Structure and wear resistance of TiN and TiAlN coatings on AZ91 alloy deposited by multi-arc ion plating

In order to investigate the microstructure of TiN and TiAlN coatings and their effect on the wear resistance of Mg alloy, TiN and TiAlN coatings were deposited on AZ91 magnesium alloy by multi-arc ion plating technology.TiN and Ti70Al30N coatings were prepared on the substrate,respectively,which exhibited dark golden color and compact microstructure.The microstructures of TiN and Ti70Al30N coatings were investigated by X-ray diffractometry(XRD)and scanning electron microscopy(SEM).The micro-hardness and wear resistance of TiN and Ti70Al30N coatings were investigated in comparison with the uncoated AZ91 alloy. The XRD peaks assigned to TiN and TiAlN phases are found.The hardness of TiN coatings is two times as high as that of AZ91 alloy, and Ti70Al30N coating exhibits the highest hardness.The wear resistance of the hard coatings increases obviously as result of their high hardness.

Composition demixing effect on cathodic arc ion plating

The composition demixing effect has been found often in alloy coatings deposited by cathodic arc ion plating using various alloy cathode targets. The characteristics of composition demixing phenomena were summarized. Beginning with the ionization zone near the surface of the cathode target, a physical model in terms of the ions generated in the ionization zone and their movement in the plating room modified by bias electric field was proposed. Based on the concept of electric charge state, the simulation calculation of the composition demixing effect was carried out. The percentage of atoms of an element in coating and from the alloy target was demonstrated by direct comparison. The influences of the composition change of the alloy target and the bias electric field on the composition demixing effect were discussed in detail. It is also proposed that the average charge states of the elements may be used to calculate the composition demixing effect and to design the composition of the alloy target.

Approximate Design of Alloy Composition of Cathode Target

An empirical formula for composition demixing analysis in cathodic arc ion plating using alloy target is established based on the concepts of average charged state and relative demixing parameter. The level of composition demixing effect is presented by demixing degree of one element. For binary constituent alloy target, the composition change trend in coating is discussed and the limit of demixing degree for each element is determined. The content of one element with higher average charged state gets larger in coating than in alloy target, at meantime, the content of one element with lower average charged state gets less. For each one of the two constituents, the less the atom percent in alloy target, the larger the difference of its contents between the coating and the target. For triple constituent alloy target, the content change of one element with moderate average charged state is discussed in detail. Its content in coating getting larger or less is determined by the combination result of the contents of the other two elements in alloy target. For a given content of the element with moderate average charged state in triple alloy target, the content deviation level of that element from coating to alloy target will be not larger than that using binary alloy target containing only that element and one of the two others. According to the wanted coating composition, the composition design of alloy target is easily deduced from the formula.

多弧离子镀(Ti,W)_xN合金涂层组织与性能

采用 Ti/ W复合靶用多弧离子镀技术沉积了 (Ti,W) x N合金涂层 ,并对该涂层的组织与性能进行了研究。结果表明 ,涂层组织致密 ,孔隙率极低 ,主要结构为 (Ti,W) 2 N,并具有较高的显微硬度和抗氧化性。在沉积过程中存在着多元合金涂层与复合靶的成分离析现象 ,这与靶材的结构有关。

Mo对多弧离子镀(Ti,Mo)_xN涂层组织与性能的影响

采用Ti/Mo复合靶 ,用多弧离子镀技术沉积了 (Ti,Mo) xN多元涂层 ,研究了Mo对该涂层组织与性能的影响。结果表明 ,涂层的主要结构为 (Ti,Mo) 2 N ,其中Mo的固溶度可达 4 56% (质量分数 ) ,并具有较高的显微硬度、抗氧化性和低的孔隙率。在沉积过程中存在着多元合金涂层与复合靶的成分离析现象 ,这与靶材的结构有关。

多弧离子镀合金涂层的成分控制及阴极靶源的成分设计

采用多弧离子镀制备的合金涂层成分与合金阴极靶之间通常存在一定程度的偏差。这种离析效应导致了合金涂层成分控制及合金靶材成分设计的困难。现在的研究工作提出了一个简易的公式an=[(an0 · fn) / i(ai0 · fi) ]· 10 0用于解决这些问题。此公式可以根据合金元素的离化率计算涂层的合金成分。计算结果与实验结果取得了较好的一致。改变该公式的表达方式 an0 =[(an/ fn) / i(ai/ fi) ]·10 0 % ,则易于完成阴极靶源的成分设计 ,并且实现合金涂层的理想成分。

多弧离子镀合金涂层成分离析效应的物理机制研究

提出了一种关于多弧离子镀合金涂层成分离析效应的物理模型。利用该模型，从理论上较为圆满地解释了成分离析的影响因素及其作用机制。

Ni-Fe-Cr基高温合金表面AICrN涂层制备及高温氧化性能

采用阴极弧离子镀法在Ni-Fe-Cr基高温合金表面制备了AlCrN涂层.通过电子扫描电镜、能谱仪、X射线衍射仪和X射线光电子谱仪等分析了AlCrN涂层表面和界面的形貌、能谱、物相以及结合能谱,并进行了800和900℃高温氧化实验,研究了AlCrN涂层抗高温氧化性能及其机理.实验结果表明:AlCrN涂层主要成分为Al、Cr和N元素,添加Al元素后表现出较强的AlN择优取向;Al2p峰谱为Al—N和Al—O结合键,Cr2p峰谱为Cr—O和Cr—N结合键,N1s峰谱以Cr—N和Al—N的形态存在,另外含有少量的N—Cr—O和N—Al—O结合键;经过高温氧化后AlCrN涂层表面氧化物为Cr_2O_3,对高温合金基体有良好的保护作用.