Impervious graphite

Semicorex Impervious Graphite is a type of composite material which is corrosion resistant, thermally conductive, and has high strength. Semicorex is produced to enhance the mechanical and chemical performance of conventional graphite by utilizing state-of-the-art technologies to impregnate a resin or polymer into a suitably porous graphite substrate. In employing a synthetic resin under high pressure, Semicorex produces a sufficient carbonized and graphitized graphite structure to create a high-density microstructure, which is non-porous, denser than a porous structure. This microstructure is ideal for use in heat exchangers, thermal systems, and chemical processing equipment.

The construction of impervious graphite begins by preparing the raw materials under controlled conditions. The graphite powder and coke are uniformly blended into a solid block using a process referred to as extrusion. The resulting block is not fully dense, however; under the second step of manufacturing, the material goes through a carbonization and graphitization process at higher temperatures in order to create a fine grained matrix that is still porous in nature. The third step is the proprietary process with high pressures utilized to impregnate the open porosity created in the graphite body with a thermosetting resin or polymer; filling the porosity in the graphite body results in a seal in the internal pore structure and assists the matrix with combining the best properties of carbon and polymers in the composite. The graphite resin body is cured and treated to obtain full denisification and stability.

The impregnation of a synthetic resin or polymer in a porous graphite base significantly increases the thermal conductivity and strength of the resultant impervious graphite, and highly resists corrosion. This provides the best value in performing heat treatment in heat exchangers. The impervious graphite is manufactured by mixing graphite powder and coke, extruding the mixture into blocks, and then carbonizing and graphitizing the blocks created from the mixture. The resin or polymer is then impregnated into the resulting blocks of impervious graphite.

This process results in a non-permeable graphite material with greatly enhanced mechanical strength, corrosion resistance, and thermal performance. Unlike standard graphite, which is naturally porous and vulnerable to gas or liquid infiltration, impervious graphite provides a sealed structure that prevents leakage, chemical attack, and structural degradation even under harsh process conditions.

From Porous to Perfect: Our Advanced Manufacturing Process

The process of making Impervious Graphite takes several critical steps in transforming the starting graphite material. Rather than simply coating the graphite, we completely re-engineer it.

Step 1 - Foundation: The process starts by using a carefully selected combination of high-purity graphite powder, and specialty petroleum coke.

Step 2 - Formation: The combination is then either extruded or pressed into solid, solid blocks, tubes or whatever shape is required under extremely high pressures.

Step 3 - Graphitization: These blocks are then placed into a high-temperature graphitization and carbonization process.  This step purges impurities and essentially, creates the "graphite skeleton" you see here – highly porous, and with a remarkable degree of purity and thermal conductivity, but a porous structure.

Step 4 - Impregnation: This is arguably the most important step. The porous graphite substrate is put into a vacuum break and the impregnating resin (such as a phenolic or furan resin) is introduced to the chamber. Through a series of vacuum and pressure cycles, the resin is injected deeply into the open-pore structure of the graphite, causing the resin to penetrate almost all the way to the center of the material.

The result is a new, void-free, composite material. The graphite provides the thermal and chemical backbone, while the resin provides an impenetrable seal and superior mechanical strength.

The Indispensable Material for Critical Applications

The unique property set of Impervious Graphite makes it the gold standard for equipment handling highly corrosive media in heat transfer operations. It is the indispensable material for:

Block and Shell & Tube Heat Exchangers

Condensers, Coolers, and Heaters

Absorbers and Distillation Columns

Pumps, Valves, and Piping Systems

In the chemical, petrochemical, and pharmaceutical industries, where process reliability is paramount, our Impervious Graphite is the backbone of efficient and safe thermal processing.