Strongly Adherent Ceramic Surface Layers by Ion Implantation
Abstract
Many applications exist for specialized coatings which must never debond during their working life. Ceramic coatings on metals are particularly important for this special category, but the dissimilar properties of the two types of materials make most existing coating techniques unacceptable. Ion implantation is well-known to produce totally adherent depositions of atoms, because the high energy of the ion beam causes the atoms to come to rest inside the target material rather than lay upon it. Thus, there is no discrete surface for debonding. Unfortunately, it has rarely been possible to accumulate enough ion implanted atoms in one place to form a pure layer because the sputtering coefficient is usually greater than unity. This research has developed a technique of codepositing a sacrificial layer together with ion implantation in order to create an effective sputtering coefficient of zero. Implanted atoms can accumulate to arbitrarily thick layers which are physically merged to the substrate. A demonstration of the general techniques has been performed using Zirconium as the ion. The Zirconium has been converted to zirconia, ZrO2, by reaction with a low pressure background of oxygen in the process chamber. The zirconia coatings show extreme adhesion using scratch testing and by repeated 600 deg C fast thermal cycling. Many observed properties as well as Auger analysis confirm they are ZrO2. Coatings were tested as a base layer for conventional ZrO2 coating technologies, and deposition on both flat and curved surfaces was demonstrated. Coating, ZrO2, Ion implantation, Adhesion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 1991
- Accession Number
- ADA248882
Entities
People
- Stephen N. Bunker