Hartstoffschichten für das Pressen und Prägen von Gläsern bei hohen Temperaturen

Abstract

In reaktiven Bcschichtiingsverfahren wurden diinne Schichten aus dem terniiren System Titan-Aluminiumnitrid, TiAIN, auf verschiedenen Substratiiiaterialicn unter Variation der Abscheidebedingung abgeschieden. Angewendet wurden das Hochfrequenz-Magnetron-Sputterverfahren, das lonciistrahlzerstiiuben und die Abscheidung energetischer Cluster im ECI-Vcrfahren (energetic cluster impact). Variicrt wurden Parameter wie Partialdrucke und Flusse der ProzeBgase Argon und Stickstoff sowic Energien der auf das Substrat auftreffenden und an der Schichtbildung bcteiligten Partikel. Zur Analyse von Mikrostruktur und Schichtmorphologie wurden Querschnittspriiparate von Schichtproben mit dem Transmissionselektronenmikroskop untersucht. Durch Vermessung der Verwolbung von Substraten vor und nach dem Beschichten wurden Schichteigenspannungen rnittels Interferenzmikroskopie ermittelt. Durch Anwendung dieser Merhode auch bei hoheren Ternperaturen konnten Abhiingigkeiten thermisch induzierter Eigenspannungen von der Temperatiir direkt beobachtet und Veriinderungen der intrinsischen Schichteigenspannung init Vorgiingen in der Schicht in Zusammenhang gebracht werdcn. In den1 Beitrag werden charakteristische Bedingungen dcr verschicdenen aut atomarer Ebene ablaufenden Abschcideprozessc untersucht und im Zusammenhang mit Schichtniikrostruktur und Schichteigenspannungen diskutiert. Einbezogen in die Diskussion werden Beispiele aus der Anwendung heschichteter Werkzeuge fur die Herstellung von optischen Komponenten aus Gliisern durch Press-und Prageformgehung.Hard and wcar resistant coatings of Titanium Aluminium Nitride TiAlN were deposited o n various substrates by the application of different reactive deposition processes: RF-magnetron-sputtering, ion beam-sputtering and by the energetic cluster impact (ECI) process. The deposition of the coatings was performed under variation of biasing conditions and of process parameters such as pressures and flow rates of the process gases argon and nitrogen as well as of energies of species hitting the substrate surfaces. The microstructure particularly the growth morphology of several films was investigated by pictures of' I'ilin cross sections recorded by transmission electron microscopy. Residual intrinsic film stresses were analyzed by measuring detlections of substrates in an interference optical microscope before and after the deposition of the coatings. By heating coated substrates and in-situ observation of deflections at elevated temperatures dependencies of thermally induced stresses on temperatures and variations of intrinsic stresses due to changes within the films could be analyzed and related to microstructure and growth conditions. In the paper specific characteristics of the deposition processes occuring on the scale both of atoms and of clusters which may contain several thousands of atoms are described and related to microstructure, residual stress states and damaging conditions. Different contributions to residual film stresses are analyzed on the base of theoretical consideration...

Effects of Elevated Temperatures and Oxidation on Residual Stresses in (Ti,Al)N Coatings

“…For values of E s and m s refer to the literature. [9] For coatings deposited in the RF magnetron sputtering process at a high total pressure of 1.3 Pa, tensile stresses of about 700 MPa were observed whereas at lower total pressure (0.13 Pa) compressive stresses of about 600 MPa were determined. Also the coatings deposited in the DC sputtering process showed a transition from tensile to compressive stresses.…”

“…Such processes seem to be predominant up to assist-ion energies of U A » 60 eV, whereas at further increased energies a densification of the coating materials and an increase of the intrinsic compressive stresses occurs. [9] As the coatings deposited in the DC triode process were prepared by application of substrate heating, the thermally induced stresses can not be neglected. By calculating r th for T d = 500, 600, and 700 C according to Equation 2 and subtracting these values from r r , r i was calculated for these specimens.…”