Glossary
Ceramics Glossary: Reading a Quotation and a Test Report
Ceramics vocabulary comes largely from the workshop floor and from national standards, which makes it easy to get lost on first contact. Terms are grouped here into process, material, defect and trade sets, in Chinese and English, so both sides can align language during inquiry, sampling and inspection.
Updated 2026-08-13
Process terms
These describe the states and actions a piece passes through from clay to finished ware. They are what make a producer's process documents and lead-time plan legible.
- 坯体body / greenware
- The formed but unfired piece — wet when just shaped, dry once moisture is driven off.
- 泥浆slip
- The fluid slurry produced by ball-milling, used for casting.
- 陈腐aging
- Letting slurry or clay rest so moisture distributes evenly and plasticity improves.
- 除铁de-ironing
- Removing iron impurities, usually magnetically, to prevent dark specks and colour shift.
- 滚压成型roller pressing
- Forming round ware with a roller head in a mould; the cheapest volume route for bowls and plates.
- 注浆成型slip casting
- Pouring slip into plaster moulds, which absorb water to build a wall; used for handled and irregular forms.
- 修坯fettling
- Trimming burrs, rims and foot rings; this sets dimensional accuracy and how the piece feels in hand.
- 素烧bisque firing
- The first firing, before glazing — roughly 800–900°C for ordinary dailyware, but 1240–1255°C for bone china.
- 釉烧glaze firing
- The firing after glazing that vitrifies body and glaze. For bone china it runs cooler than the bisque.
- 烤花decal firing
- The low-temperature pass that fixes decals or gilding, typically 750–800°C for on-glaze work.
- 匣钵saggar
- The refractory box ware is fired in, shielding it and shaping heat flow. Bone china uses thin profiled saggars with inverted setting to resist warping.
Materials and indicators
This set is what can go into a contract and be backed by a test report. Describing requirements as indicators rather than adjectives is the single most effective way to avoid disputes.
- 骨炭 / 骨粉bone ash
- Herbivore bone degreased, calcined and finely milled; the source of tricalcium phosphate in bone china.
- 磷酸三钙tricalcium phosphate
- Ca₃(PO₄)₂. GB/T 13522-2024 requires at least 36% in the fired bone-china body — the only reliable test of authenticity.
- 吸水率water absorption
- A measure of vitrification, tested per GB/T 3299. Bone china must not exceed 0.5%.
- 抗热震性thermal shock resistance
- The ability to survive abrupt temperature change, per GB/T 3298; small bone china must pass a 140°C to 20°C differential.
- 白度whiteness
- A number measured per QB/T 1503, which can be written into a contract as an acceptance criterion.
- 透光度translucency
- How much light passes through the body. Highest in bone china, lower in strengthened porcelain, absent in stoneware.
- 铅镉溶出量lead & cadmium release
- The core food-contact safety indicator, measured after soaking in 4% acetic acid as food simulant; limits differ by market.
Defect terms
GB/T 3303 gives defects standardised names and GB/T 3301 defines how their size is measured. Most inspection disputes come from the two sides naming defects differently or judging severity differently; citing the standard numbers removes that ambiguity outright.
- 缩釉crawling
- The glaze pulls back during firing, exposing bare body as unglazed patches.
- 针孔pinhole
- Tiny holes in the glaze surface, usually from gas that failed to escape in time.
- 釉裂 / 惊釉crazing
- A fine network of cracks in the glaze, typically from mismatched body and glaze expansion.
- 落渣kiln dirt
- Debris falling inside the kiln and fusing onto the glaze as raised specks.
- 变形deformation
- Departure from intended geometry — oval rims, warped foot rings — inspected per GB/T 3300.
- 显见面 / 非显见面visible / non-visible surface
- Standards weight defects differently depending on whether they fall on a conspicuous surface, which drives grading into first, second or qualified class.
Trade terms
The working vocabulary of cross-border ceramics sourcing. Combined with the indicators above, an inquiry becomes specific enough for a producer to quote something actionable.
- 最小起订量MOQ (minimum order quantity)
- The lowest quantity a producer will accept, usually counted per shape and per pattern; new moulds or exclusive transfers raise the floor.
- 打样sampling
- Producing a confirmation sample before mass production to verify shape, glaze, pattern and packaging; approved samples should be sealed and retained.
- 开模mould tooling
- Making moulds for a new shape — a one-off investment, normally billed separately with ownership agreed in writing.
- 贴牌 / 代工OEM
- Producing to the buyer's brand and specification, with the buyer's marks on backstamp and packaging.
- 验厂factory audit
- The buyer's on-site review of capacity, quality systems and compliance; routine before a large order.
- 抽检 / AQLsampling inspection / AQL
- Batch inspection against an acceptance quality limit under standards such as GB/T 2828.1, rather than checking every piece.