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一、前言在硬质合金生产中,氢气是最常用的还原一保护气体。氧化钨还原时几乎毫无例外地都是采用氢气作还原剂。尽管真空烧结工艺对硬质合金制品有着无可争辩的优点,但合金制品的脱胶(蜡)、预烧及一些制品的最终烧结,仍广泛地采用氢气作还原—保护气体。作为一种传统的例外,一些硬质合金厂(如美国EX—Cell—O公司及金属碳化物公司)曾采用加有少量氢(10~15%)的氮基气氛,代替氨分解气体来作硬质合金烧结时的保护气体,并认为这种气体具有成本更低、纯度高、具有中性的渗碳势及安全性强等优点。
I. Introduction In the production of cemented carbide, hydrogen is the most commonly used to restore a protective gas. Almost without exception, the use of hydrogen as a reducing agent for tungsten oxide reduction. Although the vacuum sintering process has indisputable advantages for cemented carbide products, hydrogen is still widely used as a reducing-shielding gas for degumming (waxing), calcining and final sintering of some products. As a traditional exception, some cemented carbide plants such as EX-Cell-O Corp. and Metal Carbide Corp. have used a nitrogen-based atmosphere with a small amount of hydrogen (10-15%) instead of ammonia to decompose gas Cemented carbide sintering gas, and that the gas has the advantages of lower cost, high purity, with a neutral carburizing potential and safety.