| Thermal Shock Resistance of Chemical Vapour
Deposited Zinc Sulfide at Elevated Temperatures |
Tianbao Cheng,1 Weiguo Li,1, * Zhaoliang Qu,2 Weibin Wen2 and Daining Fang3
Pages : 215-219
DOI : /10.1080/0371750X.2016.1210026 |
| Abstract |
| For traditional bulk ceramics, the compressive strength is much greater than the
tensile strength. Thus, only the tensile failure is usually considered in the thermal
shock resistance (TSR) of these ceramics. However, the compressive strength of
chemical vapour deposited (CVD) zinc sulfide (ZnS) is relatively low. It thus becomes
critical in evaluating the TSR of CVD ZnS at elevated temperatures. In the present
work, the compressive and tensile strengths are measured from room temperature to
600oC and then the TSR of CVD ZnS is studied. It is found that the TSR of CVD ZnS
under aerodynamic thermal environments will be over-estimated significantly if the
compressive strength is neglected. The study also shows the importance of
considering the temperature dependence of the material properties to evaluate the
TSR of CVD ZnS. Moreover, convective cooling can improve the TSR of CVD ZnS
caused by aerodynamic heating at the upper surface. However, it can also lead to
thermal down shock at the lower surface. To ensure that convective cooling will not
cause the fracture of CVD ZnS, heat transfer condition should be less than the
corresponding critical heat transfer condition. |
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