顾名思义,超硬材料就是硬度极高的材料。一般来说,金刚石的硬度最高,莫氏硬度为10,CBN的硬度略低于金刚石。因此,超硬材料通常是指金刚石和CBN,或以这两种材料为主要成分制成的复合材料。

刚玉、碳化硅、硬质合金和高速钢这四种被用作“工业牙齿”的硬质材料,其硬度远低于金刚石和立方氮化硼。因此,超硬材料也被称为最坚硬、最锋利的“工业牙齿”或“材料之王”。

1. 钻石

Like other carbon materials, the main chemical element composition of diamonds is carbon. No matter it is a natural diamond or a man-made diamond, no matter what kind of diamond will contain more or less impurities. Diamond generally contains nitrogen impurities. According to the difference of nitrogen content in diamond crystal, diamond can be divided into two types (type I diamond and type II diamond).

近年来,碳材料是一种非常热门的材料。 21世纪也被称为“碳时代”。碳材料以其优异的性能被广泛应用于各个领域,特别是在国家战略性新兴产业,如石墨烯及碳纳米材料、碳纤维及其复合材料、金刚石碳基薄膜和传统碳材料(炭黑、多孔碳、石墨、特种石墨等)在锂电池、电容器、储能、光伏、半导体、光电显示、5G通讯、传感器、通用航空、未来交通、高端装备等领域具有广阔的应用前景

除了金刚石,你还知道哪些超硬材料? 1

2、cBN

Cubic boron nitride (CBN) is the second largest variety of superhard materials. The chemical structure formula of boron nitride is BN, which is composed of boron and nitrogen. Boron nitride has four different crystal structures, mainly hexagonal boron nitride (hBN), cubic boron nitride (CBN), rhombic boron nitride (RBN) and dense hexagonal boron nitride (WBN). The nitrogen and boron atoms in hBN and RBN are hybridized in SP2, while the nitrogen and boron atoms in CBN and WBN are hybridized in SP3.

CBN的硬度略低于金刚石,晶体颜色与杂质的种类和数量有关。 CBN具有独特的光电特性。合成大尺寸、高质量的CBN单晶是功能器件应用的必然选择。然而,CBN晶体的大尺寸远不如金刚石成功。这可能是因为大颗粒CBN的合成条件比较严格,其应用还没有找到合适的领域。

超硬材料的应用

1、超硬材料产品

超硬材料及其制品和工具已广泛应用于工业。它们不仅解决了传统工具无法加工或难以加工的问题,而且显着提高了传统加工效率,显着降低了消耗和废物排放。

除了金刚石,你还知道哪些超硬材料? 2

 

几种超硬材料产品和工具(A.刀片;B.砂轮;C.锯片;D.钻头)

超硬材料产品和工具的主要品种包括锯切工具、磨具(包括固结磨具、涂附磨具和松散磨具)、切削工具、钻孔工具、精加工工具、拉丝模具、其他工具和不同功能的零件。

2. 天然和人造钻石

(1) 天然金刚石

从天然钻石中提取的钻石称为天然钻石。天然钻石明亮、华丽、稀有、珍贵。它们被视为珍宝。有一则广告写着“一颗钻石永存,永恒”,这是中国妇女和儿童所熟知的。

除了金刚石,你还知道哪些超硬材料? 3

天然钻石除了用作首饰外,更多地用于工业。金刚石的工业用途长期以来一直是利用其特殊的高硬度。切割玻璃的金刚石刀提醒我们,金刚石是用来为地质勘探和石油和煤炭开采准备钻头的。金刚石在高温下会被氧不同程度地氧化,特别是与铁的亲和性好,不适合黑色金属加工。

(2) 人造金刚石

Artificial diamond, also known as laboratory synthetic diamond or cultivated diamond in the industry. Artificial diamonds with large particles or single crystals have been used to process synthetic diamond jewelry. Artificial diamonds are also genuine diamonds, with the same composition and structure as natural diamonds. The two can only be distinguished in a very special way. For example, under the cathodoluminescence instrument, the growth texture of the former is geometric, and the latter is annular. Since 2006, GIA and other jewelry institutions have started to provide identification services and issue certificates, mainly to prevent merchants from selling synthetic diamonds with lower prices as natural diamonds. In the past, researchers in the diamond industry have been looking for efficient synthetic methods of artificial diamonds, but there has been no breakthrough. The two main obstacles come from cost and production factors. After decades of research, the technology of synthesizing large diamond single crystals by ultra-high pressure and high temperature method under the condition of static catalyst has been mature. China has made rapid development in the technical development and application of synthetic diamond large single crystal synthesized by ultra-high pressure and high temperature method and synthetic diamond synthesized by microwave plasma CVD method. Synthetic diamond jewelry has been sold in the market and has begun to take shape.

三、CBN的主要应用

CBN与金刚石相比具有独特的优势,如高热稳定性和与铁族元素的化学惰性。

目前,CBN主要用于两个方面:一是制造磨具,二是制造多晶立方氮化硼作为工具材料。因此,CBN在加工黑色金属材料方面独树一帜,为硬、韧难加工的铁基材料提供了一种新的加工工具。

用作研磨材料。不仅可用于铁基材料的加工,也可用于有色金属材料的加工。

用作工具材料。多晶立方氮化硼一般用于刀具。 PCBN是由CBN单晶制备的微粉。它是通过添加碳化钛、钴和其他粘合剂,然后用六面顶压机在高压和高温下烧结而成。对黑色金属及其合金的加工特别有效,特别适用于高速切削和干切削。实现了以车代磨、以铣代磨,大大提高了生产效率。

除了金刚石,你还知道哪些超硬材料? 4

用作功能材料。高导热CBN可应用于光电功能器件。

超硬材料是许多不同材料的小变种,但它是一种不可替代的材料,可能会逐渐取代其他一些材料。

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