|
| Abstract No.: |
|
Scheduled at:
|
Thursday, May 22, 2014, Hall H1 12:00 PM
Automotive Industry 2
|
|
| Title: |
Thermal cycling assessment of steel-based thermal barrier coatings for Al protection
|
|
| Authors: |
Dominique Poirier* / National Research Council of Canada, Canada
Jean-Michel Lamarre / National Research Council of Canada (NRC), Canada
Jean-Gabriel Legoux/ National Research Council of Canada (NRC), Canada
|
|
| Abstract: |
In the last years, the transportation industry has been facing increasing pressure to decrease the vehicle weight in order to reduce fuel consumption as well as the associated emissions. Significant weight reduction can be achieved by replacing steel components by aluminum parts. However, as aluminum exhibits poor wear and lower temperature resistance compared to the current iron parts, there is a rising interest in shielding aluminum parts with protective coatings to alleviate those issues. While ceramics offer good insulating properties and high hardness, their poor toughness is of concern for such application. One possible alternative is to use metal-base thermal barrier coatings. For instance, amorphous metals offer low thermal conductivity as well as high toughness, hardness and wear resistance, all desirable properties for a protective coating. The objective of this study was to assess the potential of an amorphous-type steel as a thermal barrier coating through the evaluation of its spalling resistance under thermal cycling. Plasma spray offers unique capability of producing this type of materials as coatings: its high heat input enabling full melting of the alloys is combined with a high cooling rate associated with the rapid solidification of the molten droplets upon impact. A specialised alloyed steel powder was deposited via plasma spray and thoroughly characterised for its amorphicity through XRD and SEM. The thermal cycling behavior of the resulting coatings was evaluated by cycling the coated face of coupons to a maximum cycle temperature of 500°C, with heating rates in the range of 50°C/s. These tests were performed in a home-designed laser rig, capable of achieving thousands of cycles. The performance of the amorphous steel is compared with a conventional arc sprayed steel coating.
|
|