刀具边界情况,建立单涂层刀具热传导物理模型和数学模型,用数学解析的方法推导出正交高速干切削过程中单涂层刀具体内部的温度分布公式。利用推导出的温度公式对TiN、TiC、Al2O3涂层刀具的切削温度分布进行解析计算,并将解析计算结果与数值分析结果进行比较。结果表明,解析计算结果与数值计算结果吻合很好;涂层材料与基体材料的热物理性能以及涂层的厚度对刀具的温升有重要影响;随着热流密度的增加,涂层厚度对刀具内部的温度影响增大。 相似文献
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Sheng Tianyuan 《摩擦学汇刊》2017,60(5):781-788
A WC-12Co coating prepared by high-velocity oxygen fuel (HVOF) was remelted with a CO2 laser, and the surface–interface morphologies, plane energy spectrum, and phases of the coating were analyzed by means of field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD), respectively. The friction and wear behaviors of the WC-12Co coating were investigated at high temperature with a wear test, and the morphologies and the changes in chemical elements on the wear scar after the wear test were analyzed with SEM and EDS, respectively. In addition, the influence of high temperature on the coefficient of friction (COF) and wear performance is discussed. The results show that the substrate is closely bonded with the substrate after laser remelting (LR), which includes mechanical bonding accompanied by metallurgical bonding. The average coefficient of friction (COF) at 600, 700, and 800°C is 0.6832, 0.3957, and 0.1922, respectively. The wear mechanisms of WC-12Co coating at 600 and 700°C are adhesive wear, abrasive wear, and oxidative wear, respectively, and the wear mechanism of the coating at 800°C is serious oxidative wear. 相似文献
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为了提高钛合金的高温抗氧化性能,推动钛合金在高温和复杂工况环境下的进一步工程应用,利用高能激光束作用下Ti、Al、Nb三种元素混合粉末之间的原位反应在BT3-1钛合金表面制备了高温抗氧化的高铌Ti-Al金属间化合物复合涂层。针对原位反应所制备涂层存在的缺陷,通过自行设计的热处理工艺优化了涂层和界面微观组织。借助光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)分析了热处理前后复合涂层的物相结构及显微形貌。结果表明:热处理前的涂层主要由单质Nb、金属间化合物γ-TiAl、α_2-Ti_3Al、Ti_3Al_2等物相组成;热处理后的复合涂层,单质Nb固溶到γ-TiAl和α_2-Ti_3Al中,同时形成了新相Ti_3AlNb_(0.3),涂层近似为γ-TiAl+α_2-Ti_3Al双相层片状等轴晶组织。此外,涂层中并未观察到减弱抗氧化性的单质Nb颗粒和Ti_3Al_2相,Ti、Al、Nb的宏观偏析得以消除,涂层与基材界面位置的气孔和裂纹均以消失,出现了明显的白亮带冶金结合过渡层,涂层组织也更加均匀致密。热处理对提高钛合金表面Nb的合金化程度和改善Ti-Al金属间化合物的高温抗氧化性能起到了显著的促进作用。 相似文献
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纳米陶瓷涂层磨削表面残余应力的研究进展 总被引:2,自引:0,他引:2
纳米陶瓷涂层材料具有高硬度和高耐磨性,采用超硬磨料的金刚石砂轮磨削是其最主要的加工方法,在磨削时容易出现表面残余应力而导致表面裂纹.目前,国外在纳米结构陶瓷涂层磨削表面残余应力的研究很少,我国正在对纳米陶瓷涂层材料超精密磨削后表面残余应力方面进行研究.介绍了纳米结构陶瓷涂层的研究背景,阐述了纳米结构陶瓷喷涂材料性能特点,分析了纳米结构陶瓷涂层的磨削研究动态和磨削表面残余应力的研究现状.分析研究表明,纳米结构陶瓷涂层的开发与研究将会受到越来越广泛的重视,其后续研究将是下一步的工作重点. 相似文献
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High-precision ball bearings (SUS440C) used in spacecraft mechanisms that are exposed to deep space vacuum are solid lubricated by thin, adherent Pb ion-plated coatings. The high reliability requirements with long endurance life of these mechanisms solely depend on the tribological aspects of this solid-lubrication coating. Since ion-plated, soft metallic coatings have a graded coating–substrate interface structure, a gradual change in mechanical, chemical and thermal properties is expected across the depth of the coating. This aspect of the interlayer plays a major role in determining the extent of optimum tribological properties of the coating. By improving the interlayer, both in terms of increased thickness and concentration of Pb, a corresponding improvement in the lubricity and endurance life of this Pb ion-plated coating on AISI 440C stainless steel (bearing material) can be assured. For this, a detailed examination of the interlayer of the ion-plated Pb film on the nano-micro level is mandatory. This report is focused on the cross-sectional examination of the interlayer by scanning electron microscopy. SUS440C steel disk specimens having similar properties as the bearing material and with a thin, ion-plated Pb coating processed under two different substrate bias conditions of ion-plating are used. The thickness of the Pb/steel interlayer and the elemental composition are analyzed using SEM and EDS respectively. The endurance life of the coatings is measured by repeated sliding wear tests with a pin-on-disk tester in vacuum. It is confirmed that with an increased thickness of the graded interfacial layer of the Pb ion-plated coating, the coating endurance life is extended remarkably. 相似文献