Evolution of conventional hard coatings for its use on cutting tools. (January 2017)

• Record Type: Journal Article
• Authors: Haubner, Roland; Lessiak, Mario; Pitonak, Reinhard; Köpf, Arno; Weissenbacher, Ronald
• Is Part Of: International journal of refractory metals & hard materials. Volume 62(2017)Part B
• Page Start: 210
• Page End: 218
• Publication Date: 2017-01
• Subjects: CVD -- Tools -- Multilayer -- Mixed-crystal -- Nano-crystalline; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2016.05.009
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: The investigation of hard materials started already in the 1930s by depositing TiC, although it took until the 1950s that coatings were deposited on steel substrates and further 20 years till the first commercial TiC coatings on hardmetal tools were available. The development of coatings was deemed necessary because conventional hardmetal tools were no longer cost-effective for its use in the new generation of metal working machines. However it was not until the introduction of TiN and Ti(CN) that the machines could be used to their full capability. Further progress for hard coatings was the development of CVD processes for industrial deposition of other compounds like Al2 O3, ZrN, Zr(C, N), Ti-Zr-C, TiB2, various Tax Cy - and Crx Cy -layers. Parallel to CVD the development of PVD coatings started in the 1980s. The next step was to control the microstructure of the hard coatings. The crystal size could be varied by changing the deposition temperature and adding impurities. Medium temperature (MT) and Plasma CVD processes were developed. For improving cutting tool performances various coatings were combined to multilayers like TiN/MT-TiCN/Al2 O3 /TiN. The newest investigations are interested in nano-structured coatings mixing two phases within one layer. (Al, Ti) N -coatings with high Al-content show great potential and are one example developed during the last years. Highlights: The evolution of coatings for tool is powered by the properties of hard materials and the possibility of its CVD deposition. The hard materials can be designed by changing its grain size and creating mixed crystals. During the last years also nano mixtures of hard materials were created. The highlight are the newest results of the nano lamellar structured hard material (AlTi)N. Another approach is deposition of multilayers combining the properties of various hard materials.