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| - Some of the specific hard materials include metals, such as chromium, metal alloys such as tool steels, stainless steels and carbon steels, all types of hard and super-hard materials such as alumina, titanium carbide, zirconium carbide, boron nitride, titanium nitride, tungsten carbide, silicon carbide, diamond, diamond-like carbon, their mixtures and composites, and other compounds known for thei
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