钛表面改性Al/NiCu组合涂层反应机理及抗氧化性能

Numerical Simulation and Experimental Study of Extrusion Forming of Ti-B25 Titanium Alloy Pipe

摘要:

采用等离子结合电弧喷涂的工艺方法在工业纯钛表面制备了Al/Ni Cu组合涂层,在700℃的大气环境下对Al/Ni Cu/Ti试件进行加热处理,使得Al、Ni Cu复合涂层之间发生扩散反应并原位生成具有一定抗高温氧化性能的Ni-Al金属间化合物涂层。对加热改性处理前后涂层的微观组织及Ni-Al金属间化合物的形成机理进行了研究,并对经加热和打磨处理后的Al/Ni Cu/Ti试件及无防护涂层的Ti块进行了800℃/100 h的高温氧化试验。研究结果显示,Ti基体表面Al/Ni Cu涂层经700℃炉中加热改性处理后,Al、Ni Cu涂层间可发生扩散反应并原位生成Ni Al3、Cu Al2、Ni2Al3及含有一定Cu元素的Ni Al金属间化合物,但只有高熔点的Ni Al金属间化合物能够始终稳定地存在,且此金属间化合物对Ti基体起到了较好的高温防护作用。

Abstract:

The Al/Ni Cu composite coatings were deposited on the surface of a pure Ti substrate by plasma spray technology and arc spray technology,and then the sprayed Al/Ni Cu/Ti specimen was then heated in the furnace at 700 ℃.A Ni-Al intermetallic compound protective coating with oxidation resistance formed through in-situ reaction between Al and Ni Cu composite coatings. The microstructure of the coatings before and after heat modification treatment and the formation mechanism of Ni-Al intermetallic compounds were studied. In addition,the oxidation tests of the Al/Ni Cu/Ti specimen( after heating and polishing treatment) and the uncoated Ti at 800 ℃ for 100 h were conducted. The results show that,by modifying Al/Ni Cu spray coatings on Ti substrate with furnace heating treatment at 700 ℃,Ni Al3,CuAl2,Ni2 Al3 and Ni Al intermetallic compounds with certain Cu elements form through in-situ reaction between Al/Ni Cu composite coatings. However,only the Ni Al intermetallic compound with high melting point can stay stable,and this intermetallic compound can protect Ti substrate under high temperature.