表面粗糙度对锌涂层防腐性能的影响

通过极化电阻及腐蚀电位长时间的测试,研究了电弧喷涂锌涂层在3.5%NaCl溶液中电化学行为。实验结果表明:锌涂层表面粗糙度在浸泡初期与腐蚀产物联合控制着腐蚀的过程,但以表面粗糙度的控制为主。浸泡后期主要表现为腐蚀产物的控制。

Development of Diamond-like Carbon Fibre Wheel

A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned no rmally to the grinding wheel surface by laminating Al sheets together with DLC fibres. In this paper, the formation process of DLC fibres and the fabrication process of a DLC fibre wheel were investigated. Many grinding experiments were also carried out on a precision NC plane milling machine using a newly developed DLC wheel. Grinding of specimens of silicon wafers, optical glasses, quartz, granites and hardened die steel SKD11 demonstrated the capabilities of nanometer surface finish. A smooth surface with a roughness value of Ra2.5 nm (Ry26 nm) was achieved.

热喷涂过程中热障涂层的残余应力

热障涂层技术是解决航空发动机和燃气轮机高温服役的核心技术之一。它不仅能阻隔热燃气,还能防止叶片被氧化、腐蚀、侵蚀等造成的损坏。当热障涂层在复杂服役环境中长时间使用时,制备中产生的残余应力容易导致热障涂层与基体之间产生剥落和开裂等问题。因此,深入研制热障涂层制备过程中的热应力因素,对热障涂层的设计、制备和强度评估具有重要意义,对航空发动机和燃气轮机的安全服役具有重要意义。介绍了热障涂层热喷涂制备中应力问题的最新研究进展。总结了近5年制备技术(主要包括:喷涂参数、粘结层温度和粗糙度、热处理、激光表面重熔)对热应力影响的研究,涉及理论、实验和数值分析几个方面。