CMSX-4单晶合金上铂铝涂层制备及高温氧化性能评价

Preparation and High Temperature Oxidation Performance of Platinum-aluminum Coating on CMSX-4 Single Crystal Superalloy

为研究铂铝涂层高温氧化性能,针对第二代镍基单晶高温合金CMSX-4,采用电镀铂和气相渗铝工艺,制备铂铝涂层,评价涂层服役过程中组织结构变化及其退化机制。在恒温氧化过程中,涂层中的Al元素与环境中的O元素不断反应导致涂层中的Al含量不断降低,由Al含量较高的β-(Ni,Pt)Al相连续转变为Al含量较低的γ'相;同时铂铝涂层与CMSX-4基体之间发生的元素互扩散也会导致涂层中Al元素快速损失。这两种途径是导致铂铝涂层中Al元素含量降低进而失效的主要原因。

In order to study the oxidation performance of platinum-aluminum coating at high temperature,platinum aluminum coating for the second-generation Ni-based single crystal superalloy CMSX-4 was prepared by electroplating platinum and vapor phase aluminizing process.The organizational structure change and degradation mechanism during the coating service were evaluated.During the constant temperature oxidation process,the Al element in the coating continuously reacted with the O element in the environment,resulting in the continuous reduction of the Al content in the coating,and the continuous transformation from theβ-(Ni,Pt)Al phase with higher Al content to theγ'phase with lower Al content;At the same time,the interdiffusion of elements between the platinum-aluminum coating and the CMSX-4 matrix also led to the rapid loss of Al in the coating.These two ways were the main reasons for the reduction of Al content in the platinum-aluminum coating to cause the failure.