激光熔覆Mo_(2)NiB_(2)熔覆层的制备及其性能表征  

Investigation on the Preparation and Property of the Laser-Cladded Mo_(2)NiB_(2) Coatings

作　　者：倪晓杰 刘福康 胡肇炜[2] 赵忠贤 王生泽[1] 赵远涛 李文戈[2] Ni Xiaojie;Liu Fukang;Hu Zhaowei;Zhao Zhongxian;Wang Shengze;Zhao Yuantao;Li Wenge(School of Mechanical Engineering,Donghua University,Shanghai,201620,China;Merchant Marine College,Shanghai Maritime University,Shanghai,201306,China)

机构地区：[1]东华大学机械学院,上海201620 [2]上海海事大学商船学院,上海201306

出　　处：《应用激光》2021年第1期122-130,共9页Applied Laser

基　　金：国家自然科学基金(52072236);国家自然科学基金(52002242)。

摘　　要：Mo_(2)NiB_(2)三元硼化物具有高硬度与良好耐腐蚀等性能,可应用于Q235钢的表面防护。以Mo、Ni与B粉末为原料,采用激光熔覆技术在Q235基材表面原位合成Mo_(2)NiB_(2)基金属陶瓷熔覆层,研究了激光熔覆次数对熔覆层组织结构与性能的影响。研究发现,Mo_(2)NiB_(2)熔覆层由Mo_(2)NiB_(2)陶瓷硬质相与FeNi合金黏结相构成,随着激光熔覆次数的增加,Mo_(2)NiB_(2)陶瓷相含量先增后减。Mo_(2)NiB_(2)陶瓷相趋于熔覆层中间部位聚集,且熔覆层与Q235基材间形成成分梯度变化的冶金结合区。随着激光熔覆次数的增加,Mo_(2)NiB_(2)熔覆层的硬度与耐腐蚀性能均先提高后降低,在3次激光熔覆时两者为最优,其硬度高于Q235基材1个数量级,而自腐蚀电流密度低于Q235基材2个数量级。Mo_(2)NiB_(2)熔覆层性能主要取决于熔覆层的组织结构与陶瓷相的相对含量。Due to high hardness and corrosion resistance, the Mo_(2)NiB_(2) ternary boride could be used in the surface protection engineering of Q235 steel. In this work, Mo, Ni, B powders were used as raw materials to in-situ fabricate the Mo_(2)NiB_(2) based cermet coatings on Q235 substrate by the laser cladding technology. The influence of laser cladding times on the structure and property of the coatings was investigated. The results showed that the laser-cladded Mo_(2)NiB_(2) coatingwas composed of Mo_(2)NiB_(2) ceramic hard phase and FeNi alloy bonding phase. With increasing the times of laser cladding, the relative content of Mo_(2)NiB_(2) ceramic phases firstly increased and then decreased. The Mo_(2)NiB_(2) ceramic phase tended to aggregate in the middle sites of thecoatings. Besides, a metallurgical bonding zone with a gradient of composition was formed between the cladding Mo_(2)NiB_(2) coating and the Q235 substrate. As the laser cladding times increased, both the hardness and corrosion resistance of the Mo_(2)NiB_(2) coating were firstly enhanced and then weakened. Especially, the highest hardness and corrosion resistance of the coatings were obtained when the laser cladding by 3 times, which were 1 and 2 orders of magnitude higher than Q235 substrate, respectively. The changes in the properties of the Mo_(2)NiB_(2) coatingswere mainly determined by the microstructure and relative content of the ceramic phase in coatings.

关 键 词：激光熔覆 Mo_(2)NiB_(2)金属陶瓷 激光工艺 组织结构 性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]