Thermal Sprayed Ceramic Coating with Self-Healing-Up Effect

已经证实，在空气中加热时，亚晶石原子扩散到喷涂的氧化铝涂层中形成脉状氧化物，空洞或裂纹通过脉状氧化物的形成愈合。脉状氧化物由重复结构组成，其中包含氧、铝和金属衬底原子的尖晶石层形成在空洞或裂缝的自由表面，而不含铝的金属氧化物位于脉状氧化物的核心。认为脉状氧化物是由于在自由表面优先形成尖晶石层和随后在核心生长金属氧化物的结果。此外，镍、钴和钛的衬底有助于获得尖晶石相，从而有助于修复涂层中的空洞或裂纹。从这个角度来看，只有当选择一种衬底形成尖晶石相时，才能显示出愈合效应。结果表明，尖晶石相的形成对修复效果起着重要的作用。

It has been confirmed that atoms of substartes diffuse into the sprayed alumina coating to form veined oxides on heating in air and the voids or cracks are healed up by the veined oxide formation. The veined oxides compose of a duplicated structure where a spinel layer containing oxygen, aluminum and atoms of the metallic substrate forms at the free surface of the voids or cracks and a metallic oxide free from aluminum is located at the core of the veined oxides. It is considered that the veined oxides are performed as a results of the preferential formation of the spinel layer at the free surface and subsequent growth of the metallic oxides at the core. Furthermore, substrates of Ni, Co, and Ti are useful in obtaining the spinel phase and therefore in healing up the voids or cracks in the coating. From this point of view, the healing-up effect can reveal only when a substrate is selected so as to form the spinel phase. It is concluded that the formation of the spinel phase plays an important role in the healing-up effect.