Brushed aluminium surface-finish sample with a linear satin texture

Finish library

The full finish reference.

How each finish looks, feels, and what it does to your part, with real numbers. Pick by the job: a show face, a sliding fit, corrosion, conductivity. Every range is confirmed at DFM review. Cost is relative ($ low → $$$$ high), not a price.

The finishes, full reference

Typical production practice, confirmed per part at DFM. Cost is relative ($ low → $$$$ high), not a price.
Finish	Look & feel	Ra / thickness	Corrosion	Effect on size	Best for	Cost
As-machined	Fine tool lines	Ra 1.6–3.2 µm (turned 0.8–1.6)	Low	None	Non-cosmetic, lower cost	$
Bead blast	Uniform matte	Ra 1.6–6.3 µm	Cosmetic	Slight	Even look, hides marks, pre-anodize base	$$
Brushed	Directional satin	Ra 0.4–1.6 µm	Cosmetic	Slight	Premium visible faces	$$
Polishing	Reflective → mirror	Ra 0.1–0.8 µm	Cosmetic	Removes a little	Sealing faces, cosmetic, optical	$$$$
Anodize II (Al)	Matte–satin, any colour/RAL	3–5 µm, ~300–400 HV	Moderate	+½ thickness / face	Colour + corrosion on aluminium	$$
Anodize III hard (Al)	Dark, very hard	8–25 µm, ~400–600 HV	High	+~0.01 mm / face	Wear surfaces, slides, aerospace	$$$
Chem film / chromate (Al)	Clear or gold	<3 µm	Low–mod	Negligible	Paint primer, light corrosion, keeps conductivity	$
Passivation (SS)	No visible change	none added	Moderate	None	Stainless corrosion resistance; medical/food	$
Electropolish (SS)	Mirror-bright	removes 5–25 µm, Ra 0.1–0.4	High	Removes 5–25 µm	Hygienic/cleanable stainless, deburr	$$$$
Black oxide (steel)	Matte black	<3 µm	Low (needs oil)	Negligible	Tooling, fasteners, low-glare	$
Zinc plate (steel)	Clear / yellow / black	5–12 µm	Moderate (sacrificial)	+5–12 µm	Economical steel corrosion protection	$
Electroless nickel	Even satin, any geometry	8–25 µm, uniform	High	+8–25 µm, even	Complex parts, bores, hardness, aluminium	$$$
Hard chrome	Bright, very hard	25–250 µm	High	+25–250 µm	Wear/abrasion: rods, pistons, bearing surfaces	$$$$
Powder coat	Durable colour film	50–100 µm	High	+50–100 µm	Tough coloured steel/aluminium parts	$$

Material note: anodize is aluminium only; passivation & electropolish are for stainless; black oxide & zinc are for steel; electroless nickel, hard chrome and powder coat take to most metals.

See the finishes

As-machined 6061 aluminium with fine tool marks — As-machined

Bead-blasted aluminium, uniform matte — Bead blast

Brushed aluminium, directional satin — Brushed

Electroless nickel-plated part, uniform satin — Electroless nickel

Polished stainless steel turned part, satin sheen — Polished

Colour-anodized aluminium, Type II satin colour — Anodize II · colour

Type III hard-anodized aluminium, dark hard coat — Anodize III · hard black

Black Type II anodized aluminium, satin black — Anodize II · black

Passivated stainless steel, clean uniform surface — Passivation

Black-oxide steel, matte black — Black oxide

Zinc-plated steel, bright sacrificial coating — Zinc plate

Powder-coated part, durable colour coating — Powder coat

Real close-ups of every finish, photographed from our own sample plates. Every photo is confidentiality-vetted before publish.

Buyers miss #1, coatings mirror the surface: plating and anodizing mirror the surface beneath, a part at Ra 1.6 is still Ra 1.6 after coating, tool marks and all. Need them gone? We polish or brush before coating.

Buyers miss #2, dimensional growth: coatings add real thickness, a Type III hardcoat adds ~0.01 mm per face. On tight bores, threads and bearing fits we machine the feature undersize or mask it before coating, and we hold the anodize bath steady for even, repeatable colour. Mark the critical dims. Choosing between finishes? See anodizing vs powder coating.

How to call it out on your drawing

FINISH: TYPE II ANODIZE, BLACK, 18 µm NOM, SEALED (PER ISO 7599)
SURFACE: Ra 0.8 µm MAX ON FACE A (symbol per ISO 1302 / ASME Y14.36)
MASK: THREADS + BORE B PRIOR TO COATING
DIMENSIONS: MACHINE BORE B TO 12.75 mm BEFORE ANODIZE

Specify a fine Ra (or a finish) only on the faces that need it, that's what keeps a part affordable.

What each industry typically specifies

Common pairings by sector, a starting point, not a rule.
Industry	Typical material	Typical finish
Aerospace & UAV	7075 · Ti-6Al-4V	Type III hard anodize; chem film; as-machined
Medical & lab	316 stainless · PEEK	Passivation; electropolish; clean as-machined
Robotics & automation	6061 · 7075 · 17-4PH	Clear/black anodize; bead blast; electroless nickel
Consumer	6061 · 6063 · titanium	Colour anodize; bead blast; brushed
Automotive & EV	4140 · 42CrMo · 6061	Black oxide; zinc; phosphate; powder coat
Industrial	Mild/alloy steel · brass	Zinc plate; powder coat; hard chrome; as-machined

Match a finish, send a photo Read the finishes guide

每种表面处理的视觉效果、触感及其对零件性能的实际影响，均提供真实数据支撑。可按具体应用场景选择：外观面、滑动配合、耐腐蚀或导电。各项参数均在 DFM 评审阶段逐一确认。成本为相对值（$ 低 → $$$$ 高），非最终报价。

表面处理速查表

常规做法，按件在 DFM 时确认。成本为相对值（$ 低 → $$$$ 高），并非报价。
表面处理	外观手感	Ra / 厚度	耐蚀	对尺寸影响	适用	成本
本色加工	细刀纹	Ra 1.6–3.2 µm（车削 0.8–1.6）	低	无	非外观面，成本较低	$
喷砂	均匀亚光	Ra 1.6–6.3 µm	仅外观	轻微	外观均匀、盖刀纹、阳极氧化打底	$$
拉丝	方向性缎面	Ra 0.4–1.6 µm	仅外观	轻微	高档可见面	$$
抛光	反光至镜面	Ra 0.1–0.8 µm	仅外观	略去除	密封面、外观、光学	$$$$
阳极 II 型（铝）	亚光至缎面，任意颜色/RAL 色号	3–5 µm，约 300–400 HV	中	每面 +½ 厚度	铝件上色+耐蚀	$$
硬质阳极 III（铝）	深色、极硬	8–25 µm，约 400–600 HV	高	每面 +约 0.01 mm	耐磨面、滑动、航空	$$$
铬酸盐转化膜（铝）	透明或金色	<3 µm	低-中	可忽略	喷漆底、轻度耐蚀、保导电	$
钝化（不锈钢）	外观无变化	不增厚	中	无	不锈钢耐蚀；医疗/食品	$
电解抛光（不锈钢）	镜面亮	去除 5–25 µm，Ra 0.1–0.4	高	去除 5–25 µm	易清洁卫生级不锈钢、去毛刺	$$$$
发黑（钢）	亚光黑	<3 µm	低（需油封）	可忽略	工装、紧固件、低反光	$
镀锌（钢）	透明/彩锌/黑锌	5–12 µm	中（牺牲性）	+5–12 µm	经济型钢件防锈	$
化学镀镍	均匀缎面，复杂形状也能均匀覆盖	8–25 µm，均匀	高	均匀 +8–25 µm	复杂件、深孔、要硬度、铝件	$$$
硬铬	亮、极硬	25–250 µm	高	+25–250 µm	耐磨：活塞杆、轴承面	$$$$
粉末喷涂	耐用彩色涂层	50–100 µm	高	+50–100 µm	要耐用彩色涂层的钢件、铝件	$$

材料说明：阳极氧化仅适用于铝材；钝化与电解抛光适用于不锈钢；发黑与镀锌适用于钢件；化学镀镍、硬铬及粉末喷涂适用于大多数金属材质。

实拍效果

所有表面处理均提供实拍特写，源自我们自制的标准样板。每张照片在发布前均经过严格的保密审查。

买家常忽略 ①：涂层复制底层。电镀与阳极氧化会复制底层表面 —— Ra 1.6 的零件镀后仍是 Ra 1.6，刀纹照旧。要去掉？我们在涂覆前先抛光或拉丝。

买家常忽略 ②：尺寸会变大。涂层会实打实增厚 —— III 型硬质阳极每面约 +0.01 mm。严格公差的孔、螺纹与配合面，我们在镀前预留加工余量或做遮蔽，并保持阳极槽液稳定，使颜色均匀、可复现。请把关键尺寸标出来。如需在工艺间选择，请参见阳极氧化 vs 喷粉。

如何在图纸上进行标注

FINISH: TYPE II ANODIZE, BLACK, 18 µm NOM, SEALED (PER ISO 7599)
SURFACE: Ra 0.8 µm MAX ON FACE A （符号按 ISO 1302 / ASME Y14.36）
MASK: THREADS + BORE B PRIOR TO COATING
DIMENSIONS: MACHINE BORE B TO 12.75 mm BEFORE ANODIZE

仅在必要的表面标注严格的 Ra 值（或特定表面处理要求）—— 这是有效控制零件加工成本的关键。

各行业常用表面处理规范

各行业常见搭配 —— 仅作参考，并非定式。
行业	常用材料	常用表面
航空与无人机	7075 · Ti-6Al-4V	III 型硬质阳极；铬酸盐转化膜；本色加工
医疗与实验	316 不锈钢 · PEEK	钝化；电解抛光；洁净本色
机器人与自动化	6061 · 7075 · 17-4PH	透明/黑色阳极；喷砂；化学镀镍
消费电子	6061 · 6063 · 钛	彩色阳极；喷砂；拉丝
汽车与电动车	4140 · 42CrMo · 6061	发黑；镀锌；磷化；粉末喷涂
工业	普碳/合金钢 · 黄铜	镀锌；粉末喷涂；硬铬；本色加工

匹配表面，发一张照片阅读表面处理指南

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