石墨是一种非金属形式的碳 — 它的同素异形体之一, 与钻石和富勒烯并列. 它是在非金属中能够导电和导热的例外, 因为每个碳原子在其层中只与另外三个碳原子形成键, 留下一个电子可以自由移动. 天然石墨是一种矿物; 合成石墨是从石油焦或煤焦油沥青制造的. 本页介绍石墨是什么, 它的主要特性, 它的用途, and how it is machined — including diamond wire loop cutting of graphite blocks.
关键要点
Graphite is a non-metal — an allotrope of carbon, not a metal. It conducts electricity and heat, which is why it is used for electrodes.
Its layered hexagonal structure gives it lubricity, 化学惰性, and a sublimation point of about 3,900 K (大约 3,627 °C) at standard pressure.
It begins to oxidise in air above about 450 °C, so the real service limit depends on atmosphere, not temperature alone.
Machining graphite is harder than its softness suggests: it is soft, brittle and abrasive at the same time, and its dust is electrically conductive.
What Graphite Is
Graphite is one of the allotropes of carbon. Its carbon atoms are arranged in hexagonal lattices that stack into flat sheets, commonly called graphene layers. Within a layer the atoms are held together by strong covalent bonds; 在层与层之间只有弱范德华力作用. 这一单一的结构事实解释了大部分石墨的行为 — 各层相互滑动, 这就是润滑性, 每层中的离域电子可以传导电流, 这就是导电性.
Sets the real service limit for open-air use; inert atmospheres push it much higher
Strength vs temperature
Increases when heated from room temperature to about 2,500 °C
Unlike most materials, it gets stronger when hot
Thermal expansion
Low coefficient of thermal expansion
Resists thermal shock — the cracking caused by rapid temperature change
Electrical conductivity
高, and anisotropic — much higher parallel to the layers than across them
Enables electrodes; also makes machining dust a contamination hazard
Chemical resistance
Inert to most acids, alkalis and corrosive gases at moderate temperature
Crucibles, reaction vessels, and components in harsh environments
硬度
Soft — roughly Mohs 1–2
Easy to mark, yet abrasive to tooling because of how it wears
Is Graphite a Metal?
不. Graphite is a non-metal. It is carbon, and carbon is not a metal. Graphite is sometimes described as a semimetal because it conducts electricity, but that describes its behaviour rather than its classification — it does not have metallic bonding, and it is neither malleable nor ductile in the way metals are.
The confusion is understandable. Graphite is the only common non-metal that conducts electricity well, it has a metallic-looking sheen, and it is used in places where metals normally appear: 电极, brushes, heat sinks. For specification and procurement purposes, treat it as a non-metal with metal-like electrical and thermal behaviour.
Natural Graphite and Synthetic Graphite
天然石墨是一种矿物. It forms in metamorphic rocks and is mined as flake, amorphous (fine-grained) or vein (lump) material, so its properties vary from deposit to deposit.
Synthetic graphite is not a mineral — it is manufactured by graphitising petroleum coke or coal-tar pitch at high temperature. It is more consistent and purer, which is why battery anodes, electrodes and semiconductor components generally use synthetic grades.
For machining, the distinction matters twice over. Synthetic grades are more uniform, so a proven parameter set transfers from batch to batch. And both families are abrasive and produce conductive dust, so dust control is identical either way.
2. 石墨的用途:
由于其独特的特性，石墨在各个行业都有广泛的应用:
耐火材料: 石墨因其高热稳定性和耐热性而被用于耐火材料, 使其成为炉和坩埚内衬的理想选择.
电极: 它在钢制造中用作电极, 铝, 和其他金属由于其优异的导电性和耐高温性.
电池: 石墨是锂离子电池的关键部件, 为储能系统提供稳定性和导电性.
汽车工业: 它用于各种汽车零部件, 如垫圈和制动衬片, 具有自润滑和热管理特性.
3. 加工石墨:
石墨加工涉及复杂的技术，以针对特定应用对材料进行成型和精炼. One crucial method iscutting graphitewith diamond wire saw technology:
Two practical points govern graphite machining. First, graphite is soft but brittle and abrasive at the same time: edges crumble under mechanical load, and tooling wears quickly. Second, the dust it produces is electrically conductive — it contaminates spindles, guides and electronics, and it is a health hazard. Water cooling or strong extraction is therefore not optional.
The full comparison of sawing, milling, 研磨, wire EDM and diamond wire cutting — with coolant and dust-handling rules — is covered in our graphite cutting methods guide.
不. Graphite is a non-metal — an allotrope of carbon, like diamond and fullerenes. It conducts electricity, which is why it is sometimes called a semimetal, but it has none of the metallic properties such as malleability or ductility.
Is graphite a mineral or a manufactured material?
Both exist. 天然石墨是一种矿物, mined as flake, amorphous or vein material. Synthetic graphite is manufactured by graphitising petroleum coke or coal-tar pitch.
What is graphite used for?
Refractories and crucibles, electrodes for steel and aluminium production, lithium-ion battery anodes, dry lubricants, and automotive parts such as gaskets and brake linings.
Does cutting graphite require coolant?
是的. Water cooling or strong extraction is essential. 石墨粉具有导电性并会损坏主轴, guides and electronics, and it is a health hazard.
