Chemical and mechanical properties of silica hybrid films from NaOH catalyzed sols for micromachining with diamond cutting tools

• Published in: Thin solid films 2013-03, Vol.531, p.208-216
• Main Authors: Prenzel, T., Mehner, A., Lucca, D.A., Qi, Y., Harriman, T.A., Mutlugünes, Y., Shojaee, S.A., Wang, Y.Q., Williams, D., Nastasi, M., Zoch, H.-W., Swiderek, P.
• Format: Article
• Language: English
• Subjects: Carbon; Catalysis; Catalysts: preparations and properties; Chemistry; Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Cutting tools; Diamond machining; Diamond tools; Elastic recoil detection; Exact sciences and technology; General and physical chemistry; Heat treatment; Infrared spectroscopy; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Mechanical and acoustical properties; Methods of deposition of films and coatings; film growth and epitaxy; Micromachining; Molds; Nanoindentation; Physical properties of thin films, nonelectronic; Physics; Raman spectroscopy; Silica hybrid coatings; Sols; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Thin film structure and morphology; X-ray photoelectron spectroscopy
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.01.095

Manufacturing of microstructured mold surfaces was realized by the micromachining of thick sol–gel silica hybrid coatings. The films were deposited onto pre-machined steel molds by spin coating using NaOH-catalyzed sols from organosilicate precursors. The effect of the sol synthesis and the heat treatment on the mechanical and chemical properties of these films was studied in order to develop thick and crack-free films with appropriate properties for micromachining with diamond cutting tools. The hardness was measured by nanoindentation as a function of the heat treatment temperature. The transition from soft organic gel films to hard glass-like films due to the thermal treatment was characterized by X-ray photoelectron spectroscopy, elastic recoil detection, and Raman and infrared spectroscopies. The films from NaOH catalyzed sols showed a complex transition from aliphatic carbon originating from hydrocarbon groups to carbonates, carboxylates and disordered carbon clusters. ► Thick silica hybrid films were micromachined with diamond cutting tools. ► The nanoindentation hardness increased with the heat treatment temperature. ► The role of sodium hydroxide in base catalyzed silica sols was studied. ► Formation of carbonates, carboxylates and disordered carbon was observed.