OX Coatings

The OX coatings represent the complete range of aluminum anodizing treatments offered by Durox for precision mechanical applications. Each coating family is optimized for specific application and performance requirements.

The three OX coating families

OX-A - Natural Anodizing

OX-A – Natural Anodizing

Aesthetic protection | Corrosion resistance

Natural anodizing treatment compliant with MIL-PRF-8625 Type II and ISO 7599 to protect aluminum from environmental oxidation with good corrosion and wear resistance.

OX-A is a natural aluminum anodizing treatment compliant with MIL-PRF-8625 Type II and ISO 7599 standards. It is used to protect aluminum from environmental oxidation thanks to good corrosion resistance and appreciable resistance to wear and scratches.

Main characteristics:

• Standard thickness: 15 µm (tolerance ±5 µm)
• Hardness: adequate for scratch and light wear resistance
• Corrosion resistance: ≥336 hours in neutral salt spray on 6000 series alloy (>1000 hours with extended sealing)
• Applications: components with aesthetic requirements, protection in non-aggressive environments, appliances, medical

The OX-A treatment is available in several variants: OX-AN with deep black coloring, OX-AB with blue coloring, OX-AR with red coloring, and OX-A-PTFE with PTFE impregnation for applications requiring low friction.

OX-HS - Standard Hard Anodizing

OX-HS – Hard Anodizing

Maximum wear resistance | High corrosion resistance

Hard anodizing treatment compliant with MIL-PRF-8625 Type III, ISO 10074 and UNI 7796. Provides excellent corrosion and wear resistance, high hardness for aggressive environments.

OX-HS is a sulfuric acid hard aluminum anodizing treatment compliant with MIL-PRF-8625 Type III, ISO 10074 and UNI 7796 standards. It provides excellent corrosion and wear resistance, high hardness and resistance in aggressive environments.

Main characteristics:

• Standard thickness: 50 µm (tolerance ±10 µm)
• Hardness: >400 HV on 6000 series alloys, >280 HV on 2000 series
• Wear resistance: <15 mg weight loss (Taber Abraser, 10,000 cycles) on 6000 series alloys
• Corrosion resistance: ≥336 hours in neutral salt spray (>1000 hours with sealing)
• Applications: automotive, industrial machinery, components subject to high wear, marine environments

The OX-HS treatment is available in several variants: OX-HC with deep black coloring, OX-HB with dark blue coloring, OX-HR with dark red coloring, and OX-HS-PTFE with PTFE impregnation for applications requiring low friction.

OX-W - White Hard Anodizing

OX-W – White Hard Anodizing

Low roughness | Mechanical sliding

Special hard anodizing compliant with MIL-PRF-8625 Type III with lower roughness, greater corrosion resistance and lighter coloring compared to standard hard treatments.

OX-W is a special aluminum hard anodizing treatment compliant with MIL-PRF-8625 Type III, ISO 10074 and UNI 7796 standards. Compared to traditional hard anodizing treatment, OX-W features lower roughness, greater corrosion resistance and a lighter coloring.

Main characteristics:

• Standard thickness: 30 µm (tolerance ±5 µm)
• Hardness: >400 HV on 6000 series alloys, >280 HV on 2000 series
• Wear resistance: <15 mg weight loss (Taber Abraser, 10,000 cycles) on 6000 series alloys
• Corrosion resistance: ≥336 hours in neutral salt spray without any sign of corrosion (>1000 hours with sealing)
• Roughness: significantly lower compared to standard hard anodizing
• Applications: mechanical sliding, gas distribution (methane, hydrogen, oxygen), difficult alloys (2000 series, high silicon)

The OX-W treatment is available in several variants: OX-WN with deep black coloring, OX-WB with blue coloring, OX-WR with red coloring, and OX-W-PTFE with PTFE impregnation for applications requiring low friction.

Comparison between OX coatings

Available colorings

All OX treatments can be pigmented with organic dyes that penetrate the pores of the anodizing layer:

Deep black

The deep black coloring (OX-AN, OX-HC, OX-WN) is the most used in mechanical applications because:

• it uniformizes the color on different aluminum alloys
• it provides a professional and technical appearance
• it hides any surface imperfections
• it offers excellent aesthetic results

Blue and Red

The blue (OX-AB, OX-HB, OX-WB) and red (OX-AR, OX-HR, OX-WR) colorings are used for:

• component identification
• specific aesthetic requirements
• visual coding of different versions

The final color shade depends on the aluminum alloy used. The images indicatively represent the coloring obtainable on 7075 and 6061 alloys.

How to choose the OX coating

The choice of OX coating depends on several factors related to the final application and operating conditions of the component.

OX-A is the ideal choice when primarily aesthetic protection or light corrosion protection is required. This treatment is particularly suitable for non-particularly aggressive working environments, when bright colorings are required and in the absence of significant mechanical stresses.

OX-HS is recommended when maximum wear resistance is required. It is the optimal solution for components subject to abrasive or adhesive wear, when maximum protection thickness (40-60 µm) is needed, in very aggressive environments such as marine or industrial ones, and when dark color is acceptable or desired.

OX-W represents the best choice when low surface roughness is required, for components with precise mechanical sliding, for difficult-to-anodize alloys such as 2000 series or high silicon content, when light color combined with high hardness is required.

Compliance and certifications

All OX coatings comply with the main international standards:

• Technical standards: ISO 7599, ISO 10074, MIL-PRF-8625, UNI 7796
• Chemical safety: REACH, RoHS
• Food contact: EN 14392, EC Reg. 1935/2004, GMP
• Management system: ISO 9001

For more information on individual treatments and to request detailed technical specifications, consult the dedicated sections of this guide or contact Durox srl directly.