The hardness and wear of electrochemically grown tantalum oxide

Book · Thu Dec 31 04:00:00 EST 1998

OSTI ID:305518

Mulivor, A W; Mann, A B; Searson, P C; Weihs, T P ^[1]

---

1. Johns Hopkins Univ., Baltimore, MD (United States). Materials Science and Engineering Dept.

For several metallic systems, including tantalum, barrier (non-porous) oxide layers up to 200 nm thick can be grown quickly and efficiently using electrochemical techniques. The thickness of the oxide layer has been found to be linearly proportional to the voltage applied during the electrochemical growth process. These oxides can cause a substantial increase in both the hardness and wear-resistance of the surface. Ex-situ Micro and Nano indentation testing of the Ta/Ta{sub 2}O{sub 5} system has clearly shown that the indentation hardness increases with oxide thickness, even for indentation depths much greater than the oxide thickness. AFM imaging of indentations and analysis of nanoindentation curves suggests this increased hardness is due to the oxide impeding the pile-up of material at the edges of the indentation, which changes the geometry of the contact. Tribometer testing of various oxide thicknesses has shown that the oxide plays a similar role in preventing wear, specifically by preventing the transfer of material between the two contacting bodies and spreading the load over a greater area. Thus, the electrochemical growth of Ta{sub 2}O{sub 5} provides a convenient method for providing protective hard coatings.

• Sponsoring Organization: National Science Foundation, Washington, DC (United States)
• OSTI ID: 305518
• Report Number(s): CONF-971201--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
EXPERIMENTAL DATA
HARDNESS
PROTECTIVE COATINGS
TANTALUM
TANTALUM OXIDES
THICKNESS
THIN FILMS
WEAR RESISTANCE