A nickel engine part is coated with SiC to provide corrosion resistance at high temperature. If no residual stresses are present in the part at 200C, determine the thermal stresses that develop when the part is heated to 10000C during use. Linear thermal expansion coefficients of Nickel (_Ni) and SiC (_SiC) are 13.010^(-6) (oC)^(-1)and 4.310^(-6) (oC)^(-1). Young modulus of SiC (E) is 410 GPa.

(a) Show thermal stress T=E(Ni - SiC)T where T is temperature difference.!

(b) Estimate thermal stress using the above expression.

(c) Comment on the possible status of SiC at 1000oC if tensile strength of SiC is 172 MPa.!