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ALUM HARDCOAT RESISTANCE TO HIGH HEAT

2000

I'M DESIGNING A TRANSFER BOAT THAT WILL CARRY AN ELECTRICAL COMPONENTS THROUGH AN INLINE OVEN SET AT 660 DEG.F (350 DEG.C) BECAUSE OF MATERIAL THERMAL PROPERTIES THE BOATS WILL BE MADE OF ALUMINUM.

TO IMPROVE ITS WEAR RESISTANCE WE ARE CONSIDERING HARDCOATING THE BOAT. A BOAT WILL PASS THROUGH THE OVEN ONCE EVERY 5 MINUTES FOR A PERIOD OF 40 SECONDS. WHEN EXITING THE OVEN THE BOAT WILL BE COOLED TO 200 °F WITHIN 45 SECONDS.

• WHAT EFFECT WILL THE HIGH TEMP HAVE UPON THE COATING?
• WHAT EFFECT WILL THE COOLING HAVE UPON THE COATING?
• WILL THE THERMAL EXPANSION AND RETRACTION CRACK THE COATING?
• WILL THE COATING ACT AS A THERMAL INSULATOR, NOT ALLOWING THE BOAT TO COOL QUICKLY?

THANK YOU FOR ANY HELP.

JOHN JERACKA
assembly and test Systems - Bridgeport, CT.

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Both aluminum & the hardcoat (aluminum oxide) can withstand the temps you mention, BUT, they both have different thermal expansion & retraction properties. The coating will definitely craze during heat up / cool down... this is normal for hardcoat. The question will be how much crazing.

Regarding cooling down... the dark color of the coating should help in dissipating heat & cooling down.

My suggestion would be to have test samples made before production. Another idea is to go with Stainless Steel.

David A. Kraft
- Long Island City, New York
2000