Pyrolytic

Pyrolytic is an adjective relating to pyrolysis, the chemical decomposition of organic material by heat in the absence or limited supply of oxygen. In science and industry, it is used to describe materials, films, and coatings that are formed by pyrolysis or that possess properties typical of pyrolytic processes, often via chemical vapor deposition or other heat-driven methods.

Pyrolysis typically requires high temperatures and inert or reducing atmospheres to prevent combustion. In pyrolytic deposition, vapor-phase precursors decompose on a substrate to form a solid layer while volatile byproducts are carried away by a carrier gas. The microstructure and composition of the resulting film depend on the precursor chemistry, temperature, pressure, and residence time.

Pyrolytic carbon coatings are widely used in medical devices, notably for prosthetic heart valves and other implants, because of chemical stability, wear resistance, and biocompatibility. Pyrolytic carbon is produced by decomposing hydrocarbon gases at elevated temperatures to form a dense, graphitic-like film. Pyrolytic graphite is another well-known form formed by chemical vapor deposition; it features highly anisotropic carbon layers and excellent in-plane thermal conductivity, making it useful for heat management and certain electronic and industrial components.

The term also appears in ceramics and refractories, including pyrolytic silicon carbide and related coatings, produced by high-temperature decomposition of silicon-containing precursors. Overall, pyrolytic materials occupy a broad category defined by origin in pyrolysis rather than by a single crystal form.