| 引用本文: | 刘康诚,娄丽艳,蔡志海,邢志国,王海斗,李成新.超高速激光熔覆镍包覆c-BN颗粒增强耐磨复合涂层及摩擦磨损行为[J].中国表面工程,2024,37(5):337~345 |
| LIU Kangcheng,LOU Liyan,CAI Zhihai,XING Zhiguo,WANG Haidou,LI Chengxin.High-speed Laser Cladding Ni-coated c-BN Particles Reinforced Wear-resistant Composite Coating and its Wear Behavior[J].China Surface Engineering,2024,37(5):337~345 |
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| 摘要: |
| 钛合金拥有较轻的密度和较高的比强度被广泛应用在航空航天以及航海等领域。然而，较差的耐磨性限制了其在各种工况下的应用。为提升钛合金在极端服役条件下耐磨性能，采用超高速激光熔覆工艺在高温钛合金表面成功制备出完整、致密的镍包覆 c-BN 复合耐磨涂层。利用 XRD、SEM、EDS 和显微硬度计、摩擦磨损试验机等手段分析测试涂层微观组织形貌、 物相组成和力学性能。结果显示，c-BN 颗粒在激光照射下部分分解，并与熔池中的 Ti 反应，原位生成 TiN、TiB 等增强相； 另外在涂层凝固过程中，c-BN 表面包覆的镍进入 Ti 晶格并部分与 Ti 反应生成 Ni-Ti 金属间化合物，对涂层起到固溶强化和弥散强化，使得镍包覆的 c-BN 涂层硬度和耐磨性能相较于钛合金基体和未包覆镍的 c-BN 涂层均显著提升：涂层平均硬度值在 1 200 HV0.3以上，达到钛合金基体 3 倍以上；经过摩擦磨损试验后，其磨损体积相较于钛合金基体和未包覆镍 c-BN 涂层分别减少 72%和 22%。磨损形貌显示，钛合金基体表现出明显的黏着磨损，未包覆镍的 c-BN 涂层表现为磨粒磨损；而镍包覆的 c-BN 涂层磨痕则出现大量“鱼鳞”状磨屑。研究采用镍包覆的方式在熔覆前将 c-BN 颗粒包裹，使得 c-BN 陶瓷粉末流动性提升，并进一步增强复合涂层的显微硬度，从而提升复合涂层的耐磨性能。 |
| 关键词: 超高速激光熔覆 钛合金 表面改性 摩擦 |
| DOI：10.11933/j.issn.1007-9289.20230829001 |
| 分类号:TB333 |
| 基金项目:国家自然科学基金(52130509) |
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| High-speed Laser Cladding Ni-coated c-BN Particles Reinforced Wear-resistant Composite Coating and its Wear Behavior |
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LIU Kangcheng1，LOU Liyan1，CAI Zhihai2，XING Zhiguo2，WANG Haidou2，LI Chengxin1
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1.State Key Laboratory for Mechanical Behavior of Materials, Xi’ an Jiaotong University,Xi’ an 710049 , China ；2.National Engineering Research Center for Mechanical Product Remanufacturing,Academy of Armored Forces Engineering, Beijing 100072 , China
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| Abstract: |
| Titanium alloys are widely used in aerospace and marine industry because of their low density and high specific strengths. However, their low hardness and poor wear resistance limit their application under various working conditions. Coating is an effective and rapid surface modification method that can improve the wear resistance of titanium alloys under extreme service conditions. In this study, a complete and dense c-BN (cubic boron nitride) composite wear-resistant coating was successfully applied on the surface of titanium alloy using a novel ultra-high-speed laser cladding method. To enhance the mobility of the c-BN ceramic powder, it was coated with Ni via electroless plating, and the effects of Ni coating on the microstructure and wear performance of the coating were comparatively studied. The microstructure, phase composition, and mechanical properties of the coatings were analyzed using an XRD / SEM / EDS microhardness tester and a friction wear tester. The results showed that the c-BN particles partially decomposed under laser irradiation and reacted with Ti in the molten pool to generate TiN, TiB, and other reinforced phases in-situ. In addition, in c-BN(Ni) coatings, the Ni coating on the c-BN surface melted under laser irradiation and entered the Ti lattice or partially reacted with Ti to generate Ti-Ni intermetallic compounds in the molten pool during solidification. This strengthened the solid solution and dispersion of the coating. Thus, the microhardness of the c-BN(Ni) coatings was significantly improved compared to that of the titanium alloy and c-BN coatings without Ni coating. Furthermore, the average microhardness of this coating was more than 1 200 HV0.3, which is more than three times that of the titanium alloy. After etching, for both the c-BN coatings, the top of the coating was mainly TiN, and the bottom of the coating was fine TiB; furthermore, the middle of the coating contained mix of TiN and TiB. The results of friction wear tests using Si3N4 as a counter-abrasive pair showed that these reinforced phases produced an intense counter-abrasive wear, resulting in a high coefficient of friction for the c-BN(Ni) coating. However, a higher microhardness significantly improves the wear resistance. Under the same conditions, the width and thickness of the wear profile of the c-BN(Ni) coating were significantly reduced, and its wear volume was reduced by 72% and 22% compared with those of the titanium alloy and uncoated Ni c-BN coating, respectively. The SEM morphology of the wear surfaces showed an obvious adhesive wear on the titanium alloy, and the c-BN coating without an Ni coating exhibited abrasive wear; furthermore, the c-BN(Ni) coating showed a large number of fish-scale like wear scars, owing to the large number of debris generated by the intense grinding of Si3N4 and hard phase in the coating. The morphology of the titanium alloy showed mainly small-and large-sized debris, whereas those of the two c-BN coatings showed small-sized debris. In this study, the c-BN particles were coated by Ni electroless plating before cladding; thus, the mobility of the c-BN ceramic powder improved during the deposition process, and the microhardness of the composite coatings increased owing to solid solution strengthening and dispersion strengthening of Ni, which led to composite coatings with an excellent wear resistance. |
| Key words: high-speed laser cladding titanium alloy surface modification friction |
