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硬质陶瓷涂层一般硬度高,但韧性差,在受到较大外加冲击荷载作用时容易产生裂纹并引发失效,从而限制了硬质涂层在工程领域的应用。硬质涂层的增韧研究是当前硬质涂层研究的热点之一。常见硬质涂层增韧方法中,有些是以降低硬度为代价来提高涂层韧性,比如第二相增韧;有些是通过优化涂层结构设计,减小缺陷尺寸,在不损失涂层高硬度的前提下,提高韧性,获得兼具高硬度和高韧性的涂层;有些是通过相变(晶体结构转变)提高涂层的韧性。通过优化涂层结构设计,改变涂层晶粒尺寸、晶界尺寸与复杂程度等,使涂层致密化,从而提高涂层硬度与韧性,从而获得增韧效果,成为研究者越来越关注的焦点。单一增韧方法的局限性,可以通过多种增韧方法协同作用获得突破,协同增韧已成为硬质涂层增韧发展的趋势。目前硬质涂层的韧性评估还没有一个公认的方法,从简单实用出发,常用的有微悬臂梁弯曲法、划痕法和压痕法。
Hard ceramic coating generally high hardness, but poor toughness, when subjected to greater impact load is prone to cracking and lead to failure, thus limiting the hard coating in engineering applications. Toughening of hard coatings is one of the hot topics in the current research on hard coatings. Some common toughening toughening methods, some at the expense of reducing the hardness to improve the coating toughness, such as the second phase toughening; some by optimizing the coating structure design to reduce the size of the defect, without loss of coating height Hardness of the premise, to improve the toughness, access to both high hardness and high toughness of the coating; some through the phase transition (crystal structure change) to improve the toughness of the coating. Researchers have paid more and more attention by optimizing the structural design of coatings, changing the grain size of coatings, the size and complexity of grain boundaries, and densifying the coating to improve the hardness and toughness of the coating, thereby obtaining the toughening effect focus. The limitations of a single toughening method can be achieved through a variety of toughening methods to achieve synergies, and synergistic toughening has become a trend of toughening development of hard coatings. At present, there is no universally accepted method to evaluate the toughness of hard coatings. From the simple and practical point of view, micro-cantilever bending methods, scratching methods and indentation methods are commonly used.