Factors affecting the corrosion resistance of PVD thin films

Jari Aromaa, Helena Ronkainen, Kari Saarinen, Amar Mahiout, Simo-Pekka Hannula

Research output: Book/ReportReport

Abstract

Carbides, borides and nitrides of transition metals are increasingly used as coating materials because of their high hardness and excellent wear resistance. However, these coatings can also potentially be used in applications requiring corrosion resistance because of their inherent stability under a variety of aqueous conditions. Thin film coatings based on these materials are generally produced by PVD methods. Such coatings often exhibit porosity which usually is thought to result from pinholes formed during deposition. If local defects form a direct path between the corrosive environment and the base material the corrosion protection is lost. In this work the influence of different factors on the corrosion resistance of PVD coatings was studied. The factors evaluated were the thickness of the coating, the thickness and the type of the intermediate layer, the composition of the coating and the number of heterogeneities in the coating. Electrochemical porosity measurements which are essential for the estimation of the corrosion resistance of coated components were made in 1 N sulfuric acid solution at ambient temperature. In these conditions corrosion of a coated steel part occurs mainly in the base material. Corrosion resistance was also evaluated with immersion tests. The results of this work suggest the dominating role of the inhomogeneities on the corrosion resistance of the PVD (Ti,Al)N and TiN coatings. Preliminary analysis of the nature of the inhomogeneities is made and their possible source is discussed.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages60
ISBN (Print)951-38-4653-9
Publication statusPublished - 1995
MoE publication typeNot Eligible

Publication series

SeriesVTT Publications
Number215
ISSN1235-0621

Fingerprint

Physical vapor deposition
Corrosion resistance
Thin films
Coatings
Porosity
Borides
Corrosion protection
Sulfuric acid
Nitrides
Wear resistance
Transition metals
Carbides
Hardness
Corrosion
Defects
Steel
Chemical analysis

Keywords

  • surface coatings
  • borides
  • carbides
  • nitrides
  • corrosion resistance
  • porosity
  • thin films
  • titanium nitrides
  • titanium borides
  • titanium carbides

Cite this

Aromaa, J., Ronkainen, H., Saarinen, K., Mahiout, A., & Hannula, S-P. (1995). Factors affecting the corrosion resistance of PVD thin films. Espoo: VTT Technical Research Centre of Finland. VTT Publications, No. 215
Aromaa, Jari ; Ronkainen, Helena ; Saarinen, Kari ; Mahiout, Amar ; Hannula, Simo-Pekka. / Factors affecting the corrosion resistance of PVD thin films. Espoo : VTT Technical Research Centre of Finland, 1995. 60 p. (VTT Publications; No. 215).
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Aromaa, J, Ronkainen, H, Saarinen, K, Mahiout, A & Hannula, S-P 1995, Factors affecting the corrosion resistance of PVD thin films. VTT Publications, no. 215, VTT Technical Research Centre of Finland, Espoo.

Factors affecting the corrosion resistance of PVD thin films. / Aromaa, Jari; Ronkainen, Helena; Saarinen, Kari; Mahiout, Amar; Hannula, Simo-Pekka.

Espoo : VTT Technical Research Centre of Finland, 1995. 60 p. (VTT Publications; No. 215).

Research output: Book/ReportReport

TY - BOOK

T1 - Factors affecting the corrosion resistance of PVD thin films

AU - Aromaa, Jari

AU - Ronkainen, Helena

AU - Saarinen, Kari

AU - Mahiout, Amar

AU - Hannula, Simo-Pekka

N1 - Project code: MRG0012

PY - 1995

Y1 - 1995

N2 - Carbides, borides and nitrides of transition metals are increasingly used as coating materials because of their high hardness and excellent wear resistance. However, these coatings can also potentially be used in applications requiring corrosion resistance because of their inherent stability under a variety of aqueous conditions. Thin film coatings based on these materials are generally produced by PVD methods. Such coatings often exhibit porosity which usually is thought to result from pinholes formed during deposition. If local defects form a direct path between the corrosive environment and the base material the corrosion protection is lost. In this work the influence of different factors on the corrosion resistance of PVD coatings was studied. The factors evaluated were the thickness of the coating, the thickness and the type of the intermediate layer, the composition of the coating and the number of heterogeneities in the coating. Electrochemical porosity measurements which are essential for the estimation of the corrosion resistance of coated components were made in 1 N sulfuric acid solution at ambient temperature. In these conditions corrosion of a coated steel part occurs mainly in the base material. Corrosion resistance was also evaluated with immersion tests. The results of this work suggest the dominating role of the inhomogeneities on the corrosion resistance of the PVD (Ti,Al)N and TiN coatings. Preliminary analysis of the nature of the inhomogeneities is made and their possible source is discussed.

AB - Carbides, borides and nitrides of transition metals are increasingly used as coating materials because of their high hardness and excellent wear resistance. However, these coatings can also potentially be used in applications requiring corrosion resistance because of their inherent stability under a variety of aqueous conditions. Thin film coatings based on these materials are generally produced by PVD methods. Such coatings often exhibit porosity which usually is thought to result from pinholes formed during deposition. If local defects form a direct path between the corrosive environment and the base material the corrosion protection is lost. In this work the influence of different factors on the corrosion resistance of PVD coatings was studied. The factors evaluated were the thickness of the coating, the thickness and the type of the intermediate layer, the composition of the coating and the number of heterogeneities in the coating. Electrochemical porosity measurements which are essential for the estimation of the corrosion resistance of coated components were made in 1 N sulfuric acid solution at ambient temperature. In these conditions corrosion of a coated steel part occurs mainly in the base material. Corrosion resistance was also evaluated with immersion tests. The results of this work suggest the dominating role of the inhomogeneities on the corrosion resistance of the PVD (Ti,Al)N and TiN coatings. Preliminary analysis of the nature of the inhomogeneities is made and their possible source is discussed.

KW - surface coatings

KW - borides

KW - carbides

KW - nitrides

KW - corrosion resistance

KW - porosity

KW - thin films

KW - titanium nitrides

KW - titanium borides

KW - titanium carbides

M3 - Report

SN - 951-38-4653-9

T3 - VTT Publications

BT - Factors affecting the corrosion resistance of PVD thin films

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Aromaa J, Ronkainen H, Saarinen K, Mahiout A, Hannula S-P. Factors affecting the corrosion resistance of PVD thin films. Espoo: VTT Technical Research Centre of Finland, 1995. 60 p. (VTT Publications; No. 215).