Monolithic ceramic body and assembly

A monolithic ceramic body comprising:

• a first portion comprising a plurality of pores defining an interconnected network extending through a portion of the monolithic ceramic body, wherein the plurality of pores of the first portion consists of a network of interconnected, randomly oriented pores;
• and
• a second portion integrally formed with the first portion and defining at least a portion of a perimeter surface of the monolithic ceramic body, wherein an average pore size of the second portion is smaller than an average pore size of the first portion and the second portion has a porosity of less than 50 vol %;
• wherein the monolithic ceramic body comprises at least one first complementary engagement structure having a first shape defining a protrusion, the protrusion comprising at least a portion of the first portion and at least a portion of the second portion, and at least one second complementary engagement structure having a second shape defining an indent that extends into the first portion and has a surface that is at least partially defined by the second portion;
• and wherein the first shape and the second shape are complementary to each other.