What Is Carbon Black? How It Is Made and What It Is Used For
What is carbon black, how does it differ from soot, how is it made, and where is it used, from tires and plastics to coatings and cables? The basics to know before you buy.
2026-09-01 · 8 min read
Carbon black is produced by the millions of tons every year and turns up in almost every branch of industry, yet most people have never heard of it. This guide explains what carbon black is, how it is made and why it is so widely used, for someone who has a purchasing decision to make.
Carbon black is not soot
This is the most common misunderstanding. Soot is an unwanted by-product of combustion: its composition is random, its particle size is uncontrolled and it contains unburned hydrocarbons. Carbon black, by contrast, is an engineered product. Particle size, aggregate structure, surface chemistry and impurity level are controlled during production; the result is a nanostructured material with repeatable properties.
A typical carbon black particle is 10–100 nanometers in diameter. During production, these particles fuse into branched structures called aggregates; how branched the aggregates are determines the material's "structure" value and directly affects its performance.
How it is made
Most industrial carbon black is produced by the furnace process. Heavy aromatic oil is sprayed into a high-temperature reactor and partially burned where oxygen is limited. Because combustion is incomplete, carbon nucleates in the gas phase and nanoparticles form. Different grades are obtained by changing the reactor temperature, the air-to-fuel ratio and the residence time.
The particles are collected by filters and then pelletized. Pelletizing is a critical step: carbon black in powder form cannot be transported, poured or fed into a compound. Pellet hardness (ASTM D5230) and fines content (ASTM D1508) show the quality of this step.
Four core functions
1. Reinforcement in rubber
The largest use of carbon black is the tire and rubber industry. Rubber alone cannot provide the required abrasion resistance and tensile strength. Carbon black particles form physical and chemical bonds with the polymer chains and literally reinforce the material. Roughly a quarter of a tire's weight is carbon black.
2. UV protection
Polyolefins such as polyethylene and polypropylene degrade in sunlight: the chains break, and the material turns brittle and cracks. Carbon black absorbs ultraviolet radiation and traps the free radicals formed during degradation. That is why underground pipes, agricultural films and cable jackets are black; it is an engineering decision, not an aesthetic one.
3. Pigment
It is the black pigment with the highest tinting strength per unit cost. In paints, inks, plastics and coatings, it provides a deep black and high hiding power even at very low levels. Unlike organic black pigments, it is exceptionally resistant to light and weathering.
4. Electrical conductivity
Used at a sufficient level, it builds a continuous conductive network inside an insulating polymer. This property is used in the semiconductive layers of power cables, in antistatic packaging and in battery electrodes.
The situation in Turkey
Turkey meets all of its carbon black demand through imports. A domestic production investment has been announced but is not yet in operation. For manufacturers in Turkey, this makes the reliability of the supply chain as important as price: the cost of a delay that stops a line is far higher than a difference of a few cents per kilogram.
Choosing the right grade
Carbon black is not a single product but a family of grades defined by ASTM D1765. The right choice starts with three questions: will the product wear, will it flex continuously, or are color and UV protection the priority? Depending on the answers, a hard or a soft grade is chosen.
