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Transition metal dichalcogenides of (MoS2, WS2,NbSe2, etc.) are the most common space solid lubricants.They are applied as powders mixed with variousorganic and inorganic binders, burnished to the surface from powders, or deposited by spray and vacuum deposition methods. These lubricants are soft, not abrasion resistant, and oxidize in air. To comply with endurance requirements of space applications, more advanced approaches were explored. One of them was selflubricating composites, where solid lubricant was pressed into a supporting matrix, such as in bronze/lead composites, glass-fiber- and polyimide-reinforced PTFE composites coated with MoS2. The composite approach was also used in high-temperature tribological coatings, such as the NASA PS-200 series coatings produced by plasma spray which consisted of BaF2/CaF2 lubricant, Ag lubricant and binder, and Cr3C2 support. In the NASA PS-300 series coatings, Cr3C2 was replaced with Cr2O3 to improve high temperature stability and reduce processing cost. Development of vacuum deposition methods added new capabilities for controlling the chemistry, structure, morphology, and thickness of solid lubricants. This improved their friction, endurance, environmental adaptation and allowed precision components to be coated. Examples are textured MoS2 films, metal doped MoS2 and WS2 films, CFx doped WS2 films, metal–MoS2 multilayers, temperature adaptive PbO/MoS2, ZnO/MoS2, ZnO/WS2 and moisture resistant PTFE/MoS2, LaF3/MoS2 composites, etc. Vacuum deposition technologies can be also used to produce nanocomposite and nanostructured coatings, whose mechanical and tribological properties are not subjected to volume mixture rules but depend on grain boundary effects and synergetic interactions of the composite constituents. Nanostructured designs offered aunique opportunity to produce adaptive or smart tribological coatings, which were termed ‘‘chameleon’’ for their ability to resist friction and wear by changing surface chemistry and microstructure in response to environment and loading changes, much like a chameleon changing its skin color to avoid predators. Although quite challenging, practical realization of smart coatings is extremely rewarding for tribological pairs subjected to multiple environmental changes, as for example in aerospace applications. The tribological coating adaptive concept was first explored with previously mentioned coatings of oxides and dichalcogenides (PbO/MoS2, ZnO/MoS2, ZnO/WS2), which can operate in a broad range of temperatures. Multilayer structures were then designed to combine these composites with buried diffusion barrier layers and achieve surface self-adaptation during repeated temperature cycling. Recently, novel wear resistant materials were developed, which combine nanocrystalline carbides (TiC, WC), oxide based ceramics (YSZ and AlON), dichalcogenides (MoS2, WS2), and amorphous diamond-like carbon (DLC) into nanocomposite structures. DLC is often referenced as a potential space tribological material due to its high hardness, low friction, and low wear. However, in long duration, heavily loaded, and/or high sliding speed applications, the use of DLC leads to its graphitization and associated increase of friction coefficient in the high vacuum environment. A hydrogenated DLC phase increases life through hydrogen termination of active carbon bonds, but not for long durations due to hydrogen depletion after about 104 cycles. An alternative approach is incorporation of dichalcogenide space lubricants, such as MoS2 or WS2, into a carbide/DLC/dichalcogenide composite. For example, ‘‘chameleon’’ coatings made of an amorphous DLC matrix with incorporation of nanocrystalline TiC, WC, WS2 and laser processed MoS2 reservoirs demonstrated an order of magnitude improvement in toughness above that of single phase carbides while maintaining the same level of hardness, a low friction coefficient in cycling from dry to humid environments, and an extremely long life in both terrestrial and space environments. The surface chemistry, structure, and mechanical behavior of these nanocomposite materials were shown to reversibly change in the tribological contact, depending on applied loads and operational environment to maintain low friction and prevent wear. While maintaining the low friction in any environment is important, wear resistance requires an additional blend of both hardness and fracture toughness. This is especially true for space applications due to the reliability and unattended durability requirements. The following sections of this paper discuss the most recentdevelopments in smart nanocomposite tribological coatings, starting with design criteria and examples of tough tribological nanocomposites and progressing to ‘‘chameleon’’ coatings. All coatings were prepared by hybrid physical vapor deposition processes, combining magnetron sputtering and pulsed laser deposition. Discussion of the preparation processes can be found in. |
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wang17152
木虫 (知名作家)
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wangbing108222(金币+15,VIP+0):非常感谢！加油继续！
wangbing108222(金币+15,VIP+0):非常感谢！加油继续！
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Transition metal dichalcogenides of (MoS2, WS2,NbSe2, etc.) are the most common space solid lubricants.They are applied as powders mixed with various organic and inorganic binders, burnished to the surface from powders, or deposited by spray and vacuum deposition methods. These lubricants are soft, not abrasion resistant, and oxidize in air. To comply with endurance requirements of space applications, more advanced approaches were explored. One of them was self lubricating composites, where solid lubricant was pressed into a supporting matrix, such as in bronze/lead composites, glass-fiber- and polyimide-reinforced PTFE composites coated with MoS2. The composite approach was also used in high-temperature tribological coatings, such as the NASA PS-200 series coatings produced by plasma spray which consisted of BaF2/CaF2 lubricant, Ag lubricant and binder, and Cr3C2 support. In the NASA PS-300 series coatings, Cr3C2 was replaced with Cr2O3 to improve high temperature stability and reduce processing cost. 过渡金属的硫族化物（MoS2, WS2,NbSe2等）是最常见的固体润滑剂。它们以粉末形式与各种有机和无机粘结剂混合，或以喷剂和真空沉积的方法贮存，在粉末的作用下使表面光滑。这些润滑油质软，不耐磨，并可在空气中氧化。为了符合空间应用耐磨性要求，探索了更多先进的方法。其中之一是自润滑复合材料，其中的固体润滑剂被压成一个支撑基质，如铜/铅复合材料，玻璃纤维和包覆二硫化钼复合材料聚四氟乙烯-聚酰亚胺材料。该复合材料的方法也被用在高温摩擦磨损涂层，如美国航天局的聚苯乙烯-200系列涂层，是由含有BaF2/CaF2润滑剂、银润滑剂和粘合剂以及Cr3C2的等离子喷剂生产出的。在美国航天局的聚苯乙烯300系列涂料，Cr3C2取代铬提高了高温稳定性并降低了加工成本。 Development of vacuum deposition methods added new capabilities for controlling the chemistry, structure, morphology, and thickness of solid lubricants. This improved their friction, endurance, environmental adaptation and allowed precision components to be coated. Examples are textured MoS2 films, metal doped MoS2 and WS2 films, CFx doped WS2 films, metal–MoS2 multilayers, temperature adaptive PbO/MoS2, ZnO/MoS2, ZnO/WS2 and moisture resistant PTFE/MoS2, LaF3/MoS2 composites, etc. 真空沉积方法的发展为固体润滑剂在化学，结构，形态和厚度控制中增加了新的功能。这提高了它们的摩擦，耐磨性，环境适应，并可用于精密零件的涂层。例子有质感的MoS2膜，掺有MoS2和WS2膜的金属，掺有WS2膜的CFX，金属–MoS2多层膜，PbO/MoS2温度适应性， ZnO/MoS2 ， ZnO/WS2和防潮性能的PTFE/MoS2 ， LaF3/MoS2复合材料等等。 |
2楼2008-12-15 17:32:53
wang17152
木虫 (知名作家)
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好了，有个别地方不是太顺利，参考一下吧
★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★
wangbing108222(金币+30,VIP+0):xiexie
wangbing108222(金币+30,VIP+0):xiexie
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Transition metal dichalcogenides of (MoS2, WS2,NbSe2, etc.) are the most common space solid lubricants.They are applied as powders mixed with various organic and inorganic binders, burnished to the surface from powders, or deposited by spray and vacuum deposition methods. These lubricants are soft, not abrasion resistant, and oxidize in air. To comply with endurance requirements of space applications, more advanced approaches were explored. One of them was self lubricating composites, where solid lubricant was pressed into a supporting matrix, such as in bronze/lead composites, glass-fiber- and polyimide-reinforced PTFE composites coated with MoS2. The composite approach was also used in high-temperature tribological coatings, such as the NASA PS-200 series coatings produced by plasma spray which consisted of BaF2/CaF2 lubricant, Ag lubricant and binder, and Cr3C2 support. In the NASA PS-300 series coatings, Cr3C2 was replaced with Cr2O3 to improve high temperature stability and reduce processing cost. 过渡金属的硫族化物（MoS2, WS2,NbSe2等）是最常见的固体润滑剂。它们以粉末形式与各种有机和无机粘结剂混合，或以喷剂和真空沉积的方法贮存，在粉末的作用下使表面光滑。这些润滑油软，不耐磨，并可在空气中氧化。为了符合空间应用耐磨性要求，探索了更多先进的方法。其中之一是自润滑复合材料，其中的固体润滑剂被压成一个支撑基质，如铜/铅复合材料，玻璃纤维和包覆二硫化钼复合材料聚四氟乙烯-聚酰亚胺材料。该复合材料的方法也被用在高温摩擦磨损涂层，如美国航天局的聚苯乙烯-200系列涂层，是由含有BaF2/CaF2润滑剂、银润滑剂和粘合剂以及Cr3C2的等离子喷剂生产出的。在美国航天局的聚苯乙烯300系列涂料，Cr3C2取代铬提高了高温稳定性并降低了加工成本。 Development of vacuum deposition methods added new capabilities for controlling the chemistry, structure, morphology, and thickness of solid lubricants. This improved their friction, endurance, environmental adaptation and allowed precision components to be coated. Examples are textured MoS2 films, metal doped MoS2 and WS2 films, CFx doped WS2 films, metal–MoS2 multilayers, temperature adaptive PbO/MoS2, ZnO/MoS2, ZnO/WS2 and moisture resistant PTFE/MoS2, LaF3/MoS2 composites, etc. 真空沉积方法的发展为固体润滑剂在化学，结构，形态和厚度控制中增加了新的功能。这提高了它们的摩擦，耐磨性，环境适应，并可用于精密零件的涂层。例子有质感的MoS2膜，掺有MoS2和WS2膜的金属，掺有WS2膜的CFX，金属–MoS2多层膜，PbO/MoS2温度适应性， ZnO/MoS2 ， ZnO/WS2和防潮性能的PTFE/MoS2 ， LaF3/MoS2复合材料等等。 Vacuum deposition technologies can be also used to produce nanocomposite and nanostructured coatings, whose mechanical and tribological properties are not subjected to volume mixture rules but depend on grain boundary effects and synergetic interactions of the composite constituents. Nanostructured designs offered aunique opportunity to produce adaptive or smart tribological coatings, which were termed ‘‘chameleon’’ for their ability to resist friction and wear by changing surface chemistry and microstructure in response to environment and loading changes, much like a chameleon changing its skin color to avoid predators. 真空镀膜技术也可用于生产纳米复合材料和纳米涂层，其机械和摩擦学性能不受限于体积混合规则，而是取决于复合成分的晶界效应和相互协调作用。纳米结构设计提供唯一的方法来生产自适应性或智能摩擦性涂层， '他们有能力随着环境和填料的变化改变表面化学和微观结构来抵御摩擦和磨损，这被称之为“变色龙”涂层，就像变色龙改变其皮肤颜色，以避免天敌。 Although quite challenging, practical realization of smart coatings is extremely rewarding for tribological pairs subjected to multiple environmental changes, as for example in aerospace applications. The tribological coating adaptive concept was first explored with previously mentioned coatings of oxides and dichalcogenides (PbO/MoS2, ZnO/MoS2, ZnO/WS2), which can operate in a broad range of temperatures. Multilayer structures were then designed to combine these composites with buried diffusion barrier layers and achieve surface self-adaptation during repeated temperature cycling. Recently, novel wear resistant materials were developed, which combine nanocrystalline carbides (TiC, WC), oxide based ceramics (YSZ and AlON), dichalcogenides (MoS2, WS2), and amorphous diamond-like carbon (DLC) into nanocomposite structures. 虽然很有挑战性，切实实现智能涂料对摩擦学适应多种环境的变化是非常有益的，例如在航空航天应用方面。摩擦性涂层适应的概念最早是在前面提到的的氧化物涂料和硫族化合物（PbO/MoS2，ZnO/MoS2，ZnO/WS2）时探讨出来的，这类涂层可以在广泛的温度范围内使用。多层结构设计用于化合这些扩散式叠层材料，并在反复温度循环中实现表面自我适应。最近，新型耐磨材料，如结合纳米碳化物（TiC，WC），氧化物基陶瓷（YSZ和AlON），硫族化合物（MoS2，WS2）和纳米复合材料结构的非晶类金刚石碳（DLC）等等，都已开发应用。 DLC is often referenced as a potential space tribological material due to its high hardness, low friction, and low wear. However, in long duration, heavily loaded, and/or high sliding speed applications, the use of DLC leads to its graphitization and associated increase of friction coefficient in the high vacuum environment. A hydrogenated DLC phase increases life through hydrogen termination of active carbon bonds, but not for long durations due to hydrogen depletion after about 104 cycles. An alternative approach is incorporation of dichalcogenide space lubricants, such as MoS2 or WS2, into a carbide/DLC/dichalcogenide composite. 类金刚石（DLC）涂层由于其高硬度、低摩擦和低磨损往往作为空间摩擦性材料的参照。然而，在长时间运行，超负荷运载，高速度应用时，在高真空环境中使用类金刚石将导致石墨化作用和摩擦系数的相应增加。金刚石氢化阶段由于活性炭键的氢终结化而延长使用生命，大约104个周期后由于氢气耗尽不能持续很长的时间。另一种做法是将硫族化合物空间润滑油混合使用，如将MoS2或WS2 ，与电石/DLC/ 硫族化合物混合。 For example, ‘‘chameleon’’ coatings made of an amorphous DLC matrix with incorporation of nanocrystalline TiC, WC, WS2 and laser processed MoS2 reservoirs demonstrated an order of magnitude improvement in toughness above that of single phase carbides while maintaining the same level of hardness, a low friction coefficient in cycling from dry to humid environments, and an extremely long life in both terrestrial and space environments. The surface chemistry, structure, and mechanical behavior of these nanocomposite materials were shown to reversibly change in the tribological contact, depending on applied loads and operational environment to maintain low friction and prevent wear. 例如，由非晶金刚石基体与TiC，WC，WS2和激光加工的MoS2等纳米晶体结合的“变色龙”涂料显示巨大的改善效果，其韧性高于同水平硬度的单相碳化物，在循环中从干燥到湿润环境的低摩擦系数，以及在地面和空间环境中的较长的使用寿命。纳米复合材料的表面化学，结构和力学性能在摩擦接触方面均表现可逆性变化，这取决于所用负载和运行环境以保持低摩擦和低磨损。 While maintaining the low friction in any environment is important, wear resistance requires an additional blend of both hardness and fracture toughness. This is especially true for space applications due to the reliability and unattended durability requirements. The following sections of this paper discuss the most recent developments in smart nanocomposite tribological coatings, starting with design criteria and examples of tough tribological nanocomposites and progressing to ‘‘chameleon’’ coatings. All coatings were prepared by hybrid physical vapor deposition processes, combining magnetron sputtering and pulsed laser deposition. Discussion of the preparation processes can be found in. 在任何环境中保持低摩擦是很重要的，耐磨性取决于硬度和断裂韧性这两个因素。这尤其适用于空间应用中无人式可靠性和耐久性的要求。本文以下各节件讨论了在智能复合涂层摩擦学最近的发展情况，从高强度摩擦性纳米复合材料到“变色龙”涂料发展的设计标准开始讨论。所有涂料通过混合物理气相沉积过程，结合磁控溅射和脉冲激光沉积的制备。探讨了已发现的制备工艺。 [ Last edited by wang17152 on 2008-12-15 at 19:26 ] |
3楼2008-12-15 17:51:18
