两相流合金（NiCrWRe）粉体涂层炉内熔结及磨蚀性能研究

【作者】 黄仲佳；

【导师】 王智平； 苏义祥；

【作者基本信息】 兰州理工大学 ， 材料学， 2005， 硕士

【摘要】 现代技术的发展要求材料具有高的硬度、强度、耐磨性、耐腐蚀性、耐高温抗氧化等性能。在工程材料的实际服役过程中,磨损现象大多发生在材料的表面,材料的最终服役性能取直接决定于材料表面的物理化学特性,往往脱离于整体材料的其本性能。解决方法是应用表面工程的技术制造表面覆层材料,既具有良好综合性能的新型材料和传统的材料结合在一起。目前,表面技术已得到较快的发展,但是对于大平面涂层它们的生产率低;及被涂覆的基体体积薄时,由于喷涂层和基体的温度差别大,造成基体的过热和变形量大,容易产生内应力及基体丌裂。而这两种情况下,炉内烧结就有优势。 炉内熔结可对大平面的、复杂的金属工件进行表面覆层处理,并可进行,合金粉末覆层的烧结和铸钢或铸铁的基体的热处理同时进行,从而大大提高生产率和节约生产成本。目前,有关真空熔结的研究较多,但无保护气氛炉内熔结的研究即很少有报道。因此本研究热处理炉内熔结的方法制备NiCrWRe合金涂层。 本文对涂层的两种黏结剂进行比较,确定最好的黏结剂。选定炉内熔结的各个参数,并找出合适的工艺参数,以便能制备出综合性能良好的涂层材料。熔结温度对涂层材料的性能有很大的影响。对于温度的主要要求是,在熔结过程中能够保证生产液相。使用高于液相形成的温度可以提高材料原子的扩散率、润湿性和固相在液相中的溶解度,降低液相的黏度和增加液相的数量。涂层的孔隙率随着烧结温度的升高而急速降低,但孔隙的尺寸却并不是简单随着烧结温度的升高而减少,而是有一个小孔隙迁移合并过程,因此存在一段温度范围,在此温度范围内孔隙尺寸基本不变。熔结涂层与基体结合面达到冶金结合,结合面附近的基体没有热影响区,组织均匀。涂层与基体之间结合良好,界面干净整齐,无未熔合、裂纹和夹杂物等缺陷。结合牢固的涂层为保证涂层具有良好的耐磨性创造了条件。 同时对涂层的摩擦磨损性能进行研究,探导涂层的摩擦磨损性能机制。与Cr18Ni12Mo2Ti材料相比涂层有很好的耐磨性能。在低于100N的载荷下,涂层材料的质量损失和摩擦系数随载荷增加而变化的幅度不大。而当载荷大于150N时,随着载荷的增大,涂层的磨损质量损失和摩擦系数都激烈的增加。从磨损型貌来看,涂层能给硬质相提供良好承载能力。稳固的硬质相使涂层材料具有超强的耐磨性能。更多还原

【Abstract】 Development of modern technique require material possess supernal rigidity, intensity; wear resistance, causticity resistance, high temperature resistance and oxidation resistance. In the course of serve of engineering material, most of wear phenomenon take place on the surface of material. The finally serve capability depend directly on characteristic of physical chemistry of material surface. Sometimes they are divorced from capability of integer stuff. The resolvent is applying surface engineering in making coating. It hang colligate capability new material with conventional material. Now, surface engineering had developed rapidly. But they have low productivity in making big coating. When bulk of substrate is thin, the great temperature difference between coating and substrate make great distortion and heat of substrate, on the other hand, remelting in the stove is good.Remelting in stove can deal with the big surface of metal work piece. And it can deal with the coating and heat treatment substrate at one time. So it can improve productivity rapidly and saving produce cost. Now, there is much study of vacuum remelting. But there a fat lot study of remelting in stove, which has no unprotected atmosphere. So this paper study method of remelting NiCrWRe coating in heat treatment stove.This paper compared with two sort of cling matter, ascertain the best one. Selecting every parameter of remelting in stove, so that the favorable colligate capability coating can be made. Heating temperature influence on the capability of coating. Heating temperature must be sure to yielding liquid in the course of remelting. Using the temperature that above liquid formative temperature can improve diffusivity of atom, solubility of solid and depress the stickiness of liquid. The rate of hole of coating depress rapidly with increasing of remelting temperature. The dimension of hole don’ t depress with the increasing of remelting temperature. The small hole has to move and unite. So there is a range of temperature, in which the dimension of hole don’ t change with the remelting temperature. There is metallurgy combine between coating and substrate. There is not a heat effect section of substrate. The firm combine of coating and substrate provide the coating with favorable wear resistance.At the same time , the capability of friction and abrasion were studied, discussed the principle of the capability of friction and abrasion. The result showed: it has better capability compared with Crl8Nil2Mo2Ti. Under the load of 100N, the change of lose weight of coefficient and friction coefficient is not very evident. But when the load exceed 150N, with the increment of load, the lose weight and friction coefficient will be changedobviously. So coating can provided with better capacity of bear the weight for rigid phase form the shape of abrasion, and coating materials well have the good capacity of friction because of rigid phase.,更多还原