Chromium nitride coatings grown by unbalanced magnetron (UBM) and combined arc/unbalanced magnetron (ABS ™) deposition techniques

• Published in: Surface & coatings technology Vol. 86; no. 1-3; pp. 192 - 199
• Main Authors: Hurkmans, T., Lewis, D.B., Brooks, J.S., Münz, W.-D.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01.12.1996; Elsevier
• Subjects: Adhesion; Applied sciences; Cathodic arc/unbalanced magnetron; Chromium nitride; Composition; Exact sciences and technology; Metals. Metallurgy; Nonmetallic coatings; Production techniques; Stoichiometry; Surface treatment; Stoichiometry; Composition; Adhesion; Chromium nitride; Cathodic arc/unbalanced magnetron; Ferritic stainless steel; Magnetron; Phase composition; Unbalanced conditions; Hardness; Non metal coating; Sputtering; Surface treatment; Deposition process; Chemical composition; High speed tool steel; Crystalline structure
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/S0257-8972(96)02949-0

Increasingly chromium nitride coatings are being used as a replacement for electroplated hard chromium in various applications. This paper reports an investigation of chromium nitride coatings deposited at 250°C on various substrates at different N 2 partial pressures using both UBM sputtering and ABS techniques. The effect of process parameters on structure, composition, hardness and adhesion have been investigated by XRD, SNMS, SEM and a range of mechanical testing techniques. The presence of Cr, Cr + N, Cr 2N, CrN, and mixtures of the phases have been identified and related to both the film composition and the process parameters. Substoichiometric Cr 2N films had the greatest hardness with values up to 2100 HV. However, films of this hardness exhibited poor adhesion with critical loads, L c, of 30 N (HSS) and HR c-DB of “4”, if deposited with UBM only. X-ray diffraction indicated that the poor adhesion exhibited by these films was associated with high internal stress. The adhesion of substoichiometric films with comparable composition and crystal structure deposited in combination with metal ion etching (ABS) increased the critical load values up to 60 N (HSS) and improved the HR c-DB to “1” (HSS).