Thermal Shock Properties of Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 Composite Coatings

2011 ◽  
Vol 275 ◽  
pp. 47-50
Author(s):  
Asma Salman ◽  
Brian Gabbitas ◽  
De Liang Zhang

Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings have a potential to reduce dissolution and aluminium soldering tendency of H13 tool steel used in the aluminium processing industry. The thermal shock resistance of H13 tool steel coated with Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite powders sprayed using a high velocity oxygen fuel (HVOF) technique was studied. The thermal shock behaviour of the composite coatings was investigated by subjecting the coated coupons to a number of cycles, each cycle consisting of a holding time of 30 seconds in molten aluminium at 700 ± 10 °C followed by quenching into water. The surfaces of the coupons were examined for Al soldering and an evaluation of surface spallation. Any cracks found in the coatings were studied to explain their thermal shock behaviour. The results of this study showed that both Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings on H13 tool steel have good thermal shock resistance with a thermal shock life between 300 to 400 cycles. The composite coatings and fracture surfaces were analyzed using scanning electron microscopy.

2009 ◽  
Vol 66 ◽  
pp. 108-111 ◽  
Author(s):  
Yong Hu ◽  
Ming Zhong Li ◽  
Qiang Shen ◽  
Wei Ping Xu

In the present paper, Al2TiO5-Al2O3 composites with 10, 20, 40, 60, 80, and 90 Vol. % of Al2O3 respectively were prepared by the sintering of Al2TiO5 and Al2O3 powers. The thermal expansion ratio was measured and the quenching-strength method was used to study the thermal shock-resistance performance. The thermal expansion ratio was found to increase from zero for the sample with 10-20Vol.%Al2O3 to that of 0.007% as the content of Al2O3 increased . The results of quenching-strength test showed that the residual strength of Al2TiO5-Al2O3 composites decreased with increasing of Al2O3 content and the thermal shock cycles. The Al2TiO5/Al2O3 composite with 20Vol.% Al2O3 remained a strength of 33.4MPa after three cycles and exhibited good thermal shock-resistance performance.


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