Improvement of surface corrosion resistance for magnesium alloy by combining thermal spray and cast-infiltration

The present work focuses on a new method combining cast-infiltration with thermal spraying technology to improve the surface corrosion resistance of magnesium alloy.A zinc-based alloy layer was fabricated on the surface of AZ91D magnesium alloy. The microstructure of the layer was characterized by scanning electron microscopy equipped with an energy dispersive X-ray spectroscopy(EDS).The phase constituent of these alloys was identified by X-ray diffractometry(XRD).The analysis results reveal that a zinc-based alloy layer with a thickness of 700μm can form on the surface of AZ91 alloy matrix.The layer is composed of Mg7Zn3,MgZn and a small amount of α-Mg solid solution.The results indicate that the corrosion-resistance of the specimen with a zinc-based alloy layer is much better than that of the specimen without the layer after being immersed in 5%NaCl solution for 240 h, and the layer is more protective for the AZ91 alloy.     

SHS铸渗法制备表面金属-陶瓷复合材料

介绍了SHS铸渗法的实验方法 ,工艺参数以及影响铸渗溶覆质量的因素 ,利用自蔓延高温合成熔铸技术将 (Al2 O3-Fe -Cr)金属 -陶瓷的高温熔体铸渗在试样表面 ,形成厚度几毫米的铸渗熔覆层。在此基础上 ,使熔覆层中的Cr -Fe作梯度改变 ,从而获得梯度熔覆层结构 ,有利于提高熔覆层与基体的结合强度。     

铸渗机理与改善铬铸渗层质量的研究

提出了铬铸渗层是田合金烧结层、纤焊层和熔合层三个区域构成的。指出机器高压制造合金膏块是改善铬铸渗层质量的有效工艺措施。     

反应铸渗法制备Fe-WC表面复合材料的工艺研究

试验研究了工艺参数对反应铸渗法制备Fe—WC表面复合材料的影响。结果表明：在低放热反应体系（w＋C）的压坯中添加高放热反应体系（2Al＋3CuO）的助燃剂可以有效地促进反应铸渗的进行；压坯致密度过大时，反应铸渗不能进行完全：浇注温度太低时，不能引燃和维持反应铸渗的进行。较好的工艺参数组合是：（2Al＋3CuO）助燃剂5％-10％，压坯致密度30％左右．浇注温度1450-1550℃。     

Fe-WC surface composites produced by reactive cast-infiltration

1 .Introduction Metal-matrix composites (MMCs) have developed since they first appeared in the 1960s. However, the high cost of current monolithic MMCs hampers their production on a large industrial cale From the point of view of their application, the service life of components usually relies on their surface properties. It is desirable