In one aspect, the invention includes a heat stable, formed ceramic component that includes a multimodal grain distribution including (i) at least 50 wt % of coarse grains including stabilized zirconia, the coarse grains comprising a D50 grain size in the range of from 5 to 800 μm, based upon the total weight of the component; and (ii) at least 1 wt % of fine grains comprising a D50 average grain size not greater than one-fourth the D50 grain size of the coarse grain, dispersed within the coarse grains, based upon the total weight of the component; wherein after sintering, the component has porosity at ambient temperature in the range of from 5 to 45 vol. %, based on the formed volume of the component. In other embodiments, the invention includes a process for the manufacture of a hydrocarbon pyrolysis product from a hydrocarbon feed using a regenerative pyrolysis reactor system, comprising the steps of: (a) heating a pyrolysis reactor comprising a bi-modal stabilized zirconia ceramic component to a temperature of at least 1500° C. to create a heated reactive region, wherein after exposing the component to a temperature of at least 1500° C. for two hours the component has a bulk porosity measured at ambient temperature in the range of from 5 to 45 vol. %, based on the bulk volume of the component; (b) feeding a hydrocarbon feed to the heated pyrolysis reactor to pyrolyze the hydrocarbon feed and create a pyrolyzed hydrocarbon feed; and (c) quenching the pyrolyzed hydrocarbon feed to produce the hydrocarbon pyrolysis product.