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前言机械密封上,特别是用在含有研磨颗粒的介质中,一般选用纯 WC-Co 型。然而,纯 WC-Co 型硬质合金不能用于酸性溶液中,因为钴基金属胶结剂相在酸性溶液中会被溶解。在腐蚀性介质中,有时使用镍基硬质合金,如纯 WC-Ni 型。但镍基胶结剂相的耐腐蚀性虽比钴基胶结剂相略好,而机械性能则稍差。特殊的 TiC-Ni 基硬质合金化学稳定性很高,但其缺点是脆性较高,导热性较差,应用范围必然受到限制。为了适用于包括海水和工业泵的机械密封,最近研制成功的 WC-Ni-Cr-Mo 型硬质合金可满足要求在这里作一介绍。各种硬质合金的基本性能物理性能和机械性能(见表1)
Preface Mechanical seals, especially in the medium containing abrasive particles, the general selection of pure WC-Co type. However, pure WC-Co cemented carbide can not be used in acidic solutions because the cobalt-based metal binder phase is dissolved in an acidic solution. In corrosive media nickel-based cemented carbides are sometimes used, such as pure WC-Ni. However, the corrosion resistance of the nickel-based binder phase is slightly better than the cobalt-based binder phase, while the mechanical properties are slightly worse. Special TiC-Ni-based carbide high chemical stability, but the disadvantage is the higher brittleness, poor thermal conductivity, the application range is bound to be limited. In order to be suitable for the mechanical seal including the sea water and the industrial pump, WC-Ni-Cr-Mo cemented carbide recently developed can meet the requirement to make an introduction here. The basic performance of various cemented carbide Physical properties and mechanical properties (see Table 1)