Ti-Al球磨粉反应等离子喷涂工艺

Reactive Plasma Spraying of Ti-Al Milled Powders

为制备Ti-Al金属间化合物复合涂层,采用Ti、Al球磨粉在Q235钢表面进行反应等离子喷涂研究,获得了由Al3Ti、TiN、Al2O3、TiAl以及残留Al和Ti组成的复合涂层。虽然球磨可以使Ti-Al混合粉细化与活化,使喷涂时的反应更容易、更充分,但喷涂时Al和Ti仍难以充分反应,且在空气环境中喷涂容易氧化和氮化。涂层与基体之间没有形成冶金结合,而是镶嵌式的机械结合。其结合强度最高值达到了44.75MPa,显微硬度最高值达到了379HV0.5。文中还分析了反应等离子喷涂各工艺参数对涂层组织与性能的影响,并采用正交试验对其在一定范围内进行了优化。得到优化的工艺参数为:喷涂距离为120mm、主气流量为35L/min、喷涂电流为600A、球磨时间为6h。

Reactive plasma spraying of Ti-Al mechanically milled powders on Q235 steel surface was investigated to prepare the composite coating of Ti-Al intermetallic compounds,and the composite coatings consisting of Al3Ti,TiN,Al2O3,TiAl,residual Al and Ti were obtained.Ti-Al mixed powders can be refined and activated by mechanical milling,making the reactions easier and more thorough in the spraying.However,Al and Ti are still very difficult to react completely during spraying,and also easy to be oxidized and nitrified while being sprayed in air.Not metallurgical bonding but insert mechanical bonding is formed between the coating and the matrix.The maximum of the bond strength attained 44.75 MPa,and the maximum of micro-hardness attained 379 HV0.5.The effects of the reactive plasma spraying parameters on the microstructure and properties of the coatings were analyzed,and the parameters were optimized by orthogonal design experiments in some extent.The optimized parameters are as following： spraying distance of 120 mm,main gas flow rate of 35 L/min,spraying current of 600 A,milling time of 6 h.