【作者】 王谦之；

【导师】 周飞；

【作者基本信息】 南京航空航天大学 ， 机械设计及理论， 2013， 博士

【摘要】 本文分别通过过渡族元素Ti、Cr掺杂及C掺杂，缓解非晶碳（a-C）薄膜及TiN、CrN薄膜的内应力；增加膜基间粘附强度；提高薄膜硬度；并系统地研究了过渡族元素Ti、Cr掺杂量对a-C薄膜及C掺杂量对TiN、CrN薄膜成分、结构、力学性能、水环境中摩擦学及模拟人体体液中电化学性能的影响；探讨了薄膜结构变化与摩擦机制之间的内在联系：1）采用非平衡磁控溅射制备了不同Ti掺杂量的Ti/a-C薄膜。当Ti靶电流为0.5A时，低含量的Ti以固溶体形式存在于Ti/a-C-0.5薄膜中，晶格畸变效应使薄膜的硬度提高至27.5GPa，缩短a-C薄膜的磨合距离并降低摩擦副的磨损率；而当Ti靶电流提高至1~2A时，类金属Ti和TiC颗粒形成并分布在a-C基材中，打断a-C薄膜中碳网的连续性，导致硬度下降至15~17.5GPa，且TiC颗粒的磨粒作用使Ti/a-C-1、Ti/a-C-1.5、Ti/a-C-2薄膜与SiC及Al2O3球在水中对磨时发生剥落失效。而Si3N4球水合反应生成的润滑膜和SUS440C球氧化反应生成的氧化物粘附在薄膜表面，使得Ti/a-C-1、Ti/a-C-1.5、Ti/a-C-2薄膜保持完好。2）采用非平衡磁控溅射制备了不同Cr掺杂量的Cr/a-C薄膜。当Cr靶电流为0.5~2A时，Cr/a-C薄膜中均形成了类金属Cr或碳化铬颗粒，打断了a-C薄膜碳网的连续性，使薄膜的硬度下降至11.6~13.7GPa。具有较好韧性的Cr/a-C-0.5薄膜缩短了a-C薄膜的磨合距离并降低摩擦副的磨损率；而当Cr靶电流为1~2A时，碳化铬颗粒易发生水合反应生成氧化铬，在对磨过程中氧化铬作为磨粒主导了磨损机制，无论对磨件为何种材料，均使Cr/a-C-1、Cr/a-C-1.5、Cr/a-C-2薄膜发生了剥落失效。3）采用非平衡磁控溅射制备了不同C含量的TiN(C)薄膜。由于a-CNx相的存在，使TiN(C)薄膜的硬度提高至27~32GPa，然而随着C掺杂量的提高，TiN(C)薄膜中逐渐形成a-C相，使得薄膜硬度呈线性下降趋势；因SiC、Si3N4球水合反应生成的润滑膜，TiN、TiN(C1)、TiN(C2)、TiN(C3)薄膜与之对磨时显示较低的摩擦系数且保持完好，而TiN(C4)薄膜由于硬度过低发生磨穿失效；Al2O3球的高硬度及稳定性，使TiN(C)薄膜与之对磨时都发生磨穿失效；而SUS440C球在水中容易发生粘着磨损，增大了摩擦界面的粗糙度，导致摩擦系数高且不稳定。4）采用非平衡磁控溅射制备了不同C含量的CrN(C)薄膜，随着C掺杂量的提高，薄膜中逐渐形成了a-CNx及碳化铬晶相。后者在对磨过程中易发生水合反应，生成具有磨粒作用的Cr2O3，因此当CrN(C)薄膜与高硬度的SiC及Al2O3球对磨时，CrN(C)薄膜均发生磨穿失效；由于Si3N4球在水中易发生水合反应，生成具有润滑效果的氧化硅胶状膜，保护了CrN(C1)薄膜，而CrN(C2)、CrN(C3)、CrN(C4)薄膜中较多的碳化铬生成的Cr2O3磨粒打破了氧化硅胶状膜的保护作用，使薄膜发生磨穿失效；类似的，SUS440C在水中易发生氧化反应，生成的氧化物粘附在薄膜表面，保护了CrN(C1)薄膜，而CrN(C2)、CrN(C3)、CrN(C4)薄膜同样发生磨穿失效。5）Ti/a-C及Cr/a-C薄膜在模拟人体体液中均能起到保护316L不锈钢的作用。随着Ti掺杂量的提高，Ti/a-C薄膜中sp2键含量提高，增加了薄膜的导电性，且薄膜致密度下降，导致薄膜呈现逐渐削弱的电化学特性，而随着Cr掺杂量的提高，Cr/a-C薄膜中sp3键含量提高，增加了薄膜的绝缘性，促使薄膜呈现逐渐增强的电化学特性；CNx相的生成，使TiN(C1)、TiN(C2)、TiN(C3)薄膜在模拟人体体液中表现出优于316L不锈钢的抗腐蚀特性，而TiN薄膜稀疏的表面形貌及TiN(C4)薄膜中高含量的a-C，削弱了其在模拟人体体液中的抗腐蚀特性。类似的，CrN、CrN(C1)、CrN(C2)、CrN(C3)薄膜因其致密的表面形貌及氧化铬钝化膜，在模拟人体体液中表现出优于316L的抗腐蚀特性，而CrN(C4)薄膜中高含量的a-C，削弱其在模拟人体体液中的抗腐蚀特性。更多还原

【Abstract】 This thesis aimed to release the internal stress, enhance the adhesive strength, increase thehardness of amorphous carbon (a-C) and TiN, CrN coatings by doping transition metal Ti, Cr and Celements, respectively. Moreover, the influence of incorporating contents of Ti, Cr and C elements onthe compositon, microstructure, mechanical and tribological properties in water and electrochemicalproperty in simulated body fluid for a-C and TiN, CrN coatings was investigated systematically. Atlast, the relationship between microstructure variation and wear mechanism was discussed:1) The Ti/a-C coatings with different Ti doping content were deposited by unbalanced magnetronsputtering. When the current of Ti target was0.5A, the low concentration Ti atoms existed inTi/a-C-0.5coatings as solid solution. The lattice deformation increased the hardness of Ti/a-Ccoatings to27.5GPa, and Ti/a-C coatings shortened the running-in distance and decreased the wearrate of a-C coatings. But when the currents of Ti target varied in the range of1A to2A, the metal-likeTi and TiC nanoparticles were formed and dispersed in a-C matrix. The metal-like Ti and TiCnanoparticles broke the continuity of carbon network, and made the hardness decrease to15~17.5GPa.Besides, under abrasive effect of the TiC nanoparticles, the delamination occurred for Ti/a-C-1、Ti/a-C-1.5、Ti/a-C-2coatings sliding against SiC and Al2O3balls in water. However, the lubricationfilms induced from hydration action of Si3N4balls and oxides induced from oxidation of SUS440Cballs adhered on the coatings’ surface, and made the Ti/a-C-1、Ti/a-C-1.5、Ti/a-C-2coatings maintainintegrity.2) The Cr/a-C coatings with different Cr doping content were deposited by unbalancedmagnetron sputtering. When the currents of Cr target varied in the range of0.5A to2A, the metal-likeCr or chromium carbides were formed. The metal-like Cr and chromium carbides broke the continuityof carbon network, and made the hardness of Cr/a-C coatings decrease to11.6~13.7GPa. TheCr/a-C-0.5coatings with better toughness shortened the running-in distance and decreased the wearrate of a-C coatings. However, when the currents of Cr target varied in the range of1A to2A, theformation of chromium oxides originated from hydration reaction of chromium carbides dominatedthe wear mechanism. Thus, whatever the counterparts were, the Cr/a-C-1、Cr/a-C-1.5、Cr/a-C-2coatings occurred delamination.3) The TiN(C) coatings with different C doping content were deposited by unbalanced magnetronsputtering. Owing to the formation of a-CNx, the hardness of TiN(C) coatings increased to27~32GPa.But with the increasing carbon content, the more a-C made the hardness decrease continuously. Since the SiC and Si3N4balls could generate lubrication film due to hydration, the unbroken TiN, TiN(C1),TiN(C2), TiN(C3) coatings with low friction coefficient were obtained. But the TiN(C4) coatingsoccurred delamination due to decreasing hardness. All of the TiN(C) coatings confronteddelamination because of no hydration reaction for Al2O3balls with high hardness. For SUS440C balls,the adhesive wear increased the roughness between contact area and made the friction coefficient highand unstable.4) The CrN(C) coatings with different C doping content were deposited by unbalancedmagnetron sputtering. With the increasing carbon content, the a-CNxand chromium carbides wereformed gradually. The latter would act with water and generated Cr2O3which acted as wear debrisduring wear process. Thus, when the CrN(C) coatings slid against SiC and Al2O3balls with highhardness, the CrN(C) coatings were all worn out. Owing to the protection effect of the silicon oxidesgel originated from hydration action of Si3N4, the CrN(C1) coatings maintained whole. However, themore Cr2O3resulted from chromium carbides in the CrN(C2), CrN(C3) and CrN(C4) coatingsdestroyed the protection effect of silicon oxides gel, and made the CrN(C2), CrN(C3) and CrN(C4)coatings peel off. Similarly, the oxides resulted from oxidation of SUS440C balls would adhere on thecoatings, protected the CrN(C1) coatings, but the CrN(C2), CrN(C3) and CrN(C4) coatings wereworn out.5) Both the Ti/a-C and Cr/a-C coatings could protect the316L stainless steel in simulated bodyfluid. With the increasing Ti content, the increasing conductivity of Ti/a-C coatings due to increasingsp2content and high porosity density weakened the electrochemical properties in simulated body fluid.However, with the increasing Cr target current, the insulativity of Cr/a-C coatings increased becauseof increasing sp3content, and enhanced the electrochemical properties in simulated body fluid. Due tothe formation of CNx, TiN(C1), TiN(C2) and TiN(C3) coatings enhanced the anti-corrosion propertiesof316L, whereas the poor surface quality of TiN coatings and high a-C content of TiN(C4) coatingsmade them exhibit inferior anti-corrosion properties of316L. Similarly, due to favorable surfacequality and chromium oxides passive coatings, the CrN, CrN(C1), CrN(C2) and CrN(C3) coatingsexhibited superior electrochemical properties than316L. But the high a-C content of CrN(C4)coatings weaken the anti-corrosion properties in simulated body fluid.更多还原