Diamond Thin Dense Chrome Coating
XADC® diamond thin dense chrome coating for wear-resistant shafts, sleeves and tooling, with coating allowance planning and final inspection.
Why precision CNC parts need surface protection
CNC machining controls shape, diameter, flatness and fit — but these features can change after the part enters service. Repeated contact can wear a shaft, enlarge a sleeve's clearance, damage a sealing surface or cause a sliding component to seize. A thin functional coating can protect the surface without redesigning the part.
Repeated sliding, rotating or reciprocating motion
Metal-to-metal contact with risk of galling
Abrasive particles or glass-filled polymer contact
Limited or intermittent lubrication
Corrosive chemicals, moisture or process gases
High local loads on a small contact area
A tight fit that must hold over a long service period
What is XADC® diamond thin dense chrome coating?
XADC® is a proprietary Armoloy coating that co-deposits synthetic diamond particles within a thin dense chromium matrix, forming a hard, micro-nodular surface rather than a thick decorative chrome layer. The diamond content improves resistance to abrasive and adhesive wear, while the chromium matrix contributes hardness, corrosion resistance and strong adhesion to the substrate.
Because the coating is thin and applied at a low processing temperature, it suits precision parts where distortion and dimensional change must stay tightly controlled — it's a functional engineering surface, not a cosmetic finish. Where corrosion attacks the part alongside wear, XADC® is also used as the outer layer of a nickel-chrome composite coating (Bi-Protec®).
XADC® coating properties at a glance
The values below come from the published XADC® technical literature. Final coating thickness and performance must be confirmed for the specific substrate, geometry and service condition.
| Property | Published Value | Why It Matters |
|---|---|---|
| Surface hardness | Above 80 HRC | Protects working surfaces against abrasive and sliding wear |
| Typical deposit thickness | 2.5–7.6 μm (0.0001–0.0003 in) | Wear protection with a small dimensional change |
| Processing temperature | Below ~65°C (150°F) | Reduces the risk of heat-related distortion |
| Wear index | Below 1.2 TWI (AMS 2438) | Indicates high wear resistance under the referenced test |
Custom parts that benefit from diamond chrome coating
JF Precision can machine parts to customer drawings and apply XADC® coating where the application needs extra surface protection — shafts, bushings and sleeves usually start as custom CNC turned parts.
| Part Type | Common Surface Problem | Coating Benefit |
|---|---|---|
| Shafts and guide pins | Scoring, diameter loss, galling | Maintains the working diameter and sliding surface |
| Bushings and sleeves | Bore wear, clearance growth | Improves wear resistance on the working surface |
| Mold cores and ejector components | Sticking, glass-fibre abrasion | Reduces wear and improves release performance |
| Pump and valve components | Friction, corrosion, repeated movement | Adds a hard, corrosion-resistant surface |
| Rollers and tooling | Repeated contact, dimensional loss | Extends the life of high-contact areas |
How JF Precision plans machining and coating together
A coating only a few micrometres thick still changes an outside diameter, bore or mating clearance, so we review the required finished dimensions before machining begins.
Reviewing the 3D model and drawing, including fits, threads and service conditions
Identifying the surfaces to coat and any areas to mask
Confirming the target coating thickness
Calculating the pre-coating machining dimensions
Machining the part and inspecting pre-coating dimensions
Coordinating the XADC® coating process
Inspecting the coated part for coverage and final dimensions
Providing dimensional or coating records when specified in the RFQ
How coating thickness affects final dimensions
Coating an outside diameter increases the finished diameter by roughly twice the coating thickness; coating an internal bore decreases it by the same amount. A 5 μm coating on an outside diameter, for example, produces about a 10 μm total diameter increase. This is why the final dimension, tolerance and coating thickness must be reviewed together — see our guide to coating allowance for worked examples.
Which surfaces require coating and which must stay uncoated
Whether drawing dimensions are specified before or after coating
Required final diameters, bores and fit tolerances
Target coating thickness
Masking requirements for threads, holes or sealing areas
Inspection after coating
A coating project is complete only when the final part meets the agreed drawing requirements. Learn more about our inspection capabilities and what a coated part's inspection report contains.
Final outside and inside diameter checks
Fit and clearance verification
CMM inspection of critical geometry
Thread or gauge inspection on uncoated and masked features
Visual inspection of coating coverage and surface condition
Review of coating documentation and inspection records
Why choose JF Precision for CNC parts with diamond chrome coating?
We combine drawing-based custom CNC machining, coating planning and quality inspection in one project — one point of contact for both the precision component and its functional surface treatment. If you are still choosing a system, see how the two coating systems compare.
Custom CNC milling and turning based on customer drawings
Support for prototypes, small batches and repeat production
Review of coating areas, masking and final dimensional requirements
Pre-coating machining allowance planning
XADC® diamond thin dense chrome coating for suitable parts
Final dimensional and visual inspection after coating
Inspection reports and coating documentation on request
FAQ: Diamond thin dense chrome coating
Questions about ordering, lead times or shipping? Our FAQ page answers the most common questions.
A thin functional chromium coating with a synthetic diamond co-deposit. XADC® uses this composite structure for high hardness, wear resistance, low friction and corrosion protection on suitable metal substrates.
Yes. We review the drawing, plan the coating allowance, machine the part, coordinate the coating process and inspect the final component.
Typically 2.5–7.6 μm (0.0001–0.0003 in), within a broader effective range of 1.3–17.8 μm. The required thickness is confirmed for the specific part and application.
Yes. An outside diameter increases and an internal bore decreases by roughly the coating thickness on each surface. We plan the pre-coating machining dimensions accordingly.
Shafts, guide pins, sleeves, bushings, mold components, pump and valve parts, automation components and tooling exposed to wear, friction, galling or corrosion.
Your 3D model, 2D drawing, material grade, quantity, coating surfaces, final tolerances, target coating thickness and any masking or documentation requirements.
Continue reading
Ni + NTDC vs Ni + XADC®
Which nickel-chrome composite system fits your part: balanced protection or maximum wear resistance.
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Coating Allowance for Precision CNC Parts
How coating thickness changes diameters, bores, threads and fits — and how to plan the pre-coating dimensions.
Read article →
Nickel-Chrome Composite Coating
Bi-Protec® dual-layer protection where corrosion and wear attack the same component.
Read article →