【作者】 张宁；

【导师】 张楠楠；

【作者基本信息】 沈阳工业大学 ， 材料科学与工程， 2019， 硕士

【摘要】 由于硼化物陶瓷TiB₂/ZrB₂具有硬度高,耐磨性好,热导系数低,不易与涂料发生粘着磨损的特点。现阶段,TiB₂/ZrB₂-M金属基陶瓷涂层已被认为是替代WC-Co和NiCr-Cr₃C₂等传统陶瓷涂层应用于涂布刮刀刀具的最佳候选材料。本文采用与其润湿性较好且耐磨性优异的NiCr作为金属粘结相,结合高能球磨方法和等离子喷涂技术分别制备出NiCr-TiB₂、NiCr-ZrB₂和NiCr-TiB₂-ZrB₂三种金属基陶瓷复合涂层,并研究工艺参数对涂层的组织和力学性能等方面的影响。经研究发现,当粉末中只含有一种陶瓷相TiB₂或ZrB₂时,随着陶瓷相含量的增加,涂层硬度逐渐增加,耐磨性有所增强。而当陶瓷相含量增加到20wt%,NiCr-TiB₂和NiCr-ZrB₂两种复合涂层的力学性能均达到最佳。然而随着陶瓷相的含量继续增加,涂层的硬度和耐磨性却发生下降。这是由于在大气等离子喷涂过程中陶瓷相与基体之间发生反弹的作用力大于粘结相与陶瓷相之间的结合力,这导致涂层沉积效率降低,涂层中孔隙率增大,从而导致涂层耐磨性下降。当粉末中含有TiB₂和ZrB₂两种陶瓷相时,且两相的含量分别达到15wt%时,涂层硬度最高,可达1102 HV_0.2,涂层耐磨性最佳。其中TiB₂粒子弥散分布于涂层中,钉扎在NiCr金属粘结相上,主要起到硬质相强化的作用,提高了涂层的耐磨性。而ZrB₂粒子则溶解于金属粘结相中,提高了粘结相的硬度,在一定程度上增强了与陶瓷相的结合。更多还原

【Abstract】 Boride ceramics（TiB₂/ZrB₂）have high hardness,good wear resistance,low thermal conductivity and is not easy to adhere to the paint.At present,metal-based ceramic（TiB₂/ZrB₂-M）coating has been considered to be the best candidate materials for the application of traditional ceramic coatings such as WC-Co and NiCr-Cr₃C₂ for coating blades.In this paper,three kinds of metal-based ceramic composite coatings NiCr-TiB₂,NiCr-ZrB₂ and NiCr-TiB₂-ZrB₂ were prepared by using NiCr with good wettability and excellent abrasion resistance as metal bonding phase,combined with high energy ball milling method and air plasma spraying technology respectively.And the effects of process parameters on the microstructure and mechanical properties of the coatings were also studied.It was found that when the powder contained only one ceramic phase TiB₂ or ZrB₂,with the increase of ceramic phase content,the hardness of the coatings increased gradually,and the wear resistance was enhanced.The mechanical properties of two coatings（NiCr-TiB₂ and NiCr-ZrB₂）were the best when the ceramic phase content increased to20wt%.However,as the content of the ceramic phase continued to increase,the hardness and wear resistance of the coatings decreased.This was due to the fact that the repulsive force between the ceramic phase and the substrate during spraying process was greater than bonding force between the bonding phases and the ceramic phases,resulting in lower deposition efficiency,increased porosity in the coating and decreased wear resistance of the coating.When the powder contained two kinds of ceramic phases（TiB₂ and ZrB₂）,and the content of the two phases was 15wt%respectively,the coatings hardness could reach up to1102 HV_0.2,the best wear resistance.The TiB₂ particles were distributed in the coating and nailed on the NiCr metal bondingr phases,which mainly played the role of hard phase strengthening and improved the wear resistance of the coating.The ZrB₂ particles were dispersed in the metal bonding phase,which increased the hardness of the binding phase and enhanced the bonding with the ceramic phase to some extent.更多还原