模具钢TiAlN和TiAlSiN涂层的制备及性能

Preparation and properties of TiAlN and TiAlSiN coatings on die steels

采用高功率脉冲磁控溅射(HiPIMS)技术在H13(4Cr5MoSiV1)热作模具钢和Cr12MoV冷作模具钢表面制备了TiAlN和TiAlSiN涂层。通过X射线衍射仪、扫描电镜、划痕仪和电化学工作站等分析了TiAlN和TiAlSiN涂层的微观结构、形貌和综合性能。结果表明:涂层表面较平整致密,截面无明显裂纹、孔洞等缺陷。TiAlN和TiAlSiN涂层的主要相结构均为TiN,涂层和基体结合较紧密,膜基之间存在元素互扩散。在残余应力的作用下Si元素的加入使TiAlSiN涂层结合力弱于TiAlN涂层。涂层提高了基体的耐蚀性,在3.5%NaCl溶液中涂层的自腐蚀电位相对于基体均正移,与基体相比,TiAlN涂层的自腐蚀电流密度降低了一个数量级,TiAlSiN涂层的自腐蚀电流密度降低了两个数量级,耐蚀性优于TiAlN涂层。涂层腐蚀机制主要是点蚀。涂层大幅降低了H13钢基体的氧化增重速率,TiAlSiN涂层中形成的SiO_(2)和Al_(2)O_(3)共同组成阻氧膜层,进一步提高了基体的抗高温氧化性能。

TiAlN and TiAlSiN coatings were deposited on H13(4Cr5MoSiV1)hot working die steel and Cr12MoV cold working die steel by high power impulse magnetron sputtering(HiPIMS)technique.Microstructure,morphology and comprehensive properties of the TiAlN and TiAlSiN coatings were analyzed by means of X-ray diffractometer,scanning electron microscopy,scratch tester and electrochemical workstation.The results show that the surface of the coatings is smooth and compact,and there are no obvious cracks,holes and other defects in the cross section.The main phase structure of the TiAlN and TiAlSiN coatings is TiN.The coating is closely combined with the substrate,and there is element diffusion between the coating and the substrate.Under the action of residual stress,the addition of Si element makes the adhesion of TiAlSiN coating weaker than TiAlN coating.The coating improves the corrosion resistance of the substrate.In 3.5%NaCl solution,the self-corrosion potential of the coatings moves positively relative to the substrate.Compared with the substrate,the self-corrosion current density of the TiAlN coating decreases by one order of magnitude,and the self-corrosion current density of the TiAlSiN coating decreases by two orders of magnitude,its corrosion resistance is better than TiAlN coating.The corrosion mechanism of the coatings is mainly pitting corrosion.The oxidation mass gain rate of the H13 steel substrate is greatly reduced by the coatings,and the SiO_(2) and Al_(2)O_(3) formed in the TiAlSiN coating form an oxygen barrier film,which further improves the high-temperature oxidation resistance of the substrate.